bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of emergent aquatic insects on bat foraging in a riparian forest
Authors: FUKUI DAI , MURAKAMI MASASHI , NAKANO SHIGERU , AOI TOSHIKI 
Published: September 2006

SummaryRiparian zones serve several ecological functions for bats. They provide a source of prey and likely provide favourable structural habitats and shelter from predators. Many studies have shown that bats use the space above streams, ponds or riparian vegetation as feeding habitat. These studies, however, have never distinguished between the effects of habitat structure and prey availability on the foraging activities of bats. Such effects can only be distinguished by an experimental approach. We predicted that bat activity along a stream is influenced by the number of emerged aquatic insects.We evaluated the response of terrestrial consumers, insectivorous bats, to changes in the abundance of emergent aquatic insects by conducting a manipulative field experiment. In a deciduous riparian forest in Japan, aquatic insect flux from the stream to the riparian zone was controlled with an insect‐proof cover over a 1·2 km stream reach.We estimated the abundance of emergent aquatic and flying terrestrial arthropods near the treatment and control reaches using Malaise traps. The foraging activity of bats was evaluated in both treatment and control reaches using ultrasonic detectors.The insect‐proof cover effectively reduced the flux of emergent aquatic insects to the riparian zone adjacent to the treatment reach. Adjacent to the control reach, adult aquatic insect biomass was highest in spring, and then decreased gradually. Terrestrial insect biomass increased gradually during the summer at both treatment and control reaches.Foraging activity of bats was correlated with insect abundance. In spring, foraging activity of bats at the control reach was significantly greater than at the treatment reach, and increased at both sites with increasing terrestrial insect abundance.Our result suggests that the flux of aquatic insects emerging from streams is one of the most important factors affecting the distribution of riparian‐foraging bats. As is the case with other riparian consumers, resource subsidies from streams can directly enhance the performance or population density of riparian‐dependent bats. To conserve and manage bat populations, it is important to protect not only forest ecosystems, but also adjacent aquatic systems such as streams.
From plankton to top predators: bottom‐up control of a marine food web across four trophic levels
Authors: FREDERIKSEN MORTEN , EDWARDS MARTIN , RICHARDSON ANTHONY J. , HALLIDAY NICHOLAS C. , WANLESS SARAH 
Published: September 2006

Summary

Abundant mid‐trophic pelagic fish often play a central role in marine ecosystems, both as links between zooplankton and top predators and as important fishery targets. In the North Sea, the lesser sandeel occupies this position, being the main prey of many bird, mammal and fish predators and the target of a major industrial fishery. However, since 2003, sandeel landings have decreased by > 50%, and many sandeel‐dependent seabirds experienced breeding failures in 2004.
Despite the major economic implications, current understanding of the regulation of key constituents of this ecosystem is poor. Sandeel abundance may be regulated ‘bottom‐up’ by food abundance, often thought to be under climatic control, or ‘top‐down’ by natural or fishery predation. We tested predictions from these two hypotheses by combining unique long‐term data sets (1973–2003) on seabird breeding productivity from the Isle of May, SE Scotland, and plankton and fish larvae from the Continuous Plankton Recorder survey. We also tested whether seabird breeding productivity was more tightly linked to sandeel biomass or quality (size) of individual fish.
The biomass of larval sandeels increased two‐ to threefold over the study period and was positively associated with proxies of the abundance of their plankton prey. Breeding productivity of four seabirds bringing multiple prey items to their offspring was positively related to sandeel larval biomass with a 1‐year lag, indicating dependence on 1‐year‐old fish, but in one species bringing individual fish it was strongly associated with the size of adult sandeels.
These links are consistent with bottom‐up ecosystem regulation and, with evidence from previous studies, indicate how climate‐driven changes in plankton communities can affect top predators and potentially human fisheries through the dynamics of key mid‐trophic fish. However, the failing recruitment to adult sandeel stocks and the exceptionally low seabird breeding productivity in 2004 were not associated with low sandeel larval biomass in 2003, so other mechanisms (e.g. predation, lack of suitable food after metamorphosis) must have been important in this case. Understanding ecosystem regulation is extremely important for predicting the fate of keystone species, such as sandeels, and their predators.
Population limitation of the northern red‐backed vole in the boreal forests of northern Canada
Authors: BOONSTRA RUDY , KREBS† CHARLES J. 
Published: September 2006

