bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fitness advantage from nuptial gifts in female fireflies
Authors: Rooney Jennifer , Lewis Sara M. 
Published: March 2003

Abstract 1. In many insects, males provide nuptial gifts to females in the form of spermatophores, sperm‐containing structures produced by male accessory glands.2. The work reported here examined the influence of both spermatophore number and spermatophore size on female reproductive output in two related firefly beetles, Photinus ignitus and Ellychnia corrusca (Coleoptera: Lampyridae). Based on differences in adult diet, male spermatophores were predicted to increase female reproductive output to a greater extent in P. ignitus than in E. corrusca.3. Female fecundity was significantly higher in triply mated females than in singly mated females in both species, with no difference between mating treatments in female lifespan or egg hatching success. No effects of second male spermatophore size on fecundity, lifespan, or egg hatching success were detected in either species.4. These results suggest a direct fitness advantage from multiple mating for females in both species, although enhanced fecundity may be due either to allocation of spermatophore nutrients to eggs or to other substances transferred within the spermatophore acting as oviposition stimulants.
Opposing survivorship and fecundity effects of host phenology on the gall‐forming aphid Hormaphis hamamelidis
Authors: Rehill Brian , Schultz John 
Published: March 2003

Abstract  1. This study examined the synchronisation and roles of host and insect phenology for fundatrices of the gall‐forming aphid Hormaphis hamamelidis, which forms galls on the leaves of the understorey tree Hamamelis virginiana.2. Host and insect phenologies varied widely among years and individual host trees.3. Most winter eggs (≈ 85%) hatched before budbreak and galls could be initiated but in 2 years there was no inherent risk for earlier hatching fundatrices in terms of greater mortality. Egg hatch was not synchronised tightly with host trees but instead seemed to occur well in advance of budbreak as a conservative, bet‐hedging strategy to ensure the opportunity to form galls.4. Fundatrices that formed galls later had higher fecundity, contrary to typical patterns for insects that feed on the first flush of leaves in temperate forests, where later herbivores have lower fecundity. Also, unlike many other systems, trees that had later budbreak had greater densities of galls.
Differential vulnerability of prey to an invading top predator: integrating field surveys and laboratory experiments
Authors: Woodward Guy , Hildrew Alan G. 
Published: March 2003

Abstract1. A new top predator, the dragonflyCordulegaster boltonii, invaded Broadstone Stream (U.K.) in the mid‐1990s. This provided a rare opportunity to assess the impact of a new, large carnivore on a community that has been studied since the 1970s and has one of the most detailed food webs yet published. The vulnerability of the resident species to the invader was assessed by integrating experiments, which examined discrete stages in the predation sequence, with empirical survey data.2. Although the new predator preyed on nearly every macro‐invertebrate in the food web, vulnerability varied considerably among prey species. Size‐related handling constraints initially set the predator's diet, resulting in strong ontogenetic shifts, with progressively larger prey being added while small prey were retained in the diet, as predators grew. Within the size range of vulnerable prey, encounter rate limited the strength of predation, with mobile, epibenthic species being most at risk. Contrary to most studies of interactions between freshwater predators (usually stoneflies) and prey (usually mayflies), the new predator did not elicit avoidance responses from its prey, probably because it combined a highly cryptic feeding posture with an extremely rapid attack response.3. The invader exploited its prey heavily in experiments, even at prey densities orders of magnitude above ambient. In the field,electivityreflected prey availability, as determined by mobility and microhabitat use, rather than prey abundance or active predator choice. Consequently, the invader had skewed effects within the prey assemblage, with sedentary, interstitial species being far less vulnerable than more active, epibenthic species, some of which, including a previous top predator, have declined markedly since the invasion.4. By examining the predation sequence in detail and integrating surveys with experiments, species traits and system characteristics that determine the strength of trophic interactions may be identified, and their potential importance in natural food webs assessed. In so doing, greater insight can be gained into which species (and systems) will be most vulnerable to invading or exotic predators, an imperative in both pure and applied ecology.
The influence of host plant diversity and food quality on larval survival of plant feeding heteropteran bugs
Authors: Di Giulio Manuela , Edwards Peter J. 
Published: March 2003

