bluuebunny/crossref_metadata_2025 huggingface dataset:
The Roles of Vascular Smooth Muscle Cells in the Aortic Wall Thinness under Prolonged Continuous Flow Left Heart Bypass
Authors: Mizuno Toshihide , Nishinaka Tomohiro , Ohnishi Hiroyuki , Tatsumi Eisuke , Tsukiya Tomonori , Oshikawa Mitsuo , Shioya Kyoko , Takewa Yoshiaki , Homma Akihiko , Takano Hisateru , Kitamura Soichiro , Taenaka Yoshiyuki
Published: October 2003

Abstract: Aortic wall thinness was one of the most characteristic changes observed in experimental animals under prolonged continuous flow left heart bypass. The goal of this study was to determine the roles of smooth muscle cells in the vascular remodeling process in cases demonstrating aortic wall thinness under prolonged continuous flow left heart bypass. The aortic samples from three goats in which continuous flow left heart bypass was performed were subjected to histological and immunohistochemical analyses. After 4 weeks of observation, the pulse pressure in the goats under the continuous flow left heart bypass was clearly lower than that in the normal healthy goats. The aortic walls of these goats became thinner, an effect caused by the dilation of their internal diameter. These aortic smooth muscle cells maintained contractile formation due to the fact that they contained abundant alpha‐smooth muscle actin (SMA) and smooth muscle myosin heavy chain (SMMS). These cells also synthesized redundant matrix metalloproteinase‐2 and ‐9, and the ratio of the SMMS‐positive to the SMA‐positive area was significantly lower (0.76) than that observed in the control goat (1.00; P < 0.05). The smooth muscle cells demonstrated synthetic‐dedifferentiated formation, which is one of the phenotypes of smooth muscle cell function. In conclusion, aortic wall thinness under prolonged continuous flow left heart bypass is caused by over‐synthesis of matrix metalloproteinase in smooth muscle cells, and this refers the vascular remodeling process of the extracellular matrix.
Design Progress of the Ultracompact Integrated Heart Lung Assist Device—Part 2: Optimization of the Diffuser Vane Profile
Authors: Tsukiya Tomonori , Tatsumi Eisuke , Nishinaka Tomohiro , Katagiri Nobumasa , Takewa Yoshiaki , Ohnishi Hiroyuki , Oshikawa Mitsuo , Mizuno Toshihide , Taenaka Yoshiyuki , Takano Hisateru , Kitamura Soichiro
Published: October 2003

Abstract: The configuration of the vaned diffuser of the integrated heart lung assist device (IHLAD) has been revised to reduce mechanical blood trauma caused by the device. The flow visualization study of the flow near the diffuser vanes revealed the existence of a rotating stall which deteriorates the hydrodynamic performance of the device and augments the chance for blood cells to pass through the regions with intense shearing forces. Design changes of the diffuser included decrease in vane number from 7 to 5 and decrease in passage width from 3 mm to 2 mm. This design change was effective to suppress initiation of a rotating stall. Improvement of hydrodynamic performance and antihemolytic properties was confirmed with the newly designed configuration based on the flow visualization study.
Evaluation of Pulsatile and Nonpulsatile Flow in Microvessels of the Bulbar Conjunctiva in the Goat with an Undulation Pump Artificial Heart
Authors: Baba Atsushi , Dobsak Petr , Mochizuki Shuichi , Saito Itsuro , Isoyama Takashi , Takiura Koki , Shibata Masahiro , Abe Yusuke , Chinzei Tsuneo , Vasku Jaromir , Imachi Kou
Published: October 2003

Abstract: This study has three purposes, as follows. The first is to develop a microscopic system to observe the microcirculation of animals implanted with an artificial heart. The second is to investigate the influence of flow pattern change from pulsatile to nonpulsatile on the microcirculation. The third is to study the effects of pulsatility in blood flow on endothelium‐derived nitric oxide release in the microvasculature. When the flow pattern was changed from pulsatile to nonpulsatile, the velocity of erythrocytes in many capillaries dropped and remained at a low level, and the number of perfused capillaries decreased. After the flow pattern was returned to pulsatile, the velocity of erythrocytes recovered to the initial level. In many cases, the flow of nonperfused capillaries recovered to the initial level as well. Also, the pulsatile flow enhances the basal and flow‐stimulated endothelium‐derived nitric oxide release in microvessels.
Antithrombogenicity of the Gyro Permanently Implantable Pump with the RPM Dynamic Suspension System for the Impeller
Authors: Ichikawa Seiji , Nonaka Kenji , Motomura Tadashi , Ishitoya Hiroshi , Watanabe Kuniyoshi , Ashizawa Satoshi , Shinohara Toshiyuki , Sumikura Hirohito , Ichihashi Fumiyuki , Oestmann Daniel , Nosé Yukihiko
Published: October 2003

