bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experiments to optimize enzyme substitution therapy in pancreatic duct‐ligated pigs
Authors: Kammlott E. , Karthoff J. , Stemme K. , Gregory P. , Kamphues J. 
Published: March 2005

SummaryLigation of the pancreatic duct in pigs leads to severe maldigestion and malabsorption of crude nutrients. Supplementation with 24 capsules of Creon® (Solvay Pharmaceuticals GmbH, Hannover, Germany) per meal led to an increased digestibility of crude nutrients. With regard to optimization of the treatment of EPI no essential improvements can be achieved by adding omeprazol or lecithin to the diet. In pancreatic duct‐ligated pigs the isolated addition of omeprazol led to an increase of the pre‐caecal digestibility of crude fat and organic matter. With additional enzyme substitution, the application of omeprazol did not result in an improved fat digestibility. Isolated addition of lecithin to the diet resulted in a reduced total digestibility of crude fat. Offering the diet twice a day and using a higher frequency of enzyme applications (four or six instead of only two applications) had no effects on the digestibilty of crude fat or organic matter. According to the observations in pancreatic duct‐ligated pigs, the addition of missing enzymes to the diet led to the best treatment results in EPI. Administration of omeprazol or a higher feeding frequency as well as the application of enzymes in small proportion of the whole meal or dosages given consecutively over the day showed no advantages. Furthermore, the present study suggests that the addition of lecithin cannot be recommended in EPI, when given diets with butter as the predominant fat source as in human dietetics.
Carry over (transfer) of feed‐borne acrylamide into eggs, muscle, serum, and faeces – a pilot study with Japanese quails (Coturnix coturnix japonica)
Authors: Kienzle E. , Ranz D. , Thielen C. , Jezussek M. , Schieberle P. 
Published: March 2005

SummaryTwo groups of 10 quails each were fed for 30 days on a diet containing either 663 μg feed‐borne acrylamide (AA)/kg feed (group B) or 2472 μg AA/kg feed (group C) respectively. The concentrations of AA present in excreta and eggs were compared with those measured in eggs and excreta obtained from a control group (group A) fed on a diet low in AA (<10 μg/kg). The results clearly showed that the eggs of quails in group C contained approximately 53–112 μg AA/kg based on dry weight, while eggs collected from group A did not contain AA (limit of detection in eggs 3.5 μg/kg). Nearly 5% of the AA fed was recovered in the excreta. The AA concentrations in liver, muscle and serum were detectable, but below the limit of quantitation.
Effect of combinations of organic acids in weaned pig diets on microbial species of digestive tract contents and their response on digestibility
Authors: Franco L. D. , Fondevila M. , Lobera M. B. , Castrillo C. 
Published: March 2005

SummaryThe effect of combinations of organic acids on digestive microbial population and total tract digestibility of piglets was studied. Thirty 19–21 days weaned pigs (5.4 ± 0.23 kg, six pigs per treatment) were given a mixed feed with 10 ml water/kg (CTL) or 200 mEq/kg of formic acid (FOR), 1:1 formic:fumaric (FOFU), 1:1 formic:lactic (FOLA) or 2:1 formic:lactic (2FOLA). After 6–8 days, animals were slaughtered. In gastric contents, pH was higher (p = 0.01) with FOFU and lactobacilli tended (p = 0.08) to be lower with FOFU than CTL and FOLA, but coliform counts did not differ (p = 0.14). Acetate proportion was lower (p = 0.03), and propionate (p = 0.05) and butyrate (p = 0.01) higher, with FOFU than CTL, FOLA and 2FOLA. Intestinal coliform counts were higher (p = 0.03) with CTL than FOLA and 2FOLA, but there were no differences on lactobacilli. In intestinal contents, acetate tended (p = 0.06) to be lower with FOR than FOLA and 2FOLA, and butyrate was higher (p = 0.001) with FOR. Although not significantly, dry matter digestibility was 0.03–0.05 lower with CTL than with the other treatments. Combinations of organic acids in piglet diets modify gastric and intestinal microflora, the mixtures of formic:lactic appearing as the most interesting.
In situ ruminal degradability and intestinal digestion of raw and extruded legume seeds and soya bean meal protein
Authors: Solanas E. , Castrillo C. , Balcells J. , Guada J. A. 
Published: March 2005

