bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phylogenetic relationships of crown conchs (Melongenaspp.): thecoronacomplex simplified
Authors: Hayes Kenneth A. , Karl Stephen A. 
Published: September 2008

AbstractAim The larval stages of marine taxa are often assumed to have an overriding influence on the phylogeographical structure of a species as well as on rates of speciation. Phylogeographical disjunctions in high‐dispersal marine taxa are generally attributed to historical events or contemporary ecological factors. The lack of genetic structure in low‐dispersal marine taxa is often ascribed to rafting by juveniles, yet few studies discuss the effects of historical conditions. Around peninsular Florida, there are three species of the crown conch,Melongena, which have direct‐developing, crawl‐away larvae. One of these species,M. corona, is subdivided into three subspecies. We refer to these five taxa as thecoronacomplex. We assessed the validity of these taxa and tested for patterns of phylogeographical subdivision.Location Intertidal Florida and eastern Alabama, USA, Mexico and Panama.Methods The mitochondrial DNA cytochromecoxidase subunit I, and ribosomal DNA 16S genes were sequenced from adult individuals representing all extant taxa ofMelongena. Phylogenetic trees were constructed under maximum likelihood analysis (heuristic search with tree bisection–reconnection branch‐swapping) using the programpaup*.Results Sequence variability in the complex was low and suggested no systematic or phylogeographical partitioning in thecoronacomplex. The species complex probably consists of a single lineage exhibiting no clear pattern of genetic partitioning over the entire range.Main conclusions The present study supports the designation of only four extant species within the genus:M. corona,M. patula,M. melongenaandM. bispinosa. The subspeciesM. corona corona,M. c. johnstoneiandM. c. altispira, and the speciesM. sprucecreekensisandM. bicolor, should all be considered to beM. corona. Surprisingly, even with very low larval and adult vagility, no population subdivisions were noted in our genetic analyses. Our analyses also substantiate the paraphyletic status of the family Melongenidae.
Phylogeography of an estuarine mysid, Neomysis integer (Crustacea, Mysida), along the north‐east Atlantic coasts
Authors: Remerie Thomas , Vierstraete Andy , Weekers Peter H. H. , Vanfleteren Jacques R. , Vanreusel Ann 
Published: September 2008

AbstractAim  The brackish water mysid, Neomysis integer, is one of the most common mysid species along the coasts of the north‐east Atlantic. In the present study, the phylogeographical patterns were examined throughout the distribution range of N. integer. In particular, the latitudinal trends in genetic diversity and the distribution of genetic variation were examined in order to elucidate the imprints of the Pleistocene glaciations.Location  North‐east Atlantic coasts from the Baltic Sea to the south of Spain.Methods  A total of 461 specimens from 11 populations were analysed by means of single‐stranded conformation polymorphism analysis combined with DNA sequencing of a fragment of the mitochondrial cytochrome c oxidase I gene. The genetic structure was examined by using a progression of phylogenetic, demographic and population genetic analyses to elucidate not only the geographical structure, but also the evolutionary history producing that structure.Results  The levels of genetic diversity were relatively uniform throughout the distribution range, with the exception of a decline at the northern and southern edges of distribution. A high heterogeneity was observed between the populations analysed (global ΦST = 0.787). This is caused by the disparate distribution of the cytochrome oxidase I haplotypes, with several population‐specific haplotypes. A clear genetic break (2.4% sequence divergence) occurred between the southernmost Guadalquivir population and all other populations.Main conclusions  The present study corroborates the expectations of the genetic patterns typically observed in an estuarine species. The within‐population variability was low, whereas a significant (moderate to high) divergence was observed between populations. Phylogeographical analysis revealed that northern populations within the English Channel, North Sea and Baltic Sea are characterized by several widespread haplotypes, while the Irish population and all sites south of the Bay of Biscay consist solely of unique haplotypes. This pattern, combined with the relative high levels of genetic diversity, could be indicative for the presence of a glacial refugium in the English Channel region. Under this scenario N. integer must have survived the Last Glacial Maximum in the palaeoriver system present in that region.
Geographical patterns of abundance: testing expectations of the ‘abundance optimum’ model in two taxa of ectoparasitic arthropods
Authors: Krasnov Boris R. , Shenbrot Georgy I. , Khokhlova Irina S. , Vinarski Maxim , Korallo‐Vinarskaya Natalia , Poulin Robert 
Published: September 2008

