bluuebunny/crossref_metadata_2025 huggingface dataset:
The digestion by cattle of silage-containing diets fed at two dry matter intakes
Authors: Greife H. A. , Rooke J. A. , Armstrong D. G.
Published: May 2005

1. In a 4 x 4 Latin square experiment four cows were given, twice daily, diets consisting of (g/kg dry matter (DM)) 500 barley, 400 grass silage and 100 soya-bean meal. The diets were given at either 1.15 (L) or 2.3 (H) times maintenance energy requirements and the soya-bean meal was either untreated (U) or formaldehyde (HCH0)-treated (T).

2. The passage of digesta to the duodenum was estimated using chromic oxide as a flow marker;35S was used to estimate the amount of microbial protein entering the small intestine. A microbial fraction was prepared by differential centrifugation from duodenal digesta. Samples of bacteria and of protozoa from rumen digesta were also prepared.

3. The total amino acid contents of feedingstuffs, duodenal digesta, duodenal microbial material, rumen bacteria and rumen protozoa were determined by ion-exchange chromatography. The D-alanine and D-glutamic acid contents of the samples were determined by gas–liquid chromatography.

4. The quantity of each amino acid entering the small intestine was significantly (P < 0,001) increased by increasing DM intake and tended to be increased by formaldehyde-treatment of the soya-bean meal. There were net losses of all amino acids across the forestomachs except for lysine, methione, o-alanine and D-glutamic acid for which there were net gains.

5. There were significant (P < 0.05) differences in amino acid composition between rumen bacteria and duodenal microbial material; differences in amino acid composition between rumen bacteria and rumen protozoa were also observed.

6. D-Alanine and D-glutamic acid were present in the silage but not in the barley or either of the soya-bean meals. All samples of microbes and digesta contained D-alanine and D-glutamic acid.

7. The use of D-ahine and D-glUtamiC acid as markers for microbial nitrogen entering the small intestine was assessed. Estimates of the quantities of microbial N entering the small intestine based on the D-alanine or D-glutamic acid contents of rumen bacteria or duodenal microbes were significantly higher than those determined using 35S as a marker.
Duodenal xanthine oxidase (EC 1.2.3.2) and ferroxidase activities in the rat in relation to the increased iron absorption caused by peroral xylitol
Authors: Hämäläinen Mauri M. , Mäkinen Kauko K.
Published: May 2005

1. The effect of peroral administration of xylitol on the absorption of iron and the activities of xanthine oxidase (EC 1. 2. 3. 2) and ferroxidase in rat duodenal wall was studied.

2. Adult male rats were given the basal diet containing 200 g xylitol/kg or the same diet containing no added carbohydrates for 8 weeks. Both feeding groups comprised twelve animals.

3. Xylitol significantly increased serum and liver Fe concentrations with a concomitant, significant increase in the duodenal xanthine oxidase activities, but caused a marginal increase in the duodenal ferroxidase activities.

4. In vitro, sugar alcohols reduced the binding rate of Fe to transferrin.

5. The xylitol-induced increase of Fe absorption may involve the following mechanism: the high intraluminal xylitol concentration of the xylitol-fed rats keeps Fe in the form of a soluble complex for a prolonged period of time, due to the slow absorption of xylitol. The polyol-Fe complex in turn induces xanthine oxidase and ferroxidase formation.
Ytterbium acetate as a particulate-phase digesta-flow marker
Authors: Siddons R. C. , Paradine J. , Beever D. E. , Cornell P. R.
Published: May 2005

1. The ability of ytterbium acetabe (Yb acetate) to fulfil the requirements of a particulate-phase digesta-flow marker in a dual-phase marker system, and of the indigestible acid-detergent-fibre fraction of the feed (IADF) to act as a digesta flow marker, were examined using six mature wether sheep given a diet of dried grass (1 kg dry matter (DM)/d).

2. CrEDTA was continuously infused (240 mg chromium/d) into the rumen of all sheep and Yb acetate was also continuously infused (100 mg Yb/d) into the rumen of three of the sheep. At this level of infusion the equilibrium concentration of Yb in rumen, duodenal and ileal digesta and in faeces could be reliably measured by atomic absorption spectrometry.

3. Estimates of faecal DM excretion based on either Yb or IADF did not differ (P > 0.05) from that determined by total collection, whereas estimates based on Cr were significantly (P < 0.05) lower. Urinary excretion accounted for 3.1% of the infused Cr but no Yb was detected in urine. Estimates of ileal DM flow, assuming total marker recovery, were similar (P > 0.05) with all three markers, whereas the estimate of duodenal DM flow based on IADF was lower (P < 0.05) than the estimates based on either Cr or Yb.

4. Compared with the infusion of Cr alone, the infusion of Cr and Yb had no effect (P > 0.05) on nutrient flows at the duodenum, ileum and in faeces nor on microbial degradative activity, volatile fatty acid production and N metabolism in the rumen.

5. Polyester bag and in vitro studies showed that pre-labelling the dried grass with up to 285 mg Yb>g DM did not affect its susceptibility to microbial degradation.

6. The Yb in rumen, duodenal and ileal digesta was predominantly (> 90%) associated with the particulate matter but was not uniformly distributed and its concentration increased as particle size decreased.

7. The use of CrEDTA and Yb acetate as a dual-phase marker system proved more reliable in estimating ‘true’ duodenal flow than the use of the individual markers when the digesta sample was unrepresentative.
Glucose and protein metabolism during late pregnancy in triplet-bearing ewes given fresh forages ad lib.
Authors: Barry T. N. , Manley T. R.
Published: May 2005

1. Ewes of the Booroola x Romney genotype carrying triplet lambs were given fresh forages ad lib. in late pregnancy. In Expt 1, groups of three ewes were given kale (Brassica oleracea), perennial ryegrass (Loliumperenne) or perennial ryegrass (0.75)–barley (0.25). In Expt 2, groups of two or three ewes were given fresh perennial ryegrass and infused into the abomasum with iso-energetic quantities of casein and glucose in a 2 x 2 factorial arrangement. Post-lambing ewe live weights were 40–50 kg. Glucose irreversible loss (GIL) was determined from dilution of D-[U-14C]glucose.