Abstract. 1. In a laboratory experiment, the influence of host plant diversity and food quality, in terms of nitrogen content, on the larval survival of two oligophagous bug species (Heteroptera, Miridae: Leptopterna dolobrata L., Notostira erratica L.) was investigated. Both species are strictly phytophagous and capable of feeding on a wide range of grass species. Moreover, they typically change their host plants during ontogenesis; it has been suggested that this behaviour is a response to the changing protein content of the hosts.2. To investigate the importance of host plant diversity for these insects, the development of insects reared on grass monocultures was compared with that on mixtures of four grass species. In addition, the host grasses were grown under two nitrogen regimes to test whether nitrogen content is the key factor determining host plant switching.3. Both species had a significantly higher survival rate when feeding on several host plants but only L. dolobrata showed a significant response to food nitrogen content. Furthermore, there was no correlation between the nitrogen content of the host plants and the survival rate of N. erratica larvae.4. The study suggests that at least some Stenodemini need a variety of host plants during larval development but that the level of host plant nitrogen is not the main factor responsible for the observed diversity effect.
Nucleopolyhedroviruses of forest and western tent caterpillars: cross‐infectivity and evidence for activation of latent virus in high‐density field populations
Authors: Cooper Dawn , Cory Jenny S. , Theilmann David A. , Myers Judith H. 
Published: March 2003

Abstract. 1. Cyclic population dynamics of forest caterpillars are often associated with epizootics of nucleopolyhedrovirus, but it is not known how these viruses persist between generations or through the fluctuations in host population density.2. To explore the question of virus persistence at different phases of the population cycle, the nucleopolyhedroviruses of two species of tent caterpillar that co‐occur in British Columbia, Canada, Malacosoma californicum pluviale (western tent caterpillar) and Malacosoma disstria (forest tent caterpillar), were characterised. The cross‐infectivity of the viruses in these two host species was investigated to determine whether there might be a route for virus persistence via the alternative host species. Any virus produced in the cross‐infections was characterised to confirm true cross‐infection or to ascertain whether cross‐inoculation triggered latent virus persisting within the population.3. The virus associated with forest tent caterpillars (MadiNPV) did not infect western tent caterpillars from low‐density populations, nor did it trigger a latent virus infection; however, inoculation of forest tent caterpillars from high‐density populations with virus from western tent caterpillars (McplNPV) resulted in viral infection, but without a dose–response relationship.4. Analysis of DNA profiles of virus resulting from cross‐infection of the forest tent caterpillar with McplNPV, revealed that 88% of these infections were caused by MadiNPV rather than McplNPV; however the virus from all 44 infected individuals was identical and differed in DNA profile from the stock MadiNPV used for cross‐infection. This suggests strongly that forest tent caterpillars from high‐density field populations harbour a latent, persistent, or sublethal form of MadiNPV that was triggered by exposure to nucleopolyhedrovirus from the western tent caterpillar.5. Virus was not activated in western tent caterpillars collected over 2 years of late population decline and the first year of population increase.
Biological warfare in the garden pond: tadpoles suppress the growth of mosquito larvae
Authors: Mokany Allie , Shine Richard 
Published: March 2003

Abstract. 1. Although tadpoles and mosquito larvae may compete for scarce resources in natural freshwater systems, the mechanisms involved in such competition remain largely unstudied.2. Replicated artificial ponds were set up to examine the role of pathogenic interference (water‐borne growth inhibitors) in two tadpole–mosquito systems from south‐eastern Australia. One system comprised taxa that are commonly sympatric in freshwater ponds (tadpoles of Limnodynastes peronii and larvae of Culex quinquefasciatus) while the other comprised species that co‐occur in brackish water ponds (tadpoles of Crinia signifera and larvae of Ochlerotatus australis).3. Water that had previously contained tadpoles suppressed the rates of survival and pupation of mosquito larvae in both systems. Fungicide reduced or eliminated this effect, suggesting that the growth inhibitors may be fungal organisms (possibly the yeast Rhodotorula glutinis) from tadpole faeces. Fungicide also enhanced growth rates of tadpoles.4. These results suggest that interference competition between tadpoles and mosquito larvae is mediated by other organisms in some ecological systems.
Species richness and parasitism in an assemblage of parasitoids attacking maize stem borers in coastal Kenya
Authors: Zhou Guofa , Overholt William A. , Kimani‐Njogu Susan W. 
Published: March 2003