AbstractAim The ‘abundance optimum’ hypothesis predicts that species abundance peaks in the locality with the most favourable conditions and decreases with an increase of distance from that locality. We tested this prediction for 9 fleas and 13 gamasid mite species.Location We used published data on fleas and gamasid mites that are parasitic on small mammals throughout the Palaearctic.Methods For each ectoparasite, we computed the correlation between the relative abundance on its principal host species in a region and the distance from that region to the region of maximum abundance. Then, the correlation coefficients were used in a meta‐analysis. We also made a cross‐species comparison between relative abundances in localities (a) closest to and (b) furthest from the locality of maximum abundance.Results Although the relationship between the relative abundance in a region and the distance from that region to the region of maximum abundance was negative in 19 out of 22 ectoparasites, it was only statistically significant in three of them. However, a meta‐analysis of coefficients of correlations across all species revealed a significant negative effect of the distance from the region of maximum abundance on relative abundance in a particular region. A cross‐species comparison between relative abundances in the localities closest to and furthest from the locality of maximum abundance demonstrated that the former were significantly higher than the latter.Main conclusions A lack of strict host specificity in the ectoparasites studied, and the absence of any strong spatial correlations among the environmental variables affecting ectoparasite reproduction and abundance, may provide an explanation for the spatial independence in abundance values of most species. However, a preference for a particular host even in host‐opportunistic parasites combined with species‐specific environmental preferences could be the reason behind the weak, but significant, negative abundance–distance relationship across species. The contradiction between results obtained when separate species were considered and when the overall pattern was analysed across species suggests that there exists a general underlying spatial pattern that can often be masked by other factors.
The effect of island area on body size in a primate species from the Sunda Shelf Islands
Authors: Schillaci Michael A. , Meijaard Erik , Clark Terrence 
Published: September 2008

AbstractAim  We examine the effect of island area on body dimensions in a single species of primate endemic to Southeast Asia, the long‐tailed macaque (Macaca fascicularis). In addition, we test Allen’s rule and a within‐species or intraspecific equivalent of Bergmann’s rule (i.e. Rensch’s rule) to evaluate body size and shape evolution in this sample of insular macaques.Location  The Sunda Shelf islands of Southeast Asia.Methods  Body size measurements of insular macaques gathered from the literature were analysed relative to island area, latitude, maximum altitude, isolation from the mainland and other islands, and various climatic variables using linear regression.Results  We found no statistically significant relationship between island area and body length or head length in our sample of insular long‐tailed macaques. Tail length correlated negatively with island area. Head length and body length exhibited increases corresponding to increasing latitude, a finding seemingly consistent with the expression of Bergmann’s rule within a single species. These variables, however, were not correlated with temperature, indicating that Bergmann’s rule is not in effect. Tail length was not correlated with either temperature or increasing latitude, contrary to that predicted by Allen’s rule.Main conclusions  The island rule dictating that body size will covary with island area does not apply to this particular species of primate. Our study is consistent with results presented in the literature by demonstrating that skull and body length in insular long‐tailed macaques do not, strictly speaking, conform to Rensch’s rule. Unlike previous studies, however, our findings suggest that tail‐length variation in insular macaques does not support Allen’s rule.
Structuring asynchronous discussion groups: the impact of role assignment and self‐assessment on students' levels of knowledge construction through social negotiation
Authors: De Wever B. , Van Keer H. , Schellens T. , Valcke M. 
Published: September 2008

AbstractThis article examines the impact of the introduction of roles and the added value of self‐assessment on students' level of knowledge construction in online asynchronous discussions in a first‐year university course in instructional sciences. Students' postings in 20 discussion groups were used as the research data for this study. All messages, submitted during the 12‐week discussion period and comprising four discussion themes of 3 weeks each, were analysed. Repeated‐measures multilevel modeling was adopted to analyse the data from the content analysis. The results point at a significant positive impact of assigning roles to students. However, this positive impact depends on the moment of the introduction of the roles. Higher levels of social knowledge construction were found in discussion groups where roles were introduced right at the start of the discussions and faded out towards the end. The results further indicate that self‐assessment has no significant added value.
Identification of the novel penicillin biosynthesis gene aatB of Aspergillus nidulans and its putative evolutionary relationship to this fungal secondary metabolism gene cluster
Authors: Spröte Petra , Hynes Michael J. , Hortschansky Peter , Shelest Ekaterina , Scharf Daniel H. , Wolke Sandra M. , Brakhage Axel A. 
Published: September 2008

