bluuebunny/crossref_metadata_2025_split huggingface dataset:
The sugar phosphotransferase system of Streptomyces coelicolor is regulated by the GntR‐family regulator DasR and links N‐acetylglucosamine metabolism to the control of development
Authors: Rigali Sébastien , Nothaft Harald , Noens Elke E. E. , Schlicht Maximilian , Colson Sévrine , Müller Marisa , Joris Bernard , Koerten Henk K. , Hopwood David A. , Titgemeyer Fritz , Van Wezel Giles P. 
Published: August 2006

SummaryMembers of the soil‐dwelling, sporulating prokaryotic genus Streptomyces are indispensable for the recycling of the most abundant polysaccharides on earth (cellulose and chitin), and produce a wide range of antibiotics and industrial enzymes. How do these organisms sense the nutritional state of the environment, and what controls the signal for the switch to antibiotic production and morphological development? Here we show that high extracellular concentrations of N‐acetylglucosamine, the monomer of chitin, prevent Streptomyces coelicolor progressing beyond the vegetative state, and that this effect is absent in a mutant defective of N‐acetylglucosamine transport. We provide evidence that the signal is transmitted through the GntR‐family regulator DasR, which controls the N‐acetylglucosamine regulon, including the pts genes ptsH, ptsI and crr needed for uptake of N‐acetylglucosamine. Deletion of dasR or the pts genes resulted in a bald phenotype. Binding of DasR to its target genes is abolished by glucosamine 6‐phosphate, a central molecule in N‐acetylglucosamine metabolism. Extracellular complementation experiments with many bld mutants showed that the dasR mutant is arrested at an early stage of the developmental programme, and does not fit in the previously described bld signalling cascade. Thus, for the first time we are able to directly link carbon (and nitrogen) metabolism to development, highlighting a novel type of metabolic regulator, which senses the nutritional state of the habitat, maintaining vegetative growth until changing circumstances trigger the switch to sporulation. Our work, and the model it suggests, provide new leads towards understanding how microorganisms time developmental commitment.
Factors affecting the activity of ethephon in stimulating seed germination of Striga hermonthica (Del.) Benth.
Authors: BABIKER A. G. T. , HAMDOUN A. M. 
Published: August 2006

SummaryEthephon (2‐chloroethylphosphonic acid), which generates ethylene, stimulated the germination of pre‐conditioned seeds of Striga hermonthica when it was added to the alkaline Gezira clay soil at concentrations of 2.5 to 30 mg kg−1. As little as 5 min contact with treated soil was enough to stimulate germination. Ethephon in soil did not cause germination of unconditioned seeds for periods of up to 12 days and also had an adverse effect on seed germination when such seeds were given a second ethephon exposure after a storage period which was adequate, in untreated soil, to give the necessary pre‐conditioning. Ethephon activity persisted in air‐dry soil but declined over a 14 day period in moist soil. In the field ethephon at 0.6 to 4.8 kg ha−1 decreased the number of Striga shoots and increased sorghum height and flowering.
Leaf herbivory and nutrients increase nectar alkaloids
Authors: Adler Lynn S. , Wink Michael , Distl Melanie , Lentz Amanda J. 
Published: August 2006

AbstractCorrelations between traits may constrain ecological and evolutionary responses to multispecies interactions. Many plants produce defensive compounds in nectar and leaves that could influence interactions with pollinators and herbivores, but the relationship between nectar and leaf defences is entirely unexplored. Correlations between leaf and nectar traits may be mediated by resources and prior damage. We determined the effect of nutrients and leaf herbivory by Manduca sexta on Nicotiana tabacum nectar and leaf alkaloids, floral traits and moth oviposition. We found a positive phenotypic correlation between nectar and leaf alkaloids. Herbivory induced alkaloids in nectar but not in leaves, while nutrients increased alkaloids in both tissues. Moths laid the most eggs on damaged, fertilized plants, suggesting a preference for high alkaloids. Induced nectar alkaloids via leaf herbivory indicate that species interactions involving leaf and floral tissues are linked and should not be treated as independent phenomena in plant ecology or evolution.
Arthropods within the woody element of hedgerows and their distribution pattern
Authors: Pollard K. A. , Holland J. M. 
Published: August 2006