SummaryAn experiment was performed to evaluate the effect of extrusion and carbohydrate addition on rumen degradation and intestinal digestion of raw legume seeds and solvent extracted soya bean meal (SBM) protein. Whole soya beans (WSB) without or with maize added (75:25) (WSB‐M), peas, lupins and SBM were extruded at 140 °C. Protein rumen degradation and intestinal digestibility of unprocessed and extruded protein sources were measured by in sacco and mobile bag procedures, respectively, in two dairy cows cannulated in rumen and duodenum. Between 12 and 15 polyester bags with 4 g of each protein source were incubated in rumen for 12 h and the residues, pooled by feed, were introduced into the duodenum in small nylon bags after pre‐incubation in a pepsin solution, and recovered from faeces the day after. Extrusion significantly (p < 0.001) reduced N degradation of all protein sources, from 98.1%, 91.6%, 90.5% and 64.8% to 53.1%, 73.8%, 70.3% and 44.2% for peas, lupins, WSB and SBM respectively. The addition of maize to WSB strengthened the effect of extrusion on rumen N degradation, from 88.2% to 52.6%. Residues from rumen incubation of extruded feeds showed a higher (p < 0.001) intestinal N digestibility except for SBM (87.0%, 82.9%, 66.3%, 85.0% and 97.2%, and 99.1%, 95.8%, 96.8%, 97.8% and 98.7%, respectively, for non‐extruded and extruded, peas, lupins, WSB, WSB‐M and SBM). In conclusion, the extrusion of studied legume seeds and SBM promotes a clear and significant increase of their metabolizable protein value, particularly in peas, and the inclusion of a source of carbohydrates before extrusion increase this response.
Use of Grafting and Calcium Cyanamide as Alternatives to Methyl Bromide Soil Fumigation and their Effects on Growth, Yield, Quality and Fusarium Wilt Control in Melon
Authors: Bletsos F. A. 
Published: March 2005

AbstractGrafting melon (Cucumis melo L.) seedlings on to the Fusarium oxysporum f. sp. melonis (Fom) commercial resistant squash rootstocks ‘Mamouth’ and ‘Nun 9075 RT’ and soil sterilization with calcium cyanamide (CaCN2, Perlka) were tested in 2001 and 2002 as alternatives to methyl bromide (MB) soil fumigation. Ungrafted seedlings of the F1 melon hybrid ‘Galia’ were cultivated: (i) in soil sterilized by MB and then artificially infested with Fom (this served as a control), (ii) in soil artificially infested with Fom and then sterilized by MB, (iii) in soil artificially infested with Fom and then sterilized with CaCN2 (Perlka), grafted seedlings on the commercial rootstocks, (iv) ‘Mamouth’ and (v) ‘Nun 9075 RT’ were cultivated in soil sterilized with MB and then artificially infested with Fom. The grafted plants on ‘Mamouth’ and ‘Nun 9075 RT’ and plants in the Perlka treatment (2001) developed mild symptoms, as indicated by the significantly lower leaf symptom index (LSI; average values 1.06, 1.08 and 1.07) and disease index (DI; average values 1.60, 1.25 and 2.33), respectively, when compared with the controls (average values of LSI = 2.65 and DI = 5.06). Plants grafted on ‘Mamouth’ and ‘Nun 9075 RT’ and plants in the Perlka treatment (2001) were more vigorous than the controls as assessed on plant height, stem diameter and root biomass. When compared with the controls, this resulted in an increased (over years) early production (326.3, 265.8 and 489.1%) and late production (371.0, 357.0 and 404.2%). Fruit size was also larger in early production (29.2, 50.9 and 32.3) and late production (4.3, 15.2 and 26.0). The total soluble solids (oBrix) increased (over years) in early production (27.4, 39.6 and 47.9) and late production (7.59, 10.07 and 5.6) when compared with the controls. Thus, grafting on resistant squash rootstocks ‘Mamouth’ and ‘Nun 9075 RT’ and soil sterilization with Perlka had positive effects on growth, production and fusarium wilt control in melon.
Helmholtz coils revisited
Authors: Purcell Edward M. 
Published: March 2005

