bluuebunny/crossref_metadata_2025_split huggingface dataset:
The lizard assemblage from Seasonally Dry Tropical Forest enclaves in the Cerrado biome, Brazil, and its association with the Pleistocenic Arc
Authors: Werneck Fernanda P. , Colli Guarino R. 
Published: July 2006

AbstractAim To determine if the distributions of lizard species from Seasonally Dry Tropical Forest (SDTF) enclaves within the Cerrado biome in central Brazil are associated with the Tropical Seasonal Forests Region, a recently proposed phytogeographic unit of South America, corroborating the existence of a Pleistocenic Arc of SDTFs.Location SDTF remnants in the Paranã River valley, municipality of São Domingos, Goiás, Brazil.Methods Lizards were extensively sampled using haphazard sampling, funnel traps, and pitfall traps with drift fences during four expeditions. The composition of the SDTF lizard assemblage was compared with those from other South American phytogeographic regions (Caatinga, Cerrado, Chaco, Llanos, and the dry forests of Colombia and Bolivia), based on the literature and our own unpublished data.Results The SDTF lizard assemblage contained 20 species, including 11 species with extensive distributions among the regions considered, seven species shared exclusively with Cerrado localities, a single species shared exclusively with other SDTFs, and one endemic species. The presence ofLygodactylusklugei(Smith, Martin & Swain, 1977), presumably endemic to the Pleistocenic Arc formed by the Tropical Seasonal Forests Region, considerably extends the known distribution of this species, suggesting historical connections between Caatinga and Cerrado SDTF enclaves.Main conclusions The composition of the lizard assemblage in Cerrado SDTF enclaves seems to corroborate the recent proposal that the SDTF should be recognized as a phytogeographic unit (or dominium). The presence of disjunct populations and endemic species highlights the urgency of considering the uniqueness of the Paranã River valley SDTFs and the importance of its conservation.
Biological Flora of the British Isles: Sarcocornia perennis (Miller) A.J. Scott
Authors: DAVY A. J. , BISHOP G. F. , MOSSMAN H. , REDONDO‐GÓMEZ S. , CASTILLO J. M. , CASTELLANOS E. M. , LUQUE T. , FIGUEROA M. E. 
Published: July 2006

Summary

This account reviews information on all aspects of the biology of Sarcocornia perennis that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, and conservation.
Sarcocornia perennis (Miller) A.J. Scott (Salicornia perennis Miller; Salicornia radicans Sm.; Arthrocnemum [Arthrocnemon]perenne (Miller) Moss) of the European and African coasts is now considered also to include Salicornia virginica L., S. ambigua Michx. and S. gaudichaudiana Moq. of the Americas. Sarcocornia perennis is a spreading, jointed‐stemmed, halophyte that differs from the closely related Salicornia in being a shrubby perennial and in aspects of inflorescence structure. In Britain, it is found mainly on the coasts of south‐east England, on gravelly or sandy foreshores, and well‐drained sediments of tidal salt marshes.
Sarcocornia perennis occurs relatively low in the tidal frame but only in well‐drained situations, as seedling establishment and long‐term survival are intolerant of highly reducing surface sediments. It has a role in the early stages of salt‐marsh succession, sometimes as the primary colonist on sandy substrates. In southern Europe, its invasion may be facilitated by the raised clonal tussocks of Spartina maritima, a primary colonist; subsequently, S. perennis dominates the tussocks and supports their rapid radial and upward growth by trapping silt. Pollen flow from the high marsh species Sarcocornia fruticosa may allow invasion by hybrids between the two species.
Hybridization between the diploid S. perennis and octaploid S. fruticosa in south‐west Spain has been confirmed by analysis of random amplified DNA (RAPDs). This has also clarified the relationship between the two subspecies present there (the widely distributed ssp. perennis and the more upright, rigid Iberian endemic ssp. alpini (Lag.) Castroviejo).
Sarcocornia perennis maintains low water potentials and a positive carbon balance under highly saline conditions. Salinity treatment had no effect on the efficiency of Photosystem II (Fv/Fm). Total germination was also unaffected by salinity up to 2%, although above this it was progressively inhibited; the reduction in germination at seawater concentrations was mainly osmotically enforced dormancy, which would promote dispersal by tides and currents.
Deep genetic subdivision within a continuously distributed and highly vagile marine mammal, the Steller's sea lion (Eumetopias jubatus)
Authors: HOFFMAN J. I. , MATSON C. W. , AMOS W. , LOUGHLIN T. R. , BICKHAM J. W. 
Published: July 2006

