bluuebunny/crossref_metadata_2025 huggingface dataset:
Root morphology of mandibular premolars in 40 patients with Turner syndrome
Authors: Kusiak A. , Sadlak‐Nowicka J. , Limon J. , Kochańska B.
Published: October 2005

Aim  To analyse root morphology of mandibular premolars in 40 females with Turner syndrome.

Methodology  All patients aged 18–50 years (mean ± SD: 26.2 ± 6.22) were clinically and cytogenetically diagnosed and divided into three groups according to karyotype: I – with 45,X (n = 19); II – with 46,X,i(Xq) and other structural changes of this chromosome (n = 8); III – with mos45,X/46,XX and other mosaic karyotype (n = 13). The control group consisted of 30 healthy women aged 20–50 years (mean ± SD: 31.52 ± 5.21) who underwent dental treatment at the Department of Conservative Dentistry and Department of Periodontology and Oral Mucosa Diseases, Medical University of Gdańsk, Poland. The root morphology of mandibular premolars was studied based on orthopantomogram X‐ray images. The results were analysed using chi‐square test with Yates's adjustment.

Results  Separate mesial and distal root canals and separate root apices were noted on orthopantomograms in patients with Turner syndrome. Two‐rooted mandibular first premolars were observed in 34% of cases in group 45,X (group I), in 31% of cases in the group with structural aberrations of chromosome X (group II) and in 31% of cases with mosaic karyotypes (group III). Two‐rooted mandibular second premolars were observed in 39% cases in group 45,X and in 31% of cases in the group with structural aberrations of chromosome X and in 35% of cases with mosaic karyotypes. This type of root morphology was not observed in the control group. No significant difference was found between the three groups of Turner syndrome.

Conclusion  Highly significant differences in root morphology of mandibular premolars between patients with Turner syndrome and a population control group were found.
Determining the apical terminus of root‐end resected teeth using three modern apex locators: a comparative ex vivo study
Authors: ElAyouti A. , Kimionis I. , Chu A.‐L. , Löst C.
Published: October 2005

Aim  To assess ex vivo the accuracy of various electronic apex locators in locating the apical terminus of root‐end resected teeth.

Methodology  Ninety extracted human posterior teeth (182 root canals) were prepared to a minimum size of 40 and filled with gutta‐percha and sealer. After resection of the apical 3 mm of the root, the root canal filling was removed using HERO rotary instruments. The size of the root canal at the apical terminus after removal of the filling ranged from size 50 to 90. The root canal length to the apical terminus was determined using 3 apex locators (Root ZX, Raypex®4 and Apex Pointer). A new mounting model that utilized a micrometer was used to perform the measurements and to visually determine the actual position of the apical terminus. The frequency of locating the apical terminus and the corresponding 95% confidence interval (CI) were calculated. Additionally, the coefficient of repeatability of each apex locator and the limits of inter‐operator agreement were determined.

Results  All apex locators showed an acceptable repeatability (0.02–0.03 mm coefficient of repeatability) and narrow limits of inter‐operator agreement (+0.07 and −0.07 mm). The accuracy of determining the apical terminus within 1 mm in the root canal was as follows: Root ZX 90% (164/182 root‐canals) [95%CI: 86–94%], Raypex®4 74% (135/182 root‐canals) [95%CI: 68–80%], and Apex Pointer 71% (129/182 root canals) [95%CI: 65–77%]. No over‐instrumentation resulted when the Root ZX device was used. In contrast, using the Raypex®4 or the Apex Pointer device resulted in over‐instrumentation in 8 of 182 root canals (4%).

Conclusions  Under the conditions of this study all three apex locators were able to detect the apical terminus of root‐end resected teeth with an acceptable range. The Root ZX device was the most accurate without over‐instrumentation of the root canals.
The chemical constitution and biocompatibility of accelerated Portland cement for endodontic use
Authors: Camilleri J. , Montesin F. E. , Di Silvio L. , Pitt Ford T. R.
Published: October 2005

Aim  To evaluate the biocompatibility of mineral trioxide aggregate and accelerated Portland cement and their eluants by assessing cell metabolic function and proliferation.

Methodology  The chemical constitution of grey and white Portland cement, grey and white mineral trioxide aggregate (MTA) and accelerated Portland cement produced by excluding gypsum from the manufacturing process (Aalborg White) was determined using both energy dispersive analysis with X‐ray and X‐ray diffraction analysis. Biocompatibility of the materials was assessed using a direct test method where cell proliferation was measured quantitatively using Alamar BlueTM dye and an indirect test method where cells were grown on material elutions and cell proliferation was assessed using methyltetrazolium assay as recommended by the International standard guidelines, ISO 10993‐Part 5 for in vitro testing.

Results  The chemical constitution of all the materials tested was similar. Indirect studies of the eluants showed an increase in cell activity after 24 h compared with the control in culture medium (P < 0.05). Direct cell contact with the cements resulted in a fall in cell viability for all time points studied (P < 0.001).