Two circular coaxial current rings of radius a, separated by a distance b, are usually called Helmholtz coils if b=a. That is the well-known prescription for greatest uniformity of field in the neighborhood of the center of symmetry. Examined here is the magnetic field of a pair of current rings at a distance r from the center large compared to the ring radius a. Expanding the distant field in powers of a/r, each term may be associated with a magnetic 2k-pole source and a field falling off as (a/r)k+2. The dipole field k=1, falling as (a/r)3, has as its source the total dipole moment of the two rings. It eventually swamps the contribution of higher multipoles. The term (a/r)5 with k=3 has for its source the octupole (23-pole) moment of the pair of rings. Its coefficient vanishes if b=a. Thus the Helmholtz pair, thanks to its seemingly irrelevant specialization for uniform central field, is also endowed with zero octupole moment. The term-by-term connection between the expansion of the distant field and the expansion of the central field holds for currents entirely confined to the surface of a sphere, which is the case for the Helmholtz pair of thin current rings. The dipole field can be nullified by nesting the Helmholtz pair within a larger Helmholtz pair designed to have equal area × ampere–turns but carrying reversed current.
At the cost of a minor reduction in central field and without compromising the central field’s uniformity, the total dipole moment of the four rings can thus be made zero. The current system now has zero dipole moment and zero octupole moment. As 2k -poles with k even are ruled out by symmetry, the lowest surviving multipole is the 25-pole, the ‘‘32-pole.’’ The residual distant field, of which it is now the dominant source, falls as (a/r)7. An exact calculation of the ratio of field magnitude B to central field B0 shows that B/B0 is closely proportional to (a/r)7 everywhere in the field beyond r≊5a. Already at r≊6a, B/B0 has fallen to 10−4. It is shown how equivalent results can be achieved with coils of finite cross section. This scheme can drastically reduce the ‘‘stray field’’ around a superconducting magnet. In effect, it closely confines most of the return flux. Another application involves the induction of alternating currents by precessing magnetic moments. The four coils connected in series constitute a receiving coil tightly coupled to any oscillating dipole at its center, but virtually immune to disturbance by external sources.
Feline Calicivirus VP2 Is Essential for the Production of Infectious Virions
Authors: Sosnovtsev Stanislav V. , Belliot Gaël , Chang Kyeong-Ok , Onwudiwe Oge , Green Kim Y. 
Published: March 2005

ABSTRACT

The third open reading frame (ORF3) located at the 3′ end of the genomic RNA of feline calicivirus (FCV) encodes a small (12.2-kDa) minor structural protein of 106 amino acids designated VP2. Point mutations and deletions were introduced into an infectious FCV cDNA clone in order to evaluate the functional importance of ORF3 and its encoded protein, VP2. Deletion of the entire ORF3 sequence was lethal for the virus, and evidence was found for strong selective pressure to produce the VP2 protein. Extended deletions in the 5′ end and small deletions in the 3′ end of ORF3, as well as the introduction of stop codons into the ORF3 sequence, were tolerated by the viral replication machinery, but infectious virus could not be recovered. Infectious virus particles could be rescued from a full-length FCV cDNA clone encoding a nonfunctional VP2 when VP2 was provided in
trans
from a eukaryotic expression plasmid. Our data indicate that VP2, a protein apparently unique to the caliciviruses, is essential for productive replication that results in the synthesis and maturation of infectious virions and that the ORF3 nucleotide sequence itself overlaps a
cis
-acting RNA signal at the genomic 3′ end.
Antigenic Domain 1 Is Required for Oligomerization of Human Cytomegalovirus Glycoprotein B
Authors: Britt William J. , Jarvis Michael A. , Drummond Derek D. , Mach Michael 
Published: March 2005

ABSTRACT
Human cytomegalovirus (HCMV) glycoprotein B (gB) is an abundant virion envelope protein that has been shown to be essential for the infectivity of HCMV. HCMV gB is also one of the most immunogenic virus-encoded proteins, and a significant fraction of virus neutralizing antibodies are directed at gB. A linear domain of gB designated AD-1 (antigenic domain 1) represents a dominant antibody binding site on this protein. AD-1 from clinical isolates of HCMV exhibits little sequence variation, suggesting that AD-1 plays an essential role in gB structure or function. We investigated this possibility by examining the role of AD-1 in early steps of gB synthesis. Our results from studies using eukaryotic cells indicated that amino acid (aa) 635 of the gB sequence represented the carboxyl-terminal limit of this domain and that deletion of aa 560 to 640 of the gB sequence resulted in loss of AD-1 expression. AD-1 was shown to be required for oligomerization of gB. Mutation of cysteine at either position 573 or 610 in AD-1 resulted in loss of its reactivity with AD-1-specific monoclonal antibodies and gB oligomerization. Infectious virus could not be recovered from HCMV bacterial artificial chromosomes following introduction of these mutations into the HCMV genome, suggesting that AD-1 was an essential structural domain required for gB function in the replicative cycle of HCMV. Sequence alignment of AD-1 with homologous regions of gBs from other herpesviruses demonstrated significant relatedness, raising the possibility that this domain may contribute to multimerization of gBs in other herpesviruses.
Acid-Resistant Bovine Pestivirus Requires Activation for pH-Triggered Fusion during Entry
Authors: Krey Thomas , Thiel Heinz-Jürgen , Rümenapf Till 
Published: March 2005

