bluuebunny/crossref_metadata_2025 huggingface dataset:
The relationship between bone mineral density and the number of remaining teeth in community‐dwelling older adults
Authors: YOSHIHARA A. , SEIDA Y. , HANADA N. , NAKASHIMA K. , MIYAZAKI H.
Published: September 2005

summary Tooth loss and osteoporosis may share common aetiologic agents which influence the process of both diseases. The purpose of this study was to evaluate the relationship between bone mineral density (BMD) of the os calcis and the number of remaining teeth, controlling the known confounding factors. Among all 70‐year‐old inhabitants in Niigata City, Japan, 600 people were selected randomly in order to have approximately the same number of each gender. We analysed 460 subjects. We evaluated the BMD of the os calcis using an ultrasound bone densitometer, then we counted the number of remaining teeth excluding the third molars. Stiffness is a clinical index which is calculated by the spread speed of supersonic waves. To monitor the general health condition of the subjects, serum levels of disease markers and smoking habits were also investigated. The mean number of remaining teeth for the osteopenia group (OG) and the no‐osteopenia group (NOG) was 15·97 ± 9·98 and 18·31 ± 8·06, respectively in females, and 16·32 ± 9·93 and 18·12 ± 9·33, respectively in males (OG versus NOG, P = 0·047 by two‐way anova). In addition, stiffness was significantly associated with the number of remaining teeth (CV = −0·157, P = 0·005) using linear multiple regression analysis adjusted by four other variables. In this study, there was a significant relationship between the number of remaining teeth and BMD of the os calcis.
A decade‐long sour‐taste sensation successfully treated with a proton‐pump inhibitor
Authors: MANTANI N. , ITO K. , KOGURE T. , HOSHINO A. , KAWADA E. , SAKAMOTO H. , FUJITA K. , TAMURA J.
Published: September 2005

summary We report a case study of a 54‐year‐old Japanese woman who persistently suffered from a sour‐taste sensation in her mouth for 10 years, and was treated with a proton‐pump inhibitor (PPI). She found sour‐tasting meals irritable, and after eating such meals the sour‐taste sensation worsened. She also complained of eructation and regurgitation. Upper gastrointestinal (GI) endoscopy showed duodenal erosion, superficial gastritis, and erosive oesophagitis. After 2 weeks of PPI therapy (lansoprazole, 30 mg day−1) the sour taste subjectively decreased to 70%, and after 6 weeks the symptoms disappeared. In addition to increased sensitivity of the mouth, gastro‐oesophageal reflux might have created her obstinate sour‐taste sensations. It is suggested that in such cases PPI therapy should be attempted.
Immediate replacement removable partial dentures with cobalt–chromium frameworks: rationale, technology and a case report
Authors: HASSAN L. , JUSZCZYK A. S. , CLARK R. K. F.
Published: September 2005

summary The advantages of removable partial dentures with cobalt–chromium frameworks over those made entirely of acrylic resin, in oral health and hygiene, are well documented. However, in cases where teeth are to be extracted for fitting the removable partial denture, a difficulty arises because of the need to test the fit of the removable partial denture framework. The advent of two modern technologies – laser welding and metal bonding agents – make it possible to test the fit of the major part of the framework prior to adding additional metal components to support artificial teeth. A case is described in which the four lower incisors were extracted. The main part of the framework was constructed and its fit tested. A second casting was laser‐welded to the lingual plate of the first casting to support the artificial incisor teeth. This technique avoids the need to make an acrylic resin temporary denture but incurs the cost of the additional technical work and so the advantages may be considered to be economically neutral.
The evaluation of vertical heights of maxillary and mandibular bones and the location of anatomic landmarks in panoramic radiographs of edentulous patients for implant dentistry
Authors: GÜLER A. U. , SUMER M. , SUMER P. , BIÇER I.
Published: September 2005

summary The purpose of this study was to determine variations in the vertical height measurements in the edentulous maxilla and mandible, and to assess positions of the maxillary sinus, mandibular foramen, and the mandibular canal, which are important for implant length selection and planning using panoramic radiographs. The study sample included 346 edentulous alveolar ridges of 90 men and 83 women. Sixty‐three dentate patients’ panoramic radiographs were used for location of the first premolar and molar area. Panoramic radiographs were made with a Siemens Orthophos panoramic machine which had been standardized previously. All radiographs were made using a standardized manner by the same technician. Fourteen sites were measured on every panoramic radiograph whenever possible, eight sites in the maxilla and six sites in the mandible. Correlation analyses were performed between age groups and all measurements to determine if age is significant as a covariate. In order to examine the effect of gender the statistical analysis of differences between men and women was performed with Student t‐test. The 5% significance level was used for statistical significancy. The height of the maxilla and the mandible in the anterior, first premolar, and first molar regions were significantly greater in men than in women. A majority of the most inferior border of the maxillary sinuses was located anterior to the first molar area (premolar regions) both in men (48·9%) and women (55·4%). Although, there was no statistically significant difference between edentulous men and women for the vertical distances from the mental foramen to the alveolar crest, and horizontal distances from mental foramen to midline, there were statistically significant differences between edentulous men and edentulous women for the vertical distances from the upper border of the mandibular canal to the alveolar crest in the first molar area. Mental foramens were located at the crest of the ridge in 7·2% of the edentulous women, and 6·7% of the edentulous men. The results of this study may guide clinicians to make primer decision of implant insertion area for implant supported prosthesis in edentulous patients.
Assessment of genetic damage induced by dental bleaching agents on mouse lymphoma cells by single cell gel (comet) assay
Authors: RIBEIRO D. A. , MARQUES M. E. A. , SALVADORI D. M. F.
Published: September 2005

