bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gene flow and functional connectivity in the natterjack toad
Authors: STEVENS VIRGINIE M. , VERKENNE CATHERINE , VANDEWOESTIJNE SOFIE , WESSELINGH RENATE A. , BAGUETTE MICHEL 
Published: May 2006

AbstractFunctional connectivity is a key factor for the persistence of many specialist species in fragmented landscapes. However, connectivity estimates have rarely been validated by the observation of dispersal movements. In this study, we estimated functional connectivity of a real landscape by modelling dispersal for the endangered natterjack toad (Bufo calamita) using cost distance. Cost distance allows the evaluation of ‘effective distances’, which are distances corrected for the costs involved in moving between habitat patches in spatially explicit landscapes. We parameterized cost‐distance models using the results of our previous experimental investigation of natterjack's movement behaviour. These model predictions (connectivity estimates from the GIS study) were then confronted to genetic‐based dispersal rates between natterjack populations in the same landscape using Mantel tests. Dispersal rates between the populations were inferred from variation at six microsatellite loci. Based on these results, we conclude that matrix structure has a strong effect on dispersal rates. Moreover, we found that cost distances generated by habitat preferences explained dispersal rates better than did the Euclidian distances, or the connectivity estimate based on patch‐specific resistances (patch viscosity). This study is a clear example of how landscape genetics can validate operational functional connectivity estimates.
High genetic diversity in a rare and endangered sunflower as compared to a common congener
Authors: ELLIS J. R. , PASHLEY C. H. , BURKE* J. M. , McCAULEY D. E. 
Published: May 2006

AbstractDetermining the genetic structure of isolated or fragmented species is of critical importance when planning a suitable conservation strategy. In this study, we use nuclear and chloroplast SSRs (simple sequence repeats) to investigate the population genetics of an extremely rare sunflower,Helianthus verticillatusSmall, which is known from only three locations in North America. We investigated levels of genetic diversity and population structure compared to a more common congener,Helianthus angustifoliusL., using both nuclear and chloroplast SSRs. We also investigated its proposed hybrid origin fromHelianthus grosseserratusMartens andH. angustifolius. Twenty‐two nuclear SSRs originating from the cultivated sunflower (Helianthus annuusL.) expressed sequence tag (EST) database, and known to be transferable toH. verticillatusand its putative parental taxa, were used in this study thereby allowing for statistical control of locus‐specific effects in population genetic analyses. Despite its rarity,H. verticillatuspossessed significantly higher levels of genetic diversity thanH. angustifoliusat nuclear loci and equivalent levels of chloroplast diversity. Significant levels of population subdivision were observed inH. verticillatusbut of a magnitude comparable to that ofH. angustifolius.Inspection of multilocus genotypes also revealed that clonal spread is highly localized. Finally, we conclude thatH. verticillatusis not of hybrid origin as it does not exhibit a mixture of parental alleles at nuclear loci, and it does not share a chloroplast DNA haplotype with either of its putative parents.
Relationships between optically assessed polyphenols and chlorophyll contents, and leaf mass per area ratio in woody plants: a signature of the carbon–nitrogen balance within leaves?
Authors: MEYER S. , CEROVIC Z. G. , GOULAS Y. , MONTPIED P. , DEMOTES‐MAINARD S. , BIDEL L. P. R. , MOYA I. , DREYER E. 
Published: May 2006