SummaryAcross the vast boreal forests of North America, no population cycles inClethrionomysspecies occur. In Eurasia, by contrast, someClethrionomyspopulations of the same species undergo regular 3–5‐year cycles. We examined the effects of nutrients, food, competitors, predators and climate on population limitation in the northern red‐backed vole (Clethrionomys rutilusPallas) in the south‐western Yukon to determine why this difference occurs.From 1986 to 1996 we added food, reduced large mammal predators and excluded snowshoe hares (Lepus americanusErxleben) from large plots and found that none of these manipulations affected red‐backed vole abundance. Adding nutrients as nitrogen, phosphorus and potassium (NPK) fertilizer had a slight negative effect, probably acting through a reduction in dwarf shrub productivity caused by competition from grasses.We monitored weasel populations directly through trapping and indirectly through snow tracking. Predation by these vole specialists was irrelevant as a limiting factor most of the time because voles in this area do not reach the densities needed to sustain weasel populations. Other boreal forest mammal and bird predators did not focus on red‐backed voles. However, when red‐backed vole populations increased in the forest andMicrotusvoles also increased in the meadows, weasel populations increased and may have temporarily depressed red‐backed voles in winter.We monitored one major potential food, white spruce seeds, but seed fall was not related to population changes in red‐backed voles, even after mast years.We assessed the impact of weather variables, and the average depth of the snow pack during winter (October–March) was correlated directly with vole demography, having both direct effects in that year and delayed effects in the following year.Our long‐term trapping data (1973–96) indicate thatClethrionomyspopulations fluctuated, with peaks following hare peaks by 2–3 years.We propose that the key variable limiting these vole populations is overwinter survival, and this is a function of overwinter food from berries produced during the previous summer by dwarf shrubs. These shrubs may be stimulated by abundant moisture from winter snows or by periodic fertilization from large quantities of pellets produced at snowshoe hare peaks.
Distribution of a naturally fluctuating ungulate population among heterogeneous plant communities: ideal and free?
Authors: JONES OWEN R. , PILKINGTON JILL G. , CRAWLEY MICHAEL J. 
Published: September 2006

Summary

Herbivore distribution is often assumed to follow the ideal free distribution (IFD) model. This assumes that organisms are omniscient about forage quality and availability within the area available to them and are free to move, with negligible cost, throughout this environment. If this were the case we would expect that, at lowest densities, all animals would be found in the best habitat patches, with less desirable habitats being occupied stepwise as population density increases. We test this using data from a naturally fluctuating population of feral Soay sheep.
We show that, although the distribution of individuals is correlated positively with food quality, in line with patterns reported for hill sheep in Scotland, their distribution does not conform to the predictions of the IFD model. We argue that it is the dynamic nature of their food resource that causes this departure from the predictions of the IFD model and make the case that the IFD model, in its unmodified form, is inappropriate for use in modelling distribution among patches containing dynamic resources.
Pili with strong attachments: Gram‐positive bacteria do it differently
Authors: Scott June R. , Zähner Dorothea 
Published: September 2006

SummaryBacteria attach to their appropriate environmental niche by using adhesins. To maximize their contact with the environment, adhesins are often present on the ends of long hairlike structures called pili. Recently, attention has focused on pili of Gram‐positive bacteria because they may be vaccine candidates in important human pathogens. These pili differ from the well‐studied pili of Gram‐negative bacteria because their subunits are covalently linked, they do not require specific chaperones for assembly, and the tip protein (likely to be the adhesin) is not required to initiate formation of the pilus structure. In Gram‐positive bacteria, the genes for pili occur in clusters, which may constitute mobile genetic elements. These clusters include the transpeptidase(s) of the sortase family that is/are required for polymerization of the subunit proteins. However, efficient covalent attachment of the completed pilus structure to the cell wall is accomplished, in cases where this has been studied, by the ‘housekeeping’ sortase, which is responsible for attachment to the peptidoglycan of most surface proteins containing cell wall sorting signals. This enzyme is encoded elsewhere on the genome. Because pili of Gram‐positive bacteria have not been extensively investigated yet, we hope that this MicroReview will help to pinpoint the areas most in need of further study.
Identification of the first Oomycete annexin as a (1→3)‐β‐d‐glucan synthase activator
Authors: Bouzenzana Jamel , Pelosi Ludovic , Briolay Anne , Briolay Jérôme , Bulone Vincent 
Published: September 2006