Abstract1 The diversity and abundance of arthropods within hedgerows was investigated using insecticide fogging. In total, 13 390 arthropods were collected from 181 m3of hedge (2% of the total volume). The taxonomic diversity of the total sample included 51 families in 13 orders, all within the phylum Arthropoda. Five orders accounted for 90% of all arthropods: Araneae, Coleoptera, Diptera, Hemiptera and Hymenoptera. The predators were the dominant functional group accounting for 40% of the total sample.2 The linear distribution of hedgerow arthropod assemblages was investigated by sampling arthropods in 13 hedges at seven equidistant points along each hedge. Abundance of most arthropod taxa and the four functional groups (predators, parasitoids, herbivores and scavengers) consistently showed a clumped distribution along hedges, with high numbers at both ends and in the middle section. Hedge ends were defined either as a node, where the hedge intersected with another hedge, or as a gateway prior to an adjacent landscape feature such as a wood. Aggregation of arthropods at the nodes may reflect preferable microclimatic conditions at hedgerow junctions, whereas aggregation at a gap suggests the gap acted as a barrier to movement. The aggregation at the centre remains unexplained but may be a manifestation of the movement of individual arthropods along the hedgerow.3 The great abundance and diversity of arthropods found in the present study emphasizes the status of hedges as one of the most important noncrop habitats on farmland. The arthropods that they contain may act as food for other farmland species, aid pest control and contribute to crop pollination.
Effects of delayed mating on reproductive output of female oriental beetle Anomala orientalis (Coleoptera: Scarabaeidae)
Authors: Wenninger Erik J. , Averill Anne L. 
Published: August 2006

Abstract1 Although management of the oriental beetle Anomala orientalis (Waterhouse) by mating disruption shows promise across a range of agricultural systems, relatively little is known about aspects of the reproductive biology of this species relevant to its management. We studied the effects of delayed mating on several aspects of the oviposition behaviour and biology of the oriental beetle using females mated in the laboratory at 4–13 days posteclosion.2 Females exhibited a gradual decline in fecundity with increased age at mating that was largely a function of a decline in duration of the oviposition period, as well as lower female fertility: females mated at 11 days were less likely to lay any fertile eggs. However, egg fertility did not vary with female age at mating.3 Because mating delay did not affect longevity, females mated at older ages experienced decreased oviposition periods; however, females laid more eggs per day with increased age at mating, which partially offset shorter oviposition periods.4 A mating delay of ≥ 6 days relative to females mated within the first day of reaching sexual maturity resulted in an approximately 35–50% lower mean fecundity.5 These results suggest that, for mating disruption to be a successful management tool for the oriental beetle, mating must be prevented rather than delayed. We compare the findings of the present study with the published research on delayed mating in moths and discuss the importance of these results in relation to management of the oriental beetle using female sex pheromones.
Responses of ovipositing moths to host plant deprivation: life history aspects and implications for intercropping
Authors: Åsman Karolina , Ekbom Barbara 
Published: August 2006

Abstract1. When considering intercropping as a strategy to reduce pest oviposition, knowledge about the insect’s oviposition behaviour is very important. Physiological effects on the insect because of difficulties in finding a suitable oviposition site may also be important.2. In the present study, the effects that delays in access to host plants have on lifetime fecundity on diamondback moth and leek moth were examined. The ability to postpone egg laying, fecundity and lifetime oviposition are discussed in relation to intercrop/cover crop as a strategy to reduce oviposition on crop plants.3. When faced with host plant deprivation, the diamondback moth is relatively more dependent upon host plant stimuli for the onset of egg production. By contrast, leek moth is able to postpone egg production for a longer time. There even appeared to be a tendency for leek moth females to extend their lifetime when faced with host plant deprivation.4. We conclude that leek moths have the ability to postpone production of eggs and lay them later in life when finally encountering host plants after a period of host plant deprivation. Therefore, the use of intercropping as a strategy to reduce oviposition is questionable. For such an insect, use of a trap crop might be a better option because the female will lay her eggs in the trap crop and not get the opportunity to lay them later in life when finally encountering crop plants.
Verbenone‐releasing flakes protect individualPinus contortatrees from attack byDendroctonus ponderosaeandDendroctonus valens(Coleoptera: Curculionidae, Scolytinae)
Authors: Gillette Nancy E. , Stein John D. , Owen Donald R. , Webster Jeffrey N. , Fiddler Gary O. , Mori Sylvia R. , Wood David L. 
Published: August 2006

