bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrate, a signal relieving seed dormancy in Arabidopsis
Authors: ALBORESI A. , GESTIN C. , LEYDECKER M.‐T. , BEDU M. , MEYER C. , TRUONG H.‐N. 
Published: March 2005

ABSTRACTNitrate is an important nitrogen source for plants, but also a signal molecule that controls various aspects of plant development. In the present study the role of nitrate on seed dormancy in Arabidopsis was investigated. The effects of either mutations affecting the Arabidopsis nitrate reductase genes or of different nitrate regimes of mother plants on the dormancy of the seeds produced were analysed. Altogether, data show that conditions favouring nitrate accumulation in mother plants and in seeds lead to a lower dormancy of seeds with little other morphological or biochemical differences. Analysis of germination during seed development indicated that nitrate does not prevent the onset of dormancy but rather its maintenance. The effect of an exogenous supply of nitrate on seed germination was tested: nitrate in contrast to glutamine or potassium chloride clearly stimulated the germination of dormant seeds. Data show, moreover, that the Arabidopsis dual affinity nitrate transporter NRT1.1 (CHL1) may be involved in conveying the nitrate signal into seeds. Thus, nitrate provided exogenously or by mother plants to the produced seeds, acts as a signal molecule favouring germination in Arabidopsis. This signalling may involve interaction with the abscisic acid or gibberellin pathway.
Colostrum management in calves: effects of drenching vs. bottle feeding
Authors: Kaske M. , Werner A. , Schuberth H.‐J. , Rehage J. , Kehler W. 
Published: March 2005

SummaryThe objective was to examine whether the administration of colostrum by a drencher is a safe method to achieve satisfying immunoglobulin concentrations in newborn Holstein Friesian (HF)‐calves. Twenty‐one calves were fed 1 h postnatum with 2 l colostrum from their dam using a nipple bottle (group I); 15 calves were drenched with 4 l colostrum from their dam 1 h postnatum (group II). Thereafter, all calves were fed milk replacer exclusively. Serum concentration of total immunoglobulin [analysed by Sandwich‐enzyme‐linked immunosorbent assay (ELISA)] 24 h postnatum was higher in drenched calves (25.2 g/l; 12.8/52.2; median and 10/90 percentiles) compared with bottle‐fed calves (14.1 g/l; 9.2/24.7). To characterize the kinetics of immunoglobulin absorption, 17 blood samples were taken frequently within 72 h postnatum using a jugular catheter in five calves fed 2 l colostrum by nipple bottle and five calves drenched with 4 l colostrum 1 h postnatum. A slightly delayed increase of serum immunoglobulin concentration (approximately 3 h) was obvious in drenched calves compared with bottle‐fed calves, but drenched calves reached significantly higher immunoglobulin concentrations compared with bottle‐fed calves. It is concluded that the proper application of colostrum by a drencher is a useful method for adequate colostral supply in newborn calves. The failure of the oesophageal groove reflex in drenched calves caused no clinical consequences.
Comparison of feed preference and digestion of three different commercial diets for cats and ferrets
Authors: Fekete S. Gy. , Fodor K. , Proháczik A. , Andrásofszky E. 
Published: March 2005

SummaryDiet preference and digestibility experiments were conducted using a total of 10 cats and 10 ferrets. The composition of the three different kinds of dry cat feed was as follows (each data are given in dry matter, DM): (i) normal diet (N): 95.3% DM, 33.7% crude protein (CP), 20.4% ether extract (EE), 37.6% nitrogen‐free extract (NFE); (ii) ‘light diet’ (L): 94.2% DM, 31.6% CP, 10.7% EE, 52.2% NFE; (iii) ‘veterinary diet’ (D): 94.57% DM, 38.7% CP, 9.6% EE, 47.2% NFE. During the period of the preference test, the average daily dry matter intake (calculated with the mean of the three diets: 94.7% DM) was 98.0, 15.0 and 16.7 g DM in cats and 25.0, 7.3 and 8.1 g DM in ferrets. The preference rates of the three different diets, expressed in percentage of their total consumption, were as follows: 60.4% N (54.4 g DM), 12.4% L (12.1 g DM) and 27.2% D (26.6 g DM) in cats, and 46.2% N (11.6 g DM), 29.9% L (7.5 g DM) and 23.9% D (6.0 g DM) in ferrets. This indicates that cats and ferrets have a clear preference for diets of higher fat content. In all three diets, the digestibility of CP was significantly (p < 0.05) lower (70.1 ± 5.4 vs. 75.9 ± 5.8) while that of EE was significantly (p < 0.05) higher (95.6 ± 1.5 vs. 89.4 ± 5.3) in ferrets than in cats. The average digestible/metabolizable energy (DE/ME) ratio of feeds turned to be 95.6% for cats and 90.6% for the ferrets. From the data one can conclude that the ferret cannot be used as a model animal for cats either for preference or digestibility studies.
Dioxin residues in the edible tissue of finishing pigs after dioxin feeding
Authors: Spitaler M. , Iben C. , Tausch H. 
Published: March 2005