ABSTRACTChlorophyll (Chl) and epidermal polyphenol (EPhen) contents were estimated in vivo using two optical leaf‐clips, SPAD‐502 and Dualex, respectively. The area‐based measurements were transformed into mass‐based data by taking into account the leaf dry mass per area (LMA). Measurements were performed on forest trees and on saplings grown under controlled conditions. While LMA increased with irradiance along a vertical transect in a beech canopy or in saplings grown under different and increasing irradiance levels, mass‐based EPhen (EPhenm) increased, whereas mass‐based Chl (Chlm) decreased. This was a signature of a gradual switch of investment from protein into polyphenol production. A similar signature was obtained in saplings grown on nitrogen‐deficient soil with respect to fertilized controls. However, nitrogen effects remained moderate compared to irradiance‐induced effects. EPhenm and Chlm both declined with plant ageing‐induced increases in LMA, under all tested growth conditions. This was a signature of an accumulation of dry matter that diluted Chl and EPhen. The described competition between Chl and EPhen in leaves fits well with the predictions of the Protein Competition Model (PCM), that is, that the total leaf mass‐based polyphenols content (Phent) is controlled by the competition between protein and polyphenol biosynthetic pathways and its metabolic regulation.
Temperature dependence of nitrate reductase in the psychrophilic unicellular alga Koliella antarctica and the mesophilic alga Chlorella sorokiniana
Authors: DI MARTINO RIGANO VITTORIA , VONA VINCENZA , LOBOSCO ORNELLA , CARILLO PETRONIA , LUNN JOHN E. , CARFAGNA SIMONA , ESPOSITO SERGIO , CAIAZZO MARIANNA , RIGANO CARMELO 
Published: May 2006

ABSTRACTTemperature responses of nitrate reductase (NR) were studied in the psychrophilic unicellular alga, Koliella antarctica, and in the mesophilic species, Chlorella sorokiniana. Enzymes from both species were purified to near homogeneity by Blue Sepharose (Pharmacia, Uppsala, Sweden) affinity chromatography and high‐resolution anion‐exchange chromatography (MonoQ; Pharmacia; Uppsala, Sweden). Both enzymes have a subunit molecular mass of 100 kDa, and K. antarctica NR has a native molecular mass of 367 kDa. NR from K. antarctica used both NADPH and NADH, whereas NR from C. sorokiniana used NADH only. Both NRs used reduced methyl viologen (MVH) or benzyl viologen (BVH). In crude extracts, maximal NADH and MVH‐dependent activities of cryophilic NR were found at 15 and 35 °C, respectively, and retained 77 and 62% of maximal activity, respectively, at 10 °C. Maximal NADH and MVH‐dependent activities of mesophilic NR, however, were found at 25 and 45 °C, respectively, with only 33 and 23% of maximal activities being retained at 10 °C. In presence of 2 µm flavin adenine dinucleotide (FAD), activities of cryophilic NADH:NR and mesophilic NADH:NR were stable up to 25 and 35 °C, respectively. Arrhenius plots constructed with cryophilic and mesophilic MVH:NR rate constants, in both presence or absence of FAD, showed break points at 15 and 25 °C, respectively. Essentially, similar results were obtained for purified enzymes and for activities measured in crude extracts. Factors by which the rate increases by raising temperature 10 °C (Q10) and apparent activation energy (Ea) values for NADH and MVH activities measured in enzyme preparations without added FAD differed slightly from those measured with FAD. Overall thermal features of the NADH and MVH activities of the cryophilic NR, including optimal temperatures, heat inactivation (with/without added FAD) and break‐point temperature in Arrhenius plots, are all shifted by about 10 °C towards lower temperatures than those of the mesophilic enzyme. Transfer of electrons from NADH to nitrate occurs via all three redox centres within NR molecule, whereas transfer from MVH requires Mo‐pterin prosthetic group only; therefore, our results strongly suggest that structural modification(s) for cold adaptation affect thermodynamic properties of each of the functional domains within NR holoenzyme in equal measure.
The spatial and temporal variability of sand erosion across a stabilizing coastal dune field
Authors: LEVIN NOAM , KIDRON GIORA J. , BEN‐DOR EYAL 
Published: May 2006