2. For ewes given kale, perennial ryegrass and perennial ryegrass—barley in Expt 1, mean metabolizable energy (ME) intakes were 0.50, 0.82 and 0.83 MJ/kg live Weight0.75 per d, GIL was 112, 142 and 157 g/d, and mean birth weight 2.22, 3.05 and 2.95 kg/lamb.

3. In Expt 2, infusion of glucose, casein, and glucose+casein depressed herbage ME intake respectively by 1.6, 0.9 and 0.3 times the amount of ME infused. GIL (185–325 g/d) was increased by 800 and 350 g respectively for each kg of glucose or casein infused. Casein infusion increased calculated amino acid absorption from 0.18 to 0.36 of ME, increased wool growth and increased calculated maternal N balance. Birth weight was unaffected by nutritional treatment and averaged 3.29 kg/lamb.

4. When values from both experiments were combined, birth weight was related to GIL by a hyperbolic relation, with maximum predicted birth weight being 4.1 kg/lamb. It was postulated that this value was never attained in practice, due to uterine expansion being restricted by the low maternal body size. Marked decreases in birth weight occurred when GIL decreased below 173 g/d.

5. It was calculated that ewes in all treatment groups were in negative energy balance, and that glucose supplied by the kale and unsupplemented ryegrass diets were respectively below and equal to calculated conceptus uptakes of glucose necessary to maintain growth of triplet fetuses. It was further calculated that amino acid requirements of triplet-bearing ewes in late pregnancy were likely to exceed substantially net absorption from digestion of fresh forage diets, and that maternal tissues go into negative N balance to ensure fetal growth, thus explaining the lack of response to abomasal casein infusion.
Prevalence and stability of human serum antibodies to simian virus 40 VP1 virus-like particles
Authors: Lundstig Annika , Eliasson Linda , Lehtinen Matti , Sasnauskas Kestutis , Koskela Pentti , Dillner Joakim
Published: May 2005

Possible human infection with simian virus 40 (SV40) has been of great concern ever since SV40 was discovered in polio vaccines. Human populations are SV40-seropositive, but because of serological cross-reactivity between SV40 and the human polyomaviruses BK virus (BKV) and JC virus (JCV), it is debatable whether these antibodies are specific. An SV40-specific serological assay was established, based on purified virus-like particles (VLPs), where the SV40 VLPs were blocked with hyperimmune sera to BKV and JCV. Competition with SV40 hyperimmune sera was used as a confirmatory test. Among 288 Swedish children of between 1 and 13 years of age, 7·6 % had SV40-specific antibodies. SV40 seroprevalence reached a peak of 14 % at 7–9 years of age. Among 100 control patients with benign tumours, 9 % were SV40-seropositive. However, SV40 DNA was not detectable in corresponding buffy-coat samples. In serial samples taken up to 5 years apart from 141 Finnish women participating in the population-based serological screening for congenital infections, only two of 141 women were SV40-seropositive in both samples. Six women seroconverted and eight women had a loss of antibodies over time. None of the SV40-seropositive samples contained detectable SV40 DNA. In conclusion, there is a low prevalence of SV40-specific antibodies in the Nordic population. The SV40 antibodies appear to have a low stability over time and their origin is not clear.
Characteristics of the promoters derived from the single-stranded DNA components of Milk vetch dwarf virus in transgenic tobacco
Authors: Shirasawa-Seo Naomi , Sano Yoshitaka , Nakamura Shigeo , Murakami Taka , Seo Shigemi , Ohashi Yuko , Hashimoto Yoshifumi , Matsumoto Tsuguo
Published: May 2005

Predicted promoter regions of Milk vetch dwarf virus (MDV) components (C1–C11) were isolated and fused with a β-glucuronidase (GUS) reporter gene and the characteristics of the promoters were examined. In transgenic tobacco calli, promoters of MDV C4 (encoding a cell-cycle link protein), C5 and C7 (both encoding unknown proteins), C6 (encoding a nuclear-shuttle protein) and C8 (encoding a movement protein) generated a stronger level of GUS expression than the Cauliflower mosaic virus 35S RNA promoter (P35S). In leaves of transgenic tobacco plants, the promoters of C5 and C8 conferred a level of GUS activity comparable to that of P35S. Histochemical GUS analysis showed that the promoters of C4–C9, the latter encoding a capsid protein, were active in phloem and meristematic tissue. The promoter of C8 was also active in mesophyll and cortex cell types. A low level of activity was found for the promoters of C11, which encodes a master replication-initiator protein (Rep), and C1, C2, C3 and C10, which encode additional Reps, in both transgenic tobacco calli and plants.
Measles virus nucleoprotein induces cell-proliferation arrest and apoptosis through NTAIL–NR and NCORE–FcγRIIB1 interactions, respectively
Authors: Laine D. , Bourhis J. M. , Longhi S. , Flacher M. , Cassard L. , Canard B. , Sautès-Fridman C. , Rabourdin-Combe C. , Valentin H.
Published: May 2005

