bluuebunny/crossref_metadata_2025_split huggingface dataset:
PROPERTIES OF PHOSPHOENOLPYRUVATE CARBOXYKINASE FROM ASCOPHYLLUM NODOSUM (PHAEOPHYCEAE)1
Authors: Kerby Nigel W. , Evans Leonard V. 
Published: November 2004

ABSTRACTPhosphoenolpyruvate carboxykinase was purified to electrophoretic homogeneity from the brown alga. Ascophyllum nodosum (L.) le Jol. Its molecular mass was 60 kDa as determined by gel filtration. The pH optimum of the carboxylating reaction was 7.9 and the apparent Km for PEP4, ADP and HCO3‐ were 0.036, 0.0116 and 50 mol · m‐3, respectively. Rates of light and dark carbon fixation are also reported for A. nodosum apices and it is shown that rates of in vitro PEPCK activity would account for the observed rate of dark fixation. The physiological role of PEPCK is discussed in relation to light‐independent carbon fixation.
HETEROMORPHIC LIFE‐HISTORY STRATEGIES IN THE BROWN ALGA SCYTOSIPHON LOMENTARIA (LYNGB.) LINK1
Authors: Littler Mark M. , Littler Diane S. 
Published: November 2004

ABSTRACTThe adaptive significance of a life‐history strategy, expressed as divergent morphological forms, was examined for the heteromorphic alga Scytosiphon lomentaria. Successional studies were performed by physically clearing mature, temporally‐constant intertidal communities on San Clemente I., California. At week six, after clearing, complanate thalli dominated the successional plots (mean cover = 23.5%) and began to decline as the cylindrical form became abundant. The latter attained its peak cover (82.3%) at week 13, whereupon it too began a precipitous reduction. The crustose ralfsioid form appeared surprisingly early (4–13 wks) in trace amounts but did not achieve its greatest cover (85.0%) until week 43. The ranking from high to low primary productivity (cylindrical form = 8.1 mg C · g dry. wt‐1·h‐1, complanate form = 6.5 mg, crustose form = 0.5 mg) corresponded closely with the data for photosynthetic vs. structural components (cylindrical = 92.3% pigmented, complanate = 65.3%, crustose = 32.0%). This finding indicates that selection in the crust form, which is more readily accessible to epilithic grazers, has tended to increase allocation of materials to nonpigmented structural tissue at the expense of photosynthetic tissue and reduced production rates. The results for thallus losses to urchin grazing over 48 h were complanate form = 82.7% lost, cylindrical = 81.4% and crustose = 16.2%, which correlates with the calorific contents of the three forms (i.e. complanate = 4.97 kcal · ash‐free g dry wt.‐1, cylindrical = 4.46 kcal and crustose = 3.55 kcal). The crustose form had tougher thalli (26 g · mm‐2 to penetrate thallus) than either the complanate form (12 g) or the cylindrical form (15 g). It is likely that opposing selective factors have resulted in the evolutionary divergences observed in algae with heteromorphic life histories. Previous work may have overemphasized the selective role of grazing because the crustose form is also adapted to withstand physical forces (sand‐scouring, burial and wave‐shearing) or as an overwintering stage under physiologically stressful conditions.
THE BOTTOM‐ICE MICROALGAL COMMUNITY FROM ANNUAL ICE IN THE INSHORE WATERS OF EAST ANTARCTICA1
Authors: McConville Malcolm J. , Wetherbee Richard 
Published: November 2004

ABSTRACTThe structure, productivity and heterotrophic potential of an extensive microalgal community growing on the underside of sea ice near the Australian Antarctic Station of Casey, are described. Underwater observations made near the Australian Antarctic stations of Davis and Mawson are also reported. This community develops during September, is largely suspended from the bottom surface of annual sea ice and often extends into the underlying water column as conspicuous strands up to 15 cm long. The algal community structure in the strands is dominated by an unidentified tube diatom belonging to the Amphipleura/Berkeleya group and chains of a species of Entomoneis cf. Amphiprora paludosa var. hyperborea (Grunow) Cleve. Unlike previously described bottom ice environments, a brash ice layer under the hard sea ice is absent. Living cells, predominantly Nitzschia frigida Grunow, also occur in microbrine channels in the bottom 3 cm of the ice. Maximal primary production rates of 81 μg C · L‐1· h‐1 occurred during November, then began declining near the end of December. Minimal rates (2.8 μg C · L‐1· h‐1) were reached in mid‐January and coincided with changes in the physical structure of the sea ice and in the stability of the water column. An abundant epibacterial community associated with the microalgal strands assimilated 3H‐labelled amino acids suggesting significant heterotrophic recycling of dissolved organic matter. Turnover times of assimilated amino acids in the bottom ice community averaged 55 h during November while negligible turnover of these substrates occurred in the water column 1.5 m below the ice. These bottom ice communities have higher primary productivity than typical brash ice communities; they are also accessible to marine herbivores and so may be more important to the Antarctic marine food chain than previously supposed.
THE GENUS ACTINOCYCLUS (BACILLARIOPHYCEAE): FRUSTULE MORPHOLOGY OF A. SAGITTULUS SP. NOV. AND TWO RELATED SPECIES1
Authors: Villareal Tracy A. , Fryxell Greta A. 
Published: November 2004

