bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficient production of active chicken avidin using a bacterial signal peptide in Escherichia coli
Authors: HYTÖNEN Vesa P. , LAITINEN Olli H. , AIRENNE Tomi T. , KIDRON Heidi , MELTOLA Niko J. , PORKKA Eevaleena J. , HÖRHÄ Jarno , PALDANIUS Tiina , MÄÄTTÄ Juha A. E. , NORDLUND Henri R. , JOHNSON Mark S. , SALMINEN Tiina A. , AIRENNE Kari J. , YLÄ-HERTTUALA Seppo , KULOMAA Markku S. 
Published: November 2004

Chicken avidin is a highly popular tool with countless applications in the life sciences. In the present study, an efficient method for producing avidin protein in the periplasmic space of Escherichia coli in the active form is described. Avidin was produced by replacing the native signal sequence of the protein with a bacterial OmpA secretion signal. The yield after a single 2-iminobiotin–agarose affinity purification step was approx. 10 mg/l of virtually pure avidin. Purified avidin had 3.7 free biotin-binding sites per tetramer and showed the same biotin-binding affinity and thermal stability as egg-white avidin. Avidin crystallized under various conditions, which will enable X-ray crystallographic studies. Avidin produced in E. coli lacks the carbohydrate chains of chicken avidin and the absence of glycosylation should decrease the non-specific binding that avidin exhibits towards many materials [Rosebrough and Hartley (1996) J. Nucl. Med. 37, 1380–1384]. The present method provides a feasible and inexpensive alternative for the production of recombinant avidin, avidin mutants and avidin fusion proteins for novel avidin–biotin technology applications.
A novel UBA and UBX domain protein that binds polyubiquitin and VCP and is a substrate for SAPKs
Authors: McNEILL Helen , KNEBEL Axel , ARTHUR J. Simon C. , CUENDA Ana , COHEN Philip 
Published: November 2004

A widely expressed protein containing UBA (ubiquitin-associated) and UBX (ubiquitin-like) domains was identified as a substrate of SAPKs (stress-activated protein kinases). Termed SAKS1 (SAPK substrate-1), it was phosphorylated efficiently at Ser200in vitro by SAPK3/p38γ, SAPK4/p38δ and JNK (c-Jun N-terminal kinase), but weakly by SAPK2a/p38α, SAPK2b/p38β2 or ERK (extracellular-signal-regulated kinase) 2. Ser200, situated immediately N-terminal to the UBX domain, became phosphorylated in HEK-293 (human embryonic kidney) cells in response to stressors. Phosphorylation was not prevented by SB 203580 (an inhibitor of SAPK2a/p38α and SAPK2b/p38β2) and/or PD 184352 (which inhibits the activation of ERK1 and ERK2), and was similar in fibroblasts lacking both SAPK3/p38γ and SAPK4/p38δ or JNK1 and JNK2. SAKS1 bound ubiquitin tetramers and VCP (valosin-containing protein) in vitro via the UBA and UBX domains respectively. The amount of VCP in cell extracts that bound to immobilized GST (glutathione S-transferase)–SAKS1 was enhanced by elevating the level of polyubiquitinated proteins, while SAKS1 and VCP in extracts were coimmunoprecipitated with an antibody raised against S5a, a component of the 19 S proteasomal subunit that binds polyubiquitinated proteins. PNGase (peptide N-glycanase) formed a 1:1 complex with VCP and, for this reason, also bound to immobilized GST–SAKS1. We suggest that SAKS1 may be an adaptor that directs VCP to polyubiquitinated proteins, and PNGase to misfolded glycoproteins, facilitating their destruction by the proteasome.
Rofecoxib decreases renal injury in obese Zucker rats
Authors: DEY Aparajita , MARIC Christine , KAESEMEYER Wayne H. , ZAHARIS Constantine Z. , STEWART Janet , POLLOCK Jennifer S. , IMIG John D. 
Published: November 2004