Summary(1→3)‐β‐d‐Glucans are major components of the cell walls of Oomycetes and as such they play an essential role in the morphogenesis and growth of these microorganisms. Despite the biological importance of (1→3)‐β‐d‐glucans, their mechanisms of biosynthesis are poorly understood. Previous studies on (1→3)‐β‐d‐glucan synthases from Saprolegnia monoica have shown that three protein bands of an apparent molecular weight of 34, 48 and 50 kDa co‐purify with enzyme activity. However, none of the corresponding proteins have been identified. Here we have identified, purified, sequenced and characterized a protein from the 34 kDa band and clearly shown that it has all the biochemical properties of proteins from the annexin family. In addition, we have unequivocally demonstrated that the purified protein is an activator of (1→3)‐β‐d‐glucan synthase. This represents a new type of function for proteins belonging to the annexin family. Two other proteins from the 48 and 50 kDa bands were identified as ATP synthase subunits, which most likely arise from contaminations by mitochondria during membrane preparation. The results, which are discussed in relation with the possible regulation mechanisms of (1→3)‐β‐d‐glucan synthases, represent a first step towards a better understanding of cell wall polysaccharide biosynthesis in Oomycetes.
Yellow vein‐affected blackberries and the presence of a novel Crinivirus
Authors: Susaimuthu J. , Tzanetakis I. E. , Gergerich R. C. , Martin R. R. 
Published: September 2006

During the last 5 years, blackberry plants in Arkansas and North and South Carolina exhibited virus‐like symptoms of vein yellowing and mosaic, followed in some cases by death. Diagnostic tests for known blackberry viruses failed to identify a causal agent. Double‐stranded RNA was extracted from affected plants and cloned. A new member of the Closteroviridae was identified and designated Blackberry yellow vein associated virus (BYVaV). Molecular and immunological assays have been developed for BYVaV, and examination of plants with symptoms revealed a close association of disease symptoms with the presence of BYVaV, although the virus was also found in symptomless plants. Molecular characterization of isolates from plants exhibiting different degrees of disease severity indicated that sequence diversity is probably not the cause of the observed phenotypic differences.
Response of interspecific Brassica juncea/Brassica rapa hybrids and their advanced progenies to Albugo candida (white blister)
Authors: Gupta K. , Prem D. , Nashaat N. I. , Agnihotri A. 
Published: September 2006

Transfer of factors for resistance to white blister disease caused by Albugo candida between Brassica species involving two genotypes each of B. juncea and B. rapa was studied in hybrids. More hybrids were obtained by in vivo than in vitro techniques, although an in vitro phase was a prerequisite for the establishment of in vivo hybrids. Hybrids were identified by PCR‐based inter‐simple sequence repeat (ISSR) markers with both male and female species‐specific bands being identified. There was a positive correlation between disease severity and number of days after sowing (r > 0·93), the highest being towards pod formation and plant maturity at 110 days after sowing. The plants from F2 and BC1 progeny showed higher resistance to A. candida than either of the parents. Plants of B. juncea and B. rapa with high field resistance (disease index < 1·0) were selected from BC2 and F2BC1 generations. The frequency of plants classified as resistant in BC2 progeny ranged from 4·5 to 39·0% in cross‐combinations involving B. juncea genotypes as female parent, compared with 100% in the reciprocal cross involving B. rapa as female parent.
PCR‐based sensitive and specific detection of Pectobacterium atrosepticum using primers based on Rhs family gene sequences
Authors: Park D. S. , Shim J. K. , Kim J. S. , Kim B. Y. , Kang M. J. , Seol Y. J. , Hahn J. H. , Shrestha R. , Lim C. K. , Go S. J. , Kim H. G. 
Published: September 2006