Abstract.1. Parasitoids were reared from four species of lepidopteran stem borer collected in maize in southern coastal Kenya from 1992 to 1999. The stem borers included three native species,Sesamia calamistisHampson,Busseola fuscaFuller, andChilo orichalcociliellus(Strand), and one exotic borer,Chilo partellus(Swinhoe). A total of 174 663 caterpillars was collected, of which 12 645 were parasitised.2. Twenty‐six primary parasitoid species were reared from the exotic borer,C. partellus, indicating a rapid accumulation of native parasitoids on the alien borer.3. The three most abundant parasitoids were the larval parasitoidsCotesia sesamiaeCameron,Cotesia flavipes(Cameron), and the pupal parasitoidPediobius furvusGahan. The pupal parasitoidDentichasmias busseolaeHeinrich and the larval parasitoidGoniozus indicusAshmead were also common. All used an ingress‐and‐sting method of attack.4.Cotesia flavipes, introduced into Kenya in 1993, was found in all seasons from 1997 onwards, and has become the most abundant stem borer larval parasitoid in the area. A native congener,Cotesia sesamiae, appeared in all seasons from 1992 to 1999. Together, these two parasitoids accounted for 83.3% of the parasitised borers.5. Thirty parasitoid species were recovered in Kilifi district, 27 in Kwale, and 15 in Taita Taveta. Parasitism was much greater in Taita Taveta district than in Kilifi or Kwale districts.
Impact of recombinant human growth hormone treatment on psychological profiles in hypopituitary patients with adult‐onset growth hormone deficiency
Authors: Giusti  , Meineri  , Malagamba  , Cuttica  , Fattacciu  , Menichini  , Rasore  , Giordano  
Published: March 2003

BackgroundWe examined the effect of growth hormone (GH) administration on the psychological capacity and sense of well‐being in 25 patients with adult‐onset GH‐deficiency (GHD).MethodsVery low dosages (0.5–1.0 UI day−1 s.c. at bed‐time) of recombinant human (rh)‐GH (n = 13; aged 50 ± 15 years, mean ± SD) or placebo (n = 12, 53 ± 14 years) were given at random for a 6‐month period. Quality of life was assessed by using the Italian version of the self‐rating Kellner Symptom Questionnaire (KSQ) and the Hamilton Depression Scale (HDS).ResultsNo difference in insulin‐like growth factor I (IGF‐I) levels was noted between groups on entry to the study. A significant increase in IGF‐I (month 0 56.2 ± 10.4 μg L−1 vs. month 6 125.7 ± 16.7 μg L−1; P < 0.001) levels was noted only in the rh‐GH‐treated group. There was no difference in overall scores on the KSQ between the rh‐GH‐treated and control groups on entry. A slight, non‐significant, decrease in overall scores was noted in both groups of subjects. Subsection analysis of items from the KSQ did not show significant differences in either group during the 6‐month period. A significant decrease (month 0 28 ± 1 vs. month 6 25 ± 1; P = 0.02) in the HDS score was noted in rh‐GH‐treated but not in placebo‐treated patients. There was a significant correlation (rs, –0.56, P = 0.05) between increase in IGF‐I levels and decrease in HDS scores in rh‐GH treated patients.ConclusionThe data demonstrate that low rh‐GH dosages significantly improve psychological profiles as rated by HDS evaluation in adult‐onset patients with GHD. On the other hand, a 6‐month period of treatment does not produce any significant differences in quality of life as measured by KSQ between treated patients and placebo controls.
Inhibitory effects of hyperglycaemia on fed jejunal motility: potential role of hyperinsulinaemia
Authors: Byrne  , Pluntke  , Wank  , Schirra  , Arnold  , Göke  , Katschinski  
Published: March 2003