AbstractThe Steller's sea lion Eumetopias jubatus is an endangered marine mammal that has experienced dramatic population declines over much of its range during the past five decades. Studies using mitochondrial DNA (mtDNA) have shown that an apparently continuous population includes a strong division, yielding two discrete stocks, western and eastern. Based on a weaker split within the western stock, a third Asian stock has also been defined. While these findings indicate strong female philopatry, a recent study using nuclear microsatellite markers found little evidence of any genetic structure, implying extensive paternal gene flow. However, this result was at odds with mark–recapture data, and both sample sizes and genetic resolution were limited. To address these concerns, we increased analytical power by genotyping over 700 individuals from across the species’ range at 13 highly polymorphic microsatellite loci. We found a clear phylogenetic break between populations of the eastern stock and those of the western and Asian stocks. However, our data provide little support for the classification of a separate Asian stock. Our findings show that mtDNA structuring is not due simply to female philopatry, but instead reflects a genuine discontinuity within the range, with implications for both the phylogeography and conservation of this important marine mammal.
Phylogeographic analyses of a circumarctic coastal and a boreal lacustrine mysid crustacean, and evidence of fast postglacial mtDNA rates
Authors: AUDZIJONYTE ASTA , VÄINÖLÄ RISTO 
Published: July 2006

AbstractPhylogeographic structures of two weakly dispersing Mysis sibling species, one with a circumarctic coastal, the other with a boreal lacustrine‐Baltic distribution, were studied from mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. Mysis segerstralei showed high overall diversity and little phylogeographic structure across the Arctic, indicating late‐glacial dispersal among coastal and lake populations from Alaska, Siberia and the north of Europe. A strongly divergent refugial lineage was however identified in Beringia. The boreal ‘glacial relict’Mysis salemaai in turn displayed clear structuring among postglacially isolated Scandinavian lake populations. The inferred pattern of intralake mitochondrial DNA (mtDNA) monophyly in Scandinavia suggested relatively small population sizes and a remarkably fast postglacial mtDNA divergence rate (0.27% per 10 000 years). Nevertheless, the broader phylogeographic pattern did not support distinct eastern and western glacial refugia in Northern Europe, unlike in some other aquatic taxa. In all, the two species comprised three equidistant mitochondrial lineages (approximately 2% divergence), corresponding to M. salemaai, to the bulk of M. segerstralei, and to the Beringian M. segerstralei lineage. The lack of reciprocal monophyly of the two species in respect to their mitochondrial genealogy could indicate postspeciation mitochondrial introgression, also exemplified by an evidently more recent capture of M. segerstralei mitochondria in a Karelian population of M. salemaai. Overall, the data suggest that the continental boreal M. salemaai has a relatively recent ancestry in arctic coastal waters, whereas two other boreal ‘glacial relict’Mysis sibling species in Europe (Mysis relicta) and North America (Mysis diluviana) have colonized inland waters much earlier (approximately 8% COI divergence).
Size breeds success: multiple paternity, multivariate selection and male semelparity in a small marsupial, Antechinus stuartii
Authors: HOLLELEY C. E. , DICKMAN C. R. , CROWTHER M. S. , OLDROYD B. P. 
Published: July 2006

