bluuebunny/crossref_metadata_2025 huggingface dataset:
Paucity of somaclonal variation from immature embryo culture of barley
Authors: Luckett DJ , Rose D , Knights E
Published: November 2004

Intact immature embryos of barley (cv. Golden Promise) and component tissues (the scutellum and embryonic axis) were cultured to produce callus. Regenerant plants were obtained from this callus and SC2 families raised. These families were examined in a field trial to search for somaclonal variation. No obvious variants were found confirming our previous unpublished results. The lack of somaclonal variation generated by barley tissue culture (which is in contrast to other species) was not a result of the tissue origin of the regeneration event.
Physiological responses of wheat (Triticum aestivum) to infection with Mycosphaerella graminicola causing Septoria tritici blotch
Authors: Cornish PS , Cornish PS , Baker GR , Baker GR , Murray GM , Murray GM
Published: November 2004

Glasshouse and field experiments examined the physiological responses of wheat to infection with Mycosphaerella graminicola (anamorph Septoria tritici) with the main aim of elucidating the possible effect of a translocated toxin on plant water relations. It is concluded that infection with M. graminicola reduces water use and growth in well-watered, well-managed crops only if leaf area index is reduced below the value required for full interception of solar radiation. Where this occurs after anthesis, the lower rate of assimilation may be compensated by translocation of assimilates from stem to the grain and possibly by greater green leaf area duration. There was no evidence for effects of a translocated toxin on the measured parameters of plant water relations. The loss in yield in the field experiment is much less than in earlier studies with cvv. Robin and Heron and highlights the need for crop loss assessment in a wider range of years and with modern cultivars which are generally more resistant to M. graminicola than either Robin or Heron.
Dietary calcium and phosphorus repletion of lambs
Authors: Ternouth JH , Sevilla CC
Published: November 2004

Three-month-old Corridale lambs, confined in metabolism crates, were repleted with calcium or phosphorus or both Ca and P for 6 weeks (repletion diets HL, LH, HH, respectively, Ca 5.0 and P 3.7 g/kg) after being offered a low Ca and P (Ca 1.25 and P 0.66 g/kg) roughage-based diet (LL) for 12 weeks. At the end of the experiment, the Ca and P kinetics of the lambs was studied using a combination of balance studies and isotope techniques. The depletion diet substantially reduced the plasma P concentrations, DM intake and digestibility, liveweight gain, and Ca and P content of the bones. During repletion, lambs fed on the HL, LH and HH diets consumed minus16, 28 and 46% more DM than the lambs on the LL diet. The liveweight gains were 15.5, minus17.8, 41.1 and 134.5 g/day for lambs given diets LL, HL, LH and HH, respectively, during the repletion period. During the 6-week repletion period, there was complete remineralization of the rib bones of lambs fed on diet HH, but only partial remineralization of the metatarsal bones. The results indicated the need to feed supplementary Ca as well as P during dietary mineral repletion. The DM digestibilities of the lambs fed on the LL depletion diet did not improve during repletion. There were strong correlations between DM intake and plasma inorganic P, muscle P or exchangeable P pool, but not DM digestibility, suggesting that the reductions in feed intake with P deficiency are due to some effect on intermediary metabolism of the animal rather than on the gastrointestinal tract. When the lambs were repleted with diet HL, they had the highest Ca absorption coefficient, level of exchangeable body Ca, bone accretion of Ca and bone resorption of Ca. The LH repletion diet lambs had the highest rate and coefficient of absorption of P, but HH lambs had the highest levels of exchangeable body P, and rates of accretion and resorption of soft tissue and osseous P.
Seasonal changes in wheat-grain quality associated with high temperatures during grain filling
Authors: Blumenthal CS , Batey IL , Bekes F , Wrigley CW , Barlow EWR
Published: November 2004

Wheat plants exposed to higher than usual temperatures during ripening produced grain with weaker dough properties in glasshouse, field experiments and crop samples. In a review of Prime Hard wheat samples from 1960/61 to 1988/89, those seasons when the dough properties were particularly weak coincided with the years when the number of hours over 35�C during the grain filling period (October to December) was greatest. A five-day period of heat stress in 1988 provided an opportunity to directly investigate the effects of heat stress in the field. A weakening of dough properties was shown, for four varieties, by longer dough development times and faster breakdown in the Farinograph and also by shorter resistance to extension (at 5 cm) in the Extensograph. These (and similar changes for glasshouse grown grain) were accompanied by an increase in the proportion of gliadin (monomeric) proteins. That this increase was associated with the heat stress was shown by demonstrating increased accumulation of 14C amino acids into the gliadin fraction for heat-stressed heads in culture. These results support the hypothesis that episodes of high temperature during grain filling activate the heat shock elements of gliadin genes in wheat causing the mature grain to contain more gliadin and thus to produce weaker doughs.
Interpretation of grain quality results from wheat variety trials with reference to high temperature stress
Authors: Blumenthal CS , Bekes F , Batey IL , Wrigley CW , Moss HJ , Mares DJ , Barlow EWR
Published: November 2004