Abstract1 In a study site in interior northern California, twenty individual lodgepole pinesPinus contortawere sprayed with a suspension of DISRUPT Micro‐Flake®Verbenone (4,6,6‐trimethylbicyclo(3.1)hept‐3‐en‐2‐one) Bark Beetle Anti‐Aggregant flakes (Hercon Environmental, Emigsville, Pennsylvania) in water, with sticker and thickener, from ground level to a height of 7 m. Twenty trees sprayed with just water, sticker and thickener served as controls. All trees were baited immediately after spraying with mountain pine beetleDendroctonus ponderosaeaggregation pheromone lures, and lures were refreshed after 4 weeks.2 Trees treated with verbenone had significantly lower attack density byD. ponderosaethan controls at 2, 4, 6 and 8 weeks after application of flakes.3 None of the treated trees was attacked by red turpentine beetleDendroctonus valens, whereas control trees averaged nearly twoD. valensattacks per tree, 8 weeks after treatment.4 A dry frass index, used to predict ultimate tree mortality, was significantly higher in control trees than treated trees for all four sampling intervals. This index proved to be a significant predictor of ultimate tree mortality.5 Ten months after application, treated trees showed significantly lower mortality than control trees.
Oxalate ions and calcium oxalate crystal‐induced up‐regulation of osteopontin and monocyte chemoattractant protein‐1 in renal fibroblasts
Authors: UMEKAWA TOHRU , IGUCHI MASANORI , UEMURA HIROTSUGU , KHAN SAEED R. 
Published: August 2006

OBJECTIVETo examine the responses of renal fibroblasts to high oxalate (Ox) and calcium Ox (CaOx) crystals, as the latter are found in the renal interstitium of patients with primary or enteric hyperoxaluria, and in animals with experimental CaOx nephrolithiasis, and are associated with tubulointerstitial inflammation (TI). TI might begin with the production of chemoattractants by the renal epithelial cells exposed to high Ox and/or CaOx crystals; as Ox levels are also high in the renal interstitium and crystal deposition in nephrolithiasis might start in the interstitium, we hypothesized that renal fibroblasts might also be involved in the development of TI.MATERIALS AND METHODSWe exposed renal fibroblast cells of line NRK 49F in vitro to Ox ions (500 µmol/L) or CaOx monohydrate crystals (67 µg/cm2). We assessed the production of osteopontin and monocyte chemoattractant protein‐1 (MCP‐1), and expression of their mRNA, in the cells. We also determined the cellular malondialdehyde content as a marker of reactive oxygen species (ROS)‐induced lipid peroxidation, and Trypan blue staining and the release of lactate dehydrogenase as markers of injury.RESULTSSimilar to renal epithelial cells, renal fibroblasts were stimulated by exposure to Ox and CaOx crystals. They showed signs of injury and ROS‐induced lipid peroxidation. The mRNA expression and production of osteopontin and MCP‐1 increased significantly.CONCLUSIONSThese results indicate that fibroblasts respond to high Ox and CaOx crystals by up‐regulating specific pathways producing pro‐inflammatory conditions. Migration of monocytes/macrophages to sites of interstitial crystal deposits can lead to localized interstitial inflammation and fibrosis.
Percentage of positive biopsy cores, preoperative prostate‐specific antigen (PSA) level, pT and Gleason score as predictors of PSA recurrence after radical prostatectomy: a multi‐institutional outcome study in Japan
Authors: YOKOMIZO AKIRA , MURAI MASARU , BABA SHIRO , OGAWA OSAMU , TSUKAMOTO TAIJI , NIWAKAWA MASASHI , TOBISU KEN‐ICHI , KINUKAWA NAOKO , NAITO SEIJI 
Published: August 2006