summary Dental bleaching is a simple and conservative procedure for aesthetic restoration of vital discoloured teeth. However, dental bleaching agents may represent a hazard to human health, especially by causing DNA strand breaks. Genotoxicity tests form an important part of cancer research and risk assessment of potential carcinogens. In the current study, the genotoxic potential associated with exposure to dental bleaching agents was assessed by the single cell gel (comet) assay in vitro. Six commercial dental bleaching agents (Clarigel Gold – Dentsply; Whitespeed – Discus Dental; Nite White – Discus Dental; Magic Bleaching – Vigodent; Whiteness HP – FGM and Lase Peroxide – DMC) were exposed to mouse lymphoma cells in vitro. The results pointed out that all dental bleaching agents tested contributed to the DNA damage as depicted by the mean tail moment. Clear concentration‐related effects were obtained for DNA damaging, being the strongest effect observed at the highest dose of the hydrogen peroxide (Whiteness HP and Lase Peroxide, at 35% concentration). On the contrary, Whitespeed (Discus Dental) induced the lowest level of DNA breakage. Taken together, these results suggest that dental bleaching agents may be a factor that increases the level of DNA damage as detected by the single cell gel (comet) assay.
The influence of altered occlusal guidance on condylar displacement during submaximal clenching
Authors: OKANO N. , BABA K. , OHYAMA T.
Published: September 2005

summary As cited in literatures, canine protected occlusion has a potential to reduce clenching induced temporomandibular joint loadings. However, these previous studies did not perform a control of the clenching level which differed with the depending occlusal conditions. This result may be due largely to an associated reduced jaw closing muscle activity. The present study has investigated clenching induced condylar displacements with controlled clenching level. Twenty healthy human subjects (15 males and five females with an average age of 26·5 years) volunteered to participate in this study. Metallic occlusal overlays were fabricated for the lower working side canine and overlaid to the second molar and the non‐working side second molar in order to simulate a canine protected occlusion, group function occlusion and bilateral balanced occlusion. Electromyographic (EMG) activity from the bilateral masseter, anterior temporalis, and posterior temporalis was recorded. These signals were rectified, summarized, and presented to each subject using an oscilloscope screen. Using this visual feedback, subjects were asked to perform clenching tasks at a 50% level of maximal voluntary contraction exerted with simulated group function occlusion and three‐dimensional condylar displacements were recorded. An experimental occlusal pattern that shows statistically significant affects on condylar displacements (anova: P < 0·001) was found. When compared with the simulated canine protected occlusion, the simulated group function occlusion caused smaller working side condylar displacement and the simulated bilateral balanced occlusion caused significantly smaller non‐working side and working side condylar displacements. These results suggest that the increased working side tooth contacts have a potential to reduce working side joint loadings, and a balancing side contact has a potential to reduce non‐working side joint loadings, under the laboratory condition where the clenching level is controlled.
Anxiety and personality traits in patients with muscle related temporomandibular disorders
Authors: PALLEGAMA R. W. , RANASINGHE A. W. , WEERASINGHE V. S. , SITHEEQUE M. A. M.
Published: September 2005

summary This study tested the hypothesis that muscle related temporomandibular disorder patients with cervical muscle pain exhibit greater degree of psychological distress compared with patients without cervical muscle pain and controls. Thirty‐eight muscle related temporomandibular disorder patients including 10 patients with cervical muscle pain and 41 healthy individuals as controls participated in the study. State and trait anxiety levels were assessed with the Spielberger's state and trait anxiety inventory. Personality traits (extroversion, neuroticism, psychoticism and social desirability) were assessed using the Eysenck's personality questionnaire, and the pain intensities described over the muscles were recorded using a 100 mm visual analogue scale. The muscle related temporomandibular disorder patients, in general, exhibited significantly higher degrees of neuroticism and trait anxiety. The patients with cervical muscle pain demonstrated a significantly higher level of psychoticism compared with the patients without cervical muscle pain and the controls and a significantly higher state anxiety level than the controls. They also demonstrated higher pain intensities in masseter and temporalis muscles compared with patients without cervical muscle pain. It has been suggested that either subjects with psychological distress are prone to temporomandibular disorders, or psychological distress is a manifestation of existing chronic pain conditions. The present findings demand further investigations and broader approach in management, as muscle related temporomandibular disorder patients with cervical muscle pain were both physically and psychologically compromised to a greater degree compared with patients without cervical muscle pain.
Clinical marginal and internal gaps of In‐Ceram crowns fabricated using the GN‐I system
Authors: KOKUBO Y. , NAGAYAMA Y. , TSUMITA M. , OHKUBO C. , FUKUSHIMA S. , von STEYERN P. VULT
Published: September 2005