Grain quality results for variety trials extending over 27 years (3 sites and 5 varieties) were compared with the temperature profiles during the grain filling period (56 days prior to harvest) to determine the effects on quality of high temperatures (>35�C) during this period of growth. Heat stress episodes have been frequent at two (Narrabri, N.S.W., and Turretfield, S.A.) of the three sites studied; spring temperatures were more moderate at the third site, Wongan Hills, W.A. There were highly significant (P< 0.01) correlations of heat stress (as hours above 35�C, during grain filling) with protein content (positive) and with grain yields (negative) at Narrabri for all varieties. In many combinations of site and variety, heat stress correlated negatively with loaf volume, and with dough strength (as Rmax, resistance to stretching with the Extensograph). Heat stress episodes in the Narrabri (N.S.W.) region in 1981 and 1982 gave further opportunity to examine these relationships. Results showed very clearly that high temperatures late in grain filling were associated with weaker dough properties (lower Rmax) in the resulting grain. These trends may form the basis of a predictive system by which to estimate crop quality and to interpret the results of variety trials.
Adaptation of soybean (Glycine max (L.) Merrill) to the dry season of the tropics. I. Genotypic and environmental effects on phenology
Authors: Mayers JD , Lawn RJ , Byth DE
Published: November 2004

Eight soybean genotpes were sown at weekly intervals in three tropical dry season environments to examine genotypic and environmental effects on phenology. A series of simple linear models was used to test the relationships, for individual genotypes, between rate of development for the vegetative (Rf) and reproductive (Rr) phases and photoperiod and temperature. For each genotype, most (> 85%) of the variation across sites, years and sowing dates in Rf and more than half the variation in Rr could be accounted for by variation in photoperiod and/or temperature. Rf was generally negatively associted with mean maximum temperature and mean photoperiod, and positively with mean minimum temperature. Rr was generally positively associated with either mean, or mean maximum, temperature and negatively with mean photoperiod. It was concluded that variations in photothermal regime across sites, years and sowing dates within the tropical dry season are sufficiently large to induce instability in time to flowering of most present soybean cultivars. Most genotypes are also poorly adapted to the relatively long day-warm temperature conditions experienced by dry season crops during podfilling, presumably because they have been developed as summer crops. Breeding soybeans for the dry season will therefore need to place strong emphasis on photothermal effects during post-flowering as well as pre-flowering development.
Definition of infection period for field infection of scald in Victoria
Authors: Brown JS
Published: November 2004

Conditions suitable for infection of barley with Rhynchosporium secalis were determined by exposing seedlings to inoculum from scald-infected barley plants growing in the field. Maximum infection occurred when the duration of leaf surface wetness was c. 12 h and the average temperature during those periods was c. 6�C. On this basis potential infection periods were defined as periods of leaf surface wetness of >12 h duration with an average temperature of >6�C during the period. Meterological records indicated that during the 1983-89 growing seasons there was an average of 91 periods of leaf surface wetness per year at Walpeup and 104 at Horsham and that c. 20% were potential infection periods. The modal duration of leaf surface wetness category was >9-12 h at Horsham and >0-3 h at Walpeup and the modal average temperature category during periods of leaf surface wetness was >6-9�C at both locations. None of the six most commonly occurring combinations of duration and temperature during periods of leaf surface wetness met the criteria for potential infection periods defined above.
Effects of surface-applied phosphorus and superphosphate on the solution chemistry and phytotoxicity of subsurface aluminium: sand/solution and soil experiments
Authors: McLaughlin MJ , James TR
Published: November 2004

Experiments using split-root sand/solution culture and reconstituted soil profiles were undertaken to examine the influence of P supply to surface roots of subterranean clover (Trifolium subterraneum var. Woogenellup) on root penetration into Al-toxic subsurface strata. In sand/solution culture increasing P supply to surface (0-40 mm) roots enchanced root penetration into Al-toxic nutrient solutions in the subsurface (40-100 mm), but only at low to moderate concentrations of Al. At high concentrations of Al, surface P supply had no effect on root penetration into the lower compartment. Results from the soil experiments confirmed the observations obtained in sand/solution culture. Topdressed P (as single superphosphate-SSP) enhanced root penetration into the Al-toxic subsurface stratum. Plants suffering P stress showed poor root growth in the acidic subsurface stratum. Gypsum in the SSP confounded P treatment effects at high rates of P application. The gypsum quickly dissolved and was able to move through the limited surface soil (0-40 mm, pH 5. O), to the acidic subsurface stratum, as evidenced by Ca concentrations in soil solution. This raised the ionic strength and reduced the pH of the soil solution, and raised solution Al concentrations. Under conditions of limiting leaching, and where the subsurface horizon was very acidic (pH 3.9), the gypsum in SSP caused yield reductions at high rates of application and produced a quadratic yield response curve to topdressed SSP.
Increased manganese content of barley seeds can increase grain yield in manganese-deficient conditions
Authors: Longnecker NE , Marcar NE , Graham RD
Published: November 2004

Manganese (Mn) deficiency which decreases barley (Hordeurn vulgare L.) yields can be difficult to eliminate by fertilizer applications. We hypothesized that higher Mn content of barley seed could decrease the severity of Mn deficiency and thus decrease yield loss due to that deficiency. Galleon barley with different amounts of Mn in the seed (low Mn seed: 0.08-0.26 8g per seed; medium Mn seed: 0.34-0 -62 8g per seed; high Mn seed: 0-74-1.208g per seed) was grown in field, glasshouse and growth cabinet experiments. In two experiments, seeds were soaked in MnS04 and had Mn contents of approximately 50 8g per seed. High Mn seed, either obtained artificially by soaking seed in MnSO4 before sowing, or naturally from the parent plant, increased grain yield of barley grown in Mn-deficient conditions. In both -Mn and +Mn treatments, barley grown from high Mn seed had a greater grain yield than that from low Mn seed. High seed Mn increased root dry weight, Mn content of both roots and shoots, shoot dry weight, number of early tillers, plant survival and number of grains per plant, but had no effect on weight per seed. Maximum grain yield was achieved by sowing seed with a high Mn content and applying Mn fertilizer; neither treatment completely corrected Mn deficiency on its own.
Sulfonylurea herbicides applied to acidic sandy soils: a bioassay for residues and factors affecting recoveries
Authors: Blacklow WM , Blacklow WM , Pheloung PC , Pheloung PC
Published: November 2004