Measles virus (MV) nucleoprotein (N) is a cytosolic protein that is released into the extracellular compartment after apoptosis and/or secondary necrosis of MV-infected cellsin vitro. Thus, MV-N becomes accessible to inhibitory cell-surface receptors: FcγRIIB and an uncharacterized nucleoprotein receptor (NR). MV-N is composed of two domains: NCORE(aa 1–400) and NTAIL(aa 401–525). To assess the contribution of MV-N domains and of these two receptors in suppression of cell proliferation, a human melanoma HT144 cell line expressing (HT144IIB1) or lacking FcγRIIB1 was used as a model. Specific and exclusive NCORE–FcγRIIB1 and NTAIL–NR interactions were shown. Moreover, NTAILbinding to human NR predominantly led to suppression of cell proliferation by arresting cells in the G0/G1phases of the cell cycle, rather than to apoptosis. NCOREbinding to HT144IIB1 cells primarily triggered caspase-3 activation, in contrast to HT144IIB1/IC−cells lacking the FcγRIIB1 intra-cytoplasmic tail, thus demonstrating the specific inhibitory effect of the NCORE–FcγRIIB1 interaction. MV-N- and NCORE-mediated apoptosis through FcγRIIB1 was inhibited by the pan-caspase inhibitor zVAD-FMK, indicating that apoptosis was dependent on caspase activation. By using NTAILdeletion proteins, it was also shown that the region of NTAILresponsible for binding to human NR and for cell growth arrest maps to one of the three conserved boxes (Box1, aa 401–420) found in N ofMorbilliviruses. This work unveils novel mechanisms by which distinct domains of MV-N may display different immunosuppressive activities, thus contributing to our comprehension of the immunosuppressive state associated with MV infection. Finally, MV-N domains may be good tools to target tumour cell proliferation and/or apoptosis.
Coat protein enhances translational efficiency of Alfalfa mosaic virus RNAs and interacts with the eIF4G component of initiation factor eIF4F
Authors: Krab Ivo M. , Caldwell Christian , Gallie Daniel R. , Bol John F.
Published: May 2005

The three plus-strand genomic RNAs ofAlfalfa mosaic virus(AMV) and the subgenomic messenger for viral coat protein (CP) contain a 5′-cap structure, but no 3′-poly(A) tail. Binding of CP to the 3′ end of AMV RNAs is required for efficient translation of the viral RNAs and to initiate infection in plant cells. To study the role of CP in translation, plant protoplasts were transfected with luciferase (Luc) transcripts with 3′-terminal sequences consisting of the 3′ untranslated region of AMV RNA 3 (Luc–AMV), a poly(A) tail of 50 residues [Luc–poly(A)] or a short vector-derived sequence (Luc–control). Pre-incubation of the transcripts with CP had no effect on Luc expression from Luc–poly(A) or Luc–control, but strongly stimulated Luc expression from Luc–AMV. From time-course experiments, it was calculated that CP binding increased the half-life of Luc–AMV by 20 % and enhanced its translational efficiency by about 40-fold. In addition to the 3′ AMV sequence, the cap structure was required for CP-mediated stimulation of Luc–AMV translation. GlutathioneS-transferase pull-down assays revealed an interaction between AMV CP and initiation factor complexes eIF4F and eIFiso4F from wheatgerm. Far-Western blotting revealed that this binding occurred through an interaction of CP with the eIF4G and eIFiso4G subunits of eIF4F and eIFiso4F, respectively. The results support the hypothesis that the role of CP in translation of viral RNAs mimics the role of the poly(A)-binding protein in translation of cellular mRNAs.
No influence of amyloid-β-degrading neprilysin activity on prion pathogenesis
Authors: Glatzel Markus , Mohajeri M. Hasan , Poirier Raphael , Nitsch Roger M. , Schwarz Petra , Lu Bao , Aguzzi Adriano
Published: May 2005

Transmissible spongiform encephalopathies are characterized by the accumulation of PrPSc, a protease-resistant form of a host-derived protein termed PrPC. Substantial evidence indicates that PrPScrepresents an essential component of the infectious agent, which is termed prion. The accumulation of PrPScwithin the central nervous system of prion-infected organisms is a dynamic process that is regulated both by production and by clearance of PrPSc. Although several proteases have been implicated in proteolysis of PrPC, the mechanisms underlying proteolysis of PrPScremain unclear. Here, it was investigated whether neprilysin, a metalloprotease known to degrade extracellular amyloidogenic proteins such as amyloid-β, plays a role in prion pathogenesisin vivo. As neprilysin has a broad substrate specificity and is localized subcellularly in the vicinity of PrP, it represents a plausible candidate for prion degradation. Prions were therefore administered to mice lacking or overexpressing neprilysin in brain. However, the gene dosage of neprilysin did not modulate accumulation of PrPScin brain. Also, incubation times and clinical course of prion disease, as well as brain infectivity titres at terminal stage, were unaffected. These data rule out neprilysin as a major modulator of PrPScaccumulation and prion pathogenesis.
Virulence of Newcastle disease virus is determined by the cleavage site of the fusion protein and by both the stem region and globular head of the haemagglutinin–neuraminidase protein
Authors: de Leeuw Olav S. , Koch Guus , Hartog Leo , Ravenshorst Niek , Peeters Ben P. H.
Published: May 2005

Virulence of Newcastle disease virus (NDV) is mainly determined by the amino acid sequence surrounding the fusion (F) protein cleavage site, since host proteases that cleave the F protein of virulent strains are present in more tissues than those that cleave the F protein of non-virulent strains. Nevertheless, comparison of NDV strains that carry exactly the same F protein cleavage site shows that significant differences in virulence still exist. For instance, virulent field strain Herts/33 with the F cleavage site 112RRQRRF117 had an intracerebral pathogenicity index of 1·88 compared with 1·28 for strain NDFLtag, which has the same cleavage site. This implies that additional factors contribute to virulence. After generating an infectious clone of Herts/33 (FL-Herts), we were able to map the location of additional virulence factors by exchanging sequences between FL-Herts and NDFLtag. The results showed that, in addition to the F protein cleavage site, the haemagglutinin–neuraminidase (HN) protein also contributed to virulence. The effect of the HN protein on virulence was most prominent after intravenous inoculation. Interestingly, both the stem region and the globular head of the HN protein seem to be involved in determining virulence.
Reduced expression of the rotavirus NSP5 gene has a pleiotropic effect on virus replication
Authors: López Tomás , Rojas Margarito , Ayala-Bretón Camilo , López Susana , Arias Carlos F.
Published: May 2005