summary The marginal and internal gaps of ceramic crowns with alumina copings fabricated using a computer‐aided design, computer‐aided manufacturing system, were evaluated in vivo using silicone materials. Black and white silicone materials were used to record the marginal and internal gaps of 82 In‐Ceram crowns before final cementation. The silicone materials were sectioned bucco‐lingually and mesio‐distally and viewed under a microscope to measure the thickness of the white silicone layer. Sixteen reference points were measured on each specimen. The mean marginal gaps were compared among the anterior, premolar and molar teeth, and the mean gaps at the reference points within the groups were compared by analysis of variance and the Dunnett T3 test. The mean marginal gap was 66·8 μm. There were no differences in marginal gaps among the three groups. In all the groups, the marginal gaps were the smallest, whereas the occlusal gaps were the largest. The mean marginal gaps of the In‐Ceram crowns with the alumina copings fabricated using the GN‐I system were within the range of clinically acceptable values.
Late Pleistocene divergence between eastern and western populations of wood ducks (Aix sponsa) inferred by the ‘isolation with migration’ coalescent method
Authors: PETERS JEFFREY L. , GRETES WILLIAM , OMLAND KEVIN E.
Published: September 2005

During the Late Pleistocene, glaciers sundered many species into multiple glacial refugia where populations diverged in allopatry. Although deeply divergent mitochondrial DNA (mtDNA) lineages often reflect the number of refugia occupied, it is unlikely that populations that split during the recent Wisconsin glaciations will have reached reciprocal monophyly. We examined mtDNA control region sequences from eastern and western populations of wood ducks (Aix sponsa) to determine whether their current, disjunct distribution is consistent with the occupancy of two glacial refugia. We used the ‘isolation with migration’ coalescent method (im) to simultaneously estimate effective population sizes, maternal gene flow, and time since divergence. We found 24 unique haplotypes, none of which were shared between the eastern and western populations, but we did not find diagnostic monophyletic lineages suggestive of long‐term isolation in multiple glacial refugia. However, a high ΦST (0.31) indicates that eastern and western populations are well differentiated in mtDNA, and results from im suggest that these populations have been diverging, without extensive gene flow, for 10 000 to 124 000 years. Results from im further suggest that these populations most likely split about 34 000 years ago, and this time of divergence is consistent with the occupancy of multiple glacial refugia during the Late Wisconsin glaciation. Eastern wood ducks are characterized by high genetic diversity, a large effective population size, and a recent population expansion, while western wood ducks have much less genetic diversity, a smaller population size, and have not undergone a recent population expansion.
The panmixia paradigm of eastern Pacific olive ridley turtles revised: consequences for their conservation and evolutionary biology
Authors: LÓPEZ‐CASTRO M. C. , ROCHA‐OLIVARES A.
Published: September 2005

Previous studies of the olive ridley Lepidochelys olivacea population structure in the tropical eastern Pacific have indicated the existence of a single panmictic population ranging from Costa Rica to Mexico. This information has been used to design specific management measures to conserve primary nesting beaches in Mexico. However, little is known about olive ridleys in the Baja California Peninsula, their northernmost reproductive limit, where recent observations have shown differences in nesting female behaviour and size of hatchlings relative to other continental rookeries. We used mtDNA control region sequences from 137 turtles from five continental and four peninsular nesting sites to determine whether such differences correspond to a genetic distinction of Baja California olive ridleys or to phenotypic plasticity associated with the extreme environmental nesting conditions of this region. We found that genetic diversity in peninsular turtles was significantly lower than in continental nesting colonies. Analysis of molecular variance revealed a significant population structure (ΦST = 0.048, P = 0.006) with the inclusion of peninsular samples. Our results: (i) suggest that the observed phenotypic variation may be associated with genetic differentiation and reproductive isolation; (ii) support the recent colonization of the eastern Pacific by Lepidochelys; (iii) reveal genetic signatures of historical expansion and colonization events; and (iv) significantly challenge the notion of a single genetic and conservation unit of olive ridleys in the eastern Pacific. We conclude that conservation measures for olive ridleys in Mexico should be revised to grant peninsular beaches special attention.
Population histories of right whales (Cetacea:Eubalaena) inferred from mitochondrial sequence diversities and divergences of their whale lice (Amphipoda:Cyamus)
Authors: KALISZEWSKA ZOFIA A. , SEGER JON , ROWNTREE VICTORIA J. , BARCO SUSAN G. , BENEGAS RAFAEL , BEST PETER B. , BROWN MOIRA W. , BROWNELL ROBERT L. , CARRIBERO ALEJANDRO , HARCOURT ROBERT , KNOWLTON AMY R. , MARSHALL‐TILAS KIM , PATENAUDE NATHALIE J. , RIVAROLA MARIANA , SCHAEFF CATHERINE M. , SIRONI MARIANO , SMITH WENDY A. , YAMADA TADASU K.
Published: September 2005