Abstract: In 1995, a group at Baylor College of Medicine started to develop the NEDO biventricular assist device (BVAD) using two Gyro permanently implantable (PI) centrifugal pumps. This pump consists of a sealless pump housing and an impeller supported with a double pivot bearing. In May 2001, an RPM dynamic suspension system (RPM‐DS) for the impeller was developed to improve durability and antithrombogenicity without a complex magnetic suspension system. From March 2000 to March 2002, eight BVAD bovine experimental studies were performed for more than 1 month. Two pumps were implanted in two cases without the RPM‐DS (group A) and in six cases with the RPM‐DS (group B). In group A, the survival period was 45 and 50 days. The primary reason for termination was an increase in the requiring power, which was related to deposition of white thrombus on the bottom bearing. In group B, the survival period was 37, 48, 51, 60, 80, and 90 days. The reasons for termination were not related to thrombus formation. No thrombus was observed in the pumps except for one right pump. In that experiment, the thrombus formation may have occurred when that pump had a low flow rate at a level of 1 L/min for 6 hr. These studies demonstrate the apparent antithrombogenic effect of RPM‐DS. The NEDO BVAD is ready to move into a 3‐month preclinical system evaluation.
Basic Study to Develop an Electromagnetic Drive Method for the Rotary Undulation Pump
Authors: Abe Yusuke , Chinzei Tsuneo , Isoyama Takashi , Saito Itsuro , Ono Toshiya , Mochizuki Shuichi , Kouno Akimasa , Imachi Kou
Published: October 2003

Abstract: The rotary undulation pump, which is composed of a disk with a convex shape on both sides and a pump housing with one narrow side and one wide side, is a unique continuous flow pump with a new principle. The concept of the levitation drive method for this pump was proposed. The electromagnetic driver model and drive circuit were developed to examine the possibility and the difference among the delta wired, Y wired, and repulsion methods. In the repulsion method, the disk was driven by magnetic repulsion. The model could be driven with either method, and the repulsion method was demonstrated to also be possible. With either method, owing to the wide gap between the permanent magnets and coils, the output was not enough when the load was high. The efficiency was almost the same in the delta wired and Y wired methods. In the repulsion method, however, it was less than 50% of that in the other two methods. From the results, the delta wired and Y wired methods with an active control of the gap distance were considered to be better than the repulsion method, which required no active gap control.
An Advanced Physiological Controller Design for a Left Ventricular Assist Device to Prevent Left Ventricular Collapse
Authors: Wu Yi , Allaire Paul , Tao Gang , Wood Houston , Olsen Don , Tribble Curt
Published: October 2003

Abstract:A continuous flow left ventricle assist device (LVAD), which is mainly composed of a continuous flow blood pump and a physiological controller, has only one control input, the rotational speed of the pump, but at least three performance criteria to meet. The challenge for the physiological controller of a long‐term continuous flow LVAD is the adaptability to different cardiovascular loading situations and the ability to handle systemic and parametric uncertainties with only one control input. The physiological LVAD controller presented in this article exhibits good performance in terms of the three performance criteria in different physiological loading conditions, such as disturbance, resting, and moderate exercise, for a patient with congestive heart failure. The collapse of the left ventricle, which is an inherent problem for a continuous flow LVAD, has been prevented because of the control algorithm design.
Leakage Flow Measurements in a Bio‐Centrifugal Ventricular Assist Device Model
Authors: Chua Leok Poh , Ong Kang Shiu , Yu Ching Man Simon , Zhou Tongming
Published: October 2003