A sensitive and specific assay was developed to detect potato blackleg caused by Pectobacterium atrosepticum in potato. Primers PEAF and PEAR from the Rhs family gene homologous to RhsA (cell envelope biogenesis – outer membrane) were used to amplify a 904 bp DNA fragment. PCR was used to detect the pathogen in artificially inoculated potato seed tubers. The PCR product was only produced from 12 isolates of P. atrosepticum from various countries among 36 isolates of other species of Pectobacterium, Pseudomonas, Xanthomonas, as well as Escherichia coli and the soilborne fungus Fusarium oxysporum f.sp. dianthi.
Resistance in water yam (Dioscorea alata) cultivars in the French West Indies to anthracnose disease based on tissue culture‐derived whole‐plant assay
Authors: Onyeka T. J. , Pétro D. , Ano G. , Etienne S. , Rubens S. 
Published: September 2006

Reactions of 60 water yam (Dioscorea alata) cultivars to three isolates of the yam anthracnose fungal pathogen (Colletotrichum gloeosporioides) were evaluated using tissue culture‐derived whole‐plant assay. Three disease parameters: single score on a scale of 0–6 at the seventh day after inoculation (SD7); area under the disease progress curve (AUDPC); and disease progress rate (Rd) were compared, and cultivars were classified into disease‐response groups using a rank‐sum method based on AUDPC scores for the two most virulent isolates. A wide range of variation in resistance of the D. alata cultivars, and significant effects of pathogen isolate and isolate–cultivar interactions, were observed for all disease parameters. The three disease parameters were positively correlated; however, four cultivars showed great dispersions from the regression lines for comparisons of SD7 with the multiple assessments based AUDPC and Rd. The 60 cultivars were separated into resistant (n = 12), moderately resistant (n = 19), moderately susceptible (n = 18) and susceptible (n = 11) groups. The potential of the tissue culture‐derived whole‐plant assay to resistance breeding programmes and further understanding of the yam anthracnose pathosystem is discussed.
Effects of isoflurane, pentobarbital, and urethane on apoptosis and apoptotic signal transduction in rat kidney
Authors: Aravindan N. , Cata J. P. , Hoffman L. , Dougherty P. M. , Riedel B. J. , Price K. J. , Shaw A. D. 
Published: September 2006

Background:  Renal cell apoptosis contributes significantly to the pathogenesis of acute renal failure. Anesthetic agents have been shown to modulate apoptotic signal transduction in various tissues. We examined the effects of 6 h of different general anesthetic techniques on renal cell apoptosis in rat kidneys.Methods:  Twenty‐one male Sprague–Dawley rats were randomly allocated into four groups: (i) control, non‐anesthetized rats (n= 3) and rats anesthetized with (ii) inhaled isoflurane (n= 6), (iii) intraperitoneal pentobarbital (n= 6), and (iv) intraperitoneal urethane (n= 6). Animals were sacrificed 6 h after the induction of anesthesia.Results:  Apoptosis was assessed by terminal deoxynucleotidyl transferase‐fluorescein end‐labeling analysis. RNA was extracted from the left kidney to probe cDNA microarrays. Gene expression was measured as a percentage of glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) and subsequently confirmed using reverse transcriptase‐polymerase chain reaction (RT‐PCR). Compared with the control (no anesthesia), urethane significantly (P < 0.001) induced apoptosis in both the renal cortex and medulla. Isoflurane significantly (P < 0.001) inhibited apoptosis in the medulla. Microarray analysis revealed that urethane up‐regulated more (74) genes than pentobarbital (16) and isoflurane (10). Isoflurane down‐regulated more genes (85) than pentobarbital (74) and urethane (12). These anesthetic‐induced modulations were significant (P < 0.05) for 60 isoflurane‐, 30 pentobarbital‐ and 4 urethane‐modulated genes.Conclusion:  Our results suggest that general anesthetic drugs have an effect on renal cell apoptosis and apoptotic signal transduction, and thus may potentially affect the risk of subsequent acute renal failure.
Post‐void residual volume in labor: a prospective study comparing parturients with and without epidural analgesia
Authors: Weiniger C. F. , Wand S. , Nadjari M. , Elchalal U. , Mankuta D. , Ginosar Y. , Matot I. 
Published: September 2006