Conclusions  Biocompatibility testing of the cement eluants showed the presence of no toxic leachables from the grey or white MTA, and that the addition of bismuth oxide to the accelerated Portland cement did not interfere with biocompatibility. The new accelerated Portland cement showed similar results. Cell growth was poor when seeded in direct contact with the test cements. However, the elution made up of calcium hydroxide produced during the hydration reaction was shown to induce cell proliferation.
Taxonomic distinctness as a measure of diversity applied over a large scale: the benthos of the Norwegian continental shelf
Authors: ELLINGSEN K. E. , CLARKE K. R. , SOMERFIELD P. J. , WARWICK R. M.
Published: October 2005

Data on soft‐sediment macrobenthos from the Norwegian continental shelf (56–71°N) was used to examine the use of average taxonomic distinctness (Δ+, a measure of the average degree to which species are related to each other) as a diversity measure.

Δ+ for all taxa combined decreased with both latitude and depth. In contrast Δ+ for annelids and crustaceans (71% of the fauna) was positively correlated to latitude and depth, whereas molluscs (20·1% of the fauna) were not related to latitude or depth. Depth explained most of the variance in Δ+ for annelids and crustaceans. Neither latitude nor grain size appeared to be important in explaining large‐scale patterns in the taxonomic breadth of the three dominant phyla. In contrast latitude rather than depth explained most of the variance in Δ+ of all taxa combined.

The finding that molluscs showed different patterns of Δ+ than the two other dominant phyla shows that the biodiversity of different phyla responded differently to environmental gradients and that one phylum cannot be used as a surrogate for others in such studies. The most likely explanation for the inconsistency in Δ+ is because the taxonomic classification system also varies between different phyla, and taxonomically related biodiversity measures might be more meaningfully applied to a single phylum than to all taxa combined.

Δ+ and species richness (S) displayed different patterns of biodiversity. Thus Δ+ is not a surrogate for species richness. Species richness of all taxa combined and annelids were highest in the middle depth range, and lowest in the shallowest and deepest parts of the shelf. Most of the variance in species richness is accounted for by depth, followed by latitude and grain size for all three dominant phyla and all taxa combined.
The natal dispersal of tree swallows in a continuous mainland environment
Authors: WINKLER DAVID W. , WREGE PETER H. , ALLEN PAUL E. , KAST TRACEY L. , SENESAC PIXIE , WASSON MATTHEW F. , SULLIVAN PATRICK J.
Published: October 2005

To minimize study‐area artefacts in a study of natal dispersal distances in tree swallows, we intensively banded nestlings and adults in nest‐boxes in upstate New York and recruited and trained 70 volunteer banders within a 400 km radius of Ithaca. We banded 26 567 nestlings in the years 1985 through 1998, and captured 4774 adults at the nest, 630 of which had been banded as nestlings and were recaptured the year after fledging.

To correct for spatial variation in capture intensity, we resampled the distribution of all boxes where an adult capture was made under uniform, exponential and Cauchy null hypotheses. Compared to the null distributions, the frequency of observed dispersal events was significantly higher at 0–10 km and lower for all larger dispersal distances. The Cauchy distribution came closest to approximating the observed dispersal distance distribution.

Dispersal distances were sensitive to the distribution of nesting sites, and all measurements of dispersal distance distributions must be seen as being habitat‐specific. We could detect no effect of dispersal distance on the subsequent timing of breeding and no effect of the timing of fledging on dispersal distance. The sexual differences in raw mean dispersal distances (8·38 km for females, 2·44 km for males) are similar to those reported for other species.

While it is tempting to conclude that studies in smaller areas have not missed a great deal, even a study area of 10 km extent (substantially larger than most) would have missed 11% of the dispersing birds detected and 95% of the range of distances recorded. Despite this sizeable component that would have been missed with a smaller study area, the relatively low frequencies of long‐distance dispersal overall reinforce the conclusion that tree swallows, and probably most other migratory passerines, generally disperse much less far from their natal sites than the distances of their annual migrations might lead one to expect.
The impact of rare species on natural assemblages
Authors: GRAY JOHN S. , BJØRGESÆTER ANDERS , UGLAND KARL I.
Published: October 2005

Compared with most terrestrial data sets used in development of theoretical models, what characterizes data sets from marine soft sediments is that they have a very high number of species. Marine data also show large numbers of rare species, even if the extent of the study is greatly increased from a few square metres to hundreds of square kilometres.

Fitting log‐normal distributions to data on species abundance distributions (SADs) for marine benthic assemblages from the continental shelf of Norway, and for the well‐studied tropical tree data of Barro Colorado Island, Panama (BCI), show patterns suggesting that more than one log‐normal distribution occurs.

We have developed a simple model of SADs comprising two groups of log‐normally distributed species, a group of rare species and a group of common species. The model appears to fit the marine data and also applies to the BCI tropical tree data and yet is simpler than Hubbell's Zero‐Sum Multinomial (ZSM) distribution model.

The plots of the model results show that the marine data are dominated by the rare group of species at all scales studied. In the tropical tree assemblage a similar pattern to that in the marine data is apparent only at small spatial scales (5 and 10 ha), but not at the larger extent (25–50 ha). It is important to note, however, that marine data at all the scales studied are samples from a given area, whereas the terrestrial data are exact counts of all species of tree within the total 50 ha plot studied.