Abstract: The magnetically suspended impeller centrifugal blood pump (MSCBP) has shown its superiority as compared to other artificial hearts. However, it is still plagued by hemolysis and thrombus formation in the clearance gap between the impeller shroud surface and the pump casing. In an early study, a 5 : 1 scaled up model was built in order to measure the radial and tangential velocities at the gap under the operating condition of a flow coefficient (Φ) of 0.04 using a hot wire anemometer. In this study, velocity profiles were obtained at two critical flow coefficients, Φ =0.078 (fully opened condition) and 0 (fully closed condition), to further the understanding of the flow field in the pump. Similar to the operating condition, the vector plot of the resultant velocity under these two flow coefficients showed that there were no vortices in the gap and a washout mechanism presented at the region around the starting of the splitter plate of the double volute. It was found that the washout mechanism was more obvious in the fully closed condition than in the fully opened condition. This has suggested that with real life operation, the pump could occasionally be operated at a relatively lower flow rate (e.g., under the resting condition of the patient) to obtain a good washout in the gap and thus reduce thrombus formation at the pump casing.
Tsukuba Remote Monitoring System for Continuous‐Flow Artificial Heart
Authors: Kosaka Ryo , Sankai Yoshiyuki , Takiya Ryoichi , Jikuya Tomoaki , Yamane Takashi , Tsutsui Tatsuo
Published: October 2003

Abstract:In order to make long‐term medical treatment with the use of an artificial heart effective, we developed the Tsukuba remote monitoring system, which enables medical staff to manage the physiological condition of patients and the driving condition of the artificial heart at anytime from a remote place. This remote monitoring system has three functions: first, a remote monitoring function, which enables medical staff to monitor measured data from a remote place anytime by using not only a personal computer but also a cellular phone; second, an analyzing function, which estimates the unmeasured physiological behavior in the body based on a mathematical physiological model; and third, a warning function, which detects physiological problems and malfunction of the artificial heart by applying the if‐then rule and sends a warning message to the medical staff. As a result of applying this system to animal experiments, we have confirmed the effectiveness of the proposed system.
Necrotizing Vasculitis: A Cause of Aortic Insufficiency and Conduction System Disturbance
Authors: Gómez Pérez Miquel , Serés García Lluís , Olivé Marqués Alejandro , López Ayerbe Jorge , Larrousse Pérez Eduardo , Arís Alejandro , Valle Tudela Vicente
Published: October 2003

Cardiac involvement in vasculitis syndromes is uncommon. We describe a 50‐year‐old male who presented with progressive dyspnea and myalgies. Echocardiogram revealed significant thickening of aortic root, aortic cusps, and anterior mitral valve leaflet, with severe aortic regurgitation that required aortic valve replacement. Furthermore, this patient suffered progressive atrioventricular block that needed implantation of a pacemaker. The study performed disclosed the presence of necrotizing vasculitis positive for perinuclear antineutrophil cytoplasmic antibody. (ECHOCARDIOGRAPHY, Volume 20, October 2003)
Live Three‐Dimensional Echocardiography: Imaging Principles and Clinical Application
Authors: Wang Xin‐Fang , Deng You‐Bin , Nanda Navin C. , Deng Jing , Miller Andrew P. , Xie Ming‐Xing
Published: October 2003

Live three‐dimensional echocardiography (L3DE) is an important breakthrough in the field of medical ultrasound. It will provide a great potential tool for clinical diagnosis and treatment. In this article, the authors first review the bottlenecks in 3D cardiac imaging and the technical principles of L3DE that have been used to overcome some of these problems. We then discuss the scanning methods, clinical usefulness, and the future of L3DE, drawing on our experiences in examining 124 human patients and in conducting animal verification studies with a live 3D ultrasound system. (ECHOCARDIOGRAPHY, Volume 20, October 2003)
Use of Contrast Enhancement for the Assessment of Left Ventricular Function
Authors: Mor‐Avi Victor , Lang Roberto M.
Published: October 2003

Endocardial visualization is essential for accurate interpretation of regional wall thickening abnormalities, which constitute the diagnostic hallmark of coronary artery disease, and for reproducible assessment of left ventricular (LV) ejection fraction. Unfortunately, in many cardiac patients, poor image quality does not allow consistent visualization, let alone automated detection, of the endocardial boundary in all segments throughout the cardiac cycle. Continuing efforts directed towards improving endocardial visualization made by both echocardiographic imaging equipment manufacturers and researchers have recently produced new objective, quantitative approaches for the assessment of global and regional LV function. Although these developments have not been integrated into routine clinical practice, they may have a positive impact on endocardial visualization and, thus, eventually improve the ability to accurately and objectively evaluate LV performance. In this review, we discuss some of the latest developments in the use of contrast for the evaluation of LV function. (ECHOCARDIOGRAPHY, Volume 20, October 2003)
Assessment of Global and Regional Left Ventricular Diastolic Function in Hypertensive Heart Disease Using Automated Border Detection Techniques
Authors: Spencer Kirk T. , Lang Roberto M. , Kirkpatrick James N. , Mor‐Avi Victor
Published: October 2003