Background:  This prospective, non‐randomized study compared post‐void residual volume in laboring and postpartum women with or without epidural analgesia.Methods:  The study was conducted over 1 year with institutional review board approval. Parturients were recruited in early labor and self‐selected to either the study (with epidural) or control (without epidural) group. Post‐void residual volume was compared between groups, using transabdominal ultrasound during labor, and on postpartum day 1 and 2. Main outcome measure was intrapartum residual bladder volume.Results:  Thirty patients were recruited to each group. During labor, residual bladder volume was significantly larger in the epidural group compared with the non‐epidural group [median (range)] 240 (12–640), ml vs. 45 (13–250) ml, respectively, P < 0.001], but was similar on postpartum day 1 and 2. Twenty‐five (83%) women with epidural analgesia required bladder catheterization during labor vs. one (3.3%) without (P < 0.0001).Conclusion:  The greater post‐void residual volume and increased inability to void in parturients with epidurals suggests that epidural analgesia plays a role in intrapartum urinary retention.
The effects of pre‐operative dexmedetomidine infusion on hemodynamics in patients with pulmonary hypertension undergoing mitral valve replacement surgery
Authors: But A. K. , Ozgul U. , Erdil F. , Gulhas N. , Toprak H. I. , Durmus M. , Ersoy M. O. 
Published: September 2006

Background:  The aim of this study was to investigate the effects of pre‐operative dexmedetomidine infusion on hemodynamics in patients with pulmonary hypertension undergoing mitral valve replacement surgery.Methods:  Patients were randomly divided into placebo (group P, n= 16) and dexmedetomidine (group D, n= 16) groups. In group D, a 1 μg/kg bolus dose of dexmedetomidine was administered 10 min before the induction of anesthesia, followed by a 0.4 μg/kg/h infusion until the surgical incision. Anesthesia was induced with lidocaine (1 mg/kg), midazolam (0.2 mg/kg) and fentanyl (5 μg/kg) in both groups. Anesthesia was maintained with 0.5% isoflurane and fentanyl depending on the hemodynamic situation. The hemodynamic values during the investigation were obtained.Results:  In group D, the mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP) and pulmonary capillary wedge pressure (PCWP) were decreased effectively in comparison with the values in the placebo group (P < 0.05), and there was an attenuation in the increase in the systemic vascular resistance index (SVRI) and pulmonary vascular resistance index (PVRI) at the post‐sternotomy period.Conclusions:  The pre‐operative administration of the α2‐agonist dexmedetomidine decreases the fentanyl requirement and attenuates the increase in SVRI and PVRI at the post‐sternotomy period relative to the baseline levels, and decreases effectively MAP, MPAP and PCWP in comparison with the values in the placebo group, in patients with pulmonary hypertension undergoing mitral valve replacement surgery.
Inhaled iloprost in eight heart transplant recipients presenting with post‐bypass acute right ventricular dysfunction
Authors: Theodoraki K. , Tsiapras D. , Tsourelis L. , Zarkalis D. , Sfirakis P. , Kapetanakis E. , Alivizatos P. , Antoniou T. 
Published: September 2006

Background:  During heart transplantation, weaning from cardiopulmonary bypass may be particularly laborious as a result of superimposed acute right ventricular dysfunction in the setting of pre‐existing pulmonary hypertension. Research in recent years has focused on inhaled vasodilatory treatment modalities which selectively target the pulmonary circulation.Methods:  We present a series of eight patients in whom inhaled iloprost, a synthetic prostacyclin analog, was used to treat pulmonary hypertension and right ventricular dysfunction detected by transesophageal echocardiography during a heart transplant procedure. In addition to conventional inotropic support, 20 μg of inhaled iloprost was administered via nebulized aerosol for a 20‐min period. Complete sets of hemodynamic measurements were obtained before inhalation and during and after cessation of the inhalation period.Results:  Inhaled iloprost decreased the transpulmonary gradient at the end of the inhalation period relative to baseline (8.2 ± 1.6 mmHg vs. 11.2 ± 0.9 mmHg, P < 0.05). The mean pulmonary artery pressure to systemic artery pressure ratio decreased over this period (0.24 ± 0.07 vs. 0.44 ± 0.09, P < 0.05). A statistically significant decrease in the pulmonary vascular resistance to systemic vascular resistance ratio was also observed (0.10 ± 0.02 vs. 0.19 ± 0.02, P < 0.05). Improved indices of right ventricular function were observed in echocardiographic monitoring.Conclusion:  During heart transplantation procedures, episodes of pulmonary hypertension can be successfully treated with inhaled iloprost administration, without untoward side‐effects or significant systemic impact.