Most ecological data are likely to be based on samples rather than exact counts so the patterns found with the marine data are likely to be common, and our findings general ones.

A biological explanation for the two‐group log‐normal model is that recruitment of rare species from outside the studied area dominates benthic assemblages of soft sediments at all sampled scales. Within the tropical forest the dominance of recruitment processes are only apparent at small scales.

Thus, the interpretation of SAD patterns depends greatly on the type of data collected, i.e. whether they are exact counts or samples. We believe that structuring processes are similar in marine and many terrestrial systems and these processes probably conform to the mass‐effects paradigm of the newly termed meta‐community concept.
Genetic and spatial structure within a swift fox population
Authors: KITCHEN ANN M. , GESE ERIC M. , WAITS LISETTE P. , KARKI SEIJA M. , SCHAUSTER EDWARD R.
Published: October 2005

We incorporated spatial data on swift foxes (Vulpes velox) with genetic analysis to assess the influence of relatedness between individuals on their social and spatial ecology. We recorded the space use patterns of 188 radio‐collared swift foxes in south‐eastern Colorado from January 1997 to December 2000. One hundred and sixty‐seven foxes were also genotyped at 11 microsatellite DNA loci and the degree of relatedness between individuals was estimated.

We described the genetic structure of the population by examining the relatedness of neighbours and the relationship between the spatial and genetic distance of all individuals. We found that close kin appeared to cluster within the population. Neighbours were significantly more related (mean R = 0·089 ± 0·01) than non‐neighbours (mean R = 0·003 ± 0·01; randomization test, P < 0·0002). Female clusters were more extensive than male clusters.

The degree of genetic relatedness among foxes was useful in explaining why foxes tolerated encroachment of their home ranges by neighbours; the more closely related neighbours were, the more home‐range overlap they tolerated (Mantel test, P = 0·0004). Foxes did not appear to orientate their home ranges to avoid neighbours and home ranges overlapped by as much as 54·77% (x = 14·13% ± 0·41). Neighbours also occasionally engaged in concurrent den sharing.

Relatedness influenced the likelihood that an individual would inherit a newly vacated home range, with a mean relatedness of range inheritors to previous owners of 0·333 ± 0·074. Thus, the genetic structure of the population and interactions between kin were interrelated to space‐use patterns and social ecology of the swift fox.
Factors affecting susceptibility of farms to crop raiding by African elephants: using a predictive model to mitigate conflict
Authors: SITATI N. W. , WALPOLE M. J. , LEADER‐WILLIAMS N.
Published: October 2005

Crop raiding by African elephantsLoxodonta africanaerodes local tolerance for elephants and thereby impedes conservation efforts, so solutions are urgently required. Within conflict zones, crop raiding is not distributed equally amongst farms, which may be a result of variation in local physical or geographical factors, or in farmers’ efforts to defend their fields. Understanding the efficacy of local conflict mitigation methods is important, but few quantitative evaluations exist.

Using a comparative survey of raided and non‐raided farms in Transmara District, Kenya, and multivariate logistic and linear regression analyses, we explored a range of factors affecting (i) the susceptibility of farms to elephant crop raiding and (ii) the amount of crop damage once elephants had entered a field.

The results revealed that farms that had been habitually raided in the past were more likely to be raided during the study period, as were those that were larger and bordered by hedges or fences. Greater guarding effort increased the likelihood that elephants were detected prior to entry and decreased the likelihood of successful crop raiding, as did the use of fire and noise.

However, there was an interaction between physical and human factors; larger farms used more advanced barrier methods at the expense of guarding effort. Farmers’ efforts did not appear to diminish the damage inflicted once elephants had entered a field.

A subsequent experimental test confirmed these results; the application of enhanced early warning and guarding effort on previously raided farms reduced incidents of crop raiding by 89·6% over 2 years in comparison with a control group of farms.

Synthesis and applications. These results suggest that early detection of elephants approaching fields, increased guarding effort, and the use of active deterrents could form the basis of an effective mitigation strategy regardless of location and the physical attributes of a farm. Validating the results of predictive models through participatory mitigation trials serves to demonstrate effective solutions to farmers themselves. Researchers and practitioners should be encouraged to replicate such field trials over broader spatial and temporal scales and to find means to encourage farmers to take up appropriate solutions.
Evolution of the Euphrasia transmorrisonensis complex (Orobanchaceae) in alpine areas of Taiwan
Authors: Wu Ming‐Jou , Huang Shing‐Fan , Huang Tseng‐Chieng , Lee Pei‐Fen , Lin Tsan‐Piao
Published: October 2005

Aims  To unravel isolation and differentiation of the genetic structure of the Euphrasia transmorrisonensis complex, a showy herb, among alpine regions of mountain peaks in subtropical Taiwan and to infer its evolutionary history.

Location  Alpine ecosystems of high‐montane regions of Taiwan.

Methods  Phylogenetic analyses of the trnL intron and the trnL–trnF intergenic spacer of chloroplast (cp) DNA, and the intertranscribed spacer (ITS) of nuclear ribosomal (nr) DNA between 18S and 26S were carried out on 18 populations of the E. transmorrisonensis complex in Taiwan.