Acoustic quantification (AQ) and color kinesis (CK) are techniques that involve automated detection and tracking of endocardial borders. These methods are useful for the evaluation of global and regional left ventricular (LV) systolic function and more recently have been applied to evaluating LV diastolic performance. Assessment of diastolic dysfunction in hypertensive heart disease is a relevant clinical issue in which these techniques have proven useful. The diastolic portion of left atrium and LV AQ area waveforms are frequently abnormal in patients with left ventricular hypertrophy (LVH). Left ventricular AQ curves consistently demonstrate reduced rapid filling fraction (RFF) and peak rapid filling rate (PRFR), elevated atrial filling fraction (AFF), peak atrial filling rate (PAFR), and reductions in the ratio PRFR/PAFR. Acoustic quantification complements traditional Doppler echocardiographic evaluation of global diastolic function. Many patients with significant LVH and normal Doppler diastolic parameters can be identified as having diastolic dysfunction with AQ. In addition, CK has allowed the evaluation of regional diastolic performance in hypertensive patients. Regional filling curves obtained from CK have demonstrated that endocardial diastolic motion is commonly delayed and heterogeneous in patients with LVH. (ECHOCARDIOGRAPHY, Volume 20, October 2003)
Transesophageal Echocardiographic Identification of Normal and Stenosed Posterior Intercostal Arteries
Authors: Ravi Barugur S. , Nanda Navin C. , Htay Thein , Dod Harvinder S. , Agrawal Gopal
Published: October 2003

We describe our experience in using transesophageal echocardiography to identify both right and left posterior intercostal arteries and assessing them for stenosis. (ECHOCARDIOGRAPHY, Volume 20, October 2003)
Responses of two parasitoid wasps to nectar odors as a function of experience
Authors: Patt Joseph M. , Hamilton George C. , Lashomb James H.
Published: October 2003

Adult parasitoid wasps can learn to recognize specific resource‐based cues, making them adept at locating essential resources within their native habitats. However, relatively little is known about their ability to recognize the odors emitted by flowers and extra‐floral nectar glands. A novel test arena mimicking the distribution of nectaries within an umbelliferous inflorescence was developed to measure and compare the responses of two eulophid wasps, Edovum puttleri and Pediobius foveolatus, to nectar‐based odors. Although both parasitoid species were able to associate nectar location with the odors emitted by both real nectaries (dill flowers and snap bean stipules) and artificial nectars (1 M sucrose solution scented with banana or lemon food flavoring), the responses of inexperienced wasps to nectary odors differed. While inexperienced E. puttleri displayed little attraction to the odor of either dill flowers or snap bean stipules, inexperienced P. foveolatus displayed a strong attraction to odors of both types of nectaries. However, once it had experienced foraging on either dill or snap bean nectar, E. puttleri responded to those nectary odors as strongly as did P. foveolatus. The responsiveness of both wasp species to the odor of artificial nectar greatly increased after they foraged on sugar solution scented with either banana or lemon odor. That parasitoid wasp species can differ in their ability to recognize food‐based cues is of fundamental and applied importance.
Pheromone‐mediated mating disruption of Choristoneura rosaceana: is the most attractive blend really the most effective?
Authors: Evenden M.L. , Judd G.J.R. , Borden J.H.
Published: October 2003