The present study tested the hypothesis that altered vascular regulation of arachidonic acid enzymes in obese Zucker rats contributes to renal damage. Protein expression of CYP450 (cytochrome P450) and COX (cyclo-oxygenase) enzymes in renal microvessels was studied in obese and lean Zucker rats at 20–21 weeks of age. Body weight and blood glucose averaged 649±13 g and 142±10 mg/dl in obese Zucker rats compared with 437±10 g and 111±5 mg/dl in age-matched lean Zucker rats. Renal microvascular CYP4A and COX-2 protein levels were increased and CYP2C protein levels decreased in obese Zucker rats. TX (thromboxane) B2 excretion was 2-fold higher and PG (prostaglandin) E2 excretion significantly lower in obese Zucker rats. Additional studies investigated the ability of the COX-2 inhibitor, rofecoxib, to slow the progression of renal injury in obese Zucker rats. Rofecoxib treatment decreased urinary PGF2α and 8-isoprostane levels in obese Zucker rats. Renal microvessel mRNA expression of pro-inflammatory chemokines was decreased in COX-2-inhibitor-treated obese Zucker rats. Urinary albumin excretion, an index of kidney damage, averaged 95±11 mg/day in vehicle-treated and 9±1 mg/day in rofecoxib-treated obese Zucker rats. Glomerulosclerosis, characterized by mesangial expansion, tubulo-interstitial fibrosis and extracellular matrix accumulation, was prominent in obese Zucker rats compared with a lack of damage in age-matched lean Zucker rats and rofecoxib-treated obese Zucker rats. These results suggest that altered vascular arachidonic acid enzymes contribute to the renal damage, and that COX-2 inhibition decreases glomerular injury in obese Zucker rats.
Non-esterified fatty acids impair endothelium-dependent vasodilation in rat mesenteric resistance vessels
Authors: SAINSBURY Christopher A. R. , SATTAR Naveed , CONNELL John M. C. , HILLIER Chris , PETRIE John R. 
Published: November 2004

Elevated circulating levels of NEFAs (non-esterified fatty acids) are associated with states of insulin resistance and increased risk of vascular disease. Previous animal and human studies have demonstrated NEFA-induced endothelial dysfunction of large conduit arteries, reversible by the antioxidant ascorbic acid. We therefore investigated the effect of NEFAs on carbachol-induced endothelium-dependent vasodilation of rat resistance arteries in vitro using the technique of wire myography. In addition, we investigated the effect of co-incubation of NEFAs and ascorbic acid. Cumulative concentration–response curves to carbachol (endothelium-dependent vasodilation) and SNAP (S-nitroso-N-acetyl-DL-penicillamine; endothelium-independent vasodilation) were constructed. Those to carbachol were repeated following a 30 min incubation with either oleic acid (10−4 M) or palmitic acid (10−4 M), demonstrating significant impairment of endothelium-dependent vasodilation with both [P&lt;0.05, comparison of pD2 values (the negative log concentration of agonist required to effect a 50% response)]. A cumulative concentration–response curve to carbachol was repeated following co-incubation with palmitic acid (10−4 M) and the antioxidant ascorbic acid (10−5 M), demonstrating an abolition of the previously observed endothelial dysfunction induced by palmitic acid. There was no impairment of vasodilation to SNAP following NEFA incubation. We conclude that NEFAs directly impair endothelial function in rat resistance arteries via an increase in oxidative stress at the vascular endothelium.
A descriptive study of stress fractures in competitive event horses in the UK
Authors: Hayton Emma , Sneddon Jennifer C 
Published: November 2004

AbstractThe impact of stress fractures on competitive event horses in the UK is completely unknown. Ninety-one replies to 450 questionnaires sent to competitive event riders across the UK indicated that 11 horses, representing 12% of the responders, had a confirmed stress fracture. As data on the total number of horses owned or ridden by the riders were not available, the true prevalence of stress fractures in this sample of horses could not be directly assessed. Within the bounds of this study, competitive level of the rider had a significant effect on stress fracture prevalence (X2(0.05, df. 2) = 24.74, P<0.05), as did years of eventing experience (X2(0.05, df. 1) = 27.80, P<0.01). Training regime was also influential (X2(0.05,df. 1) = 26.30, PX20.01). There was a predominance of fractures in geldings (X2(0.05, df. 1) = 24.45, P<0.03); however, geldings constituted 82% of reported cases. Thoroughbred cross horses had a significantly lower incidence of stress fractures than Thoroughbreds (X2(0.05, df. 1) = 20.82, P<0.01) but constituted only 18% of the sample. Horses in the oldest age category (9–12 years) had 6% of all stress fractures (X2(0.05, df. 2) = 24.54, P<0.1). All fractures occurred on the foreleg at the knee or below, with no significant effect of anatomical location. Seventy-three per cent of horses were not competing when diagnosed (X2(0.05, df. 1) = 22.27, P<0.1). These data indicate that useful preliminary data were yielded by the questionnaire and that further research with a larger sample size is justified.
Genetic influence on East African running success
Authors: Scott Robert A , Moran Colin , Wilson Richard H , Goodwin Will H , Pitsiladis Yannis P 
Published: November 2004