ABSTRACT Actinocyclus octonarius var. tenellus (Bréb.) Hendey, A. actinochilus (Ehr.) Simonsen and A. sagittulus sp. nov. were examined by light and scanning electron microscopy from field samples and/or culture material. Consistent cingulum patterns of a wide valvocopula and one narrow pleura were found. In A. actinochilus, a small third band was found filling the opening of the pleura and is probably present in the other two taxa. The observed variability of the pseudonodulus, especially in A. actinochilus but also in other members of the genus, was confirmed and our results support the literature definition of Actinocyclus as having: 1) a marginal ring of large labiate processes, laterally expanded internally, 2) no external tubes, 3) essentially radial areolation arranged in fascicles, 4) external cribrum, internal foramen, and 5) a pseudonodulus usually present, but may be absent or difficult to detect on individual valves. On the basis of the present study another characteristic should be added; 6) hyaline bands with a wide valvocopula and at least one pleura. This characteristic appears to extend throughout the family Hemidiscaceae, suggesting a close relationship to those Coscinodiscus species with a single marginal row of large labiate processes and zero or one central labiate processes. In addition, Actinocyclus has been noted to have a thin valve overhang extending outside the valvocopula for as much as one‐third of its width.
Can competition explain local rarity of a nettle aphid?
Authors: Kean John M. , Müller Christine B. 
Published: November 2004

Abstract.  1. Previous studies have shown that two aphid species, Microlophium carnosum and Aphis urticata on stinging nettle (Urtica dioica) show very different abundance patterns.2. Theory suggests that the local rarity of A. urticata in Silwood Park, U.K., might be explained by competitive exclusion by the more common species, mediated indirectly through natural enemies. Experimental aphid colonies on potted nettles were used to test for effects of M. carnosum on A. urticata in the field.3. Though there was some evidence that natural enemies aggregated on the aphid colonies, no population‐level effects of competition from M. carnosum on A. urticata could be detected. No evidence was found for competition being a major factor causing the local rarity of A. urticata.
Persistence and regression of hearing in the exclusively diurnal moths, Trichodezia albovittata (Geometridae) and Lycomorpha pholus (Arctiidae)
Authors: Muma Katherine E. , Fullard James H. 
Published: November 2004

Abstract.  1. Auditory sensitivities and ultrasound avoidance behaviour of two exclusively diurnal moths were examined to test the prediction that total isolation from the predatory effects of echolocating bats will result in the regression of these sensory systems and/or the defences they evoke.2. The silent geometrid, Trichodezia albovittata, possessed large ears with auditory neural thresholds similar to or better than those of a sympatric, exclusively nocturnal geometrid moth. Trichodezia albovittata readily responded with evasive flight to ultrasound and it is suggested that if this moth has become completely isolated from bats its ears are functionally vestigial, at least in the population studied here.3. In contrast, while the sound‐producing arctiid, Lycomorpha pholus, had low auditory sensitivity based on neural thresholds, it still responded with flight changes to ultrasound. It did not, however, produce sounds when stimulated ultrasonically. It is suggested that the ears of this moth are functionally vestigial for bat‐detection purposes but may be used for short‐distance social communication.
Prescribing for osteoporosis following the use of inhaled and oral glucocorticoids in general practice
Authors: Williams David , Bennett Kathleen , Feely John 
Published: November 2004