Right whales carry large populations of three ‘whale lice’ (Cyamus ovalis,Cyamus gracilis,Cyamus erraticus) that have no other hosts. We used sequence variation in the mitochondrialCOIgene to ask (i) whether cyamid population structures might reveal associations among right whale individuals and subpopulations, (ii) whether the divergences of the three nominally conspecific cyamid species on North Atlantic, North Pacific, and southern right whales (Eubalaena glacialis, Eubalaena japonica, Eubalaena australis) might indicate their times of separation, and (iii) whether the shapes of cyamid gene trees might contain information about changes in the population sizes of right whales. We found high levels of nucleotide diversity but almost no population structure within oceans, indicating large effective population sizes and high rates of transfer between whales and subpopulations. North Atlantic and Southern Ocean populations of all three species are reciprocally monophyletic, and North PacificC. erraticusis well separated from North Atlantic and southernC. erraticus. Mitochondrial clock calibrations suggest that these divergences occurred around 6 million years ago (Ma), and that theEubalaenamitochondrial clock is very slow. North PacificC. ovalisforms a clade inside the southernC. ovalisgene tree, implying that at least one right whale has crossed the equator in the Pacific Ocean within the last 1–2 million years (Myr). Low‐frequency polymorphisms are more common than expected under neutrality for populations of constant size, but there is no obvious signal of rapid, interspecifically congruent expansion of the kind that would be expected if North Atlantic or southern right whales had experienced a prolonged population bottleneck within the last 0.5 Myr.
Phylogeographic patterns of HawaiianMegalagriondamselflies (Odonata: Coenagrionidae) correlate with Pleistocene island boundaries
Authors: JORDAN STEVE , SIMON CHRIS , FOOTE DAVID , ENGLUND RONALD A.
Published: September 2005

The Pleistocene geological history of the Hawaiian Islands is becoming well understood. Numerous predictions about the influence of this history on the genetic diversity of Hawaiian organisms have been made, including the idea that changing sea levels would lead to the genetic differentiation of populations isolated on individual volcanoes during high sea stands. Here, we analyse DNA sequence data from two closely related, endemic Hawaiian damselfly species in order to test these predictions, and generate novel insights into the effects of Pleistocene glaciation and climate change on island organisms.Megalagrion xanthomelasandMegalagrion pacificumare currently restricted to five islands, including three islands of the Maui Nui super‐island complex (Molokai, Lanai, and Maui) that were connected during periods of Pleistocene glaciation, and Hawaii island, which has never been subdivided. Maui Nui and Hawaii are effectively a controlled, natural experiment on the genetic effects of Pleistocene sea level change. We confirm well‐defined morphological species boundaries using data from the nuclear EF‐1α gene and show that the species are reciprocally monophyletic. We perform phylogeographic analyses of 663 base pairs (bp) of cytochrome oxidase subunit II (COII) gene sequence data from 157 individuals representing 25 populations. Our results point to the importance of Pleistocene land bridges and historical island habitat availability in maintaining inter‐island gene flow. We also propose that repeated bottlenecks on Maui Nui caused by sea level change and restricted habitat availability are likely responsible for low genetic diversity there. An island analogue to northern genetic purity and southern diversity is proposed, whereby islands with little suitable habitat exhibit genetic purity while islands with more exhibit genetic diversity.
Dispersal, vicariance, and timing of diversification in Nothonotus darters
Authors: NEAR THOMAS J. , KECK BENJAMIN P.
Published: September 2005

The species diversity of North American freshwater fishes is unparalleled among temperate regions of the planet. This diversity is concentrated in the Central Highlands of eastern North America and this distribution pattern has inspired different models involving either dispersal or vicariance to explain the high species diversity of North American fishes. The most popular of these models is the Central Highlands vicariance hypothesis (CHVH), which proposes an ancient and diverse widespread fauna that existed across a previously continuous highland landscape that is much different from today. The mechanisms of isolation in the CHVH involve specific instances of vicariance that affected several diverse lineages of Central Highlands fishes. We tested predictions of the CHVH and alternative models using a cytochrome b‐inferred phylogeny of the darter clade Nothonotus. A Bayesian mixed‐model method was used for phylogenetic analysis. The phylogenetic data set included all 20 recognized Nothonotus species, and most species were represented with multiple sequences. We were able to convert genetic branch lengths to absolute age using external fossil calibrations in the freshwater perciform fish clade Centrarchidae. Using a well‐resolved Nothonotus phylogeny and divergence time estimates, we identify equal numbers of instances of both vicariance and dispersal among disjunct regions of the Central Highlands, biogeographic pseudocongruence, rather recent speciation in Nothonotus, and a surprisingly large amount of speciation within highland areas. With regard to Nothonotus, previous Central Highlands biogeographic models offer little in the way of providing possible mechanisms responsible for diversification in the clade. Patterns of speciation in Nothonotus are similar to those discovered in recent efforts that have included speciation as a parameter into classic models of island biogeography.
An unusual source of apparent mitochondrial heteroplasmy: duplicate mitochondrial control regions in Thalassarche albatrosses
Authors: ABBOTT CATHRYN L. , DOUBLE MICHAEL C. , TRUEMAN JOHN W. H. , ROBINSON ANNA , COCKBURN ANDREW
Published: September 2005