Results  In total, 10 haplotypes for cpDNA and 14 haplotypes for nrDNA were detected. Three population groups located in the northern, north‐eastern, and south‐central regions of the Central Mountain Range (CMR) were revealed according to the frequencies of haplotypes and haplotype lineages of nrDNA. Balancing selection might have played a role in the evolution of Euphrasia in Taiwan.

Main conclusions  By integrating the spatial‐genetic patterns of cpDNA and nrDNA, two possible evolutionary histories of Euphrasia in Taiwan were inferred. The favourable hypotheses for interpreting the data suggest at least three origins of the E. transmorrisonensis complex in Taiwan, corresponding to each nuclear lineage in the northern (II), northern/north‐eastern (I), and central/southern regions (III) with subsequent hybridization between lineages I and II and lineages II and III. These lineage boundaries are strengthened by the finding that haplotypes of C derived from cpDNA were found in the geographical region of lineage II of nrDNA, while haplotypes of A derived from cpDNA were found in the region of lineage III of nrDNA. Thus, the origin of chloroplasts exclusive to lineages II and III supports their long‐term isolation from one another.
The fauna of Greece and adjacent areas in the Age of Homer: evidence from the first written documents of Greek literature
Authors: Voultsiadou Eleni , Tatolas Apostolos
Published: October 2005

Aim  To study the composition of fauna in Greece and adjacent areas around 3000 years ago based on the knowledge of Homeric man about the animal kingdom.

Location  Greece and adjacent areas.

Method  Analysis of information derived from a thorough study of the first written documents of Greek literature, the epics, attributed to Homer and Hesiod.

Results  Records of 2442 animals were found, corresponding to 71 different animal names. All animal names were attributed to recent taxa, at different category levels; the majority (65%) were assigned to taxa at the species level and the rest to supraspecific taxa. Most of the animal names recorded in the epics have been retained as integral words or roots in Modern Greek and they have been used in the formation of the Latin scientific taxa names. Five animal phyla appear in the texts: (1) Chordata (mostly birds and mammals), (2) Arthropoda, (3) Mollusca, (4) Porifera, and (5) Annelida. Information in the epics also includes morphology, biology, ecology (habitat and prey–predator relationships), and behaviour. The presence of several species in the area in that period is documented on the basis of archaeological and/or palaeontological findings from various Greek localities.

Main conclusions  The knowledge of Homeric man about animals, as reflected in the epics, seems to concentrate mainly, but not exclusively, on animals involved in human activities. The populations of some common animal species of the Homeric Age in Greek populated areas have become extinct or reduced at the present time. On the other hand, some common animals of the present time do not appear in the epics, since they were introduced later. Useful zoological information can be derived from the study of classical texts, which may help historical biogeographers as a supplement to archaeology and art, in the reconstruction of faunas of older periods.
Relationships between local population persistence, local abundance and regional occupancy of species: distribution patterns of diatoms in boreal streams
Authors: Soininen Janne , Heino Jani
Published: October 2005

Aims  We have two aims: (1) to examine the relationship between local population persistence, local abundance and regional occupancy of stream diatoms and (2) to characterize the form of the species–occupancy frequency distribution of stream diatoms.

Location  Boreal streams in Finland. There were three spatial extents: (1) across ecoregions in Finland, (2) within ecoregions in Finland, and (3) within a single drainage system in southern Finland.

Methods  Diatoms were sampled from stones (epilithon), sediment (epipelon) and aquatic plants (epiphyton) in streams using standardized sampling methods. To assess population persistence, diatom sampling was conducted monthly at four stream sites from June to October. The relationships between local population persistence, local abundance and regional occupancy were examined using correlation analyses.

Results  There was a significant positive relationship between local persistence and abundance of diatoms in epilithon, epipelon and epiphyton. Furthermore, local abundance and regional occupancy showed a significant positive relationship at multiple spatial extents; that is, across ecoregions, within ecoregions and within a drainage system. The relationships between occupancy and abundance did not differ appreciably among impacted and near pristine‐reference sites. The occupancy–frequency distribution was characterized by a large number of satellite species which occurred at only a few sites, whereas core species that occurred at most sites were virtually absent.

Main conclusions  The positive relationship between local population persistence and abundance suggested that a high local abundance may prevent local extinction or that high persistence is facilitated by a high local cell density. High local persistence and local abundance may also positively affect the degree of regional occupancy in stream diatoms. The results further showed that anthropogenic effects were probably too weak to bias the relationship between occupancy and abundance, or that the effects have already modified the distribution patterns of stream diatoms. The small number of core species in the species–occupancy frequency distribution suggested that the regional distribution patterns of stream diatoms, or perhaps unicellular microbial organisms in general, may not be fundamentally different from those described previously for multicellular organisms, mainly in terrestrial environments, although average global range sizes may differ sharply between these two broad groups of organisms.
Elevational gradient analyses and the use of historical museum specimens: a cautionary tale
Authors: Rowe Rebecca J.
Published: October 2005

Aim  The value of biodiversity informatics rests upon the capacity to assess data quality. Yet as these methods have developed, investigating the quality of the underlying specimen data has largely been neglected. Using an exceptionally large, densely sampled specimen data set for non‐flying small mammals of Utah, I evaluate measures of uncertainty associated with georeferenced localities and illustrate the implications of uncritical incorporation of data in the analysis of patterns of species richness and species range overlap along elevational gradients.