SummaryThe aim of this study was to determine the contamination of finishing pigs with polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) after feeding either uncontaminated feed or feed contaminated with 0.75, 2 or 4 ng/kg toxic equivalents (TEQ; calculated by multiplying individual congener concentrations by congener‐specific toxicity equivalency factors). The feed was mixed with pure substances of PCDD/Fs to get the intended contamination. Five groups of six piglets each were fed contaminated feed, one group of five piglets served as control. One group was fed contaminated feed (4 ng TEQ/kg) only for the rearing period (6 weeks), and another group for the first 8 weeks of the fattening period (4 ng TEQ/kg feed). The other groups received the contaminated feed during the 12‐weeks fattening period. After slaughtering, the edible parts of the belly, loin and fore‐end were collected and homogenized. The samples of group 2 and 4a were investigated uncooked as well as roasted. Fattening yield and feed conversion (kg feed/kg weight gain) of the animals of all groups were in the normal range (final weight 109.7 kg; feed conversion 2.55–2.69 kg). The PCDD/F‐content in 1 kg fat of the belly, loin and fore‐end in relation to the intake was between 0.016 (4 ng TEQ/kg feed for a 6‐weeks rearing period) and 1.39% (fore‐end; 2 ng TEQ/kg feed for 12‐weeks fattening period). There was a decrease in dioxin residues after a 12‐weeks period but not after a 4‐weeks period of feeding an uncontaminated feed. When feed contaminated with 0.75, 2 and 4 ng TEQ/kg was given for a 12‐weeks fattening period, the residue concentrations of PCDD/F‐TEQ in 1 kg belly was 0.455, 1.07 and 1.55 ng, in 1 kg fore‐end 0.04 ng, 0.32 ng and 0.34 ng and in 1 kg loin 0.015 ng, 0.07 ng and 0.30 ng respectively. Roasting had no influence on the dioxin‐residues. The residues per g belly fat exceed the maximum limits for dioxin in food of 0.6 pg WHO‐PCDD/F‐TEQ/g fat (EC Recommendations 2002/201/EC), when feed containing 0.75 ng PCDD/F‐TEQ/kg is given for 12 weeks. When feed containing 0.4 ng TEQ (maximum content; EC recommendations 2002/201/EC) is given for 12 weeks, approximately 0.55 pg TEQ/g fat can be expected in the food. This value is within the action level of 0.6 pg/g fat of porks. In conclusion, the results of the study allow prediction of dioxin residues in the edible tissue of pork, if the feed contamination is known and the amount of feed intake can be estimated.
Comparison of the nutrient analysis and caloric density of 30 commercial seed mixtures (in toto and dehulled) with 27 commercial diets for parrots
Authors: Werquin G. J. D. L. , De Cock K. J. S. , Ghysels P. G. C. 
Published: March 2005

SummaryIn this paper, an overview is given of the composition of 30 commercially available parrot seed mixtures. As parrots dehull the seeds, the analysis of the total seed mixture tends to differ from that of the ingested feed. Statistical evaluation and comparison of the dehulled seeds vs. the whole seeds indicates that most parrot species are fed a diet rich in fat (31.7 ± 13.1% crude fat) and energy (22.4 ± 2.9 MJ ME/kg). As the analysis of the total seed mixtures underestimates fat and energy content of the ingested feed, it is suggested that researchers, bird nutritionists and bird food producers should calculate diets based on the analysis of the dehulled seeds. Finally, the calculated data were compared with the composition of formulated pelleted/extruded diets on the market. These data indicate that the energy density of most diets (15.6 ± 1.4 MJ ME/kg) is far below the energy density of common seed mixtures.
Studies on digestive physiology and feed digestibilities in captive Indian rhinoceros (Rhinoceros unicornis)
Authors: Clauss M. , Polster C. , Kienzle E. , Wiesner H. , Baumgartner K. , Von Houwald F. , Ortmann S. , Streich W. J. , Dierenfeld E.S. 
Published: March 2005