An attractive four‐component pheromone blend containing a major component Z11‐tetradecenyl acetate, and three minor components, E11‐tetradecenyl acetate, Z11‐tetradecenyl alcohol, and Z11‐tetradecenyl aldehyde was tested as a mating disruptant against western Canadian populations of the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), in organic apple orchards in British Columbia. Efficacy of this four‐component blend was compared to that of partial pheromone blends containing the major component plus one or two minor components. A trapping experiment confirmed that, Conrel® fibre disruption dispensers containing the four‐component blend were more attractive than disruption dispensers containing the two‐ or three‐component partial blends. A small‐plot protocol was followed to compare atmospheric treatments with these blends as mating disruptants at a release rate of 10 mg ha−1 h−1 and from 1000 dispensers ha−1. Mechanisms of mating disruption, such as false‐trail following and camouflage of pheromone plumes, that may be evoked to a greater degree by an attractive blend, did not appear to augment the effectiveness of mechanisms invoked by the less attractive blends, as the proportion of mating among tethered females was equal in plots treated with these blends and was reduced by 85–90% compared to the nontreated control. When the four‐component pheromone blend was tested at different release rates, mating disruption in small plots began to break down at a release rate of 1.3 mg ha−1 h−1 using a dispenser density of 1000 ha−1. Above 1.3 mg ha−1 h−1 there was no dose response in release rates tested and at release rates below this dose the proportion of tethered females mating was the same as in the nontreated control. The four‐component pheromone blend was tested against, and found to be no more effective than, the two‐component partial blend at the threshold release rate of 1.3 mg ha−1 h−1 when it was released from 1000 or 250 disruption dispensers. Our results suggest that disruption mechanisms evoked by the attractive blend did not enhance the mating disruption effect provided by the simple blend, therefore a two‐component blend may be useful in an operational mating disruption program for C. rosaceana.
Host size induced variation in progeny sex ratio of an aphid parasitoid Lysiphlebia mirzai
Authors: Pandey Sharmila , Singh Rajendra
Published: October 2003

A study aimed at determining the effect of host size on the pattern of sex allocation by an aphid parasitoid Lysiphlebia mirzai Shuja‐Uddin (Hymenoptera: Braconidae: Aphidiinae) was undertaken to test the validity of the following three hypotheses: (1) larger hosts will yield a greater proportion of daughters, (2) differential mortality of the sexes of the parasitoid during development is a function of host‐size, and (3) daughters emerging from larger hosts are more fecund. The results suggested a propensity in the parasitoid to deposit fertilised (diploid) eggs in large hosts (third instar nymph) and unfertilised (haploid) eggs in small hosts (first and second instar nymphs). Unpreferred fourth instar nymphs and apterous aphid adults also received more haploid eggs despite being larger in size than the preferred third instar nymphs. However, the perception of host size by the mother was dependent on the extent of temporal variation in the host size distribution and on her previous experience of host size. Developmental period, longevity, mating potential, fecundity and progeny sex ratio of L. mirzai emerging from small versus large hosts indicated that the host size affected the fitness of the daughters more than that of sons. No differential mortality of the sexes during development of L. mirzai was observed in small versus large hosts. This shows that L. mirzai, while ovipositing in growing stages of the host, adjusts progeny sex ratio according to the host size and by doing so she tends to contribute maximally to progeny fitness without knowing about the future host quality.
DNA sequences and cross‐breeding experiments in the hawthorn spider mite Amphitetranychus viennensis reveal high genetic differentiation between Japanese and French populations
Authors: Navajas Maria , Gutierrez Jean , Lagnel Jacques , Fauvel Guy , Gotoh Tetsuo
Published: October 2003

Sequence variation of the complete second internal transcribed spacer (ITS2, 445 bp) of nuclear ribosomal DNA and part of the mitochondrial cytochrome oxidase I gene (COI, 350 bp) was examined in Amphitetranychus viennensis (Zacher) mites (Acari:Tetranychidae) from four French and four Japanese locations. Sequence analysis consistently revealed the separation of the samples in two major groups: French mites differed from Japanese by 3.8–4.1% of the nucleotide divergence in COI sequences. These two groups also displayed distinct ITS2 consensus sequences (2.1% nucleotide divergence). A few variations, not affecting the diagnostic sites around the consensus sequence, were revealed among cloned copies of the same individual. Reciprocal crosses and backcrosses between one French and two Japanese populations disclosed strong reproductive incompatibility. However, fertile hybrid females were obtained, indicating the conspecificity of the tested mites. Despite the presence of Wolbachia in the French strain, but not in the Japanese ones, our crosses did not display the unidirectional incompatibility typically produced by this microorganism, but rather a bidirectional – although asymmetrical – incompatibility pattern. The post‐zygotic incompatibilities in A. viennensis cannot be explained by the presence of Wolbachia but to some extent by mite genome divergence resulting from limited gene exchange between allopatric populations. Experiments of Wolbachia elimination by antibiotic treatment and subsequent crosses with cured strains are still needed to fully understand the reproductive incompatibility patterns in this mite species.
Larval predation by Chrysomya albiceps on Cochliomyia macellaria, Chrysomya megacephala and Chrysomya putoria
Authors: Faria Lucas Del Bianco , Orsi Letícia , Trinca Luzia Aparecida , Godoy Wesley Augusto Conde
Published: October 2003