Aims  Systemic absorption from inhaled glucocorticoids may lead to bone loss. We determined the extent to which their use alone and in addition to short courses of oral glucocorticoids was associated with increased prescribing for osteoporosis in a large general practice population.Methods  In a cohort study with follow‐up of co‐prescribing of antiosteoporotic drug therapy in the Irish national prescribing database (1.1 million people over 16 years), we identified 32 081 patients who received inhaled glucocorticoids alone during a 12‐month period (following an identical lead‐in period). We determined the odds ratio (OR), adjusting for age and gender for the co‐prescription of bisphosphonates or other antiosteoporotic therapy with inhaled glucocorticoids by logistic regression.Results  The adjusted OR (95% confidence interval) for co‐prescribing of bisphosphonates and all inhaled glucocorticoids was 1.87 (1.71, 2.04); 1.58 (1.41, 1.78) for inhaled beclomethasone, 2.11 (1.75, 2.54) for inhaled budesonide and 3.29 (2.65, 4.1) for inhaled fluticasone. The ORs were significantly increased when patients who also received oral glucocorticoids were included and greater still in those under 45 years: 14.03 (10.6, 18.6). The results remained significant when the effects of comorbidity were adjusted for. The odds of receiving bisphosphonate therapy increased linearly with increasing exposure to inhaled glucocorticoids during the study period.Conclusions  Treatment with inhaled glucocorticoids in general practice is associated with an increased risk of co‐prescribing for antiosteoporotic therapy in a potency‐ and a dose‐related manner. Exposure to a course of oral glucocorticoids doubles this risk. These results suggest that the systemic effects on bone mineral density from using inhaled glucocorticoids may be clinically relevant but may also reflect prescribers’ concerns for the development of osteoporosis in these patients.
Operational nitrogen fertilizer management in dairy farming systems: identification of criteria and derivation of fertilizer application rates
Authors: Vellinga Th. V. , André G. , Schils R. L. M. , Oenema O. 
Published: November 2004

AbstractFertilizer‐nitrogen (N) management is a decisive factor in grass‐based, intensive dairy farming, as it strongly influences economic and environmental performance but little attention has been paid to providing guidance on N‐fertilizer management at an operational level to meet these criteria of performance. Essential criteria in operational N‐fertilizer management were identified as target dry matter (DM) yield of herbage, growth period per cut, herbage N concentration, N use efficiency (NUE), amounts of unrecovered N and marginal N response. Statistical relationships between fertilizer‐N application rates per cut and these criteria were derived from field experiments. These relationships were then used to explore the effects of the criteria on optimum fertilizer‐N applications.Optimum fertilizer‐N rates depended strongly on target levels for NUE, amounts of unrecovered N, growth period and DM yield of herbage. Calculations showed that target DM yield of herbage and growth period per cut are essential in estimating the effect of applied N on marginal N response, NUE and amounts of unrecovered N. The derived relationships can be used to explore the effects of changes in target levels of the criteria on optimum fertilizer‐N applications. The study showed that operational fertilizer‐N management set constraints to the decisions made at strategic and tactical management levels and vice versa.
Nodulation and root growth of forage legumes sown into tall fescue swards
Authors: Staley T. E. , Belesky D. P. 
Published: November 2004

AbstractEstablishing forage legumes into endophyte‐infected tall fescue (Festuca arundinacaeSchreb.) pastures is problematic, especially in well‐established stands. A oversowing field experiment determined if this problem was because of poor nodulation. Four renovation techniques, clipped sward (treatment A), herbicided + rye seeding in the previous autumn (treatment B), herbicided in the autumn and spring (treatment C) and herbicided to suppress the sward (treatment D), were investigated to determine their effect on nodulation and root growth of lucerne (Medicago sativaL.), red clover (Trifolium pratenseL.) and white clover (T. repensL.) at 16, 22 and 29 d after sowing the legumes. A pot experiment was also conducted under optimal growth conditions and using the same soil to determine the nodulation and root growth potentials of these legume species. At adequate rhizobial populations (>6 × 104 cfu g−1soil), substantial nodulation of all species occurred by 29 d after sowing in treatments C and D, whereas nodulation of clovers was usually reduced in treatment A. Total root lengths for all sampling dates, species and treatments were severely restricted, especially under treatment A. A general correspondence of nodulation with root growth was observed for all species, with high correlations (r ≥ 0·85) between these variables for all legume species and treatments, suggesting that soil moisture, and possibly competition for light, were the limiting factors. These results demonstrate that weak stands of forage legumes, typically found when sown into tall fescue swards, are probably not because of inadequate nodulation. Rather, inhibition of root growth by detrimental physical/chemical conditions or allocation of limited photosynthate to shoots instead of roots is suggested.
Genetic mapping of dominant white (W), a homozygous lethal condition in the horse (Equus caballus)
Authors: Mau C. , Poncet P. A. , Bucher B. , Stranzinger G. , Rieder S. 
Published: November 2004