Rotavirus RRV gene 11 encodes two non-structural proteins, NSP5 and NSP6. NSP5 is a phosphorylated non-structural protein that binds single- and double-stranded RNA in a non-specific manner. Transient expression of this protein in uninfected cells has provided evidence for its participation in the formation of electron-dense cytoplasmic structures, known as viroplasms, which are thought to be key structures for the replication of the virus. NSP6 is a protein of unknown function that seems not to be essential for virus replication in cell culture. To study the function of NSP5 in the context of a viral infection, the expression of RRV gene 11 was silenced by RNA interference. Reduction in the synthesis of NSP5, as shown by immunoblot and immunofluorescence assays, correlated with a reduction in the number and size of viroplasms and with an altered intracellular distribution of other viroplasm-associated proteins. Silencing of gene 11 also resulted in a reduced synthesis of viral RNA(+) and double-stranded RNA and of all viral proteins, as well as in a decreased production of infectious virus. A similar phenotype was observed when the NSP5 coding gene of the lapine rotavirus strain Alabama was silenced. The fact that the NSP5 gene of rotavirus Alabama lacks the AUG initiator codon for a complete NSP6 protein, suggests that the described phenotype in gene 11-silenced cells is mostly due to the absence of NSP5. The data presented in this work suggest that NSP5 is a key protein during the replication cycle of rotaviruses.
Evidence for proteolytic cleavage of the baculovirus occlusion-derived virion envelope protein P74
Authors: Slack Jeffrey M. , Lawrence Susan D.
Published: May 2005

Baculovirus occlusion-derived virions (ODVs) are released from occlusion bodies by the alkaline environment of the insect midgut. The ODV envelope protein P74 is required for oral infectivity. A soluble form of the Autographa californica multiple nucleopolyhedrovirus P74 protein, P74sol, was engineered as part of a chimeric protein with jellyfish green fluorescent protein (GFP). P74sol–GFP was overproduced by the baculovirus expression system and purified away from the wild-type P74. Brush border membrane vesicles (BBMVs) were prepared from the midguts of third-instar Helicoverpa zea larvae. When P74sol–GFP was incubated under alkaline conditions with BBMVs, a P74sol–GFP product with a smaller molecular mass was produced. Immunoblots indicated that the smaller product was generated by N-terminal cleavage of P74. This cleavage was prevented by soybean trypsin inhibitor. Analysis of the peptide sequences of P74 homologues identified a conserved trypsin cleavage site that could generate the observed P74sol–GFP BBMV-specific cleavage product.
Human papillomavirus, viral load and proliferation rate in recurrent respiratory papillomatosis in response to alpha interferon treatment
Authors: Szeps Michael , Dahlgren Liselotte , Aaltonen Leena-Maija , Öhd John , Kanter-Lewenshon Lena , Dahlstrand Hanna , Munck-Wikland Eva , Grandér Dan , Dalianis Tina
Published: May 2005

The aim of this study was to identify recurrent respiratory papillomatosis patients who may benefit from interferon (IFN)-α treatment and to determine the means of IFN-α action. The presence of human papillomavirus (HPV) and viral load and proliferation rate in pre-, ongoing and post-treatment respiratory papillomatosis biopsies were examined retrospectively in 25 patients, 18 of whom were IFN-α treated and seven of whom were IFN-α non-treated. Using PCR, HPV was found to be present in 20/25 respiratory papillomatosis patients and HPV type was determined for 18/25 patients (12 HPV6 and six HPV11). Eighteen of the patients were treated with IFN-α, 14 of whom were HPV positive (eight HPV6, five HPV11 and one undefined HPV). Response to IFN-α therapy was observed in 12 patients (7/8 HPV6, 3/5 HPV11, 1/1 undefined HPV and 1/4 HPV negative), while six patients (1/8 HPV6, 2/5 HPV11 and 3/4 HPV negative) did not respond to therapy. Viral load, determined by quantitative real-time PCR (between 0·03 and 533 HPV copies per cell), and proliferation rate, determined as the percentage of Ki-67-positive cells (between 8 and 54 %), were similar in IFN-α-treated and non-treated patients and were generally unaffected by IFN-α treatment. In summary, most (12/18) IFN-α-treated patients responded to therapy. Moreover, there was a tendency for patients with HPV6-positive (7/8) respiratory papillomatosis to respond more frequently to IFN-α therapy than patients with HPV11 (3/5) or HPV-negative (1/4) respiratory papillomatosis. Finally, the presence of HPV and viral load and proliferation in respiratory papillomatosis biopsies was similar in patients treated or not with IFN-α and were in general unaffected by IFN-α treatment.
Infection of mature dendritic cells with herpes simplex virus type 1 dramatically reduces lymphoid chemokine-mediated migration
Authors: Prechtel Alexander T. , Turza Nadine M. , Kobelt Dieter J. , Eisemann Jutta I. , Coffin Robert S. , McGrath Yvonne , Hacker Christine , Ju Xinsheng , Zenke Martin , Steinkasserer Alexander
Published: May 2005