Molecular ecologists, in search of suitable molecular markers, frequently PCR‐amplify regions of mitochondrial DNA from total DNA extracts. This approach, although common, is prone to the co‐amplification of nuclear copies of transposed DNA sequences (numts), which can then generate apparent mitochondrial sequence heteroplasmy. In this study we describe the discovery of apparent mitochondrial sequence heteroplasmy in Thalassarche albatrosses but eliminate the possibility of true sequence heteroplasmy and numts and instead reveal the source of the apparent heteroplasmy to be a duplicated control region. The two control regions align easily but are not identical in sequence or in length. Comparisons of functionally significant conserved sequence blocks do not provide evidence of degeneration in either duplicate. Phylogenetic analyses of domain I of both control region copies in five Thalassarche species indicate that they are largely evolving in concert; however, a short section within them is clearly evolving independently. To our knowledge this is the first time contrasting evolutionary patterns have been reported for duplicate control regions. Available evidence suggests that this duplication may be taxonomically widespread, so the results presented here should be considered in future evolutionary studies targeting the control region of all Procellariiformes and potentially other closely related avian groups.
A mitochondrial DNA minisatellite reveals the postglacial history of jack pine (Pinus banksiana), a broad‐range North American conifer
Authors: GODBOUT JULIE , JARAMILLO‐CORREA JUAN P. , BEAULIEU JEAN , BOUSQUET JEAN
Published: September 2005

Jack pine (Pinus banksianaLamb.) is a broadly distributed North American conifer and its current range was covered by the Laurentian ice sheet during the last glacial maximum. To infer about the history and postglacial colonization of this boreal species, range‐wide genetic variation was assessed using a new and highly variable minisatellite‐like marker of the mitochondrial genome. Among the 543 trees analysed, 14 distinct haplotypes were detected, which corresponded to different repeat numbers of the 32‐nucleotide minisatellite‐like motif. Several haplotypes were rare with limited distribution, suggesting recent mutation events during the Holocene. At the population level, an average of 2.6 haplotypes and a mean haplotype diversity (H) of 0.328 were estimated. Population subdivision of genetic diversity was quite high withGSTandRSTvalues of 0.569 and 0.472, respectively. Spatial analyses identified three relatively homogeneous groups of populations presumably representative of genetically distinct glacial populations, one west and one east of the Appalachian Mountains in the United States and a third one presumably on the unglaciated northeastern coastal area in Canada. These results indicate the significant role of the northern part of the US Appalachian Mountains as a factor of vicariance during the ice age. A fourth distinct group of populations was observed in central Québec where the continental glacier retreated last. It included populations harbouring haplotypes present into the three previous groups, and it had higher level of haplotype diversity per population (H = 0.548) and lower population differentiation (GST = 0.265), which indicates a zone of suture or secondary contact between the migration fronts of the three glacial populations. Introgression fromPinus contortaDougl. var.latifoliaEngelm. was apparent in one western population from Alberta. Altogether, these results indicate that the mitochondrial DNA variation of jack pine is geographically highly structured and it correlates well with large‐scale patterns emerging from recent phylogeographical studies of other tree boreal species in North America.
Mating system, philopatry and patterns of kinship in the cooperatively breeding subdesert mesiteMonias benschi
Authors: SEDDON N. , AMOS W. , ADCOCK G. , JOHNSON P. , KRAAIJEVELD K. , KRAAIJEVELD‐SMIT F. J. L. , LEE W. , SENAPATHI G. D. , MULDER R. A. , TOBIAS J. A.
Published: September 2005

In the first molecular study of a member of the threatened avian family, Mesitornithidae, we used nine polymorphic microsatellite loci to elucidate parentage, patterns of within‐group kinship and occurrence of extra‐group paternity in the subdesert mesiteMonias benschi, of southwest Madagascar. We found this cooperatively breeding species to have a very fluid mating system. There was evidence of genetic monogamy and polygynandry: of the nine groups with multiple offspring, six contained one breeding pair with unrelated helpers and three contained multiple male and female breeders with related helpers. Although patterns of within‐group kinship varied, there was a strong positive relationship between group size and relatedness, suggesting that groups form by natal philopatry. There was also a strong positive correlation between within‐sex and between‐sex relatedness, indicating that unlike most cooperatively breeding birds, philopatry involved both sexes. In contrast to predictions of kin selection and reproductive skew models, all monogamous groups contained unrelated individuals, while two of the three polygynandrous groups were families. Moreover, although between‐group variation in seasonal reproductive success was related to within‐group female relatedness, relatedness among males and between the sexes had no bearing on a group's reproductive output. While kin selection may underlie helping behaviour in females, factors such as direct long‐term fitness benefits of group living probably determine helping in males. Of the 14 offspring produced by fully sampled groups, at least two were sired by males from neighbouring groups: one by a breeding male and one by a nonbreeding male, suggesting that males may augment their reproductive success through extra‐group paternity.
Worldwide structure of mtDNA diversity among Cuvier's beaked whales (Ziphius cavirostris): implications for threatened populations
Authors: DALEBOUT MEREL L. , ROBERTSON KELLY M. , FRANTZIS ALEXANDROS , ENGELHAUPT DAN , MIGNUCCI‐GIANNONI ANTONIO A. , ROSARIO‐DELESTRE RAUL J. , BAKER C. SCOTT
Published: September 2005