AbstractMating in the marsupial genus Antechinus is a synchronous annual event that is characterized by monoestry in females and abrupt postmating mortality in males. Male semelparity (multiple copulations during a single breeding season per lifetime) is often assumed to occur as a consequence of the intense mating effort expended by males in the rut, but the forces selecting for this remain elusive. Here, we investigate selection in male brown antechinus, Antechinus stuartii, and test two hypotheses for the evolution of semelparity: intermale competition and sperm competition. If intermale competition drives semelparity, we predicted that males would be under strong selection for large body size. If sperm competition is important, we predicted that selection would be strongest on scrotal size, a surrogate for testes volume. Using microsatellite markers, we found that 92% of females in free‐living conditions mated with multiple males, producing litters of eight that had up to four fathers. These observations confirm the potential for sperm competition. Using selection analysis, we then found paternity success in 119 males to be related most strongly to body mass and scrotal size, thus providing support for both hypotheses. Large males presumably experience increased paternity success by gaining more matings or prolonged copulations via mate guarding, while large testes may allow increased sperm investment per copulation. Increased levels of free corticosteroid hormones in males facilitate the extreme mating effort during the short period of rut, but lead to immune suppression and consequently to the phenomenon of postmating mortality.
Nuclear and mitochondrial markers reveal distinctiveness of a small population of bottlenose whales (Hyperoodon ampullatus) in the western North Atlantic
Authors: DALEBOUT MEREL L. , RUZZANTE DANIEL E. , WHITEHEAD HAL , ØIEN NILS I. 
Published: July 2006

AbstractSmall populations at the edge of a species’ distribution can represent evolutionary relics left behind after range contractions due to climate change or human exploitation. The distinctiveness and genetic diversity of a small population of bottlenose whales in the Gully, a submarine canyon off Nova Scotia, was quantified by comparison to other North Atlantic populations using 10 microsatellites and mitrochondrial DNA (mtDNA) control region sequences (434 bp). Both markers confirmed the distinctiveness of the Gully (n = 34) from the next nearest population, off Labrador (n = 127; microsatellites –FST= 0.0243,P < 0.0001; mtDNA –ΦST = 0.0456,P < 0.05). Maximum likelihood microsatellite estimates suggest that less than two individuals per generation move between these areas, refuting the hypothesis of population links through seasonal migration. Both males and females appear to be philopatric, based on significant differentiation at both genomes and similar levels of structuring among the sexes for microsatellites. mtDNA diversity was very low in all populations (h = 0.51, π = 0.14%), a pattern which may be due to selective sweeps associated with this species’ extreme deep‐diving ecology. Whaling had a substantial impact on bottlenose whale abundance, with over 65 000 animals killed before the hunt ceased in the early 1970s. Genetic diversity was similar among all populations, however, and no signal for bottlenecks was detected, suggesting that the Gully is not a relic of a historically wider distribution. Instead, this unique ecosystem appears to have long provided a stable year‐round habitat for a distinct population of bottlenose whales.
Presumptive horizontal symbiont transmission in the fungus‐growing termite Macrotermes natalensis
Authors: DE FINE LICHT H. H. , BOOMSMA J. J. , AANEN D. K. 
Published: July 2006

AbstractAll colonies of the fungus‐growing termite Macrotermes natalensis studied so far are associated with a single genetically variable lineage of Termitomyces symbionts. Such limited genetic variation of symbionts and the absence of sexual fruiting bodies (mushrooms) on M. natalensis mounds would be compatible with clonal vertical transmission, as is known to occur in Macrotermes bellicosus. We investigated this hypothesis by analysing DNA sequence polymorphisms as codominant SNP markers of four single‐copy gene fragments of Termitomyces isolates from 31 colonies of M. natalensis. A signature of free recombination was found, indicative of frequent sexual horizontal transmission. First, all 31 strains had unique multilocus genotypes. Second, SNP markers (n = 55) were largely in Hardy–Weinberg equilibrium (90.9%) and almost all possible pairs of SNPs between genetically unlinked loci were in linkage equilibrium (96.7%). Finally, extensive intragenic recombination was found, especially in the EF1α fragment. Substantial genetic variation and a freely recombining population structure can only be explained by frequent horizontal and sexual transmission of Termitomyces. The apparent variation in symbiont transmission mode among Macrotermes species implies that vertical symbiont transmission can evolve rapidly. The unexpected finding of horizontal transmission makes the apparent absence of Termitomyces mushrooms on M. natalensis mounds puzzling. To our knowledge, this is the first detailed study of the genetic population structure of a single lineage of Termitomyces.
Molecular marker systems in insects: current trends and future avenues
Authors: BEHURA SUSANTA K. 
Published: July 2006