BackgroundAcute hyperglycaemia is known to inhibit jejunal interdigestive motility. This study was undertaken to establish the effects of hyperglycaemia on fed jejunal motility and small intestinal transit time, and to establish if the effects of hyperglycaemia are mediated in part by hyperinsulinaemiaMethodsNine healthy male volunteers were studied in random order using three experimental conditions: (a) euglycaemic clamp (glucose 5 mmol L−1); (b) hyperglycaemic clamp (glucose 15 mmol L−1); and (c) euglycaemic hyperinsulinaemic clamp (glucose 5 mmol L−1). Fed jejunal motility was induced by an intrajejunal perfusion of lipid (Lipofundin medium‐chained triglyceride 10%) at 1.5 mL min−1 (1.5 kcal min−1) for 180 min through the most proximal port of a manometry catheter (eight ports spaced at 2‐cm intervals) located just distal to the ligament of Treitz. One minute after starting the lipid perfusion, 15 g of lactulose dissolved in 20 mL of tap water was infused. Small intestinal transit time was measured by the hydrogen breath test.ResultsAcute hyperglycaemia reduced the total number of jejunal contractions and progradely propagated contractions, the motility index (P < 0.05) and the mean amplitude of contractions and delayed intestinal transit time. Hyperinsulinaemia reduced the total number of jejunal contractions, motility index (P < 0.05) and intestinal transit time.ConclusionsThus, hyperinsulinaemia may contribute to the inhibitory effects of hyperglycaemia on jejeunal motility. In addition, this study demonstrated that intrajejunal infusion of lipid stimulates sustained glucagon‐like peptide‐1 release. In contrast to fat‐induced gastric inhibitory polypeptide release, this glucagon‐like peptide‐1 release is not inhibited by exogenous or endogenous hyperinsulinaemia (P = 0.59).
Polymorphisms of the tumour necrosis factor‐α gene, coronary heart disease and obesity
Authors: Herrmann  , Ricard  , Nicaud  , Mallet  , Arveiler  , Evans  , Ruidavets  , Luc  , Bara  , Parra  , Poirier  , Cambien  
Published: March 2003

BackgroundTumour necrosis factor‐α (TNF‐α) is a cytokine that has multiple functions. Through its effects on lipid metabolism, coagulation, insulin resistance and endothelial function, TNF‐α could be involved in cardiovascular pathophysiology. Given this possibility, we hypothesized that polymorphisms of the TNF‐α gene might be associated with a predisposition to coronary heart disease (CHD).MethodsThe entire coding region and 1053 bp upstream of the transcription start site of the TNF‐α gene were screened for polymorphisms using polymerase chain reaction–single‐strand conformation polymorphism (PCR‐SSCP) and sequencing. Five polymorphisms were identified: four were located in the upstream region at positions −857, −851, −308, −238 from the first transcribed nucleotide and one was found in a non‐translated region at position +691. Six‐hundred and forty‐one patients with myocardial infarction (MI) and 710 control subjects from the ECTIM Study were genotyped.ResultsThe genotype frequencies were similar in cases and control subjects in the high‐risk population of Belfast and in France; however, the TNF‐α/−308A allele was more frequent in Belfast than in France (0.242 vs. 0.157; P < 0.0001), and carriers of this allele were more frequently obese than non‐carriers [1.52 (1.15–1.99), P < 0.004]. No associations were found for the other polymorphisms.ConclusionsThese results suggest that polymorphisms of the TNF‐α gene are unlikely to contribute to CHD risk in an important way, but the TNF‐α/−308 polymorphism should be investigated further in relation to obesity.
Different efficacy of soluble CD14 treatment in high‐ and low‐dose LPS models
Authors: Stelter  , Witt  , Fürll  , Jack  , Hartung  , Schütt  
Published: March 2003

BackgroundAbout 50% of septic shock cases are attributed to Gram‐negative bacteria or their cell wall compound lipopolysaccharide (LPS, endotoxin). An attractive therapeutic strategy could target the binding of LPS to its cellular receptors. In vitro the soluble form of the endotoxin receptor CD14 (sCD14) competitively prevents binding of LPS to membrane‐bound CD14 and inhibits LPS‐stimulated macrophage responses.MethodsWe tested the in vivo endotoxin‐neutralizing capacity of human recombinant sCD14 using a mouse model of shock induced by 8 μg g−1 of LPS from Salmonella abortus equi.ResultsIn this model, treatment with sCD14 reduced mortality if administered before or simultaneously with LPS. However, application of sCD14 had no effect on the secretion of early proinflammatory cytokines and did not protect the animals against the development of apparent shock symptoms and liver injury. sCD14 also failed to prevent LPS‐inducible (7.5 ng g−1) liver injury in galactosamine‐sensitized mice.ConclusionIn line with these findings, sCD14 did not block LPS‐induced activation of Kupffer cells in vitro, which might explain why the compound only partially protected in vivo.
Gastrin/cholecystokinin type B receptors in the kidney: molecular, pharmacological, functional characterization, and localization
Authors: De Weerth  , Jonas  , Schade  , Schöneberg  , Wolf  , Pace  , Kirchhoff  , Schulz  , Heinig  , Greten  , Von Schrenck  
Published: March 2003