SummaryThe final step of penicillin biosynthesis in the filamentous fungus Aspergillus nidulans is catalysed by isopenicillin N acyltransferase encoded by the aatA gene. Because there is no bacterial homologue, its evolutionary origin remained obscure. As shown here, disruption of aatA still enabled penicillin production. Genome mining led to the discovery of the aatB gene (AN6775.3) which has a similar structure and expression pattern as aatA. Disruption of aatB resulted in a reduced penicillin titre. Surface plasmon resonance analysis and Northern blot analysis indicated that the promoters of both aatA and aatB are bound and regulated by the same transcription factors AnCF and AnBH1f. In contrast to aatA, aatB does not encode a peroxisomal targeting signal (PTS1). Overexpression of a mutated aatBPTS1 gene in an aatA‐disruption strain (leading to peroxisomal localization of AatB) increased the penicillin titre more than overexpression of the wild‐type aatB. Homologues of aatA are exclusively part of the penicillin biosynthesis gene cluster, whereas aatB homologues also exist in non‐producing fungi. Our findings suggest that aatB is a paralogue of aatA. They extend the model of evolution of the penicillin biosynthesis gene cluster by recruitment of a biosynthesis gene and its cis‐regulatory sites upon gene duplication.
Morphology and evolution of an anastomosed channel network where saline underflow enters the Black Sea
Authors: FLOOD ROGER D. , HISCOTT RICHARD N. , AKSU ALI E. 
Published: September 2008

AbstractThe Bosphorus Strait accommodates two‐way flow between the Aegean and Black Seas. The Aegean (Mediterranean) inflow has speeds of 5 to 15 cm sec−1 in the strait and a salinity contrast of ∼12‰ to 16‰ with the Black Sea surface waters on the shelf. An anastomosed channel network crosses the shelf and in water deeper than 70 m is characterized by first‐order channels 5 to 10 m deep, local lateral accretion bedding, muddy in‐channel barforms, and a variety of sediment waves both on channel floors and bar crests, crevasse channels entering the overbank area and levée/overbank deposits which are radiocarbon‐dated in cores to be younger than ∼7·5 to 8·0 ka. This channel network accommodates the saline density current formed by the Mediterranean inflow. The density contrast between the density underflow and the ambient water mass is ∼0·01 g cm−3, similar to the density contrast ascribed to low‐concentration turbidity currents in the deep sea. Channel‐floor deposits are sandy to gravelly with local shell concentrations. Low‐relief bedforms on the channel floor have relatively straight crests, upflow‐dipping cross‐stratification, heights 1 to 1·5 m and wavelengths 85 to 155 m. Bankfull flows are subcritical, so these probably are not antidunes. Bar tops are ornamented locally with mudwaves having heights 1 to 2 m and wavelengths ∼20 to 100 m; these are potentially antidunes formed under shallow overbank flows. Towards the shelf edge, the degree of channel bifurcation increases dramatically and bar tops are dissected locally by secondary channels, some of which terminate in hanging valleys. Conical mounds on the shelf (possibly mud volcanoes or sites of fluid seepage) interact with the channel network by promoting accretion of muddy streamlined macroforms in their lee. This channel network may be one of the largest and most accessible natural laboratories on Earth for the study of continuously flowing density currents. Although the driver is salinity contrast, the underflow transports sufficient sediment to form levée wedges and large streamlined barforms, and presumably transports sediment into deep water.
Dietary chloride deficiency due to new liquid nutritional products
Authors: Miyahara Jun , Aramaki Shuichi , Yokochi Kenji 
Published: September 2008