SummaryDominant white coat colour (W) is a depigmentation syndrome, known in miscellaneous species. When homozygous in the horse (similar in mice), the mutation responsible for the white phenotype is lethal in a very early stage of gestation. It seems, that the action of the dominant white allele is not always fully penetrant, resulting occasionally in spotted look alike offspring. These horses resemble a coat colour pattern known as sabino spotting. So far, it is not known whether dominant white (W) and sabino spotting (S) share a common genetic background. In this study, a pedigree consisting of 87 horses segregating for dominant white (W) was used to genetically localize the horse (W)‐locus. Microsatellite ASB23 was found linked to (W), which allowed us to map dominant white to a region on horse chromosome 3q22. Tyrosine kinase receptor (KIT) was previously mapped to this same chromosome region (3q21–22). KIT and its ligand (KITLG) are responsible for the normal function of melanogenesis, haematopoiesis and gametogenesis. So far, sequence analysis of different KIT gene fragments did not lead to new polymorphisms, except for a SNP detected in KIT intron 3 (KITSNPIn3). Additional microsatellites from ECA3q (TKY353 and LEX7), together with KITSNPIn3 allowed us to state more precisely the (W)‐mutation. The positional results and comparative functional data strongly suggest that KIT encodes for the horse (W)‐locus.
Studies of the Ala/Val98 polymorphism of the hepatocyte nuclear factor‐1α gene and the relationship to β‐cell function during an OGTT in glucose‐tolerant women with and without previous gestational diabetes mellitus
Authors: Lauenborg J. , Damm P. , Ek J. , Glümer C. , Jørgensen T. , Borch‐Johnsen K. , Vestergaard H. , Hornnes P. , Pedersen O. , Hansen T. 
Published: November 2004

AbstractAims  In pregnancies complicated by gestational diabetes mellitus (GDM) an increased demand for insulin is not met due to β‐cell dysfunction. An Ala/Val polymorphism at codon 98 of the hepatocyte nuclear factor‐1α (HNF‐1α) gene has been associated with decreased serum insulin and C‐peptide responses during an oral glucose tolerance test (OGTT) in glucose‐tolerant subjects. The aims of the present study were to evaluate the influence of the polymorphism on the serum insulin and C‐peptide responses to an OGTT in glucose‐tolerant women with and without previous GDM and to investigate if this polymorphism is associated with GDM.Methods  The Ala/Val98 polymorphism was measured in 376 women of Danish origin with previous GDM, and in 724 age‐matched and 310 middle‐aged glucose tolerant women using polymerase chain reaction‐restriction fragment length polymorphism.Results  The allelic frequency of the Ala/Val98 polymorphism was 0.043 [95% confidence interval (CI) 0.028, 0.057] in women with previous GDM vs. 0.037 (95% CI 0.028, 0.047) in age‐matched and 0.039 (95% CI 0.024, 0.054) in middle‐age women. Among 117 glucose‐tolerant women with previous GDM, 10 carriers of the Ala/Val98 polymorphism had a non‐significant 27% and 22% reduction in serum C‐peptide and insulin levels, respectively, at 30 min during an OGTT. Seventy‐eight control subjects carrying the Ala/Val98 polymorphism had a 10% (P = 0.001) and 16% (P = 0.004) reduction in serum C‐peptide and insulin levels, respectively, compared with 956 Ala/Ala control subjects.Conclusions  The Ala/Val polymorphism at codon98 of HNF‐1α is not associated with GDM in Danish women. However, the codon 98 variant is associated with a significant impairment of serum insulin and C‐peptide responses during an OGTT in glucose‐tolerant women without previous GDM.
Erythromelia, or Mitchell's syndrome – new names for unexplained signs of inflammation in distal symmetrical neuropathy in diabetes
Authors: Jeffcoate W. J. , Idris I. , Game F. L. 
Published: November 2004

AbstractBackground  Two cases are described in which distal symmetrical sensorimotor neuropathy complicating diabetes was associated with episodes of subacute vasodilation of one or other lower limb, and which were otherwise unexplained. The vasodilation was associated with swelling and stiffness, but was painless and self‐limiting.Interpretation  It is suggested that this phenomenon results from disordered vasoregulation in diabetic neuropathy, and is linked to the processes which underlie diabetic neuropathic osteoarthropathy (Charcot foot), as well as disorders such as complex regional pain syndrome‐1 (CRPS‐1, reflex sympathetic dystrophy) and erythromelalgia.Conclusions  As self‐limiting vasodilation may be not uncommon in distal symmetrical neuropathies, but unrecognized because the phenomenon has not been named, the terms ‘neuropathic erythromelia’ or ‘Mitchell's syndrome’ are proposed. The adoption of either of these names may lead to earlier diagnosis and prevent inappropriate investigation and treatment.
Oxidative stress and glucose levels in a population‐based sample
Authors: Menon V. , Ram M. , Dorn J. , Armstrong D. , Muti P. , Freudenheim J. L. , Browne R. , Schunemann H. , Trevisan M. 
Published: November 2004