Chlorsulfuron and triasulfuron, applied at 15-35 g ha-1, are a challenge to analytical methods because residues are phytotoxic at concentrations of pg kg-1 soil. A bioassay based on the suppression of root growth of lentils (Lens culinaris cv. Laird) can detect a minimum concentration of 0.48g kg-1 soil. The sandy loam, 20g, is extracted with methanol and extracts are made up in 5 mM CaCl2. The extracts, 20 mL, are added to 250 g of coarse white sand in plastic cups and sown with seven pre-germinated lentil seeds. The cups are enclosed in plastic bags to prevent evaporation, and incubated for 6 days at 20�C. Herbicide concentrations are brought within the range of sensitivity of the bioassay by dilutions of the extracts. The assay was easier, and more sensitive, precise and reproducible than a direct assay of soil. Herbicides in the field were lost due to photolysis (38-49% in 8 h) and in laboratory manipulations by hydrolysis with high pH extractants, such as saturated Ca(OH)2 (pH 11.2) where the half-life was about 4 h. Hydrolysis at the pH of the sandy loam and the bioassay in coarse sand, pH 5 - 8, gave a half-life of 176 and 198 days for chlorsulfuron and triasulfuron, respectively, at 20�C; at 30�C, the corresponding half-lives were 47 and 27 days. At concentrations for 50% suppressions of lentil roots (ID50 = 0.6 8g L-1 in coarsesand), adsorption in the sandy loam, estimated by the Langmuir equation, was 76% of the total residues of both herbicides. Adsorption could account for the differences in the ID50 of lentils grown in sandy loam and coarse sand for triasulfuron, but it was overcorrected for chlorsulfuron. The herbicides should be applied as near to seeding the cereal crop as possible and should be incorporated with the seeding operation so that losses from photolysis and hydrolysis in warm acidic soils are minimized before crop protection is needed.
The effect of soil temperature, sowing depth and soil bulk density on the seedling emergence of tall fescue (Festuca arundinacea Schreb.) and white clover (Trifolium repens L.)
Authors: Charles GW , Blair GJ , Andrews AC
Published: November 2004

The effects of temperature (constant 3, 6, 9, 12 and 24�C, and an alternating 6/12�C temperature regime), sowing depth (0, 15, 30 and 45 mm), and soil bulk density (1.1 and 1.3 g cm-3) were examined on the emergence of tall fescue (Festuca arundinacea, cv. Demeter) and white clover (Trifolium repens, cv. Haifa) in a factorial experiment, in controlled temperature cabinets. Mitscherlich curves were fitted to the emergence data and treatment effects on the maximum emergence percentage (A), rate of emergence (K) and time to first emergence (To), were statistically analysed. Temperature was the major factor affecting the fescue A value. The A value was low at 3 and 6�C, but increased as temperature increased to 12�C. It was depressed by the 45 mm sowing depth and by high bulk density at 30 and 45 mm. For white clover, sowing depth had a strong effect on A. Over all temperatures, A was high for surface sowing and low for deeper sowing (30 and 45 mm). For shallow sowing (15 mm), A was intermediate and increased with rising temperature. High bulk density depressed A at 15 mm. For both species, To increased as sowing depth increased, and decreased as temperature increased. The effect of sowing depth was more apparent at low temperatures. The K value for fescue increased gradually as temperature increased, but sowing depth had no effect. For clover, K increased markedly with rises in temperature for surface sowing, with smaller increases for 15, 30 and 45 mm depths. The 6/12�C regime responses for A and To were similar to the constant 12�C, while the K response was similar to the constant 9�C; these trends were similar for fescue and clover. It was concluded that establishment failures from direct drilling tall fescue on the Northern Tablelands can be related to low soil temperatures in winter (below 9�C), and for white clover, to excessive sowing depth (greater than 15 mm), particularly on high bulk density soils.
Behavioural and physiological effects in sheep of a chronic stressor and a parasite challenge
Authors: Fell LR , Lynch JJ , Adams DB , Hinch GN , Munro RK , Davies HI
Published: November 2004

Mature Merino ewes, either at pasture (paddock) or in a feedlot situation (penned), were given a serial challenge infection with the gastric nematode parasite, Haemonchus contortus, and compared with control animals for their behaviour in an arena test, their plasma cortisol concentration and haematological and immunological status. Very low levels of infection resulted and parasitic disease was not evident. There were, however, significant effects on behaviour of both the challenge infection and the feedlot situation. The parasitic treatment resulted in a reduced distance between the sheep and the person in the arena test and also an increase in locomotor activity in the case of penned sheep. Overall, the penned animals displayed twice as much locomotor activity as paddock sheep. Mechanisms whereby a infectious challenge could affect sheep behaviour require further investigation.
The influence of sodium bicarbonate and sulfur amino acids on the performance of broilers at moderate and high temperaures
Authors: Balnave D , Oliva AG
Published: November 2004