Location  Utah, USA, with emphasis on the Uinta Mountains.

Methods  Employing georeferenced specimen data from the Mammal Networked Information System (MaNIS), I converted estimates of areal uncertainty into elevational uncertainty using a geographic information system (GIS). Examining patterns in both areal and elevational uncertainty measures, I develop criteria for including localities in analyses along elevational gradients. Using the Uinta Mountains as a test case, I then examine patterns in species richness and species range overlap along an elevational gradient, with and without accounting for data quality.

Results  Using a GIS, I provide a framework for post‐hoc 3‐dimensional georeferencing and demonstrate collector‐recorded elevations as a valuable technique for detecting potential errors in georeferencing. The criteria established for evaluating data quality when analysing patterns of species richness and species range overlap in the Uinta Mountains test case reduced the number of localities by 44% and the number of associated specimens by 22%. Decreasing the sample size in this manner resulted in the subsequent removal of one species from the analysis. With and without accounting for data quality, the pattern of species richness along the elevational gradient was hump‐shaped with a peak in richness at about mid‐elevation, between 2300 and 2600 m. In contrast, the frequencies of different pair‐wise patterns of elevational range overlap among species differed significantly when data quality was and was not accounted for.

Main conclusions  These results indicate that failing to assess spatial error in data quality did not alter the shape of the observed pattern in species richness along the elevational gradient nor the pattern of species’ first and last elevational occurrences. However, it did yield misleading estimates of species richness and community composition within a given elevational interval, as well as patterns of elevational range overlap among species. Patterns of range overlap among species are often used to infer processes underlying species distributions, suggesting that failure to account for data quality may alter interpretations of process as well as perceived patterns of distribution. These results illustrate that evaluating the quality of the underlying specimen data is a necessary component of analyses incorporating biodiversity informatics.
Lentic odonates have larger and more northern ranges than lotic species
Authors: Hof Christian , Brändle Martin , Brandl Roland
Published: October 2005

Aim We analysed latitudinal range, centres of distribution and northern range boundaries of dragonflies and damselflies occurring in Europe and North America with respect to larval habitat (standing water = lentic and running water = lotic). As lentic water bodies are thought to be less predictable in space and time than lotic habitats, species adapted to standing waters depend on effective dispersal ability for long‐term survival. If species occurring in lentic habitats have a higher propensity for dispersal, then larger range sizes in lentic than in lotic species, as well as an increase in the proportion of lentic species with latitude, would be expected.

Location Europe, North America.

Methods Distributional and habitat data were collected from published sources for all odonates of Europe and North America. Species were assigned to lentic and lotic habitats according to the habitat of the larvae. From distribution maps we estimated the latitudinal range, centre of distribution and northern range boundary of each species. Differences in these distribution variables between lentic and lotic species were evaluated usinganova. We related the proportion of lentic species by latitudinal interval in Europe, and by political unit (state, province) in North America, to area, altitudinal range, longitude (only for North America) and latitude by means of generalized linear models.

Results Lentic damselflies and dragonflies had larger latitudinal spans, and more northern distribution centres and range boundaries, than lotic species. The proportion of lentic species increased with latitude. These findings were consistent between continents.

Main conclusions Our results support previous findings that distribution patterns of freshwater species depend on habitat preference. Evolution of dispersal propensity according to habitat characteristics is the most likely explanation. However, at present, alternative explanations, such as an increase in lentic habitats with latitude, cannot be ruled out.
Chronic Intermittent Cold Stress Sensitises the Hypothalamic‐Pituitary‐Adrenal Response to a Novel Acute Stress by Enhancing Noradrenergic Influence in the Rat Paraventricular Nucleus
Authors: Ma S. , Morilak D. A.
Published: October 2005

Chronic intermittent cold stress sensitises activation of the hypothalamic‐pituitary‐adrenal (HPA) axis by novel acute stress. We have shown that enhanced noradrenergic function in limbic forebrain contributes to HPA sensitisation. In the present study, we investigated whether chronic intermittent cold also induced changes in noradrenergic function in the paraventricular nucleus (PVN), the primary mediator of the HPA stress response. Rats were exposed to chronic intermittent cold (7 days, 6 h per day, 4 °C). On the day after final cold exposure, there were no differences in baseline plasma ACTH, but the peak ACTH response to 30 min of acute immobilisation stress was greater in cold‐stressed rats compared to controls. Bilateral microinjection of the α1‐adrenergic receptor antagonist benoxathian into the PVN reduced acute stress‐induced adrenocorticotrophic hormone (ACTH) levels by approximately 25% in controls. Furthermore, in cold‐stressed rats, all of the sensitisation of the ACTH response was blocked by benoxathian, to a level comparable to benoxathian‐treated controls. In a second study using microdialysis to measure norepinephrine release in the PVN, there were no differences in either baseline or acute stress‐induced increases in norepinephrine release in the PVN of cold‐stressed rats compared to controls. Thus, in a third study, we tested potential alterations in postsynaptic α1‐receptor sensitivity after chronic cold stress. Dose‐dependent activation of ACTH secretion by microinjection of the α1‐adrenergic receptor agonist, phenylephrine, into the PVN was significantly enhanced in cold‐stressed rats compared to controls. Thus, the sensitised HPA response to acute stress after chronic intermittent cold exposure is at least partly attributable to an enhanced response to α1‐adrenergic receptor activation in the PVN. Chronic stress‐induced plasticity in the acute stress response may be important for stress adaptation, but may also contribute to pathophysiological conditions associated with stress. Thus, understanding the neural mechanisms underlying such adaptations may help us understand the aetiology of such disorders, and contribute to the future development of more effective treatment or prevention strategies.
It's good to be queen: classically eusocial colony structure and low worker fitness in an obligately social sweat bee
Authors: RICHARDS MIRIAM H. , FRENCH DEANNA , PAXTON ROBERT J.
Published: October 2005