AbstractEast African athletes now dominate international distance running events from the 800 m to the marathon. Explanations for their phenomenal success have included optimal environmental conditions for developing distance running performance, psychological advantage and advantageous physiological characteristics. It is well established that genetics plays a role in determining inter-individual differences in exercise performance and adaptation to training stimuli. It is not known, however, to what extent inter-population differences (i.e. between ‘races’ and/or ethnic groups) in exercise performance can be attributed to genetics. There have been considerations that ‘black’ athletes are genetically adapted towards performance, given the concurrent success of athletes of West African ancestry in sprint events. However, the current notion of ‘race’ is not universally accepted, and genetic differences within and between populations are not clearly delineated by geographical or ethnic categorizations. Recent findings from mitochondrial DNA show that the populations from which Ethiopian athletes are drawn have not been isolated populations and are not genetically distinct from other Ethiopians. Y-chromosome analysis of the same population shows concurrent results, although some differences are present between athletes and the general Ethiopian population, suggesting an influence of the Y chromosome on athlete status in Ethiopia. It is concluded that there may be a role for genetics in the success of East African athletes; however, any genetic component to their success is unlikely to be limited to East Africans and is more likely to be found in other populations. At present it is unjustified to implicate a role for genetics in the success of East African runners when no genes have been identified as being important to their performance.
VEGETATIVE AND REPRODUCTIVE MORPHOLOGY OF EUCHEUMA ISIFORME (SOLIERIACEAE, GIGARTINALES, RHODOPHYTA)1
Authors: Gabrielson Paul W. 
Published: November 2004

ABSTRACT Eucheuma isiforme (C. Agardh) J. Agardh exhibits a combination of vegetative and reproductive features that distinguish it from other critically studied genera in the Solieriaceae. The development of the multiaxial thallus, emphasizing the arrangement of periaxial cells around each axial file; presence of reproductive nemathecia that contain carpogonial branches and auxiliary cells; and post‐diploidization stages, including gonimoblast and pericarp initiation, stages of fusion cell formation, and carposporophyte development are described and illustrated for the first time in this species. The vegetative and reproductive features observed in E. isiforme are not diagnostic of any of the recently erected tribes in the Solieriaceae. Eucheuma appears most closely related to the Indian Ocean genus, Sarconema.
MORPHOLOGICAL VARIABILITY IN POPULATIONS OF CHRYSOPHYCEAN RESTING CYSTS. I. GENETIC (INTERCLONAL) AND ENCYSTMENT TEMPERATURE EFFECTS ON MORPHOLOGY1
Authors: Sandgren Craig D. 
Published: November 2004

ABSTRACTMany chrysophycean species produce resting cysts (statospores) with purportedly species‐specific morphology. I investigated variation in the cyst morphology of a single species that may result from genetic differences among the vegetative clones involved and from variation in the temperature of the environment during cyst development. Populations ofDinobryon cylindricumImhof cysts were produced under defined conditions in vitro and then sampled for morphological analysis based on SEM micrographs. Morphological data is presented and then used in a multivariate discriminant analysis to determine the utility of each morphological character in distinguishing the six populations studied. Results suggest that some features of cyst morphology (i.e. cyst diameter) are invariant among the populations, while other features show distinctive variation. The density of spines covering the cyst body as well as the morphology of those spines appear correlated to the specific clones involved, and thus may represent useful phenotypic genetic markers. The length and definition of both the spines and the cyst collar, on the other hand, are markedly influenced by encystment temperature. The implications of these findings for paleoecological studies is discussed.
KARYOTYPES AND REPRODUCTIVE SEASONALITY OF THE GENUS BANGIA (RHODOPHYTA) IN BRITISH COLUMBIA, CANADA1
Authors: Cole Kathleen M. , Hymes Beverly J. , Sheath Robert G. 
Published: November 2004

ABSTRACTChromosome number and morphology as well as reproductive seasonally were examined in Bangia populations collected from 88 sites along the British Columbia coasts. Sexual filaments were recorded at 35 sites and asexual filaments at 58. Four different types of Bangia were determined. These were characterized by reproductive state and chromosome number, as well as by their seasonally and range of distribution. A summer‐fall three‐chromosome sexual type occurred from approximately 50° N northward and a winter‐spring four‐chromosome sexual type had a northerly limit of approximately 54° N, extending to the southernmost areas of British Columbia. Two asexual types occurred, exhibiting little seasonally, six‐chromosome populations throughout the coast and three‐chromosome populations at three southerly sites only. Karyograms were prepared for the four chromosomal types, assigning tentative centromere locations. Somatic chromosome pairing was reported for the first time in the Rhodophyta.
EVOLUTIONARY STRATEGIES IN A TROPICAL BARRIER REEF SYSTEM: FUNCTIONAL‐FORM GROUPS OF MARINE MACROALGAE1
Authors: Littler Mark M. , Littler Diane S. , Taylor Phillip R. 
Published: November 2004