Supplements of sodium bicarbonate (NaHCO3) added to the diet or drinking water of finishing broilers (3-6 weeks of age) improved food intake, live weight gain and food efficiency at high (30�C), but not at moderate (2l�C), temperatures. The improved performance was not related to increases in amino acid digestibilities which were reduced in birds kept at 30�C. Increased consumption of drinking water appears to be a major prerequisite for the improved performance at high temperatures. The methionine : total sulfur amino acid (TSAA) ratio of the diets also influenced broiler performance at 30�C with ratios of 0.43 and 0.55 giving superior growth and food conversion to a ratio of 0.62. The intake of drinking water and the water : food intake ratio were significantly reduced at the dietary methionine : TSAA ratio of 0.62, the effect being significant when the drinking water contained NaHCO3.
The effect of dwarfing genes in spring wheat in dry environments. II. Growth, water use and water-use efficiency
Authors: Richards RA
Published: November 2004

Near-isogenic lines of wheat for the dwarfing genes Rht1, Rht2, Rht3 and Rht1+Rht2 as well as tall (rht) lines were grown in dryland field environments over 7 years as well as in large pots outside and in a glasshouse. In the field above-ground dry weight and leaf area index up to maturity were greater in the taller wheats. In pot experiments there were no differences in relative growth rates between lines and the faster emergence of the tall wheats accounted for most of the difference in dry weight accumulation and leaf canopy development. Tall wheats also had a slightly higher carbon isotope discrimination which has been related to faster canopy growth in wheat. Water extraction by tall and dwarf wheats was similar in both 1 m long tubes and down to a depth of 1.9 m in the field. However, transpiration efficiency (above-ground dry weight/water transpired) and water-use efficiency (above-ground dry weight/evapotranspiration) declined with plant height in both glasshouse and field experiments. There was no evidence that tall wheats had a greater capacity for storage and remobilization of photosynthate in the stems than shorter wheats. The implications for crop improvement in dry regions are discussed.
Annual Medicago species in Morocco. I. Species and their abundance
Authors: Bounejmate M , Beale PE , Robson AD
Published: November 2004

An ecogeographic survey of the distribution of annual medics in Morocco was conducted in 1988 by sampling 161 sites within six agricultural zones. At each site all medic pods lying on the soil surface were collected from five quadrats placed at random. Of the 18 medic species reported to occur in Morocco, only 11 were recorded in 1988. M. polymorpha and M. truncatula were the most frequent. Thirty-five sites had no medics in quadrats and 15 sites had no medics in the near vicinity. The average seed yield for all collection sites was 12.6 kg ha-1. Nearly 60% of the sites yielded less than 20 kg ha-1. More than 50 kg seed ha-1 was recorded at less than 10% sites. Maximum seed yield at any site was only of 169 kg ha-1. Results suggest that genetic erosion is occurring but occasional sites can be found where medics are abundant.
A small-molecule switch for Golgi sulfotransferases
Authors: de Graffenried Christopher L. , Laughlin Scott T. , Kohler Jennifer J. , Bertozzi Carolyn R.
Published: November 2004

The study of glycan function is a major frontier in biology that could benefit from small molecules capable of perturbing carbohydrate structures on cells. The widespread role of sulfotransferases in modulating glycan function makes them prime targets for small-molecule modulators. Here, we report a system for conditional activation of Golgi-resident sulfotransferases using a chemical inducer of dimerization. Our approach capitalizes on two features shared by these enzymes: their requirement of Golgi localization for activity on cellular substrates and the modularity of their catalytic and localization domains. Fusion of these domains to the proteins FRB and FKBP enabled their induced assembly by the natural product rapamycin. We applied this strategy to the GlcNAc-6-sulfotransferases GlcNAc6ST-1 and GlcNAc6ST-2, which collaborate in the sulfation of
l
-selectin ligands. Both the activity and specificity of the inducible enzymes were indistinguishable from their WT counterparts. We further generated rapamycin-inducible chimeric enzymes comprising the localization domain of a sulfotransferase and the catalytic domain of a glycosyltransferase, demonstrating the generality of the system among other Golgi enzymes. The approach provides a means for studying sulfate-dependent processes in cellular systems and, potentially,
in vivo
.
Function recovery after chemobleaching (FRAC): Evidence for activity silent membrane receptors on cell surface
Authors: Sun Haiyan , Shikano Sojin , Xiong Qiaojie , Li Min
Published: November 2004

Membrane proteins represent ≈30% of the proteome of both prokaryotes and eukaryotes. Unique to cell surface receptors is their biogenesis pathway, which involves vesicular trafficking from the endoplasmic reticulum through the Golgi apparatus and to the cell surface. Increasing evidence suggests specific regulation of biogenesis for different membrane receptors, hence affecting their surface expression. We report the development of a pulse–chase assay to monitor function recovery after chemobleaching (FRAC) to probe the transit time of the Kir2.1 K
+
channel to reach the cell surface. Our results reveal that the channel activity is contributed by a small fraction of channel protein, providing evidence of activity-silent “sleeping” molecules on the cell surface. This method distinguishes molecular density from functional density, and the assay strategy is generally applicable to other membrane receptors. The ability of the reported method to access the biogenesis pathways in a high-throughput manner facilitates the identification and evaluation of molecules affecting receptor trafficking.
The molecular program induced in T cells undergoing homeostatic proliferation
Authors: Goldrath Ananda W. , Luckey C. John , Park Richard , Benoist Christophe , Mathis Diane
Published: November 2004