SummaryWe performed intake, digestibility and ingesta passage studies in 11 Indian rhinoceroses (Rhinoceros unicornis) from four zoological institutions, using total faecal collection for the quantification of faecal output. The regularly fed zoo ration of roughage and concentrates (ration RC) and a roughage‐only ration (ration R) were used; the roughage source differed between the facilities and comprised grass hay, grass silage, straw and lucerne hay. Dry matter intake ranged between 0.8 and 1.3% of body weight on ration RC and 0.5–1.2% on ration R. Digestibility coefficients achieved were similar to those reported for horses on diets of comparable composition. Endogenous losses as determined by linear regression analysis were within the range reported for horses. Measurements of faecal volatile fatty acids, faecal lactate and faecal pH also showed similarity to similar measurements in horses. The mean retention times of fluids (Co‐EDTA) and particles (Cr‐mordanted fibre <2 mm) in the whole gastrointestinal tract averaged 42 and 61 h, respectively, and were the longest ever recorded in a monogastric ungulate with this marker system. The results suggest that the horse is a useful model animal for designing diets for Indian rhinoceroses. Why digestive parameters are similar between these species in spite of enormous differences in body weight and retention times remains to be answered.
Influence of phytase added to a vegetarian diet on bone metabolism in pregnant and lactating sows
Authors: Liesegang A. , Loch L. , Bürgi E. , Risteli J. 
Published: March 2005

SummaryThe purpose of the study was to find out if the supplementation of phytase to a diet of gestating and lactating sows has any effects on performance and bone parameters of the animals. Forty primiparous gilts were assigned into four groups: group A with phytase [4.2 g total phosphorus (P)/kg (gestation) and 4.5 g total P/kg (lactation)], group B without phytase (with phytase supplementation in diet for rearing) and same P content as group A, group C without phytase and higher P contents [5.0 g total P/kg (gestation) and 5.5 g total P/kg (lactation)] and group D with the same diet as group B (no phytase during the rearing). A 6‐phytase was used in this trial (750 FTU/kg diet). The four diets were fed during gestation and lactation. Faeces were collected to determine apparent digestibility of minerals. Blood samples were taken to analyse minerals and bone markers. After weaning the sows were slaughtered and the bones of one hind leg were prepared to measure bone mineral density (BMD) and bone mineral content (BMC) of the tibia. Bone ash and mineral content of the phalanx III were determined. Mean P concentrations in serum decreased during gestation and lactation. But there were no significant differences between the groups. Bone formation marker bone‐specific alkaline phosphatase decreased at the beginning of lactation whereas bone resorption marker serum crosslaps increased. The BMD and BMC of the tibia were slightly higher in the groups fed higher concentrations of P and phytase. The ash and mineral contents of the phalanx were the highest for the group fed the highest concentration of P. The apparent digestibility of P increased during gestation mostly in group A (57%→ 69%). In conclusion, high P content and addition of phytase to the diet induced a slightly higher ash content of the bones. It is of high importance, that sows during gestation absorb enough P, to avoid lamenesses and sudden fractures. As not many studies with phytase have been performed during gestation and lactation in sows yet, we can recommend, that phytase as supplement can be used to keep P in the diet at a lower level without negative consequences for bone health.
Effects of a supranutritional dose of selenate compared with selenite on insulin sensitivity in type II diabetic dbdb mice
Authors: Müller A. S. , Most E. , Pallauf J. 
Published: March 2005

SummaryThe present study was performed to examine the mechanism by which selenate ameliorates the insulin sensitivity in type II diabetic dbdb mice. Therefore, 21‐adult female dbdb mice were randomly assigned to three experimental groups (0Se, SeIV and SeVI) with seven animals per group. Mice of group 0Se were fed with a selenium‐deficient diet (<0.02 mg Se/kg) based on wheat and torula yeast for 8 weeks whereas the mice of groups SeIV (selenite) and SeVI (selenate) were fed with sodium selenite and sodium selenate (up to 35% of the LD50 for mice in eighth week), in addition to the diet by daily tube feeding. Eight weeks of selenate application led to significantly elevated insulin sensitivity in comparison with selenium deficiency and selenite application. The activity of cytosolic protein tyrosine phosphatases (PTPs) as important negative regulators of insulin signalling was reduced from 53.8% to 22.5% in the liver and skeletal muscle of selenate‐treated mice in comparison with the selenium deficient and selenite‐treated controls, suggesting an inhibition of PTPs by intermediary selenate metabolites. In an additional in vitro inhibition study, selenate (oxidation state +VI) did not inhibit PTP activity. Selenium metabolites in the oxidation state +IV were found to be the actual inhibitors of PTP activity. In conclusion, the results of the present study show that one possible mechanism by which supranutritional selenate doses enhance insulin sensitivity in type II diabetic dbdb mice is based on the inhibition of PTPS as negative regulators of insulin signalling. Moreover the cellular metabolism of selenate including its intermediary reduction to the oxidation state +IV seems to play a crucial role during this process.
Characterization of Rhizoctonia solani AG 4HG‐III Causing Stem Canker and Wirestem on Green Amaranth and Chinese Amaranth
Authors: Yang G. H. , Chen H. R. , Naito S. , Ogoshi A. 
Published: March 2005