We present the first description of phylogeographic structure among Cuvier's beaked whales (Ziphius cavirostris) worldwide using mitochondrial DNA (mtDNA) control region sequences obtained from strandings (n = 70), incidental fisheries takes (n = 11), biopsy (n = 1), and whale‐meat markets (n = 5). Over a 290‐base pair fragment, 23 variable sites defined 33 unique haplotypes among the total of 87 samples. Nucleotide diversity at the control region was relatively low (π = 1.27%± 0.723%) compared to wide‐ranging baleen whales, but higher than strongly matrifocal sperm, pilot and killer whales. Phylogenetic reconstruction using maximum likelihood revealed four distinct haplotype groups, each of which displayed strong frequency differences among ocean basins, but no reciprocal monophyly or fixed character differences. Consistent with this phylogeographic pattern, an analysis of molecular variance showed high levels of differentiation among ocean basins (FST = 0.14, ΦST = 0.42; P < 0.001). Estimated rates of female migration among ocean basins were low (generally ≤ 2 individuals per generation). Regional sample sizes were too small to detect subdivisions within oceans except in the North Atlantic, where the Mediterranean Sea (n = 12) was highly differentiated due to the presence of two private haplotypes. One market product purchased in South Korea grouped with other haplotypes found only in the North Atlantic, suggesting a violation of current agreements banning international trade in cetacean species. Together, these results demonstrate a high degree of isolation and low maternal gene flow among oceanic, and in some cases, regional populations of Cuvier's beaked whales. This has important implications for understanding the threats of human impact, including fisheries by‐catch, direct hunting, and disturbance or mortality from anthropogenic sound.
Phylogeography of the Qinghai‐Tibetan Plateau endemic Juniperus przewalskii (Cupressaceae) inferred from chloroplast DNA sequence variation
Authors: ZHANG Q. , CHIANG T. Y. , GEORGE M. , LIU J. Q. , ABBOTT R. J.
Published: September 2005

The vegetation of the northeast Qinghai‐Tibetan Plateau is dominated by alpine meadow and desert‐steppe with sparse forests scattered within it. To obtain a better understanding of the phylogeography of one constituent species of the forests in this region, we examined chloroplast trnT‐trnF and trnS‐trnG sequence variation within Juniperus przewalskii, a key endemic tree species. Sequence data were obtained from 392 trees in 20 populations covering the entire distribution range of the species. Six cpDNA haplotypes were identified. Significant population subdivision was detected (GST = 0.772, NST = 0.834), suggesting low levels of recurrent gene flow among populations and significant phylogeographic structure (NST > GST, P < 0.05). Eight of the nine disjunct populations surveyed on the high‐elevation northeast plateau were fixed for a single haplotype (A), while the remaining, more westerly population, contained the same haplotype at high frequency together with two low frequency haplotypes (C and F). In contrast, most populations that occurred at lower altitudes at the plateau edge were fixed or nearly fixed for one of two haplotypes, A or E. However, two plateau edge populations had haplotype compositions different from the rest. In one, four haplotypes (A, B, D and E) were present at approximately equivalent frequencies, which might reflect a larger refugium in the area of this population during the last glacial period. Phylogenetic analysis indicated that the most widely distributed haplotype A is not ancestral to other haplotypes. The contrasting phylogeographic structures of the haplotype‐rich plateau edge area and the almost haplotype‐uniform plateau platform region indicate that the plateau platform was recolonized by J. przewalskii during the most recent postglacial period. This is supported by the findings of a nested clade analysis, which inferred that postglacial range expansion from the plateau edge followed by recent fragmentation is largely responsible for the present‐day spatial distribution of cpDNA haplotypes within the species.
Prevalence and penetrance variation of male‐killingWolbachiaacross Indo‐Pacific populations of the butterflyHypolimnas bolina
Authors: CHARLAT SYLVAIN , HORNETT EMILY A. , DYSON EMILY A. , HO PATRICK P. Y. , LOC NGUYEN THI , SCHILTHUIZEN MENNO , DAVIES NEIL , RODERICK GEORGE K. , HURST GREGORY D. D.
Published: September 2005

Male‐killing bacteria are generally thought to attain low to intermediate prevalence in natural populations, with only mild effects on the host population sex ratio. This view was recently challenged by reports of extremely high infection frequencies in three butterfly species, raising the prospect that male killers, by making males rare, might drive many features of host ecology and evolution. To assess this hypothesis, it is necessary to evaluate how often male killers actually produce a highly female‐biased population sex ratio in nature, which requires both high prevalence of infection and high penetrance of action. To this end, we surveyed South Pacific and Southeast Asian populations ofHypolimnas bolina, a butterfly in which extreme prevalence of male‐killingWolbachiabacteria has recently been recorded. Our results indicate that highly female‐biased populations are common in Polynesia, with 6 out of 12 populations studied having in excess of 70% of females infected with a fully efficient male killer. However, heterogeneity is extreme in Polynesia, with the male‐killingWolbachiaabsent from three populations. In contrast to the Polynesian situation,Wolbachiadoes not kill males in any of the three Southeast Asian populations studied, despite its very high prevalence there. We conclude that male killers are likely to have significant ongoing ecological and evolutionary impact in 6 of the 15 populations surveyed. The causes and consequences of the observed spatial variation are discussed with respect to host resistance evolution, host ecology and interference with additional symbionts.
A novel approach to an old problem: tracking dispersed seeds
Authors: GRIVET DELPHINE , SMOUSE PETER E. , SORK VICTORIA L.
Published: September 2005