Naïve T cells proliferate independently of cognate antigen when introduced into lymphopenic hosts. Lymphopenia-induced proliferation depends on low-affinity MHC/self-peptide complexes and on IL-7. To elucidate the intracellular signals mediating this proliferation, we analyzed changes in gene expression in naïve CD8
+
T cells at different times after their transfer into a lymphopenic environment. The genes induced in response to lymphopenia were largely an attenuated subset of those turned up by full antigenic stimulation, including genes related to cell cycling, whereas excluding genes specifically associated with effector activity. After the initial phase of proliferation in an empty compartment, the naïve T cells adopted a stable pattern of gene expression similar to that of antigen-experienced memory cells. Thus, T cells proliferating in lymphopenic hosts do not exhibit a unique gene-expression profile, instead relying on “traditional” signals for this antigen-independent proliferation; this process ultimately results in differentiation to “authentic” memory cells.
Cdc42 Mediates Nucleus Movement and MTOC Polarization in Swiss 3T3 Fibroblasts under Mechanical Shear Stress
Authors: Lee Jerry S.H. , Chang Melissa I. , Tseng Yiider , Wirtz Denis
Published: November 2004

Nucleus movement is essential during nucleus positioning for tissue growth and development in eukaryotic cells. However, molecular regulators of nucleus movement in interphase fibroblasts have yet to be identified. Here, we report that nuclei of Swiss 3T3 fibroblasts undergo enhanced movement when subjected to shear flows. Such movement includes both rotation and translocation and is dependent on microtubule, not F-actin, structure. Through inactivation of Rho GTPases, well-known mediators of cytoskeleton reorganization, we demonstrate that Cdc42, not RhoA or Rac1, controls the extent of nucleus translocation, and more importantly, of nucleus rotation in the cytoplasm. In addition to generating nuclei movement, we find that shear flows also causes repositioning of the MTOC in the direction of flow. This behavior is also controlled by Cdc42 via the Par6/protein kinase Cζ pathway. These results are the first to establish Cdc42 as a molecular regulator of not only shear-induced MTOC polarization in Swiss 3T3 fibroblasts, but also of shear-induced microtubule-dependent nucleus movement. We propose that the movements of MTOC and nucleus are coupled chemically, because they are both regulated by Cdc42 and dependent on microtubule structure, and physically, possibly via Hook/SUN family homologues similar to those found in Caenorhabditis elegans.
Identification and Characterization of Regulator of G Protein Signaling 4 (RGS4) as a Novel Inhibitor of Tubulogenesis: RGS4 Inhibits Mitogen-activated Protein Kinases and Vascular Endothelial Growth Factor Signaling
Authors: Albig Allan R. , Schiemann William P.
Published: November 2004

Tubulogenesis by epithelial cells regulates kidney, lung, and mammary development, whereas that by endothelial cells regulates vascular development. Although functionally dissimilar, the processes necessary for tubulation by epithelial and endothelial cells are very similar. We performed microarray analysis to further our understanding of tubulogenesis and observed a robust induction of regulator of G protein signaling 4 (RGS4) mRNA expression solely in tubulating cells, thereby implicating RGS4 as a potential regulator of tubulogenesis. Accordingly, RGS4 overexpression delayed and altered lung epithelial cell tubulation by selectively inhibiting G protein-mediated p38 MAPK activation, and, consequently, by reducing epithelial cell proliferation, migration, and expression of vascular endothelial growth factor (VEGF). The tubulogenic defects imparted by RGS4 in epithelial cells, including its reduction in VEGF expression, were rescued by overexpression of constitutively active MKK6, an activator of p38 MAPK. Similarly, RGS4 overexpression abrogated endothelial cell angiogenic sprouting by inhibiting their synthesis of DNA and invasion through synthetic basement membranes. We further show that RGS4 expression antagonized VEGF stimulation of DNA synthesis and extracellular signal-regulated kinase (ERK)1/ERK2 and p38 MAPK activation as well as ERK1/ERK2 activation stimulated by endothelin-1 and angiotensin II. RGS4 had no effect on the phosphorylation of Smad1 and Smad2 by bone morphogenic protein-7 and transforming growth factor-β, respectively, indicating that RGS4 selectively inhibits G protein and VEGF signaling in endothelial cells. Finally, we found that RGS4 reduced endothelial cell response to VEGF by decreasing VEGF receptor-2 (KDR) expression. We therefore propose RGS4 as a novel antagonist of epithelial and endothelial cell tubulogenesis that selectively antagonizes intracellular signaling by G proteins and VEGF, thereby inhibiting cell proliferation, migration, and invasion, and VEGF and KDR expression.
Hec1 and Nuf2 Are Core Components of the Kinetochore Outer Plate Essential for Organizing Microtubule Attachment Sites
Authors: DeLuca Jennifer G. , Dong Yimin , Hergert Polla , Strauss Joshua , Hickey Jennifer M. , Salmon E. D. , McEwen Bruce F.
Published: November 2004