AbstractInsects comprise the largest species composition in the entire animal kingdom and possess a vast undiscovered genetic diversity and gene pool that can be better explored using molecular marker techniques. Current trends of application of DNA marker techniques in diverse domains of insect ecological studies show that mitochondrial DNA (mtDNA), microsatellites, random amplified polymorphic DNA (RAPD), expressed sequence tags (EST) and amplified fragment length polymorphism (AFLP) markers have contributed significantly for progresses towards understanding genetic basis of insect diversity and for mapping medically and agriculturally important genes and quantitative trait loci in insect pests. Apart from these popular marker systems, other novel approaches including transposon display, sequence‐specific amplification polymorphism (S‐SAP), repeat‐associated polymerase chain reaction (PCR) markers have been identified as alternate marker systems in insect studies. Besides, whole genome microarray and single nucleotide polymorphism (SNP) assays are becoming more popular to screen genome‐wide polymorphisms in fast and cost effective manner. However, use of such methodologies has not gained widespread popularity in entomological studies. The current study highlights the recent trends of applications of molecular markers in insect studies and explores the technological advancements in molecular marker tools and modern high throughput genotyping methodologies that may be applied in entomological researches for better understanding of insect ecology at molecular level.
Detection of glycolate oxidase gene glcD diversity among cultured and environmental marine bacteria
Authors: Lau W. W. Y. , Armbrust E. V. 
Published: July 2006

SummaryOf eight laboratory cultures of marine γ‐ and α‐Proteobacteria tested, growth on glycolate as a sole carbon source was detected for only three species: Pseudomonas stutzeri, Oceanimonas doudoroffii and Roseobacter sp. isolate Y3F. Degenerate polymerase chain reaction (PCR) primers were designed to amplify glcD, which encodes the D‐subunit of the enzyme glycolate oxidase; glcD could be amplified only from those cultures that grew on glycolate. The PCR primers were used to explore glcD diversity in four field samples collected from different ocean environments: an Atlantic Gulf Stream Ring, sampled above and below the thermocline and two Pacific coastal sites, Parks Bay and San Juan Channel, WA. Environmental glcD sequences belonged to six major bacterial phylogenetic groups, with most sequences forming novel clades with no close relatives. Different patterns of glcD diversity were observed within and between the two nutrient regimes. Comparison of glcD and 16S rDNA diversity and analyses of available bacterial genomes and a metgenomic library from the Sargasso Sea show that glycolate‐utilizing potential exists in only a subset of bacteria. Glycolate is produced in marine environments mainly by phytoplankton. Examination of glcD diversity will aid in understanding the influence of phytoplankton on bacterial community structure.
The effect ofPhotorhabdus luminescens(Enterobacteriaceae) on the survival, development, reproduction and behaviour ofCaenorhabditis elegans(Nematoda: Rhabditidae)
Authors: Sicard Mathieu , Hering Sebastian , Schulte Rebecca , Gaudriault Sophie , Schulenburg Hinrich 
Published: July 2006

SummaryThe free‐living soil nematodeCaenorhabditis elegansinteracts with diverse microorganisms in its natural habitat. These microorganisms may serve as a food source or represent a harmful threat. As such, they constitute one of the most important ecological factors of the worm’s natural environment. In this study, we examined the interaction between two natural isolates ofC. elegansand three natural isolates of the entomopathogenic bacteriumPhotorhabdus luminescens.Two of the testedP. luminescensstrains were clearly pathogenic. They consistently reduced the worm’s developmental, survival and reproductive rate, most likely through the production of nematicidal compounds. The third natural isolate tested did not decrease worm fitness. These differences could be associated with a deletion of one gene (tcdA4) (∼7kb) of the toxin complex D pathogenicity island, which was found in only the non‐pathogenic strain. Our study additionally highlights the importance of behaviour in defence.Caenorhabditis elegansshowed two distinct avoidance behaviours towards the pathogenic but not the non‐pathogenicP. luminescensstrains. In particular, nematodes physically escaped and also reduced the ingestion of pathogenic bacteria. Our results strongly suggest thatC. eleganspossesses the capacity to distinguish between and subsequently respond to harmful and non‐harmful strains of the same bacterial species. The underlying mechanisms of such interactions are currently unknown. Their dissection will represent a major challenge for future research and should enhance our knowledge of the ecology of this important model organism in biological research.
Phylogenetic identification and metabolism of marine dimethylsulfide‐consuming bacteria
Authors: Vila‐Costa Maria , Del Valle Daniela A. , González José M. , Slezak Doris , Kiene Ronald P. , Sánchez Olga , Simó Rafel 
Published: July 2006