Animals are the principal vectors of dispersal for a large number of plant species. Unfortunately it is not easy to discern their movement patterns or the fate of their dispersed seeds. Many animals transport seeds by consuming them and then, some time later, defecating them. Others gather seeds and then store them for later consumption. Both circumstances lead to a set of seeds that have been dispersed in a clumped pattern, which offers a unique opportunity to assess seed movements. We introduce a novel approach that uses maternally inherited seed tissue to quantify the genetic structure of dispersed seed pools. This direct approach measures the genetic variability within and among seed pools, and estimates the scale of seed movement, without requiring a highly polymorphic battery of markers or the location and genotypes of all possible seed parents. We demonstrate this approach with the specific case of seed transport of valley oak (Quercus lobata) acorns by acorn woodpeckers (Melanerpes formicivorus). These territorial birds store acorns in drilled holes in the bark of trees, called granaries. We sampled stored acorns from different granaries, extracted DNA from the maternally inherited pericarp, and then assessed individuals for three microsatellite markers. We found extremely high genetic structure among granaries, a low number of effective seed donors per granary, and restricted seed movement. A maternity analysis performed on the same sample with seven microsatellites confirms acorn transport is limited to approximately 100‐m radius. Our findings provide insight into the foraging and seed‐dispersal behaviour of acorn woodpeckers, with an approach that can be widely extended to other systems.
Phylogeography of marine mutualists: parallel patterns of genetic structure between obligate goby and shrimp partners
Authors: THOMPSON ANDREW R. , THACKER CHRISTINE E. , SHAW EMILY Y.
Published: September 2005

The survival of many organisms depends on interspecific, mutualistic interactions. Hence, it is important to assess the phylogeography of multiple mutualistic species simultaneously to gain insight into how their metapopulations persist, spread and recover from disturbance. Consequently, we sequenced mitochondrial DNA (cytochrome b) from a gobiid fish (Ctenogobiops feroculus) and its mutualistic partner, an alpheid snapping shrimp (Alpheus djeddensis). These obligate mutualists are common in shallow coral reef lagoons, and we collected individuals from 11 Indo‐Pacific islands that were likely exposed to different disturbance histories due to sea level fluctuations associated with glaciation events [geological studies indicate that eastern oceanic islands (Cook Islands, French Polynesia) were more disturbed than western continental plate islands that have deeper, more extensive lagoons (Okinawa, Fiji)]. Both phylogenetic and population genetic analyses indicated that gobies from Okinawa and Fiji were genetically distinct both from each other and those in the Cook Islands and French Polynesia. Shrimp, by contrast, grouped into two distinct genetic groups that showed no geographic structure. Restricting the analysis to one clade of shrimp, which contained two‐thirds of the individuals, showed that these shrimp had very similar phylogeographical structure to the gobies. Mismatch distributions demonstrated that both gobies and shrimp experienced a recent, rapid population expansion into French Polynesia. Finally, nucleotide and haplotype diversities per sample location were significantly correlated between mutualists and tended to be higher on western continental than eastern oceanic islands. Our results suggest that these mutualists recovered from a major disturbance by colonizing South Pacific islands in synchrony.
Rapidly declining fine‐scale spatial genetic structure in female red deer
Authors: NUSSEY D. H. , COLTMAN D. W. , COULSON T. , KRUUK L. E. B. , DONALD A. , MORRIS S. J. , CLUTTON‐BROCK T. H. , PEMBERTON J.
Published: September 2005

A growing literature now documents the presence of fine‐scale genetic structure in wild vertebrate populations. Breeding population size, levels of dispersal and polygyny — all hypothesized to affect population genetic structure — are known to be influenced by ecological conditions experienced by populations. However the possibility of temporal or spatial variation in fine‐scale genetic structure as a result of ecological change is rarely considered or explored. Here we investigate temporal variation in fine‐scale genetic structure in a red deer population on the Isle or Rum, Scotland. We document extremely fine‐scale spatial genetic structure (< 100 m) amongst females but not males across a 24‐year study period during which resource competition has intensified and the population has reached habitat carrying capacity. Based on census data, adult deer were allocated to one of three subpopulations in each year of the study. Global FST estimates for females generated using these subpopulations decreased over the study period, indicating a rapid decline in fine‐scale genetic structure of the population. Global FST estimates for males were not different from zero across the study period. Using census and genetic data, we illustrate that, as a consequence of a release from culling early in the study period, the number of breeding females has increased while levels of polygyny have decreased in this population. We found little evidence for increasing dispersal between subpopulations over time in either sex. We argue that both increasing female population size and decreasing polygyny could explain the decline in female population genetic structure.
Specificity of the mutualistic association between actinomycete bacteria and two sympatric species of Acromyrmex leaf‐cutting ants
Authors: POULSEN M. , CAFARO M. , BOOMSMA J. J. , CURRIE C. R.
Published: September 2005