Herpes simplex virus type 1 (HSV-1) is able to establish latency in infected individuals. In order to characterize potential new immune-escape mechanisms, mature dendritic cells (DCs) were infected with HSV-1 and total cellular RNA was isolated from infected and mock-infected populations at different time points. RNA profiling on Affymetrix Human Genome U133A arrays demonstrated a dramatic downregulation of the migration-mediating surface molecules CCR7 and CXCR4, an observation that was further confirmed by RT-PCR and fluorescence-activated cell sorting analyses. Furthermore, migration assays revealed that, upon infection of mature DCs, CCR7- and CXCR4-mediated migration towards the corresponding CCL19 and CXCL12 chemokine gradients was strongly reduced. It is noteworthy that the infection of immature DCs with HSV-1 prior to maturation led to a failure of CCR7 and CXCR4 upregulation during DC maturation and, as a consequence, also induced a block in their migratory capacity. Additional migration assays with a Δvhs mutant virus lacking the virion host shutoff (vhs) gene, which is known to degrade cellular mRNAs, suggested a vhs-independent mechanism. These results indicate that HSV-1-infected mature DCs are limited in their capacity to migrate to secondary lymphoid organs, the areas of antigen presentation and T-cell stimulation, thus inhibiting an antiviral immune response. This represents a novel, previously unrecognized mechanism for HSV-1 to escape the human immune system.
Stable human lymphoblastoid cell lines constitutively expressing hepatitis C virus proteins
Authors: Wölk Benno , Gremion Christel , Ivashkina Natalia , Engler Olivier B. , Grabscheid Benno , Bieck Elke , Blum Hubert E. , Cerny Andreas , Moradpour Darius
Published: May 2005

The cellular immune response plays a central role in virus clearance and pathogenesis of liver disease in hepatitis C. The study of hepatitis C virus (HCV)-specific immune responses is limited by currently available cell-culture systems. Here, the establishment and characterization of stable human HLA-A2-positive B-lymphoblastoid×T hybrid cell lines constitutively expressing either the NS3–4A complex or the entire HCV polyprotein are reported. These cell lines, termed T1/NS3-4A and T1/HCVcon, respectively, were maintained in continuous culture for more than 1 year with stable characteristics. HCV structural and non-structural proteins were processed accurately, indicating that the cellular and viral proteolytic machineries are functional in these cell lines. Viral proteins were found in the cytoplasm in dot-like structures when expressed in the context of the HCV polyprotein or in a perinuclear fringe when the NS3–4A complex was expressed alone. T1/NS3-4A and T1/HCVcon cells were lysed efficiently by HCV-specific cytotoxic T lymphocytes from patients with hepatitis C and from human HLA-A2.1 transgenic mice immunized with a liposomal HCV vaccine, indicating that viral proteins are processed endogenously and presented efficiently via the major histocompatibility complex class I pathway. In conclusion, these cell lines represent a unique tool to study the cellular immune response, as well as to evaluate novel vaccine and immunotherapeutic strategies against HCV.
Full restoration of viral fitness by multiple compensatory co-mutations in the nucleoprotein of influenza A virus cytotoxic T-lymphocyte escape mutants
Authors: Rimmelzwaan G. F. , Berkhoff E. G. M. , Nieuwkoop N. J. , Smith D. J. , Fouchier R. A. M. , Osterhaus A. D. M. E.
Published: May 2005

Amino acid substitutions have been identified in the influenza A virus nucleoprotein that are associated with escape from recognition by virus-specific cytotoxic T lymphocytes (CTLs). One of these is the arginine-to-glycine substitution at position 384 (R384G). This substitution alone, however, is detrimental to viral fitness, which is overcome in part by the functionally compensating co-mutation E375G. Here, the effect on viral fitness of four other co-mutations associated with R384G was investigated by using plasmid-driven rescue of mutant viruses. Whilst none of these alternative co-mutations alone compensated functionally for the detrimental effect of the R384G substitution, the M239V substitution improved viral fitness of viruses containing 375G and 384R. The nucleoprotein displays unexpected flexibility to overcome functional constraints imposed by CTL epitope sequences, allowing influenza viruses to escape from specific CTLs.
Chimeric monoclonal antibodies to hypervariable region 1 of hepatitis C virus
Authors: Li Chengyao , Allain Jean-Pierre
Published: May 2005

Two chimeric monoclonal antibodies (cAbs), 2P24 and 15H4, to hypervariable region 1 (HVR1) of hepatitis C virus (HCV) were constructed by grafting the variable regions of murine monoclonal antibodies (mAbs) 2P24 and 15H4 to a human IgG1 kappa constant region. Two cAb-producing cell lines were adapted to serum-free media. Both cAb 2P24 and cAb 15H4 cell lines produced 3–5 μg antibodies ml−1 after 3–5 days culture. cAbs retained binding characteristics similar to those observed in the original mAbs. There was no clear difference in affinity between binding of cAbs and mAbs to seven HVR1 peptides. Mixtures of biotinylated cAbs or mAbs reacted with 32 (86 %) and 31 (84 %) of 37 HVR1 peptides, respectively, but not with non-HVR1 control peptides. HCV from 16 out of 18 (89 %) random HCV-containing plasmas was captured by the mixture of biotinylated cAbs. The capture from IgG-depleted plasmas suggested that cAbs captured mainly free rather than complexed HCV, irrespective of genotype. A mixture of the two cAbs inhibited HCV binding to Molt-4 cells in a dose-dependent manner. These cAbs may be useful for prevention of nosocomial HCV infection and passive immunization to prevent HCV reinfection after liver transplantation.
Coat proteins of Rice tungro bacilliform virus and Mungbean yellow mosaic virus contain multiple nuclear-localization signals and interact with importin α
Authors: Guerra-Peraza O. , Kirk D. , Seltzer V. , Veluthambi K. , Schmit A. C. , Hohn T. , Herzog E.
Published: May 2005