AbstractThis study aimed at quantifying the temporal and spatial variability in sand erosion and deposition over a coastal dune field in Israel. These were measured monthly over 2 years using 315 erosion pins over four transects that were placed perpendicular to the coastline. Vegetation cover was estimated based on aerial photographs and Landsat satellite images, whereas the relative height was based on a digital elevation model. These variables were calculated for the area upwind (south west) of the erosion pins, at various lengths, ranging from 15 to 400 m. Nine geomorphologic units were defined, five related to active units, and four to stabilized units. In active units at least 65% of the temporal variance in the annual absolute changes in sand level was explained by the index of Resultant Drift Potential, with most of the sand movement occurring during winter storms. Local rainfall had no apparent impact on sand mobility, due to the low coincidence of sand carrying winds and rainfall in Israel during the passage of frontal cyclones. As for the spatial variables, only a weak correlation was found between sand mobility with the distance from the coastline (R2 = 18%). Rather, sand erosion and deposition were influenced by vegetation cover and the relative height of an area of 100–200 m upwind. The values of Soil Adjusted Vegetation Index were significantly negatively correlated with annual absolute changes (R2 = 40%), whereas the relative height was significantly positively correlated (R2 = 36%). Applying a multiple regression model, 68% of the spatial variability in sand mobility was explained. The resulting map of sand activity clearly shows that at this stage of the stabilization process, most of the dunes are now disconnected, and movement of sand grains from the beach or between the dunes, is very limited. These methods can be applied into spatial and temporal models of sand mobility, thus assessing the impact of different management practices on coastal dunes.
Interplay between shoreline migration paths, architecture and pinchout distance for siliciclastic shoreline tongues: evidence from the rock record
Authors: LØSETH TORE M. , STEEL RON J. , CRABAUGH JEFF P. , SCHELLPEPER MAIJA 
Published: May 2006

AbstractFacies, geometry and key internal stratigraphic surfaces from eight Cretaceous and Eocene clastic shoreline tongues have been documented. The regressive parts of all the studied tongues represent storm‐wave influenced strandplains, deltas or fan‐deltas, and the regressive shoreline trajectories varied from descending to ascending. The transgressive parts of the tongues are dominated by either estuarine or coastal‐plain deposits. The distance from the coeval, up‐dip non‐marine deposits to the basinward pinchout of amalgamated shoreface sandstones, measured along depositional dip, is here termed the sand pinchout distance. The study shows that the angle of regressive‐to‐transgressive turnaround (defined by the angle between the regressive and subsequent transgressive shoreline trajectories) and the process regime during turnaround largely control the sand‐pinchout distance. The amount of transgressive erosion can also partly control the pinchout distance, but this parameter was comparable for the different examples presented here. If the type of depositional system at turnaround and the depth of transgressive erosion are constant, small angles of turnaround are associated with large pinchout distances, whereas larger angles of turnaround result in smaller pinchout distances. The model developed allows sand‐pinchout distance to be predicted, using data for the landward parts of shoreline tongues. The dataset also shows that steeply rising (aggrading) shoreline trajectories tend to produce more heterolithic sandstone tongues than those formed by lower‐angle trajectories.
Theoretical influence of female mating status and remating propensity on male sperm allocation patterns
Authors: Engqvist L. , Reinhold K. 
Published: May 2006

Abstract
Theoretical models predict that males should allocate more sperm in matings where the immediate risk of sperm competition is high. It has therefore often been argued that males should invest less sperm in matings with virgin females compared with matings with already mated females. However, with relatively polyandrous females, high sperm competition risk will covary with high sperm competition intensity leading to more unpredictable conditions, as high competition intensity should favour smaller ejaculates. With the use of a genetic algorithm, we found that males should allocate more sperm in matings with virgin females when female mating frequency is relatively high, whereas low remating rates will select for higher effort in matings with nonvirgin females. At higher remating rates, first male sperm precedence favours larger ejaculates in matings with virgin females and second male precedence favours the reverse. These results shed some light on several findings that have been difficult to explain adaptively by the hitherto developed theory on sperm allocation.
Intussusception in the Northern Territory: The incidence is low in Aboriginal and Torres Strait Islander children
Authors: Webby Rosalind J , Bines Julie E , Barnes Graeme L , Tindall Helen , Krause Vicki , Patel Mahomed 
Published: May 2006