SummaryMicrobial consumption is one of the main processes, along with photolysis and ventilation, that remove the biogenic trace gas dimethylsulfide (DMS) from the surface ocean. Although a few isolates of marine bacteria have been studied for their ability to utilize DMS, little is known about the characteristics or phylogenetic affiliation of DMS consumers in seawater. We enriched coastal and open‐ocean waters with different carbon sources to stimulate different bacterial communities (glucose‐consuming bacteria, methyl group‐consuming bacteria and DMS consumers) in order to test how this affected DMS consumption and to examine which organisms might be involved. Dimethylsulfide consumption was greatly stimulated in the DMS addition treatments whereas there was no stimulation in the other treatments. Analysis of microbial DNA by two different techniques (sequenced bands from DGGE gels and clone libraries) showed that bacteria grown specifically with the presence of DMS were closely related to the genus Methylophaga. We also followed the fate of consumed DMS in some of the enrichments. Dimethylsulfide was converted mostly to DMSO in glucose or methanol enrichments, whereas it was converted mostly to sulfate in DMS enrichments, the latter suggesting use of DMS as a carbon and energy source. Our results indicate that unlike the biochemical precursor of DMS, dimethylsulfoniopropionate (DMSP), which is consumed by a broad spectrum of marine microorganisms, DMS seems to be utilized as a carbon and electron source by specialists. This is consistent with the usual observation that DMSP turns over at much higher rates than DMS.
Prevalence of obesity, central obesity and the associated factors in urban population aged 20–70 years, in the north of Iran: a population‐based study and regression approach
Authors: Hajian‐Tilaki K. O. , Heidari B. 
Published: July 2006

SummaryObesity is an undesirable outcome of changing of lifestyle and behaviours. It is also reversible predisposing factor for the development of several debilitating diseases. This study was aimed to determine the prevalence rate of obesity, overweight, central obesity and their associated factors in the north of Iran. We conducted a population‐based cross‐sectional study with a sample of 1800 women and 1800 men with respective mean ages of 37.5 ± 13.0 and 38.5 ± 14.2 years of urban population aged 20–70 years living in the north of Iran. The demographic and lifestyle data, in particular, age, gender, marital status, marriage age, family history of obesity, educational level, occupation, occupational and leisure time physical activity, duration of exercise per week, parity and the number of children were collected with a designed questionnaire. Diagnosis of obesity and central obesity were confirmed by the WHO standard recommended method by determining of body mass index (BMI) and waist circumference (WC). Logistic regression model was used to estimate the adjusted odds ratio (OR) and its 95% confidence interval. Over half of the study subjects were at educational levels of high school or higher; 79.4% of population was married and 35.3% had a family history of parental obesity. The majority of subjects in particular women had none or low levels of physical activity. The overall prevalence rates of obesity and overweight were 18.8% and 34.8% respectively. The overall prevalence rate of central obesity was 28.3%. The rate of obesity in women was higher than men (P < 0.0001). In both genders, particularly in the women, the rate of obesity was raised by increasing age. There was an inverse relation between the risk of obesity and marriage age, the high level of education (OR = 0.19, P < 0.0001), severe occupational activity (OR = 0.44, P < 0.0001), the level of exercise (in subjects with 3–4 h exercise per week, OR = 0.58, P < 0.001) and leisure time activity. Marriage, history of parental obesity and parity ≥5 were associated with increased risk of obesity (OR = 2.2, P < 0.001 and OR = 2.43, P < 0.0001 and OR = 3.73, P < 0.0001 respectively). The results of this study indicate an increased rate of obesity and overweigh in the north population of Iran. With respect to these findings, low level of activity and education, parity, family history of obesity, marriage at earlier age and ageing are responsible for both obesity and central obesity in the north of Iran. Therefore, a community‐based multiple strategies are required to combat with increasing rate of obesity and its subsequent complications such as diabetes, coronary artery disease, hypertension and osteoarthritis.