Transport of the viral genome into the nucleus is an obligatory step in the replication cycle of plant pararetro- and geminiviruses. In both these virus types, the multifunctional coat protein (CP) is thought to be involved in this process. Here, a green fluorescent protein tagging approach was used to demonstrate nuclear import of the CPs ofRice tungro bacilliform virus(RTBV) andMungbean yellow mosaic virus-Vigna(MYMV) inNicotiana plumbaginifoliaprotoplasts. In both cases, at least two nuclear localization signals (NLSs) were identified and characterized. The NLSs of RTBV CP are located within both N- and C-terminal regions (residues 479KRPK/497KRK and 744KRK/758RRK), and those of MYMV CP within the N-terminal part (residues 3KR and 41KRRR). The MYMV and RTBV CP NLSs resemble classic mono- and bipartite NLSs, respectively. However, the N-terminal MYMV CP NLS and both RTBV CP NLSs show peculiarities in the number and position of basic residues.In vitropull-down assays revealed interaction of RTBV and MYMV CPs with the nuclear import factor importinα, suggesting that both CPs are imported into the nucleus via an importinα-dependent pathway. The possibility that this pathway could serve for docking of virions to the nucleus is discussed.
Koi herpesvirus represents a third cyprinid herpesvirus (CyHV-3) in the family Herpesviridae
Authors: Waltzek Thomas B. , Kelley Garry O. , Stone David M. , Way Keith , Hanson Larry , Fukuda Hideo , Hirono Ikuo , Aoki Takashi , Davison Andrew J. , Hedrick Ronald P.
Published: May 2005

The sequences of four complete genes were analysed in order to determine the relatedness of koi herpesvirus (KHV) to three fish viruses in the family Herpesviridae: carp pox herpesvirus (Cyprinid herpesvirus 1, CyHV-1), haematopoietic necrosis herpesvirus of goldfish (Cyprinid herpesvirus 2, CyHV-2) and channel catfish virus (Ictalurid herpesvirus 1, IcHV-1). The genes were predicted to encode a helicase, an intercapsomeric triplex protein, the DNA polymerase and the major capsid protein. The results showed that KHV is related closely to CyHV-1 and CyHV-2, and that the three cyprinid viruses are related, albeit more distantly, to IcHV-1. Twelve KHV isolates from four diverse geographical areas yielded identical sequences for a region of the DNA polymerase gene. These findings, with previously published morphological and biological data, indicate that KHV should join the group of related lower-vertebrate viruses in the family Herpesviridae under the formal designation Cyprinid herpesvirus 3 (CyHV-3).
X-ray powder diffraction structure determination of γ-butyrolactone at 180 K: phase-problem solution from the lattice energy minimization with two independent molecules
Authors: Papoular Robert J. , Allouchi Hassan , Chagnes Alexandre , Dzyabchenko A. , Carré Bernard , Lemordant Daniel , Agafonov Viatcheslav
Published: May 2005

The crystal structure of the solid phase of the dipolar aprotic solvent γ-butyrolactone (BL1), C4H6O2, has been solved using the atom–atom potential method and Rietveld-refined against powder diffraction data collected at T = 180 K with a curved position-sensitive detector (INEL CPS120) using Debye–Scherrer diffraction geometry with monochromatic X-rays. It was first deduced from the X-ray experiment that the lattice parameters are a = 10.1282 (4), b = 10.2303 (5), c = 8.3133 (4) Å, β = 93.291 (2)° and that the space group is P21/a, with Z = 8 and two independent molecules in the asymmetric unit. The structure was then solved by global energy minimization of the crystal-lattice atom–atom potentials. The subsequent GSAS-based Rietveld refinement converged to the final crystal-structure model indicator R

F
2
= 0.0684, profile factors Rp
= 0.0517 and R
wp = 0.0694, and a reduced χ2 = 1.671. After further cycles of heating and cooling, a powder diffraction pattern markedly different from the first pattern was obtained, again at T = 180 K, which we tentatively assign to a second polymorph (BL2). All the observed diffraction peaks are well indexed by a triclinic unit cell essentially featuring a doubling of the a axis. An excellent Le Bail fit is obtained, for which Rp
= 0.0312 and R
wp = 0.0511.
Ab initio structure determination of the high-temperature phase of anhydrous caffeine by X-ray powder diffraction
Authors: Derollez Patrick , Correia Natália T. , Danède Florence , Capet Frédéric , Affouard Frédéric , Lefebvre Jacques , Descamps Marc
Published: May 2005

The high-temperature phase I of anhydrous caffeine was obtained by heating and annealing the purified commercial form II at 450 K. This phase I can be maintained at low temperature in a metastable state. A powder X-ray diffraction pattern was recorded at 278 K with a laboratory diffractometer equipped with an INEL curved position-sensitive detector CPS120. Phase I is dynamically orientationally disordered (the so-called plastic phase). The Rietveld refinements were achieved with rigid-body constraints. It was assumed that on each site, a molecule can adopt three preferential orientations with equal occupation probability. Under a deep undercooling of phase I, below 250 K, the metastable state enters in a glassy crystal state.
Fine-tuning of biaryl dihedral angles: structural characterization of five homologous three-atom bridged biphenyls by X-ray crystallography
Authors: Edwards David J. , Pritchard Robin G. , Wallace Timothy W.
Published: May 2005

The homologous series of three-atom bridged biaryls comprising 5,7-dihydro-1,2,3,9,10,11-hexamethoxydibenzo[c,e]oxepine, 6,7-dihydro-1,2,3,9,10,11-hexamethoxy-6-methyl-5H-dibenzo[c,e]azepinium chloride, 5,7-dihydro-1,2,3,9,10,11-hexamethoxydibenzo[c,e]thiepine, and the 6-oxide and 6,6-dioxide derivatives of the latter have been characterized by X-ray crystal structure analysis. Within this series the endocyclic and exocyclic biaryl dihedral angles vary over 10° ranges, reflecting the changing balance of intramolecular (steric, geometric) and intermolecular (crystal packing) forces, the former being potential control elements for fine-tuning the helicity of the biaryl system.
Remarkable features in lattice-parameter ratios of crystals. I. Orthorhombic, tetragonal and hexagonal crystals
Authors: de Gelder R. , Janner A.
Published: May 2005