Chrysomya albiceps, the larvae of which are facultative predators of larvae of other dipteran species, has been introduced to the Americas over recent years along with other Old World species of blowflies, including Chrysomya megacephala, Chrysomya putoria and Chrysomya rufifacies. An apparent correlate of this biological invasion has been a sudden decline in the population numbers of Cochliomyia macellaria, a native species of the Americas. In this study, we investigated predation rates on third instar larvae of C. macellaria, C. putoria and C. megacephala by third instar larvae of C. albiceps in no‐choice, two‐choice and three‐choice situations. Most attacks by C. albiceps larvae occurred within the first hour of observation and the highest predation rate occurred on C. macellaria larvae, suggesting that C. albiceps was more dangerous to C. macellaria than to C. megacephala and C. putoria under these experimental conditions. The rates of larvae killed as a result of the predation, as well as its implications to population dynamics of introduced and native species are discussed.
Pre‐exposure affects the olfactory response of Drosophila melanogaster to menthol
Authors: Barron Andrew B. , Corbet Sarah A.
Published: October 2003

A modification of the trap assay (Woodard et al., 1989) was used to evaluate the response of Drosophila melanogaster (Meigen) to food media containing menthol. Dose‐response curves for flies to mentholic foods were produced for flies that had been pre‐exposed to menthol, during development and adult life, and flies that had not been exposed to menthol before the assay. Mentholic food media were less attractive to Drosophila than plain food medium. Rearing flies on a medium containing menthol reduced their aversion to some concentrations of menthol. The rearing effect was not simply due to lowered general activity levels resulting from developing in a medium containing menthol. There was a threshold concentration of menthol in the rearing medium below which we found no induced behavioural change.
Alfalfa physiological response to potato leafhopper injury depends on leafhopper and alfalfa developmental stage
Authors: Nielsen Gary R. , Fuentes Clara , Quebedeaux Bruno , Wang Z. , Lamp William O.
Published: October 2003

We examined the effects of potato leafhopper (Empoasca fabae) developmental stage and alfalfa (Medicago sativa) developmental stage on the physiological response of the plant to injury. We used radioactive carbon dioxide to label the photoassimilate stream and evaluate the phloem health of alfalfa. In one experiment, six first instar, four fourth instar, and three adult leafhoppers were caged by stage on single alfalfa stems for approximately one day. Only fourth instar nymphs significantly reduced the amount of label transported to injured tissues above the source of the labeled assimilate. First instar nymphs had no effect and adults reduced assimilate transport to stem tips, but this trend was not significant possibly because of confounding variables. However, injury by both first instar nymphs and adults resulted in greater concentration of labeled assimilate in portions of the stem below the feeding site. In another experiment, the developmental stage of alfalfa stems was central to the physiological response of alfalfa to leafhopper injury. A 20 h exposure to three adult leafhoppers significantly reduced the amount of label translocated to the tip and crown tissues of early vegetative plants, and to the crown tissue only of late vegetative plants. In reproductive plants, assimilate translocation was not affected by leafhopper injury. In a final experiment, we found no evidence of an effect on the photosynthesis of leaves of similar age and position to those used as source leaves in our translocation studies. Our findings contribute to our understanding of the physiological response of plants to injury by sap‐feeding insects, and suggest the need for greater refinement of economic injury levels based on leafhopper and plant developmental stage.
Do functional responses of predatory arthropods reach a plateau? A case study of Orius insidiosus with western flower thrips as prey
Authors: van, Den Meiracker R.A.F. , Sabelis M.W.
Published: October 2003