A major goal in the study of vertebrate mitosis is to identify proteins that create the kinetochore-microtubule attachment site. Attachment sites within the kinetochore outer plate generate microtubule dependent forces for chromosome movement and regulate spindle checkpoint protein assembly at the kinetochore. The Ndc80 complex, comprised of Ndc80 (Hec1), Nuf2, Spc24, and Spc25, is essential for metaphase chromosome alignment and anaphase chromosome segregation. It has also been suggested to have roles in kinetochore microtubule formation, production of kinetochore tension, and the spindle checkpoint. Here we show that Nuf2 and Hec1 localize throughout the outer plate, and not the corona, of the vertebrate kinetochore. They are part of a stable “core” region whose assembly dynamics are distinct from other outer domain spindle checkpoint and motor proteins. Furthermore, Nuf2 and Hec1 are required for formation and/or maintenance of the outer plate structure itself. Fluorescence light microscopy, live cell imaging, and electron microscopy provide quantitative data demonstrating that Nuf2 and Hec1 are essential for normal kinetochore microtubule attachment. Our results indicate that Nuf2 and Hec1 are required for organization of stable microtubule plus-end binding sites in the outer plate that are needed for the sustained poleward forces required for biorientation at kinetochores.
The maturation‐dependent production of interleukin‐16 is impaired in monocyte‐derived dendritic cells from atopic dermatitis patients but is restored by inflammatory cytokines TNF‐α and IL‐1β
Authors: Reich Kristian , Hugo Sabine , Middel Peter , Blaschke Volker , Heine Andrea , Neumann Christine
Published: November 2004

Background:  Maturation of dendritic cells (DCs) influences important DC functions such as production of cytokines. Recently, DCs were identified as a source of interleukin‐16 (IL‐16), a chemotactic factor for DCs themselves, CD4+ T cells, and eosinophils. There is evidence that DC‐derived IL‐16 may contribute to the pathogenesis of atopic dermatitis (AD).

Objective:  To investigate the production of IL‐16 during differentiation of monocytes into DCs in healthy individuals and patients with AD.

Methods:  IL‐16 production was investigated by quantitative real‐time RT‐PCR, intracellular cytokine staining, immunoblotting, and ELISA.

Results:  DCs generated from peripheral monocytes by 5‐day culture in the presence of IL‐4 and granulocyte/macrophage colony‐stimulating factor acquired the capability to synthesize, store, and secrete IL‐16. Storage and release of IL‐16 was further enhanced during final DC maturation induced by additional 3‐day culture with tumor necrosis factor‐α (TNF‐α) and monocyte‐conditioned medium. Maturation, as determined by up‐regulation of CD83 and CD86 surface expression, and production of IL‐16, but not production of IL‐10 and IL‐12p40 was impaired in day 8 DCs derived from AD patients compared to those from healthy donors. Stimulation of day 8 DCs from AD patients with TNF‐α and IL‐1β enhanced the expression of CD83 and CD86 and restored the production of IL‐16.

Conclusions:  Signals involved in the activation and maturation of DCs enhance their capacity to produce IL‐16. Functional abnormalities present in patients with AD at the monocyte level may account for impaired maturation and IL‐16 production of monocyte‐derived DCs.
Pimecrolimus – an anti‐inflammatory drug targeting the skin
Authors: Grassberger M. , Steinhoff M. , Schneider D. , Luger T. A.
Published: November 2004

Abstract:  Pimecrolimus is the most recent member of calcineurin inhibitors available for the therapy for inflammatory skin diseases. It targets T‐cells and mast cells and inhibits the production and release of cytokines and other inflammatory mediators, as well as the expression of signals essential for the activation of inflammatory T‐lymphocytes. Pimecrolimus has a cell‐selective mode of action. In contrast to corticosteroids, it does not affect, e.g., Langerhans'cells/dendritic cells (LC/DC), as demonstrated in vitro with human monocyte‐derived DC and in vivo with epidermal LC in mice, nor human primary fibroblasts. As shown in vitro with human skin and by comparison of clinical pharmacokinetic data from patients with atopic dermatitis, pimecrolimus permeates less through skin than tacrolimus and much less than corticosteroids. It, thus, has a lower potential for transcutaneous resorption after topical administration, resulting in a lower risk of systemic effects. Pimecrolimus has high anti‐inflammatory activity in animal models of skin inflammation, including a model reflecting neurogenic inflammation, but a more favourable balance of anti‐inflammatory vs. immunosuppressive activity than tacrolimus. Pimecrolimus does not affect sensitization in a murine model of allergic contact dermatitis and has a lower potency in various models of immunosuppression after systemic administration, compared to tacrolimus. In conclusion, the results of preclinical studies show that pimecrolimus has a selective pharmacological profile, suited for effective and safe treatment for inflammatory skin diseases.
Firm investment in transition
Authors: Rizov Marian
Published: November 2004

In this paper a model based on the Euler equation of optimal capital accumulation in the presence of convex adjustment costs is developed and estimated. The theoretical model explicitly allows for differential financial status across firms. The empirical analysis uses Romanian manufacturing firm panel data to estimate dynamic investment models with the generalized method of moments (GMM‐IV) technique and tests the derived hypotheses. The results indicate that the model based on the perfect market assumptions is rejected. The version of the model that allows for differential financial status of firms by using a theoretically derived sample selection rule is not rejected by the data. Controlling for soft budget constraints, common for transition economies, further improves the performance of the model.
Effective doses of vecuronium in a patient with myotonic dystrophy*
Authors: Nishi M. , Itoh H. , Tsubokawa T. , Taniguchi T. , Yamamoto K.
Published: November 2004