The investigation of the lattice-parameter ratios of tetrahedral and hexagonal–rhombohedral inorganic compounds, as reported by Constant & Shlichta [(2003), Acta Cryst. A59, 281–282], has been extended to the structural data found for organic and metal-organic compounds (CSD), for bio-macromolecular crystals (PDB) and for inorganic materials (ICSD). In this first part of the series, the frequency distribution of orthorhombic, tetragonal and hexagonal crystals is presented. The results obtained confirm the existence of sharp peaks as a function of the ratios of lattice parameters and reveal additional exponential components, decaying for large and small values of these ratios. Practically all the important peaks occur at ratios which correspond to lattices having metric tensors with rational entries, the so-called integral lattices. The exponential component is interpreted as expressing a general statistical distribution which is valid for the generic crystal lattices, i.e. those normally considered. The exponential fraction dominates the peaked component in the organic and metal-organic cases, is less important for bio-macromolecular crystals and is much less important than the sharp peaks for inorganic crystals. Remarkable is the crystallographic relevance of the isometric hexagonal lattice, characterized by the axial ratio c/a = 1 and first observed in the molecular form of a protein. In the frequency distribution of 12 117 inorganic hexagonal crystals, the highest peak of 937 crystals occurs for c = a. In the hexagonal case of the bio-macromolecules the most important peak of 422 crystals is observed near the ideal h.c.p. (hexagonal closed packing) ratio of (8/3)1/2.
Concomitant polymorphism and a temperature-dependent phase change in (E)-[1-(4-methoxyphenyl)-3-phenyl-2-propenylideneamino]oxyacetic acid
Authors: Skakle Janet M. S. , Low John N. , Wardell James L. , Glidewell Christopher
Published: May 2005

The title compound, C18H17NO4, crystallizes from ethanol at ambient temperature as two concomitant polymorphs (I) and (II), both monoclinic P21/c with Z′ = 1. The less abundant form (I) undergoes a reversible phase-transition at ca 173 K to a third monoclinic polymorph (III), P21/n, with Z′ = 2, while the more abundant polymorph (II) is unchanged down to 120 K. In each polymorph of (I)–(III) the molecules are linked by pairs of O—H...O hydrogen bonds into cyclic dimers which are crystallographically centrosymmetric in (I) and (II), and approximately, but not crystallographically, centrosymmetric in (III). There are no direction-specific interactions between the hydrogen-bonded dimers in polymorph (I); in polymorph (II) the dimers are linked into sheets by C—H...N and C—H...π(arene) hydrogen bonds; in polymorph (III) the dimers are linked into chains by a C—H...π(arene) hydrogen bond. The interconversion of polymorphs (I) and (III) is a simple displacive phase transition.
Structure of a synthetic halogen sulfosalt, Cu3Bi2S3I3
Authors: Balić-Žunić Tonči , Mariolacos Konstantin , Friese Karen , Makovicky Emil
Published: May 2005

Cu3Bi2S3I3 was crystallized during an attempt to synthesize Cu–Pb–Bi sulfosalts with iodine as the transport medium. The crystal structure was solved from a black needle-like crystal on a four-circle diffractometer with a CCD detector. The solution was obtained by direct methods and subsequent difference-Fourier syntheses. S and I atoms are arranged in a systematically distorted cubic eutaxy (close packing). Bi atoms have monocapped trigonal prismatic coordinations, while Cu atoms occupy coordination sites which vary from trigonal planar to distorted tetrahedral. A prominent feature is the distribution of Cu atoms over many closely spaced sites in the structure, the majority of them being only partly occupied, which strengthens the case for mobile Cu atoms during crystal growth at elevated temperatures. In this respect, Cu3Bi2S3I3 represents an extreme example of a statistical distribution of Cu in the structure; a frequently observed property of this element in sulfosalts.
Substituent effects in bis(arene)chromium compounds containing a CN group in the aromatic ring
Authors: Khrustalev Victor N. , Vasil'kov Alexander Yu. , Antipin Mikhail Yu.
Published: May 2005

The crystal structures of Cr(PhCN)2 (2), (PhCN)Cr(PhCH3) (3) and (PhCN)Cr(PhCF3) (4) prepared by means of the Metal Vapor Synthesis (MVS) technique have been determined. Compounds (2), (3) and (4) crystallize as discrete sandwich complexes having intrinsic C
2v
(mm2), C

s
(m) and C
1(1) symmetries, respectively. The X-ray diffraction study has revealed a synperiplanar conformation for (2) and (3), and a synclinal conformation for (4) with a torsion angle (C
ipso
1–Centroid1–Centroid2–C
ipso
2) of φ = 63.5°. The angles between the ligand planes are 2.2, 3.9 and 1.8°, respectively. The Cr atom is slightly (by 0.04–0.06 Å) displaced towards the substituents from the line connecting the centers of the opposite aromatic rings. The Cr—C
ipso
distances are 2.115 (2)–2.137 (2), 2.112 (2) and 2.185 (3) Å for CN, CF3 and CH3 groups, respectively. The CN groups as well as the H atoms lie out of the C
6 ring planes and are bent towards the Cr atom, but the C atom of the CH3 group also lying out of the C6 ring plane is bent away from the Cr atom. The C atom of the CF3 group is essentially coplanar to the C
6 ring plane. There are no unusual intermolecular contacts in the structures of (2)–(4).
Space group P1: an update
Authors: Marsh Richard E.
Published: May 2005