ABSTRACT

The route of internalization of the pestivirus bovine viral diarrhea virus (BVDV) was studied by using different chemical and biophysical inhibitors of endocytosis. Expression of the dominant-negative mutant Dyn
K44A
of the GTPase dynamin in MDBK cells, as well as the treatment of the cells with chlorpromazine and β-methyl-cyclodextrin inhibited BVDV entry. BVDV infection was also abolished by potassium (K
+
) depletion, hyperosmolarity, and different inhibitors of endosomal acidification. We conclude that BVDV likely enters the cell by clathrin-dependent endocytosis and that acidification initiates fusion with the endosomal membrane. Further studies revealed that BVDV was unable to undergo “fusion from without” at low pH. The finding that low pH is not sufficient to force adsorbed BVDV into fusion with the plasma membrane is compatible with the remarkable resistance of pestiviruses to inactivation by low pH. The importance of the abundant intra- and intermolecular disulfide bonds in BVDV glycoproteins for virus stability was studied by the use of reducing agents. The combination of dithiothreitol and acidic pH led to partial inactivation of BVDV and allowed fusion from without at low efficiency. Evidence is provided here that acid-resistant BVDV is destabilized during endocytosis to become fusogenic at an endosomal acidic pH. We suggest that destabilization of the virion occurs by breakage of disulfide bonds in the glycoproteins by an unknown mechanism.
Critical Role of Epstein-Barr Virus (EBV)-Encoded RNA in Efficient EBV-Induced B-Lymphocyte Growth Transformation
Authors: Yajima Misako , Kanda Teru , Takada Kenzo 
Published: March 2005

ABSTRACT
It was demonstrated that Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) were nonessential for B-lymphocyte growth transformation. We revisited this issue by producing a large quantity of EBER-deleted EBV by using an Akata cell system. Although the EBER-deleted virus efficiently infected B lymphocytes, its 50% transforming dose was approximately 100-fold less than that of the EBER-positive EBV. We then engineered the genome of EBER-deleted virus and generated a recombinant virus with the EBER genes reconstituted at their native locus. The resultant EBER-reconstituted EBV exhibited restored transforming ability. In addition, lymphoblastoid cell lines established with the EBER-deleted EBV grew significantly more slowly than those established with wild-type or EBER-reconstituted EBV, and the difference between the growth rates was especially highlighted when the cells were plated at low cell densities. These results clearly demonstrate that EBERs significantly contribute to the efficient growth transformation of B lymphocytes by enhancing the growth potential of transformed lymphocytes.
Consequences of Immunodominant Epitope Deletion for Minor Influenza Virus-Specific CD8+-T-Cell Responses
Authors: Andreansky Samita S. , Stambas John , Thomas Paul G. , Xie Weidong , Webby Richard J. , Doherty Peter C. 
Published: March 2005

ABSTRACTThe extent to which CD8+T cells specific for other antigens expand to compensate for the mutational loss of the prominent DbNP366and DbPA224epitopes has been investigated using H1N1 and H3N2 influenza A viruses modified by reverse genetics. Significantly increased numbers of CD8+KbPB1703+, CD8+KbNS2114+, and CD8+DbPB1-F262+T cells were found in the spleen and in the inflammatory population recovered by bronchoalveolar lavage from mice that were first given the −NP−PA H1N1 virus intraperitoneally and then challenged intranasally with the homologous H3N2 virus. The effect was less consistent when this prime-boost protocol was reversed. Also, though the quality of the response measured by cytokine staining showed some evidence of modification when these minor CD8+-T-cell populations were forced to play a more prominent part, the effects were relatively small and no consistent pattern emerged. The magnitude of the enhanced clonal expansion following secondary challenge suggested that the prime-boost with the −NP−PA viruses gave a response overall that was little different in magnitude from that following comparable exposure to the unmanipulated viruses. This was indeed shown to be the case when the total response was measured by ELISPOT analysis with virus-infected cells as stimulators. More surprisingly, the same effect was seen following primary challenge, though individual analysis of the CD8+KbPB1703+, CD8+KbNS2114+, and CD8+DbPB1-F262+sets gave no indication of compensatory expansion. A possible explanation is that novel, as yet undetected epitopes emerge following primary exposure to the −NP−PA deletion viruses. These findings have implications for both natural infections and vaccines.
Variants of Human Immunodeficiency Virus Type 1 That Efficiently Use CCR5 Lacking the Tyrosine-Sulfated Amino Terminus Have Adaptive Mutations in gp120, Including Loss of a Functional N-Glycan
Authors: Platt Emily J. , Shea Danielle M. , Rose Patrick P. , Kabat David 
Published: March 2005