OBJECTIVETo evaluate the clinical outcome of radical prostatectomy (RP) in Japan, by retrospectively analysing the clinicopathological data in patients with clinical T1‐T2 prostate cancer treated by RP, as there can be prostate‐specific antigen (PSA) recurrence after RP in substantially many patients, and its character can differ according to ethnic group and/or country.PATIENTS AND METHODSWe reviewed 1192 patients who had a RP from 1993 to 2002 with no neoadjuvant/adjuvant therapy and whose PSA level after RP decreased at least once to undetectable levels (<0.2 ng/mL). PSA recurrence was defined as ≥ 0.20 ng/mL. The patient data were collected from the Urological Oncology Study Group, a subgroup of Japan Clinical Oncology Group.RESULTSThe patients’ median (range) age was 67  (47–83) years and their PSA level before RP was 8.7 (1.0–153) ng/mL. During the median follow‐up of 45.6 months, 302 of the 1192 patients (25.3%) developed PSA recurrence. The median time to recurrence was 369  (61–2128) days after RP. A log‐rank test showed that five significant clinicopathological factors were associated with PSA recurrence after RP: The percentage of prostate needle‐biopsy cores with cancer, the biopsy Gleason score, PSA level before RP, pathological stage, and the Gleason score of the RP specimen (P < 0.001 for all). In multivariate analyses, the percentage of positive biopsy cores, PSA level before RP, pT and the Gleason score of the RP specimen were all independent significant predictors of PSA recurrence after RP in Japanese men.CONCLUSIONSThe frequency of PSA recurrence after RP was 25.3% in Japan and the percentage of positive biopsy cores, PSA level before RP, pT and the Gleason score of the RP specimen were independent significant factors for PSA recurrence.
Different vascular endothelial growth factor (VEGF), VEGF‐receptor 1 and ‐2 mRNA expression profiles between clear cell and papillary renal cell carcinoma
Authors: LJUNGBERG BÖRJE J. , JACOBSEN JAN , RUDOLFSSON STINA HÄGGSTRÖM , LINDH GUDRUN , GRANKVIST KJELL , RASMUSON TORGNY 
Published: August 2006

OBJECTIVESTo examine vascular endothelial growth factor (VEGF), VEGF‐receptor‐(R)1, and R2 mRNA levels in renal cell carcinoma (RCC), a tumour generally refractory to most medical therapy, but for which a potentially useful therapeutic alternative is inhibition of angiogenesis.PATIENTS AND METHODSVEGF, VEGF‐R1 and ‐R2 mRNA levels were analysed using the quantitative reverse transcription‐polymerase chain reaction. RNA was extracted from 84 conventional (clear cell) RCCs (cRCC), 20 papillary (pRCC), six chromophobe (chRCC), and 27 corresponding kidney cortex tissues, obtained from 110 patients in whom high‐quality RNA was available from the tumours (53 women and 57 men, mean age 64.7 years, range 25–85).RESULTSThe VEGF, VEGF‐R1, and ‐R2 mRNA levels were higher in tumour than in kidney cortex tissues. Among the RCC types, cRCC had higher VEGF levels than pRCC. In cRCC, VEGF‐R2 levels were higher in stage I–II than in more advanced stages. In pRCC, VEGF and VEGF‐R2 levels were higher in stage III than in stage I–II tumours. In cRCC, patients with VEGF levels below the median had a significantly shorter survival time than those with higher levels. By contrast, in pRCC, VEGF, VEGF‐R1 and ‐R2 RNA levels above the median were related to adverse survival. Using multivariate analysis in cRCCs, VEGF‐R1 mRNA level was the last factor to be omitted after stepwise elimination analysis.CONCLUSIONVEGF and its receptors were associated with tumour stage and survival, but were not independent prognostic factors. Different RCC types had different expression patterns of VEGF and receptor mRNA levels. We conclude that different pathways might be involved in regulating angiogenesis in the specific RCC types. Detailed knowledge of angiogenesis in RCC is essential when designing new treatment trials where angiogenesis inhibition is used.
Developmental changes in perceptions of attractiveness: a role of experience?
Authors: Cooper Philip A. , Geldart Sybil S. , Mondloch Catherine J. , Maurer Daphne 
Published: August 2006