Aim:  To describe the epidemiology, immunisation status and management of children with intussusception in the Northern Territory (NT), 1993–2003.Methods:  Intussusception data were obtained from all NT hospitals using the International Classification of Diseases (ICD 9/10) codes for children under 18 years of age between 1993 and 2003. Medical records of these children were used to collect information on demographics, admission date, clinical symptoms, signs and management. Immunisation data were obtained from the NT immunisation register. The NT mortality database was reviewed for deaths from intussusception in children between 1993 and 2003. One death in an Aboriginal and Torres Strait Islander child was found in the NT mortality database. Medical records for this child were destroyed and so the case definition for intussusception used in this study was not fulfilled and the child was excluded.Results:  Intussusception proven by radiological or surgical means was identified in 23 children from hospital records. The incidence for children with intussusception in NT is 0.65/1000 live births. The incidence of intussusception was lower in Aboriginal and Torres Strait Islander children (0.16/1000 live births) than in non‐Aboriginal and Torres Strait Islander children (0.92/1000 live births) (P < 0.01).Conclusion:  The incidence of intussusception in the NT is similar to other developed countries but Aboriginal and Torres Strait Islander children have a very low incidence of intussusception. Intussusception is a rare event in the NT and will require a sensitive surveillance system to detect any potential increased risk of intussusception after the introduction of a new rotavirus vaccine.
Adrenomedullin and total nitrite levels in children with familial Mediterranean fever
Authors: Balat Ayşe , İşlek İsmail , Çekmen Mustafa , Yürekli Muhittin , Tekin Deniz , Muslu Ali , şahinöz Saime 
Published: May 2006

Aim:  Familial Mediterranean fever (FMF) is the most frequent periodic syndrome characterised by recurrent attacks of polyserositis. However, recent studies revealed that there might be an ongoing subclinical inflammation between the attacks. As nitric oxide (NO) and adrenomedullin (AM) are both synthesised in the endothelium, and mediates many functions within immune system, we considered them to be an interesting target of investigation in FMF.Methods:  Fifteen children with FMF receiving regular colchicine, ranging in age from 3 to 16 years, were investigated in comparison with 15 healthy age‐ and sex‐matched controls. The mean age of the patients was 9.7 ± 3.9 years. Total nitrite, a stable product of NO, was quantitated by means of the Griess reaction, while AM was measured by HPLC.Results:  Plasma‐urinary AM and total nitrite levels were significantly higher in children with FMF. Plasma AM levels (pmol/mL) in patients and controls were 40.95 ± 5.99 vs. 34.86 ± 5.24, P < 0.05, and urinary AM excretion (pmol/mg creatinine) was 51.16 ± 28.15 vs. 37.5 ± 24.26, P < 0.05 respectively. Plasma total nitrite levels (µmol/L) in patients and controls were 44.80 ± 10.36 vs. 32.13 ± 9.28, P < 0.05, and urinary nitrite excretion (µmol/mg creatinine) was 2.24 ± 1.71 vs. 1.09 ± 0.96, P < 0.05 respectively.Conclusion:  This study considered that AM and NO may have a role in the immuno‐inflammatory process of FMF, although, whether these act to preserve, or protect against, further inflammatory injury is not clear. Our results further supports the hypothesis that these patients have subclinical inflammation between attacks.
Predicting respiratory syncytial virus hospitalisation in Australian children
Authors: Reeve Carole A , Whitehall John S , Buettner Petra G , Norton Robert , Reeve David M , Francis Fleur 
Published: May 2006

Background:  There is limited information on respiratory syncytial virus infections among Australians, particularly those of Indigenous descent.Aim:  This study identifies groups of infants at risk of hospitalisation with respiratory syncytial virus‐positive lower respiratory tract infection who may be targeted for prevention with palivizumab.Methods:  Case control study: the case notes of 271 children with cases of respiratory syncytial virus‐positive lower respiratory tract infection admitted to The Townsville Hospital were studied for risk factors. Controls were chosen randomly from babies born in The Townsville Hospital during that period. Multiple logistic regression analysis and classification and regression tree analysis were used to identify risk factors.Results:  Multiple logistic regression analysis identified birthweight <2500 g, maternal parity and marital status to be independent predictors of hospitalisation with respiratory syncytial virus‐positive lower respiratory tract infection. Classification and regression tree analysis identified babies born weighing <2500 g who possessed older siblings to be at highest risk. Single mothers and smoking were additional risk factors. Indigenous babies were significantly more likely to be exposed to all of the identified risk factors.Conclusion:  Babies born weighing <2500 g (especially with siblings) could be targeted for prevention. All Indigenous babies should be considered at high risk because of their exposure to multiple risk factors.
Cytomegalovirus‐associated protracted diarrhoea in an immunocompetent boy
Authors: Shimizu Masaki , Ohta Kazuhide , Wada Hideo , Sumita Ryo , Yachie Akihiro , Koizumi Shoichi 
Published: May 2006