AbstractBackground:  In infants the ingestion of chloride‐deficient formulas was previously reported to cause hypochloremic metabolic alkalosis and hypokalemia, which is referred to as dietary chloride deficiency syndrome. Since that time, however, dietary chloride deficiency has not been commonly recognized. The aim of the present study was to evaluate the clinical features of dietary chloride deficiency syndrome caused by the ingestion of newly marketed liquid nutritional products.Methods:  This was a retrospective chart review of 59 patients with severe motor and intellectual disability (SMID); they had been given newly marketed liquid nutritional products that were later found to be chloride deficient.Results:  Eight–nine weeks after changing to the new liquid nutritional products, clinical symptoms and laboratory abnormalities were noted. The main clinical finding was weight loss; 22% of subjects lost >5% of their bodyweight. A small number of the subjects had a mild bowel movement disorder; diarrhea and constipation were found in six and three patients, respectively. Hyponatremia, hypokalemia, and hypochloremia occurred in 33.9%, 44.5%, and 50.8%, respectively.Conclusions:  Chloride‐deficient liquid nutritional products can cause weight loss, hypochloremic metabolic alkalosis, and hypokalemia in persons with severe motor and intellectual disability.
Effects of dexamethasone on cardiovascular functions in acute phase in meconium‐injured rabbits
Authors: Mokra Daniela , Tonhajzerova Ingrid , Petraskova Maria , Calkovska Andrea 
Published: September 2008

AbstractBackground:  Because cardiovascular functions and their control mechanisms may be influenced by meconium aspiration and by treatment, cardiovascular parameters including heart rate variability (HRV) were evaluated after meconium instillation and treatment with dexamethasone.Methods:  Adult rabbits were anesthetized, paralyzed, and artificially ventilated. Meconium suspension (25 mg/mL, 4 mL/kg) was instilled intratracheally to induce respiratory failure. Thirty minutes later, animals received i.v. dexamethasone (0.5 mg/kg; dexa group, n = 6) or were left without treatment (control group, n = 5). All animals were ventilated for an additional 5 h. Mean heart rate (MHR), mean blood pressure (MBP), central venous pressure (CVP), and time and spectral analyses of HRV were registered and evaluated. Blood gases were measured and right‐to‐left pulmonary shunts (RLS) calculated.Results:  Immediately after meconium instillation, MBP, CVP, and RLS increased and MHR decreased (P < 0.05). MHR and MBP were restored within several minutes, while CVP and RLS remained high until the end of experiment. Thirty minutes after meconium instillation, slightly but non‐significantly higher spectral powers in all frequency bands of HRV were found (P > 0.05). Dexamethasone treatment enhanced oxygenation (P < 0.05) and slightly reduced PaCO2 (P > 0.05), increased parasympathetic activity expressed by mean squared successive difference and decreased spectral power in the very low frequency band (P < 0.05) compared to controls, but had no significant effect on MHR, MBP, CVP, and RLS.Conclusions:  Single‐dose i.v. dexamethasone showed a trend to improve gas exchange, however, increased parasympathetic activity, what should be considered in use of corticosteroids in the treatment of meconium aspiration syndrome.
Potential benefits of early addition of rosiglitazone in combination with glimepiride in the treatment of type 2 diabetes
Authors: Rosenstock J. , Chou H. S. , Matthaei S. , Seidel D. K. , Hamann A. 
Published: September 2008