Lasioglossum malachurum, a bee species common across much of Europe, is obligately eusocial across its range but exhibits clear geographic variation in demography and social behaviour. This variation suggests that social interactions between queens and workers, opportunities for worker oviposition, and patterns of relatedness among nest mates may vary considerably, both within and among regions. In this study, we used three microsatellite loci with 12–18 alleles each to examine the sociogenetic structure of colonies from a population at Agios Nikolaos Monemvasias in southern Greece. These analyses reveal that the majority of colonies exhibit classical eusocial colony structure in which a single queen mated to a single male monopolizes oviposition. Nevertheless, we also detect low rates of multiqueen nest founding, occasional caste switching by worker‐destined females, and worker oviposition of both gyne and male‐producing eggs in the final brood. Previous evidence that the majority of workers show some ovarian development and a minority (17%) have at least one large oocyte contrasts with the observation that only 2–3% of gynes and males (the so‐called reproductive brood) are produced by workers. An evaluation of the parameters of Hamilton's Rule suggests that queens benefit greatly from the help provided by workers but that workers achieve greater fitness by provisioning and laying their own eggs rather than by tending to the queen's eggs. This conflict of interest between the queen and her workers suggests that the discrepancy between potential and achieved worker oviposition is due to queen interference. Comparison of relatedness and maternity patterns in the Agios Nikolaos Monemvasias population with those from a northern population near Tübingen, Germany, points to a north–south cline of increasingly effective queen control of worker behaviour.
Colour vision and speciation in Lake Victoria cichlids of the genus Pundamilia
Authors: CARLETON KAREN L. , PARRY JULIET W. L. , BOWMAKER JAMES K. , HUNT DAVID M. , SEEHAUSEN OLE
Published: October 2005

Lake Victoria cichlids are one of the most speciose groups of vertebrates. Selection on coloration is likely playing an important role in their rapid speciation. To test the hypothesis that sensory biases could explain species differences in mating preferences and nuptial coloration, we studied seven populations of four closely related species of the genus Pundamilia that differ in visual environment and male nuptial colour. Microspectrophotometry determined that the wavelength of maximum absorption (λmax) of the rod pigment and three cone pigments were similar in all four species. Only the long wavelength sensitive (LWS) pigment varied among species, with 3–4 nm shifts in λmax that correlated with differences in the LWS opsin sequence. These subtle shifts in λmax coincided with large shifts in male body colour, with red species having longer LWS pigments than blue species. Furthermore, we observed within and between species a correlation between water transparency and the proportion of red/red vs. red/green double cones. Individuals from turbid water had more red/red double cones than individuals from clear water. The variation in LWS λmax and in the proportion of red/red double cones could lead to differences in perceived brightness that may explain the evolution of variation in male coloration. However, other factors, such as chromophore shifts and higher order neural processing, should also be investigated to fully understand the physiological basis of differential responses to male mating hues in cichlid fish.
Bayesian inference of evolutionary history from chloroplast microsatellites in the cosmopolitan weed Capsella bursa‐pastoris (Brassicaceae)
Authors: CEPLITIS ALF , SU YINGTAO , LASCOUX MARTIN
Published: October 2005

Besides showing an extraordinary degree of phenotypic variability, Capsella bursa‐pastoris (Brassicaceae) is also one of the world's most common plant species and a serious weed in many countries. We have employed a coalescent‐based Bayesian analysis of chloroplast microsatellite data to infer demographic and evolutionary parameters of this species. Two different demographic models applied to data from seven chloroplast microsatellite loci among 59 accessions show that the effective population size of C. bursa‐pastoris is very small indicating a rapid expansion of the species, a result that is in accordance with fossil and historical data. Against this background, analysis of flowering time variation among accessions suggests that ecotypic differentiation in flowering time has occurred recently in the species’ history. Finally, our results also indicate that mononucleotide repeat loci in the chloroplast genome can deteriorate in relatively short periods of evolutionary time.
Microsatellite DNA analysis shows that greater sage grouse leks are not kin groups
Authors: GIBSON ROBERT M. , PIRES DEBRA , DELANEY KATHLEEN S. , WAYNE ROBERT K.
Published: October 2005