Parameters determining the functional and numerical response of Orius insidiosus to the density of second instar larvae of the western flower thrips (WFT), Frankliniella occidentalis, were estimated with the aim to be used in models calculating adequate release ratios of predators vs prey. Especially when the prey population must decrease immediately after predator release and the time to suppression must be short, it is of crucial importance to know whether the functional response reaches a plateau or keeps on increasing with prey density within the range of densities that are realistic for the prey. Such plateaus may arise from constraints on the time budget or from constraints on gut‐fullness‐associated motivation to attack the prey. Estimates of the plateau for O. insidiosus based on prey handling times by far exceed realistic values. In addition, motivation constraints did not apply, because the level of gut fullness above which attack ceases coincides with gut capacity. This implies that the predation rate keeps on increasing linearly with the square root of the density of WFT‐larvae and does not reach a plateau within the realistic range of thrips densities (0–20 WFT per cm2). Such plateaus are likely to occur for smaller‐sized predators and smaller‐sized stages of the same predator and they may also occur when the prey stage offered has better capacities to escape or resist attack. We argue that the presence and level of plateaus in functional responses are of importance for determining initial predator‐to‐prey ratios.
Dynamic representation of odours by oscillating neural assemblies
Authors: Laurent Gilles , MacLeod Katrina , Stopfer Mark , Wehr Michael
Published: October 2003

Stimulus evoked oscillatory synchronization of neural assemblies has been most clearly documented in the olfactory and visual systems. Recent results with the olfactory system of locusts show that information about odour identity is contained in spatial and temporal aspects of an oscillatory population response. This suggests that brain oscillations may reflect a common reference for messages encoded in time. Although stimulus‐evoked oscillatory phenomena are reliable, their roles in perception, memory and pattern recognition remain to be demonstrated. Using honey bees, we demonstrated that odour encoding involves, as in locusts, the oscillatory synchronization of assemblies of neurons, and that this synchronization is, here also, selectively abolished by the GABA receptor antagonist picrotoxin. In collaboration with Dr Brian Smith's laboratory, we showed, using a behavioural learning paradigm, that picrotoxin‐induced desynchronization impairs the discrimination of molecularly similar odourants, but not that of dissimilar odours. It appears, therefore, that oscillatory synchronization of neuronal assemblies is relevant, and essential for fine odour discrimination. Finally, experiments with locust mushroom body neurons, two synapses downstream from the antennal lobe, indicate that their responses to odours become less specific when antennal lobe neurons are desynchronized by picrotoxin injection. These results suggest that oscillatory synchronization and the kind of temporal encoding it affords provide an additional dimension by which the brain can segment spatially overlapping stimulus representations.
Olfactory responses and sensilla morphology of the blackcurrant leaf midge Dasineura tetensi
Authors: Crook D.J. , Mordue (Luntz) A.J.
Published: October 2003

Olfactory responses of Dasineura tetensi (Rubs) (Diptera; Cecidomyiidae) to leaf volatiles of blackcurrant (Ribes nigrum) were tested in a 4‐way olfactometer. Newly emerged virgin females showed no response to the leaf volatiles emitted from a blackcurrant shoot. Newly emerged males (which are known to respond to a pheromone released by the female) also showed no response to the leaf volatiles. Two hours after mating females responded positively, indicating that leaf volatiles may play a role in host plant finding. Scanning (SEM) and transmission (TEM) electron microscopy of the antennae of D. tetensi showed that males and females share five sensillum types; sensilla chaetica (mechanoreceptors), sensilla trichodea, sensilla basiconica, uniporous peg sensilla and circumfila (chemoreceptors). The sensilla chaetica and sensilla trichodea resemble those found on other insects. Sensilla basiconica were found on all antennal subsegments except the tip. These are multiporous receptors with five unbranched dendrites filling the lumen. Small peg sensilla located on the tips of both male and female antennae may function as contact‐chemoreceptors. The circumfila, which are a unique type of sensilla found only on cecidomyiid antennae, form loops around each of the antennal subsegments, being attached to the surface by a series of stalks. TEM revealed that each stalk consisted of one sensillum containing a single highly branched dendrite. The distal regions of the walls of each sensillum are fused together to form the circumfila. Circumfila have multiporous walls and a lumen filled with multiple branches of dendrites. Their structure suggests that they are important olfactory receptors in both the male and female.
Experience‐based food consumption by larvae of Pieris rapae: addiction to glucosinolates?
Authors: Renwick J. A. A. , Lopez Kimberly
Published: October 2003