Aim:  To assess the efficacy and tolerability of early combination therapy with rosiglitazone (RSG) and glimepiride (GLIM) vs. GLIM monotherapy in patients with type 2 diabetes mellitus (T2DM).Methods:  Strategies for the addition of RSG in combination with GLIM were evaluated with data from two randomized, double‐blind, placebo (PBO)‐controlled studies. Study A – addition of RSG (4 or 8 mg) or PBO to continued GLIM 3 mg once daily; study B – addition of low‐dose RSG (4 mg) prior to uptitration of GLIM (from 2 to 4 mg) vs. continued uptitration of GLIM (from 2 to 8 mg).Results:  Study A reported significant reductions in fasting plasma glucose (FPG) from baseline to week 26 with the addition of both 4 and 8 mg RSG to GLIM 3 mg [−21 mg/dl (−1.2 mmol/l), p = 0.0019 and −43 mg/dl (−2.4 mmol/l), p < 0.0001, respectively] and in haemoglobin A1c (HbA1c) (−0.63%, p = 0.00015 and −1.17%, p < 0.0001, respectively) from a baseline of 8.2 and 8.1%, respectively. At the end of the study, target HbA1c <7.0% was achieved in 43 and 68% of patients in the RSG 4 mg + GLIM and RSG 8 mg + GLIM groups, respectively, compared with 32% in the PBO + GLIM (GLIM alone) group. In study B, addition of RSG to GLIM reduced mean FPG and HbA1c levels at week 24 from baseline [−28 mg/dl (−1.5 mmol/l), p < 0.0001, and −0.68%, p < 0.0001, respectively]. There were no significant changes with GLIM monotherapy in either study. Favourable effects of RSG + GLIM on insulin sensitivity, β‐cell function and cardiovascular disease biomarkers were also observed. All treatments were similarly well tolerated.Conclusions:  Early addition of RSG to GLIM is an effective and well‐tolerated treatment option to improve glycaemic control in sulphonylurea‐treated patients with T2DM.
Preglomerular and postglomerular basal diameter changes and reactivity to angiotensin II in obese rats
Authors: Roos M. H. , Eringa E. C. , Van Rodijnen W. F. , Van Lambalgen T. A. , Ter Wee P. M. , Tangelder G. J. 
Published: September 2008

Aim and Methods: Obesity in humans is associated with proteinuria and an increased glomerular filtration, possibly related to an increase in glomerular capillary pressure. We investigated in obese and lean Zucker rats (10–12 weeks old) whether this might be related to alterations in the diameter of preglomerular and postglomerular microvessels and their reactivity to the resistance regulator angiotensin II (AngII), using the hydronephrotic kidney model.Results: The obese rats exhibited a hyperinsulinaemic, euglycaemic state and hypertension. Urinary protein concentration and fluid intake were both increased threefold. Basal diameters of distal interlobular arteries (ILAs) and afferent arterioles (AAs) were larger in the obese rat than in the lean rat (ILA: 25.7 ± 0.3 vs. 23.0 ± 0.4 μm and AA: 18.8 ± 0.3 vs. 16.7 ± 0.5 μm, respectively; p ≤ 0.01), while diameters of efferent arterioles (EAs) were smaller in obese animals (14.2 ± 1.1 vs. 18.2 ± 1.2 μm; p ≤ 0.05). AngII induced a concentration‐dependent constriction in ILA, AA and EA with an augmented response in the obese compared with the lean rats. Thus, at higher concentrations, AngII abolished the diameter difference between obese and lean animals in preglomerular microvessels while exaggerating that in postglomerular arterioles.Conclusions: Our data indicate that in obese rats, a vasodilated state in small preglomerular microvessels and a vasoconstricted state in the postglomerular arterioles exist. Although AngII cancelled the former, the latter remained. Therefore, these data reveal periglomerular vascular changes that may play a role in glomerular dysfunction and renal pathology associated with obesity.
The effectiveness of glibenclamide in women with gestational diabetes
Authors: Holt R. I. G. , Clarke P. , Parry E. C. , Coleman M. A. G. 
Published: September 2008

Background:  Several studies have suggested that glibenclamide may be used safely and effectively in women with gestational diabetes mellitus (GDM). The aim of our study was to assess effectiveness and safety of glibenclamide for GDM in UK clinical practice.Methods:  Women with GDM requiring pharmacological therapy were offered a choice of insulin or glibenclamide. Maternal and foetal outcomes were assessed in women treated with insulin (45) or glibenclamide (44) and also compared with women treated with diet alone (55).Results:  Thirty‐four (77%) achieved adequate glycaemic control with glibenclamide. Women choosing glibenclamide were more likely to be Asian and had higher fasting and 2‐h glucose at diagnosis than those choosing insulin. There was no difference in maternal age or parity. Ten women treated with glibenclamide switched to insulin [inadequate control (7), unpredictable hypoglycaemia (1) and other reason (2)]. There was no difference in mode of birth, birth weight or birth weight centile between groups. One stillbirth occurred with glibenclamide. Glibenclamide treatment was associated with lower Apgar scores and increased neonatal jaundice. Neonatal hypoglycaemia occurred more frequently in babies of women treated with either glibenclamide or insulin.Conclusion:  The use of glibenclamide in pregnancy is associated with adequate glycaemic control in 77% of women and achieved similar foetal outcomes to women treated with insulin.