Aim:  Cytomegalvirus (CMV) gastroenteritis is rarely described in immunocompetent children. We describe here an immunocompetent 1‐year‐old boy with CMV‐associated protracted diarrhoea and discuss the pathogenesis of CMV infection of the gastrointestinal tract.Methods:  Immunohistochemical study was performed using a gastric and duodenal tissue of this patient. Furthermore, the detection of CMV‐DNA in stool and urine samples was performed by polymerase chain reaction method.Results:  CMV infection was proven by the detection of CMV‐DNA in stool and urine samples and CMV‐positive cells in the immunoperoxidase preparation from gastroduodenal biopsy. The biopsy specimens showed severe chronic active gastroduodenitis with numerous CD3+ T cells and CD68+ macrophages.Conclusions:  We speculated from these findings that CMV invasion of the mucosal layer induced an intense immune response characterised by massive infiltration of activated T‐cells and macrophages in this patient. Although the pathogenesis of CMV‐associated gastroenteritis in immunocompetent hosts remains generally unknown, immune mechanism may play some roles in generating the chronic inflammatory lesions.
Breastfeeding and obesity at 14 years: A cohort study
Authors: Shields Linda , O’Callaghan Michael , Williams Gail M , Najman Jake M , Bor William 
Published: May 2006

Aim:  To determine the influence of breastfeeding on overweight and obesity in early adolescence.Methods:  Data about breastfeeding duration, BMI of children at 14 years, and confounding variables, were collected from an ongoing longitudinal study of a birth cohort of 7776 children in Brisbane. Prevalence of overweight and obesity at 14 years was assessed according to duration of breastfeeding, with logistic regression being used to adjust for the influence of confounders.Results:  Data were available for 3698 children, and those not included were significantly different in age, educational level, income, race, birthweight, and small‐for‐gestational‐age status. Breastfeeding for longer than six months was protective of obesity (OR 0.6, 95% CI 0.4, 0.96) though not of overweight. When confounding variables were considered the effect size diminished and lost statistical significance OR 0.8 (95% CI 0.5, 1.3). Breastfeeding for less than 6 months had no effect on either obesity or overweight though a trend was found for increased prevalence of overweight at 14 years with shorter periods of breastfeeding.Conclusion:  This investigation contributes to the gathering body of evidence that breastfeeding for longer than 6 months has a modest protective effect against obesity in adolescence.
Concentration of lactoferrin and interleukin‐6 in cervical mucus from patients being treated for infertility
Authors: MITSUKAWA KAORI , OTSUKI KATSUFUMI , YANAIHARA ATSUSHI , SAWADA MAKI , IWASAKI SHINJI , OKAI TAKASHI 
Published: May 2006

Background:  The concentrations of the iron‐binding protein lactoferrin (LF) and interleukin‐6 (IL‐6) were measured in the cervical mucus of patients being treated for infertility throughout the menstrual cycle.Methods:  A total of 251 cervical mucus samples were obtained from the patients throughout the menstrual cycle. One hundred and fifty samples were from primary infertility patients with unexplained infertility and 101 samples were from secondary infertility patients as a control. The concentrations of LF and IL‐6 were measured by enzyme immunoassays. The standard curve of LF concentrations ranged from 1.6 to 50 ng/mL.Results:  The mean LF and IL‐6 concentrations in the cervical mucus of primary infertility patients were higher than that of the control patients (P= 0.04, P= 0.032, respectively) The LF and IL‐6 concentrations were highly correlated (P < 0.0001).Conclusion:  Elevated levels of IL‐6 and LF in the cervical mucus were obtained from primary infertility patients. We speculate that LF might also be one of the causes of infertility and might play an important role in reproductive processes in the cervix. (Reprod Med Biol 2006; 5: 105–109)