Acromyrmex leaf‐cutting ants maintain two highly specialized, vertically transmitted mutualistic ectosymbionts: basidiomycete fungi that are cultivated for food in underground gardens and actinomycete Pseudonocardia bacteria that are reared on the cuticle to produce antibiotics that suppress the growth of Escovopsis parasites of the fungus garden. Mutualism stability has been hypothesized to benefit from genetic uniformity of symbionts, as multiple coexisting strains are expected to compete and, thus, reduce the benefit of the symbiosis. However, the Pseudonocardia symbionts are likely to be involved in Red‐Queen‐like antagonistic co‐evolution with Escovopsis so that multiple strains per host might be favoured by selection provided the cost of competition between bacterial strains is low. We examined the genetic uniformity of the Pseudonocardia symbionts of two sympatric species of Acromyrmex ants by comparing partial sequences of the nuclear Elongation Factor‐Tu gene. We find no genetic variation in Pseudonocardia symbionts among nest mate workers, neither in Acromyrmex octospinosus, where colonies are founded by a single queen, nor in Acromyrmex echinatior, where mixing of bacterial lineages might happen when unrelated queens cofound a colony. We further show that the two ant species maintain the same pool of Pseudonocardia symbionts, indicating that horizontal transmission occasionally occurs, and that this pool consists of two distinct clades of closely related Pseudonocardia strains. Our finding that individual colonies cultivate a single actinomycete strain is in agreement with predictions from evolutionary theory on host–symbiont conflict over symbiont mixing, but indicates that there may be constraints on the effectiveness of the bacterial symbionts on an evolutionary timescale.
Naturally occurring variation in high temperature induced floral bud abortion across Arabidopsis thaliana accessions
Authors: WARNER RYAN M. , ERWIN JOHN E.
Published: September 2005

A system to study the basis of high temperature‐induced floral bud abortion using naturally occurring variation for heat‐tolerance of floral development among Arabidopsis thaliana (L.) Heynh. wild‐collected accessions is described. High temperature‐induced floral bud abortion was dependent on both temperature and duration of exposure. Normalizing high temperature exposures to degree‐hours (°C‐h) above 33 °C indicated that abortion of flower buds increased as exposure increased between 200 and 300 °C‐h above 33 °C and exposures > 300 °C‐h above 33 °C resulted in abortion of the entire primary inflorescence. Thirteen wild‐collected Arabidopsis accessions representing a latitudinal gradient were screened for variation in high temperature‐induced floral bud abortion, and Col‐0 and No‐0 were selected as models for heat‐tolerance and ‐sensitivity for flower development, respectively. No‐0 flower buds were heat‐sensitive across a wider range of developmental stages (stages 9–12, compared to stage 12 for Col‐0 flower buds). Exposing the inflorescence alone to high temperature was sufficient to induce floral bud abortion, and Col‐0 and No‐0 photosynthetic rates were similar during high temperature exposure and recovery, indicating that high temperature induced floral abortion is not simply due to reductions in carbon assimilation under high temperatures. Determining that exposing floral buds alone to high temperature is sufficient to induce abortion and identifying the stages of floral development sensitive to high temperature‐induced abortion will aid in identifying the developmental events subject to disruption under high temperatures.
Ca2+ and AtCaM3 are involved in the expression of heat shock protein gene in Arabidopsis
Authors: LIU HONG‐TAO , SUN DA‐YE , ZHOU REN‐GANG
Published: September 2005

The involvement of calcium and different calmodulin isoforms (Ca2+‐CaM) in heat shock (HS) signal transduction in Arabidopsis (Arabidopsis thaliana) was investigated. Using transgenic Arabidopsis plants which have the AtHsp18.2 promoter/GUS fusion gene, it was found that the level of β‐glucuronidase (GUS) activity was up‐regulated by the addition of CaCl2 and down‐regulated by the calcium ion chelator EGTA, the calcium ion channel blockers LaCl3 and verapamil, or the CaM antagonists N‐(6‐aminohexyl)‐5‐chloro‐1‐naphthalenesulfonamide (W7), chlorpromazine (CPZ) and trifluoperazine (TFP). CaCl2 not only increased the GUS activity after HS, but also up‐regulated the GUS activity under non‐HS conditions. These results provide additional support for the involvement of the Ca2+‐CaM signalling system in HSP gene expression. The expression of nine CaM genes (AtCaM1–9) from Arabidopsis was differentially regulated by HS at 37 °C. The expression of AtCaM3 and AtCaM7 genes increased during HS. The temporal expression of the AtCaM3, AtCaM7 and hsp18.2 genes demonstrated that up‐regulation of AtCaM3 expression occurred earlier than that of AtCaM7 or hsp18.2.
Correlation between leaf growth variables suggest intrinsic and early controls of leaf size in Arabidopsis thaliana
Authors: COOKSON SARAH J. , VAN LIJSEBETTENS MIEKE , GRANIER CHRISTINE
Published: September 2005

Leaf development is affected by both internal (genetic) and external (environmental) regulatory factors. The aim of this work was to investigate how leaf growth variables are related to one another in a range of environments. The leaf growth variables of wild‐type Arabidopsis thaliana and leaf development mutants (ang4, ron2‐1, elo1, elo2 and elo4) were studied under different incident light treatments (light and shade). The leaves studied were altered in various leaf development variables, such as the duration of expansion, relative and absolute expansion rates, epidermal cell size, epidermal cell number and initiation rate. Final leaf area was correlated to maximal absolute leaf expansion rate and cell number, but not to duration of leaf expansion or cell size. These relationships were common to all studied genotypes and light conditions, suggesting that leaf size is determined early in development. In addition, the early variables involved in leaf development were correlated to one another, and initial relative expansion rate was negatively correlated to the duration of expansion. These relationships between the leaf development variables were used to construct a conceptual model of leaf size control.