BackgroundGastrin/cholecystokinin type B receptors (CCKBRs) can be found on parietal cells and smooth muscle cells and are the predominant brain CCK receptors. Recent cloning studies indicate that this receptor type might also be expressed in the kidney.Materials and methodsWe used Northern blot analysis in guinea pig. kidney and reverse transcriptase polymerase chain reaction (RT‐PCR) in several murine kidney cell lines to evaluate this organ for the expression of the CCKBRs. The receptor was pharmacologically characterized by displacement experiments using [125I]‐BH‐CCKs and various agonists and antagonists. Polyclonal antibodies vs. the CCKBRs were raised in chicken, and immunohistochemistry on tissue sections was used to localize the receptor within the organ. The effect of gastrin on renal cell growth was measured using proximal tubulus (MCT) cells, which were cultured with gastrin (10−9 M) for 24–72 h. Cell counts and [3H]‐thymidine incorporation experiments were performed.ResultsCCKBR transcripts can be detected in kidney RNA (tubules > glomeruli > interstitium). RT‐PCR revealed CCKBR transcripts in proximal tubules (MCT cells) and in mesangium (MMC). The medullary thick ascending limb of Henle's loop and several control tissues such as liver and muscle were negative. Displacement experiments using [125I]‐BH‐CCK and various agonists and antagonists identified binding sites with typical CCKBR pharmacology. CCKBRs were localized in the proximal tubulus, distal collecting ducts and mesangium cells. Treatment of rested MCT cells with gastrin 17‐1 induced cell proliferation and [3H]‐thymidine incorporation by at least 40% compared with normal growth (P < 0.05).ConclusionThese results show for the first time that CCKBRs are present in selected areas of the kidney, and strongly confirm our previous observation that this organ expresses binding sites for [125I]‐gastrin. Furthermore, gastrin might act as a growth factor in the kidney.
Effects of omega‐3 fatty acids and/or antioxidants on endothelial cell markers
Authors: Seljeflot  , Arnesen  , Brude  , Nenseter  , Drevon  , Hjermann  
Published: March 2003

BackgroundIncreased expression of cell adhesion molecules and increased procoagulant activity of the vascular endothelium have been postulated to characterize dysfunctional endothelium. The cellular effects of n‐3 fatty acids (n‐3 FAs) and antioxidants are still not clarified.MethodsIn a randomized, factorial two‐by‐two design study, we have investigated 41 male smokers with hyperlipidaemia before and after 6 weeks of supplementation with either n‐3 FAs (4.8 g daily) or placebo with the addition of antioxidants (150 mg of vitamin C, 75 mg of vitamin E and 15 mg of β‐carotene daily) or placebo with regard to the effects on some endothelial cell markers: thrombomodulin (sTM), von Willebrand factor (vWF), tissue plasminogen activator antigen (tPAag) and soluble forms of the cell adhesion molecules E‐selectin, P‐selectin and vascular cell adhesion molecule 1 (VCAM‐1).ResultsIn the n‐3 FA group, significant reductions in the plasma levels of vWF (P = 0.034) and sTM (P < 0.001) were demonstrated compared with placebo, whereas increased levels were found for E‐selectin (P = 0.001) and VCAM‐1 (P = 0.010). In the antioxidant group, no differences in changes were noted for any of the variables.ConclusionThe reduction in the levels of sTM and vWF with n‐3 FA supplementation could indicate an improvement with regard to the haemostatic markers of endothelial dysfunction, whereas the simultaneous increase in the soluble forms of E‐selectin and VCAM‐1 may suggest an adverse effect on the inflammatory system. The antioxidants seem to be neutral in their effect on these endothelial cell markers in our study population of smokers. The interpretation of the soluble forms of these molecules are, however, still debatable.