ABSTRACT

By selecting the R5 human immunodeficiency virus type 1 (HIV-1) strain JR-CSF for efficient use of a CCR5 coreceptor with a badly damaged amino terminus [i.e., CCR5(Y14N)], we previously isolated variants that weakly utilize CCR5(Δ18), a low-affinity mutant lacking the normal tyrosine sulfate-containing amino-terminal region of the coreceptor. These previously isolated HIV-1
JR-CSF
variants contained adaptive mutations situated exclusively in the V3 loop of their gp120 envelope glycoproteins. We now have weaned the virus from all dependency on the CCR5 amino terminus by performing additional selections with HeLa-CD4 cells that express only a low concentration of CCR5(Δ18). The adapted variants had additional mutations in their V3 loops, as well as one in the V2 stem (S193N) and four alternative mutations in the V4 loop that eliminated the same N-linked oligosaccharide from position N403. Assays using pseudotyped viruses suggested that these new gp120 mutations all made strong contributions to use of CCR5(Δ18) by accelerating a rate-limiting CCR5-dependent conformational change in gp41 rather than by increasing viral affinity for this damaged coreceptor. Consistent with this interpretation, loss of the V4 N-glycan at position N403 also enhanced HIV-1 use of a different low-affinity CCR5 coreceptor with a mutation in extracellular loop 2 (ECL2) [i.e., CCR5(G163R)], whereas the double mutant CCR5(Δ18,G163R) was inactive. We conclude that loss of the N-glycan at position N403 helps to convert the HIV-1 envelope into a hair-trigger form that no longer requires strong interactions with both the CCR5 amino terminus and ECL2 but efficiently uses either site alone. These results demonstrate a novel functional role for a gp120 N-linked oligosaccharide and a high degree of adaptability in coreceptor usage by HIV-1.
Effects of Foot-and-Mouth Disease Virus Nonstructural Proteins on the Structure and Function of the Early Secretory Pathway: 2BC but Not 3A Blocks Endoplasmic Reticulum-to-Golgi Transport
Authors: Moffat Katy , Howell Gareth , Knox Caroline , Belsham Graham J. , Monaghan Paul , Ryan Martin D. , Wileman Thomas 
Published: March 2005

ABSTRACT
Infection of cells by picornaviruses leads to the generation of intracellular membrane vesicles. The expression of poliovirus (PV) 3A protein causes swelling of the endoplasmic reticulum (ER) and inhibition of protein trafficking between the ER and the Golgi apparatus. Here, we report that the nonstructural proteins of a second picornavirus, foot-and-mouth disease virus (FMDV), also perturb the secretory pathway. FMDV proteins 3A, 2B, 2C, and 2BC expressed alone in cells were recovered from crude membrane fractions, indicating membrane association. Immunofluorescence microscopy showed that 3A was located in a reticular structure and 2B was located in the ER, while 2C was located in both the ER and the bright punctate structures within the Golgi apparatus. 2BC gave punctate cytoplasmic staining and also caused accumulation of ER proteins in large vesicular structures located around the nuclei. The effect of the FMDV proteins on the trafficking of the vesicular stomatitis virus glycoprotein (G protein) from the ER to the cell surface was determined. Unlike its PV counterpart, the 3A protein of FMDV did not prevent trafficking of the G protein to the cell surface. Instead, surface expression of the G protein was blocked by 2BC, with retention of the G protein in a modified ER compartment staining for 2BC. The results suggest that the nonstructural proteins of different picornaviruses may vary in their ability to perturb the secretory pathway. Since FMDV 2BC can block the delivery of proteins to the cell surface, it may, as shown for PV 3A, play a role in immune evasion and contribute to the persistent infections observed in ruminants.