A new survey of the Cambridge Structural Database has uncovered 115 additional crystal structures that were described in the space group P1, but would be better described in groups of higher symmetries.
Hydrogen-bonded aggregations of oxo-cholic acids
Authors: Bertolasi Valerio , Ferretti Valeria , Pretto Loretta , Fantin Giancarlo , Fogagnolo Marco , Bortolini Olga
Published: May 2005

The crystal structures of six new crystals of oxo-cholic acids (oxo-CA) are reported: (I) 3α,12α-dihydroxy-7-oxo-5β-cholan-24-oic acid; (II) 3α,7α-dihydroxy-12-oxo-5β-cholan-24-oic acid; (III) 7α-hydroxy-3,12-dioxo-5β-cholan-24-oic acid; (IV-α) and (IV-β) 12α-hydroxy-3,7-dioxo-5β-cholan-24-oic acid; (V) 3,7,12-trihydroxy-5β-cholan-24-oic acid. (IV-β) is a pseudopolymorphic solvated form of (IV-α) and contains small channels which can trap disordered water molecules. In all the structures the four saturated cycles, forming the common alicyclic skeleton, have the same conformation, while the carboxylic side chain adopts flexible conformations in order to produce the most efficient crystal aggregations. The structures display a variety of supramolecular architectures dominated by networks of cooperative O—H...O hydrogen bonds forming different packing motifs often supported by weaker C—H...O interactions.
Phenylene lattices
Authors: Smilgies Detlef-M.
Published: May 2005

A modified choice of unit-cell vectors resolves an apparent discrepancy in the indexation of the most intense para-sexiphenyl reflections compared with other known para-phenylenes.
The effect of sulfide on the corrosion behavior of carbon steel in natural waters
Authors: Xuejun Xie , Wanqin Yang , Shunan Cao , Ling Pan , Xunjie Gong , Keru Peng
Published: May 2005

Purpose

To study the corrosion behavior and discuss the corrosion mechanism of No. 20 carbon steel in water in the presence of sulfide ions.

Design/methodology/approach

The mass‐loss method, electrochemical tests and surface analysis were used to study the corrosion behavior and discuss the corrosion mechanism of No. 20 carbon steel in water in the presence of sulfide ions.

Findings

General corrosion occurred when No. 20 carbon steel was immersed in both test solutions (concentrated sample with S2− added to 0.8 mg/L, and pure concentrated sample with no S2− added). The presence of S2− in test solutions accelerated the corrosion rate of No. 20 carbon steel.

Practical implications

In order to prevent No. 20 carbon steel in water with S2− from corroding, S2− must be removed.

Originality/value

It was found that the presence of S2− in test solutions accelerated the corrosion rate of No. 20 carbon steel in this paper. Therefore, when water containing sulfide ions is used as the source of make‐up water and cooling water, S2− in water must be removed to prevent the pipelines and facilities from corroding. This means the research results can offer theoretical guidelines for the prevention of pipelines and facilities in the power plant from corroding.
Influence of microbiologically induced corrosion of steel embedded in ordinary Portland cement and Portland pozzolona cement
Authors: Kuber Parande Anand , Muralidharan Srinivasan , Saraswathy Velu , Palaniswamy N.
Published: May 2005

Purpose

The acceleration of corrosion of rebars in concrete are due to several reasons such as carbonation, chloride attack, influence of microorganisms, etc. The aim of this investigation mainly focused on how the microorganism was involved in the corrosion process and thereby affect a mechanical property of mortar and accelerate the corrosion of steel in mortar. ordinary portland cement (OPC) and portland pozzolona cement (PPC) was used for making mortar specimens. Sodium citrate was used as an inhibitor for the corrosion of steel in mortar.

Design/methodology/approach

Compressive strength measurements were conducted for mortar at different ages in the presence of microorganisms to understand the mechanical property of mortar. Potential‐time behavior studies were carried out to determine the status of rebars inside the mortar. Weight loss measurements were adopted to quantify the corrosion level due to microorganisms. The microbial count in the water samples at the initial and final exposure period was also examined.

Findings

All these studies showed that additions of sodium citrate level of greater than 1 percent by weight of OPC and PPC severely affected both the mechanical and the corrosion resistance properties of OPC and PPC. Microbiological examination reveals that bacteria consume citrates for their survival and thereby increasing the permeability of mortar specimens.

Originality/value

Generally, citrates are considered as being good corrosion inhibitor for steel in concrete. However, results from the present study indicated that sodium citrate concentrations only of less than 1 percent by weight of OPC and PPC are suitable for use in concretes that are exposed to heterotrophic bacterial environments.
Cationic surfactant as corrosion inhibitor for aluminum in acidic and basic solutions
Authors: Al‐Rawashdeh N.A.F. , Maayta A.K.
Published: May 2005

Purpose

To investigate the inhibiting effect of the cationic surfactant cetyl trimethylammonium chloride (CTAC) on aluminum (Al).

Design/methodology/approach

Pure aluminum rods were immersed in hydrochloric acid (HCl) and sodium hydroxide (NaOH) solutions for weight‐loss tests and potentiostatic polarization measurements.

Findings

The inhibition action depends on the concentration of the inhibitor, the concentration of the corrosive media, and the temperature. The inhibition efficiency in NaOH was higher than that in HCl solutions. In both acidic and basic media, the increase in temperature resulted in a decrease of the inhibition efficiency and a decrease in the degree of surface coverage. The results were indicative of increased aluminum dissolution with increasing temperature. It was found that adsorption of CTAC on the aluminum surface follows Temkin's isotherm in HCl and Langmuir's isotherm in NaOH.

Originality/value

Clarifies the effects of concentration and temperature on the inhibition efficiency of a cationic surfactant on aluminum.