Of the forms of muscular dystrophy, myotonic dystrophy has the greatest systemic involvement. Although most patients with myotonic dystrophy show normal sensitivity to non‐depolarising neuromuscular blocking drugs, some have been reported to show greatly increased sensitivity to these drugs, and little is known about the sensitivity of different muscles. We compared effective doses of vecuronium in a patient with myotonic dystrophy at the orbicularis oculi, adductor pollicis and flexor hallucis brevis muscles during total intravenous anaesthesia. The calculated ED50 for the orbicularis oculi (7.77 μg.kg−1 (95% CI 3.10–16.8 μg.kg−1)) was lower than for the adductor pollicis (25.3 μg.kg−1 (95% CI 20.7–43.3 μg.kg−1)) and flexor hallucis brevis muscles (29.5 μg.kg−1 (95% CI 11.0–85.6 μg.kg−1; p < 0.01)). The ED90 was also lower for the orbicularis oculi (35.7 μg.kg−1 (95% CI 14.8–66.5 μg.kg−1)) than for the other muscles (51.8 μg.kg−1 (95% CI 29.3–145.0 μg.kg−1) and 50.6 μg.kg−1 (95% CI 5.29–642.0 μg.kg−1), respectively) (p < 0.01)).
Severe lactic acidosis following alcohol related generalised seizures
Authors: Hulme J. , Sherwood N.
Published: November 2004

A 45‐year‐old alcoholic man presented following several short grand‐mal seizures. He was not known to be epileptic. Initial investigations demonstrated a severe lactic acidosis. The rise in lactate was one of the highest levels reported in similar patients. The patient recovered within 4 h of management with oxygen, fluids and sodium bicarbonate. Lactic acidosis following convulsions is often associated with spontaneous resolution and a favourable outcome.
Pharmacokinetics of sevoflurane uptake into the brain
Authors: Turner M. J. , McCulloch T. J. , Kennedy R. R. , Baker A. B.
Published: November 2004

Two recent studies have examined the pharmacokinetics of sevoflurane in adults. Lu et al.(Pharmacokinetics of sevoflurane uptake into the brain and body, Anaesthesia 2003; 58: 951–6) observed that jugular bulb sevoflurane concentration initially rose unexpectedly rapidly and then approached arterial concentrations unexpectedly slowly, suggesting that a blood–brain diffusion barrier exists. They also observed a large alveolar‐arterial sevoflurane gradient, suggesting that an alveolar–arterial diffusion barrier exists. Nakamura et al. (Predicted sevoflurane partial pressure in the brain with an uptake and distribution model: Comparison with the measured value in internal jugular vein blood. Journal of Clinical Monitoring and Computing 1999; 15: 299–305) found no diffusion barriers. We used a computer model to analyse both data sets and show that the observations of Lu et al. can be explained by contamination of jugular samples with extracerebral blood. It is possible that the alveolar‐arterial gradients observed by Lu et al. are due to discrepancies in conversions between blood concentrations and gas partial pressures. Our study suggests that there is no blood–brain diffusion barrier for sevoflurane and that the data of Lu et al. must be interpreted with caution.
Characterization of T‐regulatory cells, induced by immature dendritic cells, which inhibit enteroantigen‐reactive colitis‐inducing T‐cell responses in vitro and in vivo
Authors: Gad Monika , Kristensen Nanna N. , Kury Evelyn , Claesson Mogens H.
Published: November 2004

Regulatory T (Treg) cells, derived from co‐cultures of unfractionated CD4+ T cells and immature dendritic cells (DC), suppress enteroantigen‐induced proliferation of CD4+ CD25− T cells. The DC‐induced Treg cells are a mixture of CD25+ (10–20%) and CD25− (80–90%) T cells. However, all the suppressor activity in vitro and in vivo resides in the CD25+ T‐cell subset. The CD25+ DC‐induced Treg cells can inhibit enteroantigen‐induced proliferation in vitro through a transwell membrane, and their function does not appear to depend on previous activation. DC‐induced CD25+ Treg cells display a naïve phenotype, expressing high levels of CD45RB and l‐selectin (CD62L). In addition, the DC‐induced Treg cells mediate a stronger suppressive activity than prototype CD25+ regulatory T cells. The DC‐induced Treg cells, and hereof purified CD25+ and CD25− T‐cell fractions, were co‐injected into severe combined immunodeficiency (SCID) mice with colitis‐inducing CD4+ CD25− T cells. Both unfractionated CD4+ and purified CD25+ Treg cells fully protected the recipients against the development of colitis. In contrast, co‐transfer of fractionated CD25− T cells offered no protection against disease development. Enterobacterial antigen‐exposed CD4+ T cells of the protected mice secreted higher levels of interleukin‐10 and lower levels of interferon‐γ than the unprotected mice. The present data demonstrate DC‐induced CD4+ CD25+ Treg cells, which phenotypically and functionally differ from the generally accepted prototype of CD25+ Treg cells. These data may initiate new procedures for the expansion of Treg cells for clinical use.
Site‐specific regulation of tissue dendritic cell function by granulocyte–macrophage colony‐stimulating‐factor
Authors: Lees Joanne , Boam David , Proungvitaya Tanakorn , Wood Peter J.
Published: November 2004