AbstractDuring December 2003, stem canker and wirestem were observed on the stems of green amaranth (Amaranthus viridis) and Chinese amaranth (Amaranthus tricolor) in greenhouses at Ximao district in Yunnnan Province, China. Isolates of Rhizoctonia solani obtained from the two amaranths with stem canker and wirestem, were identical to anastomosis group (AG)‐4. The isolates from diseased plant showed high virulence on young seedlings of two amaranths. Results of sequence analysis of 5.8s rDNA‐ITS of Chinese isolates showed 99–100% sequence similarity with AG‐4HG‐III tester isolates. When compared with other subgroups of AG‐4, Chinese isolates showed similarity levels of 94%. This is the first report of stem canker and wirestem of Green amaranth and Chinese amaranth caused by AG‐4HG‐III and AG‐4HG‐III in China.
The Politics of Violent Opposition in Collapsing States
Authors: Reno William 
Published: March 2005

AbstractIn violent conflicts in places like Congo, Liberia and Sierra Leone, economic interests have crowded out ideologically articulate mass-based social movements for reform or revolutionary change to a degree that was not apparent during earlier anti-colonial struggles. Some scholars offer a ‘looting model’ of rebellion that explains the predations of politicians and warlords but it is not clear why people who receive few benefits from this – or even suffer great harm from them – fail to support ideologues instead, or why self-interested violent entrepreneurs do not offer political programmes to attract more followers. Yet some groups defy this ‘looting model’. Explaining why armed groups vary so greatly in their behaviour provides a means to address important questions: is it possible to construct public authorities out of collapsed states in the twenty-first century, or do local predations and global conditions preclude indigenous state-building in these places? Why do social movements for reform there seem so ineffective? What conditions have to be present for them to succeed? This article considers the nature of rebellion in failing states, focusing on Nigeria to find clues to explain variations in the organization of armed groups.
Cloning and sequencing of Indian water buffalo interleukin‐18 cDNA
Authors: Chaudhury P. , Bera B. C. 
Published: March 2005

SummaryFull‐length cDNA (582 bp) of the interleukin‐18 (IL‐18) gene of the Indian water buffalo (Bubalus bubalis) was amplified by reverse transcriptase–polymerase chain reaction (RT‐PCR) and sequenced. The deduced amino acid sequence has 99% and 95% similarity with the IL‐18 sequences of cattle and sheep, respectively. There are two amino acid substitutions at positions 132 and 182 in buffalo IL‐18 compared with that of cattle. Phylogenetic analysis showed that the IL‐18 sequence of fish forms a different lineage and is most divergent from that of cattle, buffalo, sheep, pig, dog, horse, human, monkey, mouse, rat and chicken.
Analysis of Human Immunodeficiency Virus Cytopathicity by Using a New Method for Quantitating Viral Dynamics in Cell Culture
Authors: Speirs Christina , van Nimwegen Erik , Bolton Diane , Zavolan Mihaela , Duvall Melody , Angleman Sara , Siegel Richard , Perelson Alan S. , Lenardo Michael J. 
Published: March 2005

ABSTRACT

Human immunodeficiency virus (HIV) causes complex metabolic changes in infected CD4
+
T cells that lead to cell cycle arrest and cell death by necrosis. To study the viral functions responsible for deleterious effects on the host cell, we quantitated the course of HIV type 1 infection in tissue cultures by using flow cytometry for a virally encoded marker protein, heat-stable antigen (HSA). We found that HSA appeared on the surface of the target cells in two phases: passive acquisition due to association and fusion of virions with target cells, followed by active protein expression from transcription of the integrated provirus. The latter event was necessary for decreased target cell viability. We developed a general mathematical model of viral dynamics in vitro in terms of three effective time-dependent rates: those of cell proliferation, infection, and death. Using this model we show that the predominant contribution to the depletion of viable target cells results from direct cell death rather than cell cycle blockade. This allows us to derive accurate bounds on the time-dependent death rates of infected cells. We infer that the death rate of HIV-infected cells is 80 times greater than that of uninfected cells and that the elimination of the vpr protein reduces the death rate by half. Our approach provides a general method for estimating time-dependent death rates that can be applied to study the dynamics of other viruses.
Human Immunodeficiency Virus Type 1 Nef Potently Induces Apoptosis in Primary Human Brain Microvascular Endothelial Cells via the Activation of Caspases
Authors: Acheampong Edward A. , Parveen Zahida , Muthoga Lois W. , Kalayeh Mehrnush , Mukhtar Muhammad , Pomerantz Roger J. 
Published: March 2005