The spectacular social courtship displays of lekking birds are thought to evolve via sexual selection, but this view does not easily explain the participation of many males that apparently fail to mate. One of several proposed solutions to this ‘lek skew paradox’ is that kin selection favours low‐ranking males joining leks to increase the fitness of closely related breeders. We investigated the potential for kin selection to operate in leks of the greater sage grouse, Centrocercus urophasianus, by estimating relatedness between lekking males using microsatellite DNA markers. We also calibrated these estimates using data from known families. Mean relatedness within leks was statistically indistinguishable from zero. We also found no evidence for local clustering of kin during lek display, although males tended to range closer to kin when off the lek. These results make kin selection an unlikely solution to the lek skew paradox in sage grouse. Together with other recent studies, they also raise the question of why kin selection apparently promotes social courtship in some lekking species, but not in others.
Nck‐independent actin assembly is mediated by two phosphorylated tyrosines within enteropathogenic Escherichia coli Tir
Authors: Campellone Kenneth G. , Leong John M.
Published: October 2005

Enteropathogenic Escherichia coli (EPEC) stimulates tyrosine‐kinase signalling cascades to trigger localized actin assembly within mammalian cells. During actin ‘pedestal’ formation, the EPEC effector protein Tir is translocated into the plasma membrane, becomes phosphorylated on tyrosine‐474 (Y474) and promotes recruitment of the mammalian adaptor protein Nck to efficiently activate N‐WASP‐Arp2/3‐mediated actin polymerization. Tir also triggers localized actin assembly in the absence of Nck, but the Tir sequences involved in this signalling cascade have not been defined. To identify and characterize the phosphotyrosines that contribute to Nck‐independent pedestal formation, we investigated the regulation of Tir tyrosine phosphorylation and found that phosphorylation is stimulated by Tir clustering. In addition to Y474, residue Y454 is also phosphorylated, although at lower efficiency. These tyrosines differentially contribute to actin polymerization in a fashion reminiscent of actin ‘tail’ formation mediated by the vaccinia virus envelope protein A36R, which utilizes two similarly spaced phosphotyrosines to recruit the adaptors Nck and Grb2, respectively, in order to stimulate N‐WASP. Neither phosphorylated Y454 nor Y474 directly bind Grb2, but Tir derivatives harbouring these residues ultimately recruit N‐WASP and Arp2/3 independently of Nck, suggesting that EPEC exploits additional phosphotyrosine‐binding adaptors capable of initiating actin assembly.
All four Mycobacterium tuberculosis glnA genes encode glutamine synthetase activities but only GlnA1 is abundantly expressed and essential for bacterial homeostasis
Authors: Harth Günter , Masleša‐Galić Saša , Tullius Michael V. , Horwitz Marcus A.
Published: October 2005

Glutamine synthetases (GS) are ubiquitous enzymes that play a central role in every cell's nitrogen metabolism. We have investigated the expression and activity of all four genomic Mycobacterium tuberculosis GS – GlnA1, GlnA2, GlnA3 and GlnA4 – and four enzymes regulating GS activity and/or nitrogen and glutamate metabolism – adenylyl transferase (GlnE), γ‐glutamylcysteine synthase (GshA), UDP‐N‐acetylmuramoylalanine‐d‐glutamate ligase (MurD) and glutamate racemase (MurI). All eight genes are located in multigene operons except for glnA1, and all are transcribed in M. tuberculosis; however, some are not translated or translated at such low levels that the enzymes escape detection. Of the four GS, only GlnA1 can be detected. Each of the eight genes, as well as the glnA1–glnE–glnA2 cluster, was expressed separately in Mycobacterium smegmatis, and its gene product was characterized and assayed for enzymatic activity by analysing the reaction products. In M. smegmatis, all four recombinant‐overexpressed GS are multimeric enzymes exhibiting GS activity. Whereas GlnA1, GlnA3 and GlnA4 catalyse the synthesis of l‐glutamine, GlnA2 catalyses the synthesis of d‐glutamine and d‐isoglutamine. The generation of mutants in M. tuberculosis of the four glnA genes, murD and murI demonstrated that all of these genes except glnA1 are nonessential for in vitro growth. l‐methionine‐S,R‐sulphoximine (MSO), previously demonstrated to inhibit M. tuberculosis growth in vitro and in vivo, strongly inhibited all four GS enzymes; hence, the design of MSO analogues with an improved therapeutic to toxic ratio remains a promising strategy for the development of novel anti‐M. tuberculosis drugs.
Characterization of point mutations in the cdtA gene of the cytolethal distending toxin of Actinobacillus actinomycetemcomitans
Authors: Cao Linsen , Volgina Alla , Huang Chuang‐ming , Korostoff Jonathan , DiRienzo Joseph M.
Published: October 2005