Tissue dendritic cells (DC) are usually associated with phagocytic function but poor T‐cell immunostimulatory capacity. Following activation, dendritic cells are stimulated to leave tissue sites and migrate to lymphoid tissue, acquiring immunostimulatory capacity during the process. We provide evidence that the immunostimulatory capacity of tissue DC, but not spleen cells, can be affected in situ by granulocyte–macrophage colony‐stimulating‐factor (GM‐CSF). Initially it was found that islet cells from non‐obese diabetic and BALB/c mice, which produce GM‐CSF, showed significantly higher immunostimulatory capacity than islets from C3H and C57BL/6 mice, which do not produce GM‐CSF. Second, pretreatment of nonobese diabetic mice with anti‐GM‐CSF antibody significantly reduced the immunostimulatory capacity of islet cells, but not spleen cells, although it had no effect on the numbers of cells expressing DC‐associated antigens. Therefore the immunostimulatory function of islet DC is partially dependent on GM‐CSF. By contrast, spleen DC immunostimulatory function does not show the same dependence on GM‐CSF. This may affect the ability of dendritic cells to stimulate autoimmune responses or tolerance.
Assessment of a contrast medium as an adjunct to endodontic radiography
Authors: Bedford J. M. , Martin D. M. , Youngson C. C.
Published: November 2004

Aim  To assess if a contrast medium improved diagnostic yield of endodontic radiographs.

Methodology  Forty‐five extracted mandibular premolar teeth were radiographed in bucco‐lingual and mesio‐distal planes. Access cavities were prepared, pulpal tissue extirpated and Ultravist® contrast medium introduced under pressure. Radiographs were retaken and the teeth cleared following perfusion with India ink. Three examiners assessed all the films for: number of roots, number of root canals, curvature of root and/or root canal, presence of lateral canals, presence of a single foramen or apical delta and the presence or absence of canal obstructions. The examiners’ interpretations were compared with the anatomy revealed by clearing.

Results  Kappa scores were calculated for each of the examiners, for each set of radiographs, to assess the level of intra‐ and inter‐examiner agreement. Only moderate agreement was found throughout (κ = 0.40–0.61). For multiple root canals a false‐positive result was significantly more likely with contrast (P < 0.05). The use of contrast did not significantly improve the sensitivity of diagnosis of lateral canals or a single apical foramen. Contrast significantly increased the risk of falsely perceiving lateral canals (P < 0.002). Overall there was no statistically significant difference in the overall assessment of the anatomy of the root canals using contrast or plain radiographs (P > 0.2).

Conclusions  Plain film radiographs confidently predict the presence of root or canal curvature but apical anatomy was assessed accurately in only 46% of cases. Plain radiographs were insensitive in assessing the number of root canals present, the presence of lateral canals and the occurrence of canal obstructions. The use of Ultravist® contrast medium to improve diagnosis of root canal morphology of premolars is not supported.
Role of cytosolic free calcium in the reorientation of pollen tube growth
Authors: Malhó Rui , Read Nick D. , Pais M. Salomé , Trewavas Anthony J.
Published: November 2004

Growing pollen tubes of Agapanthus umbellatus exhibited a tip‐to‐base gradient in cytosolic free calcium ([Ca2+]c). Although this gradient is believed to be involved in pollen tube growth, its role in specifying reorientation is unknown. The direction of pollen tube growth could be modified by iontophoretic micro‐injection, electrical fields (EFs) or photolysis of caged Ca2+. Iontophoretic injection resulted in a temporary cessation of growth, an increase in [Ca2+]c and, upon recovery, reoriented growth. Weak EFs also elevated [Ca2+]c, reduced growth rates and resulted in the reorientation of pollen tubes towards the cathode. Treatment with very low concentrations of the Ca2+‐channel blocker lanthanum chloride, prior to exposure to an EF, inhibited both the increase in [Ca2+]c and reorientation whilst only slightly affecting growth rates. The responses of growth inhibition and reorientation were mimicked when [Ca2+]c was artificially elevated by photoactivating caged Ca2+ (Nitr‐5). Our data suggest that [Ca2+]c is part of a transduction mechanism which enables growing pollen tubes to successfully reorient to directional signals in the style and thus accomplish eventual fertilization of the egg.
Purification, characterization, and cDNA sequence of glucose‐6‐phosphate dehydrogenase from potato (Solatium tuberosum L.)
Authors: Graeve Kerstin , von Schaewen Antje , Scheibe Renate
Published: November 2004

Glucose‐6‐phosphate dehydrogenase (G6PDH, E.C. 1.1.1.49) has been purified from potato tuber at least 850‐fold to apparent homogeneity as judged by SDS‐PAGE. The enzyme was characterized by Km values of 260 μM for glucose‐6‐phosphate and 6 μM for NADP and a broad pH optimum between phi 7.5 and 9. NADPH, GTP, ATP, acetyl CoA and CoA inhibited G6PDH activity. Dithiothreitol (DTT) did not inactivate the enzyme. A highly specific antiserum was produced in a rabbit and used for immunodetection of G6PDH in Western blots.

A cDNA library from potato leaves was screened with DNA probes produced by the polymerase chain reaction (PCR) in the presence of g6pdh‐specific primers. A full‐length cDNA clone was analyzed and the derived amino acid sequence compared with known G6PDH sequences from various sources. The homology of the plant sequence with G6PDH sequences from animals and yeast was found to be rather high (52%), whereas there was significantly lower homology with sequences of bacterial origin (37%). The lack of a plastidic signal sequence as well as the insensitivity of the recombinant enzyme towards reduced DTT, support the view that the cDNA sequence of a redox‐independent cytosolic isoform was obtained.