AbstractObjectives  To examine the relationship between markers of oxidative status and glucose on a population basis.Study design and setting  We report here on a population‐based sample of 1315 women and 981 men, aged 35–79 years, randomly selected from residents of Erie and Niagara Counties in western New York between 1996 and 1999. Thiobarbituric reactive substances (TBARS), erythrocyte glutathione (GSH) and plasma glutathione peroxidase (GSH‐Px) were measured as markers of oxidative status. Study sample was categorized by quartiles of glucose, degree of abnormality of fasting glucose, and level of metabolic control in patients with diabetes.Results  Men and women in the uppermost quartiles of glucose had higher levels of TBARS (men: Quartile 4 = 1.55 ± 0.03, Quartile 1 = 1.36 ± 0.03, women: 1.49 ± 0.02, 1.30 ± 0.02 nmol/ml) and lower levels of GSH (men: Quartile 4 = 1.57 ± 0.03, Quartile 1 = 1.69 ± 0.03, women: 1.71 ± 0.03, 1.97 ± 0.0 mmol/l packed RBCs). In women, compared with normal fasting glucose, impaired fasting glucose was associated with higher levels of TBARS (1.29 ± 0.01 vs. 1.84 ± 0.04 nmol/ml), lower levels of GSH (1.85 ± 0.02 vs. 1.76 ± 0.05 mmol/l packed RBCs), and higher GSH‐Px activity (618.94 ± 2.64 vs. 644.77 ± 8.90 IU/l). In women, abnormal fasting glucose was associated with higher levels of TBARS (1.84 ± 0.04 nmol/ml), lower levels of GSH (1.68 ± 0.06 mmol/l packed RBCs), and higher levels of GSH‐Px (647.72 ± 9.87 IU/l) than normal or impaired fasting glucose. In men, abnormal fasting glucose was associated with higher TBARS (1.76 ± 0.04 vs. 1.37 ± 0.07 nmol/ml), and lower GSH (1.62 ± 0.05 vs. 2.78 ± 0.02 mmol/l packed RBCs), than normal fasting glucose. Poor metabolic control was associated with higher TBARS (men: 2.07 ± 0.08 vs. 1.33 ± 0.14 nmol/l, women: 2.02 ± 0.09 vs. 1.35 ± 0.18 nmol/l) and GSH‐Px activity (men: 654.34 ± 13.45 vs. 599.86 ± 24.76, women: 660.61 ± 13.25 vs. 579.42 ± 27.42 IU/l).Conclusions  Glucose levels play a role in determining oxidative status in a population sample. The balance between oxidative and antioxidant processes appears to be sensitive to glucose levels with moderate elevations of glucose affecting the oxidative status.
The cardiac cycle time effect revisited: Temporal dynamics of the central‐vagal modulation of heart rate in human reaction time tasks
Authors: Somsen Riek J. M. , Jennings J. Richard , Van der Molen Maurits W. 
Published: November 2004

Abstract Lacey and Lacey (1974) suggested that during reaction time tasks higher brain centers dynamically adjust efferent vagal nerve pulses to the sino‐atrial node of the heart, inducing phase‐dependent heart rate changes. Since then, animal and human neuro‐physiological results have provided evidence for this hypothesis. Higher subcortical and cortical brain centers may have reciprocal interactive pathways relating to autonomic control comparable to those at the level of peripheral autonomic changes and brain stem reflexes. In humans such central effects may be observed in the short latency vagal control of heart rate that has been studied mostly in reaction time (RT) tasks. RT task parameters modulate vagal pulses to the cardiac sino‐atrial node (SAN), which in turn exerts a phase‐dependent change in the ongoing cardiac interbeat interval. Simulations of human RT task effects in an animal model of heart rate change support this hypothesis. The current study examined evidence for vagal control of three human phasic heart rate responses in RT tasks. The evidence indicates that the initiation of an RT response triggers a reflexive shift from vagal activation to vagal inhibition. This shift is cardiac cycle phase dependent. Graded anticipatory cardiac deceleration during the warning interval of an RT task varies with task relevance and time uncertainty. This response may be part of a control process engaged in time keeping. Hence, temporal variables mediate the central‐autonomic‐vagal modulation of heart rate.