ABSTRACT
The lentiviral protein Nef plays a major role in the pathogenesis of human immunodeficiency virus type I (HIV-1) infection. Although the exact mechanisms of its actions are not fully understood, Nef has been shown to be essential for the maintenance of high-titer viral replication and disease pathogenesis in in vivo models of simian immunodeficiency virus infection of monkeys. Nef has also been suggested to play a pivotal role in the depletion of T cells by promoting apoptosis in bystander cells. In this context, we investigated the ability of extracellular and endogenously expressed HIV-1 Nef to induce apoptosis in primary human brain microvascular endothelial cells (MVECs). Human brain MVECs were exposed to baculovirus-expressed HIV-1 Nef protein, an HIV-1-based vector expressing Nef, spleen necrosis virus (SNV)-Nef virus (i.e., SNV vector expressing HIV-1 Nef as a transgene), and the HIV-1 strain ADA and its Nef deletion mutant, ADAΔNef. We observed that ADA Nef, the HIV-1 vector expressing Nef, and SNV-Nef were able to induce apoptosis in a dose-dependent manner. The mutant virus with a deletion in Nef was able to induce apoptosis in MVECs to modest levels, but the effects were not as pronounced as with the wild-type HIV-1 strain, ADA, the HIV-1-based vector expressing Nef, or SNV-Nef viruses. We also demonstrated that relatively high concentrations of exogenous HIV-1 Nef protein were able to induce apoptosis in MVECs. Gene microarray analyses showed increases in the expression of several specific proapoptotic genes. Western blot analyses revealed that the various caspases involved with Nef-induced apoptosis are processed into cleavage products, which occur only during programmed cell death. The results of this study demonstrate that Nef likely contributes to the neuroinvasion and neuropathogenesis of HIV-1, through its effects on select cellular processes, including various apoptotic cascades.
Roles of the Ras-MEK-Mitogen-Activated Protein Kinase and Phosphatidylinositol 3-Kinase-Akt-mTOR Pathways in Jaagsiekte Sheep Retrovirus-Induced Transformation of Rodent Fibroblast and Epithelial Cell Lines
Authors: Maeda Naoyoshi , Fu Wuxia , Ortin Aurora , de las Heras Marcelo , Fan Hung 
Published: March 2005

ABSTRACT
Jaagsiekte sheep retrovirus (JSRV) is the causative agent of ovine pulmonary adenocarcinoma (OPA), a transmissible lung cancer of sheep. The virus can induce tumors rapidly, and we previously found that the JSRV envelope protein (Env) functions as an oncogene, because it can transform mammalian and avian fibroblast cell lines. (N. Maeda, Proc. Natl. Acad. Sci. USA 98:4449-4454, 2001). The molecular mechanisms of JSRV Env transformation are of considerable interest. Several reports suggested that the phosphatidylinositol 3-kinase/Akt pathway is important for transformation of mammalian fibroblasts but not for chicken fibroblasts. In this study, we found that Akt/mTOR is involved in JSRV transformation of mouse NIH 3T3 fibroblasts, because treatment with the mTOR inhibitor rapamycin reduced transformation. We also found that H/N-Ras inhibitor FTI-277 and MEK1/2 inhibitors PD98059 and U0126 strongly inhibited JSRV transformation of NIH 3T3 fibroblasts, suggesting that the H/N-Ras-MEK-mitogen-activated protein kinase (MAPK) p44/42 pathway is necessary for the transformation. In RK3E epithelial cells, the MEK1/2 inhibitors also eliminated transformation, but FTI-277 only partially inhibited transformation. It was noteworthy that p38 MAPK inhibitors enhanced JSRV transformation in both fibroblasts and epithelial cells. Treatment of transformed cells with p38 inhibitors both increased levels of phospho-MEK1/2 and phospho-p44/42 and induced rapid enhancement of the transformed phenotype. Immunohistochemical staining of tumor tissues from naturally and experimentally induced OPA and naturally occurring enzootic nasal adenocarcinoma revealed strong activation of MAPK p44/42 in all cases examined. However, p38 activation was not generally observed. These results indicate that signaling through two pathways (in particular, H/N-Ras-MEK-MAPK and, to a lesser extent, Akt-mTOR) is important for JSRV-induced transformation and that p38 MAPK has a negative regulatory effect on transformation, perhaps via MEK1/2 and p44/42.