The Cdt is a family of gram‐negative bacterial toxins that typically arrest eukaryotic cells in the G0/G1 or G2/M phase of the cell cycle. The toxin is a heterotrimer composed of the cdtA, cdtB and cdtC gene products. Although it has been shown that the CdtA protein subunit binds to cells in culture and in an enzyme‐linked immunosorbent assay (CELISA) the precise mechanisms by which CdtA interacts with CdtB and CdtC has not yet been clarified. In this study we employed a random mutagenesis strategy to construct a library of point mutations in cdtA to assess the contribution of individual amino acids to binding activity and to the ability of the subunit to form biologically active holotoxin. Single unique amino acid substitutions in seven CdtA mutants resulted in reduced binding of the purified recombinant protein to Chinese hamster ovary cells and loss of binding to the fucose‐containing glycoprotein, thyroglobulin. These mutations clustered at the 5′‐ and 3′‐ends of the cdtA gene resulting in amino acid substitutions that resided outside of the aromatic patch region and a conserved region in CdtA homologues. Three of the amino acid substitutions, at positions S165N (mutA81), T41A (mutA121) and C178W (mutA221) resulted in gene products that formed holotoxin complexes that exhibited a 60% reduction (mutA81) or loss (mutA121, mutA221) of proliferation inhibition. A similar pattern was observed when these mutant holotoxins were tested for their ability to induce cell cycle arrest and to convert supercoiled DNA to relaxed and linear forms in vitro. The mutations in mutA81 and mutA221 disrupted holotoxin formation. The positions of the amino acid substitutions were mapped in the Haemophilus ducreyi Cdt crystal structure providing some insight into structure and function.
Unconventional distribution of facies in a continental rift basin: the Pliocene–Pleistocene Mangas Basin, south‐western New Mexico, USA
Authors: MACK GREG H. , STOUT DEANNA M.
Published: October 2005

The Pliocene–Early Pleistocene Mangas Basin in SW New Mexico, USA, was a N–NW‐trending full graben that changed southward to an eastward‐tilted half graben. Unlike the facies distribution predicted in existing models, the half‐graben part of the Mangas Basin was characterized by broad alluvial fans derived from the footwall scarp, smaller hangingwall‐derived alluvial fans, and a shallow, closed lake (Lake Buckhorn) that locally lapped onto the hangingwall hills. The distribution of facies within the full‐graben part of the Mangas Basin was also unlike that predicted in current models, primarily because of a broad belt of alluvial‐fan sediment derived from the eastern footwall scarp and a narrow belt of axial‐fluvial sediment adjacent to the western footwall scarp. The distribution of facies in the Mangas Basin does not appear to have been controlled by the eastward tilt of the floor of the half graben or ‘see‐saw’ motion of the floor of the full graben, as predicted by existing models, but rather by the large size of the alluvial fans on the eastern side of the basin. These fans were derived from large, high‐relief catchments on the footwall scarp of the Mogollon Mountains, the uplift of which began during Early Miocene. This example illustrates how earlier uplift and drainage development in a mountain range may influence facies distribution in a younger extensional basin.
Calibration of modelled mixing patterns in loess grain‐size distributions: an example from the north‐eastern margin of the Tibetan Plateau, China
Authors: VRIEND MIRJAM , PRINS MAARTEN A.
Published: October 2005

Genetically meaningful decomposition (unmixing) of sediment grain‐size distributions is accomplished with the end‐member modelling algorithm. Unmixing of the loess grain‐size distributions of a Late Quaternary loess–palaeosol succession from the north‐eastern Tibetan Plateau indicates that the loess is a mixture of three end‐members representing very fine sandy, coarse silty and medium silty loess. The unmixing approach potentially enables the unravelling of sediment fluxes from multiple dust sources, opening the way to significant advances in palaeoclimatic reconstructions from loess grain‐size distribution data. However, as laser‐diffraction size analysis is a volume‐based technique, the proportional contributions of the modelled end‐members might deviate (significantly) from weight proportions. Hence, calibration of the end‐member volume proportions to weight proportions must be established before one can calculate the source‐specific dust fluxes. This paper reports the findings of a sediment‐mixing experiment which enables calibration of the modelled mixing patterns established for the Tibetan loess–palaeosol succession.
Modified melanocortin tetrapeptide Ac‐His‐dPhe‐Arg‐Trp‐NH2 at the arginine side chain with ureas and thioureas
Authors: Joseph C.G. , Sorensen N.B. , Wood M.S. , Xiang Z. , Moore M.C. , Haskell‐Luevano C.
Published: October 2005

Abstract:  The Ac‐His‐dPhe‐Arg‐Trp‐NH2 tetrapeptide is a nonselective melanocortin agonist and replacement of Arg in the tetrapeptide with acidic, basic or neutral amino acids results in reduced potency at the melanocortin receptor (MCR) isoforms (MC1R and MC3–5R). To determine the importance of the positive charge and the guanidine moiety for melanocortin activity, a series of urea‐ and thiourea‐substituted tetrapeptides were designed. Replacement of Arg with Lys or ornithine reduced agonist activity at the mouse mMC1 and mMC3–5 receptors, thus supporting the hypothesis that the guanidine moiety is important for receptor potency, particularly at the MC3–5 receptors. The Arg side chain‐modified tetrapeptides examined in this study include substituted phenyl, naphthyl, and aliphatic urea and thiourea residues using a Lys side‐chain template. These ligands elicit full‐agonist pharmacology at the mouse MCRs examined in this study.