Abstract In three experiments, we traced the development of the adult pattern of judgments of attractiveness for faces that have been altered to have internal features in low, average, or high positions. Twelve‐year‐olds and adults demonstrated identical patterns of results: they rated faces with features in an average location as significantly more attractive than faces with either low or high features. Although both 4‐year‐olds and 9‐year‐olds rated faces with high features as least attractive, unlike adults and 12‐year‐olds, they rated faces with low and average features as equally attractive. Three‐year‐olds with high levels of peer interaction, but not those with low levels of peer interaction, chose faces with low features as significantly more attractive than those with high‐placed features, possibly as a result of their increased experience with the proportions of the faces of peers. Overall, the pattern of results is consistent with the hypothesis that experience influences perceptions of attractiveness, with the proportions of the faces participants see in their everyday lives influencing their perceptions of attractiveness.
Modelling Currency Crises in Emerging Markets: A Dynamic Probit Model with Unobserved Heterogeneity and Autocorrelated Errors*
Authors: Falcetti Elisabetta , Tudela Merxe 
Published: August 2006

AbstractThe paper investigates the causes of currency crises in emerging markets. We estimate the probability of a currency crisis by applying maximum smoothly simulated likelihood to a dynamic LDV model. This approach allows us to take explicit account of the existence of intertemporal links between crises. The results show that currency crises are influenced by real, monetary, debt and global variables. Past banking crises are significant determinants of the probability of currency crises. Moreover, countries that sharply devalued in the past are less prone to experience another currency crisis. We find evidence of unobserved heterogeneity, which may reflect differences in the countries’ institutional/historical background. Finally, the determinants of currency crises differ by type of exchange rate regime.
A Note on Additive Separability and Latent Index Models of Binary Choice: Representation Results*
Authors: Vytlacil Edward 
Published: August 2006

AbstractThe standard binary choice model in econometrics has the choice determined by a latent index crossing a threshold. The latent index is almost always assumed to be additively separable in observable and unobservable regressors, and most commonly linear in all regressors. This note provides a class of non‐separable latent index functions which will have equivalent representations as additively separable or linear index functions. These results demonstrate that assuming a linear or additively separable latent index function is less restrictive than previously recognized.
Visual exploratory behaviour in infancy and novelty seeking in adolescence: two developmentally specific phenotypes of DRD4?
Authors: Laucht Manfred , Becker Katja , Schmidt Martin H. 
Published: August 2006

Background:  The present study was designed to investigate the association between visual exploratory behaviour in early infancy, novelty seeking in adolescence, and the dopamine D4 receptor (DRD4) genotype.Methods:  Visual attention was measured in 232 three‐month‐old infants (114 males, 118 females) from a prospective longitudinal study using a habituation–dishabituation paradigm. At age 15 years, the Junior Temperament and Character Inventory (JTCI/12–18) was administered to assess adolescent novelty seeking. DNA was genotyped for the DRD4 exon III polymorphism.Results:  Boys with a higher decrement of visual attention during repeated stimulation in infancy displayed significantly higher JTCI novelty seeking at age 15 years. Furthermore, boys carrying the 7r allele of DRD4 exhibited both greater rates of attention decrement in infancy and higher scores on NS in adolescence. In contrast, no association between DRD4, visual attention and novelty seeking was observed in girls.Conclusions:  The present investigation provides further evidence supporting a role of DRD4 in novelty seeking during the course of development.
Habitat preferences of the secretive forest buffalo (Syncerus caffer nanus) in Central Africa
Authors: Melletti M. , Penteriani V. , Boitani L. 
Published: August 2006

AbstractThe forest buffalo Syncerus caffer nanus is one of the three subspecies of African buffalo inhabiting the rainforests of Western and Central Africa. Because of its secretive behaviour and main habitat (dense rainforests), there is little quantitative information on the habitat preferences of this buffalo. We present here the first data on the frequencies of this species along a habitat gradient ranging from clearings and rivers to forests, as well as the characteristics of the buffalo's resting places. We recorded information from a buffalo herd during the period January 2002–January 2004 in the Bai‐Hokou area (Dzanga‐Ndoki National Park, Central African Republic). Resting places were firstly compared with available habitat (i.e. resting vs. random sites) and, successively, comparisons were made between diurnal versus nocturnal and wet versus dry season resting places. Forest buffalos were found to be highly dependent on clearings, as well as on the more open forest stands, characterized by large trees and open canopy. Such preferences could be due to the tendency of the buffalos to rest all together; open patches are likely to facilitate social interactions between the members of the herd.