ABSTRACTPredictions of an evolutionary model were examined for 43 tropical macroalgae using a functional‐form group approach. The ranking from high to low primary producers (Sheet‐ and Filamentous‐Groups > Coarsely Branched‐ and Thick Leathery‐Groups > Jointed Calcareous‐ and Crustose‐Groups), and data from the literature, support the hypothesis that persistent forms which allocate resources for environmental resistance, interference competition or antiherbivory defenses do so at the cost of lower primary production rates. The results for percent thallus lost to fish grazing over a 24 h period support the hypothesis that members of the Thick Leathery‐, Jointed Calcareous‐ and Crustose‐Groups have evolved antipredator defenses, with a tendency for decreasing herbivore resistance toward the Sheet‐ and Filamentous‐Groups. The most heavily‐calcified species (e.g. crustose corallines) ranked among the most grazer resistant as did the thick rubbery or leathery species. The ranking of functional‐form group means for resistance to predation was as follows: Filamentous‐Group (62% lost‐24 h−1), Sheet‐Group (42%), Coarsely Branched‐Group (33%), Jointed Calcareous‐Group (10%), Thick Leathery‐Group (7%) and Crustose‐Group (0%), in accordance with the hypothesis. The algal groups generally showed an increase in mean penetration toughness from filaments (<200 g‐cm−2 to shear thallus) to sheets (216 g·cm2), coarsely branched forms (328 g·cm−2) and thick leathery species (1800 g·cm−2) in agreement with the predictions of the model. Contrary to earlier findings, there was no consistent gradation between the first four groups (i.e. fleshy algae) based on calorific values. However, in partial support of the functional‐form model, a seven‐fold difference was noted when the mean for these groups (1.7 kcal·g−1) was compared with that of the Jointed Calcareous‐ and Crustose‐Groups (0.2 kcal·g−1. The functional‐form group approach appears to have powerful capabilities in that it can indicate important morphological‐metabolic‐ecological interactions in a given community, where the macroalgae are known, without the need to examine each population in detail and without being constrained to a specific habitat or geographical region.
SEASONAL FLUCTUATIONS IN TISSUE NITROGEN FOR FIVE SPECIES OF PERENNIAL MACROALGAE IN RHODE ISLAND SOUND1
Authors: Asare Seth O. , Harlin Marilyn M. 
Published: November 2004

ABSTRACTTissue nitrogen was assessed monthly for 16 months in five species of perennial macroalgae representing three phyla at one location in Rhode Island Sound. The species showed a remarkable similarity in their pattern of seasonal fluctuation in both nitrate and total nitrogen. The period of greatest accumulation (January through March) coincided with the period of highest concentration of inorganic nitrogen in the water, and for most of these algae it was also the time of‐least growth. Conversely, the period of lowest tissue nitrogen (50% of the winter value, May through July) coincided with the period of lowest inorganic nitrogen in the water and highest algal growth. The greatest accumulation of nitrate was found in Laminaria saccharina (L.) Lamour. (80 μmol·g dry wt.−1), four times as much as that measured simultaneously in the other species and 560 times the ambient concentration. By April the concentration of internal nitrate had dropped to nearly undetectable levels, but in August it began to accumulate again—a pattern that was repeated in Chondrus crispus Stackh. In Ascophyllum nodosum (L.) Le Jolis, Fucus vesiculosus L. and Codium fragile subsp. tomentosoides (Van Goor) Silva, the period of negligible internal nitrate level extended from March to December. The greatest concentration of total tissue nitrogen was measured in C. crispus (4.8% dry wt.), double the maximum in L. saccharina (2.3% dry wt.).
MORPHOGENESIS OF MONOSTROMA OXYSPERMUM (KÜTZ.) DOTY (CHLOROPHYCEAE) IN AXENIC CULTURE, ESPECIALLY IN BIALGAL CULTURE1
Authors: Tatewaki Masakazu , Provasoli Luigi , Pintner Irma J. 
Published: November 2004

ABSTRACTThe typical morphology of Monostroma oxyspermum (Kütz.) Doty is lost in axenic culture. In synthetic media of the ASP type, it grows as a colony‐like mass composed of round cells with numerous rhizoids. Such a mass is a fragile structure which falls apart upon shaking, or slight touch, into small cell‐groups and single cells or cells with a long rhizoid. Only temporary saccate or monostromatic fronds appear and reach 1–2 mm in length when grown in enriched seawater media, but disintegrate and become a colony‐like mass. The typical morphology is easily restored by adding at specific intervals filtrates of bacterial cultures and supernatant medium from axenic brown and red algal cultures to the basal medium (ASP7), or by reinfecting the Monostroma with an appropriate bacterial flora. Furthermore, the typical morphology in also maintained by bialgal cultures between Monostroma and other axenic strains of various species of seaweeds except the species belonging to the Chlorophyceae. Monostroma thus appears to utilize some substances released by most species of brown and red algae for its typical growth. Active substances released by bacteria, brown and red algae have not yet been identified and purified. However, it is demonstrated that in axenic cultures many species of seaweeds produce active extracellular substances which play an important role in growth and Morphogenesis of other species of seaweeds.
CELL ENLARGEMENT IN SKELETONEMA COSTATUM (BACILLARIOPHYCEAE)1
Authors: Gallagher Jane C. 
Published: November 2004

ABSTRACT Skeletonema costatum (Grev.) Cl. exhibits an asexual means, of increasing cell size that is more common than auxosporulation. This phenomenon accounts for the genetic stability of S. costatum in culture and for the deficiency of heterozygotes in natural populations, and has important implications far the life history of this species.
Butterfly response to severe ENSO‐induced forest fires in Borneo
Authors: Cleary Daniel F. R. , Grill Andrea 
Published: November 2004

Abstract.  1. Little is known about animal community response to severe El Niño Southern Oscillation (ENSO)‐induced fire events. Here the response of butterflies to the 1997/98 ENSO‐induced fire event in East Kalimantan (Indonesian Borneo) is assessed. In addition to the community‐wide study, a detailed assessment of the lycaenid Jamides celeno is made.2. Species richness declined significantly from 211 species pre‐ENSO to 39 species post‐ENSO and community composition changed significantly. Along with the decline in species richness there was a marked increase in dominance. Jamides celeno, for example, increased from 3% of the pre‐ENSO assemblage to 58% of the post‐ENSO assemblage. Like J. celeno, most of the species in the post‐ENSO assemblage were generalists; most of the specialist species having disappeared from pre‐ to post‐ENSO.3. The major host plant used by J. celeno was the abundant resprouting Fordia splendidissima. Furthermore, significantly more eggs were laid on plants with the crazy ant, Anoplolepis gracilipes, present than on plants with other ants or no ant attendance. Caterpillar presence was significantly higher on plants tended by ants than on untended plants.4. The median distance moved by J. celeno was 30 m with a maximum recorded distance of 290 m.5. The abundance of J. celeno and other generalists in the post‐ENSO assemblage at Wanariset was probably related to their ability to utilise the few available resources after the fire (e.g. F. splendidissima resprouts), their presence in degraded habitats surrounding the Wanariset forest, and their ability to disperse successfully by either being strong fliers (e.g. Euploea spp.) or being able to attain very high population sizes and thereby produce a surplus of dispersers (e.g. J. celeno).
Coexistence of natural enemies in a multitrophic host–parasitoid system
Authors: Bonsall Michael B. , Hassell Michael P. , Reader Patricia M. , Jones T. Hefin 
Published: November 2004

Abstract. 1. This study explored the temporal and spatial aspects of coexistence over many generations in a multispecies host–parasitoid assemblage.2. The long‐term interaction between the cabbage root fly,Delia radicum(Diptera: Anthomyiidae), and two of its natural enemies,Trybliographa rapae(Hymenoptera: Fitigidae) andAleochara bilineata(Coleoptera: Staphylinidae), in a cultivated field at Silwood Park over 19 years was explored.3. Although time series showed that the populations were regulated, the impact of the natural enemies was highly variable. Within‐year determinants showed that the spatial response of the specialist parasitoid,T. rapae, was predominantly independent of host density whileA. bilineataacted simply as a randomly foraging generalist parasitoid.4. These findings are compared and contrasted with an earlier investigation of the same system when only the first 9 years of the time series were available. This study demonstrated the potential of long‐term field studies for exploring hypotheses on population regulation, persistence, and coexistence.