When newly hatched larvae of P. rapae were transferred to cowpea foliage, they readily accepted this non‐host as food, whereas later instars that had fed on cabbage rejected cowpea. However, when cowpea leaf discs were treated with aqueous extracts of cabbage foliage, they were accepted by cabbage‐reared larvae. Experiments were conducted to determine whether larvae reared on one host plant would be stimulated to feed by extracts of other hosts. Larvae reared on Brassica juncea, Cleome spinosa, Tropaeolum majus, Sinapis alba, Alliaria petiolata, Barbarea vulgaris and cabbage (Brassica oleracea) were offered extracts of each of the other host plants on cowpea discs in choice assays. Larvae were generally stimulated to feed by extracts of all the alternate hosts, but quantitative differences in consumption occurred. In most cases, levels of discrimination between treatment and control cowpea discs showed no significant preference for extracts of the previously experienced plant. Since the test plants (and their extracts) contain glucosinolates of widely different structures, a general addiction to glucosinolates was suggested. A single glucosinolate, sinigrin, was sufficient to elicit feeding by cabbage‐reared larvae. The time required for individual neonates to become addicted to glucosinolates as they fed on cabbage, as measured by refusal of cowpea, varied from 6 to 30 hours. Bioassays of cowpea extracts failed to show any deterrent activity and, therefore, supported the conclusion that addiction to glucosinolates is responsible for the fixation of P. rapae larvae on their host plants.
Role of visual cues and interaction with host odour during the host‐finding behaviour of the cabbage moth
Authors: Rojas Julio C. , Wyatt Tristram D.
Published: October 2003

The approach and landing responses of female Mamestra brassicae (L.) (Lepidoptera: Noctuidae) to visual cues from artificial plant leaves of different shapes and presence/absence of cabbage plant odour were investigated in a laboratory wind tunnel. The leaves were painted with cadmium yellow colour and observed under dim red light. Females showed oriented flight towards plant odours but landed significantly more often when the odour was presented with an artificial leaf. In three‐choice tests, the shape of the leaf targets (circle, square or triangle) did not influence the female response. However, the size of the target did influence the insect response: the females preferred landing on square targets with sides of 5 or 10 cm rather than on the largest target, with sides of 15 cm. The orientation of the target influenced the insects' response: females landed significantly more often on the target positioned vertically than horizontally.
Salivation into sieve elements in relation to plant chemistry: the case of the aphid Sitobion fragariae and the wheat, Triticum aestivum
Authors: Ramírez Claudio C. , Niemeyer Hermann M.
Published: October 2003

Extended sieve element salivation (E1 waveform in the electrical penetration graph) is a characteristic activity during early sieve element punctures, particularly in resistant plants. In order to explore a chemically‐mediated mechanism of resistance associated with sieve element salivation, we compared the pattern of feeding behaviour of the aphid, Sitobion fragariae (Walker), on two cultivars of the wheat Triticum aestivum L., with different concentrations of hydroxamic acids (Hx). During 24 h of electronic monitoring, aphids dedicated over 50% of the total time to phloem ingestion from the sieve elements. Total time allocated to E1 in the experiment, time to first E1 within the experiment, time allocated to E1 before a sustained phloem ingestion (E2) and the contribution of sieve element salivation to the phloem phase (E1/[E1+E2]) were significantly higher in the high‐Hx cultivar. The increased salivation in plants with higher contents of Hx suggests the existence, at least in this system, of a chemically‐mediated sieve element constraint.
Aphid responses to non‐host epicuticular lipids
Authors: Powell Glen , Maniar Sangita P. , Pickett John A. , Hardie Jim
Published: October 2003

Initiation of stylet penetration by aphids depends on the sensory assessment of a number of plant surface features including colour, texture and phytochemicals (volatile and non‐volatile). Video recording behaviour of the black bean aphid, Aphis fabae, showed that these insects rapidly inserted their stylets following contact with host plants (beans), but were reluctant to penetrate non‐hosts (oats). However, when epicuticular waxes were stripped from oats, using cellulose acetate, aphids penetrated the plant surface significantly earlier than on oats with the wax layer intact. Chloroform extraction of epicuticular lipids, followed by coupled gas chromatography‐mass spectrometry, revealed a complex blend of wax components on beans, whereas one compound (1‐hexacosanol) predominated on oats. Epicuticular lipids were applied to artificial (glass) substrates in order to investigate their behavioural activity. Initiation of a stylet penetration attempt by A. fabae was delayed when the oat extract or pure 1‐hexacosanol were applied, but the bean extract had no behavioural effect. The results suggest that epicuticular lipids play an important role in the early stages of host‐plant selection by A. fabae.
Are herbivore‐induced plant volatiles reliable indicators of herbivore identity to foraging carnivorous arthropods?
Authors: Dicke Marcel
Published: October 2003

Plants that are damaged by herbivorous arthropods provide carnivorous enemies of the herbivores with important information. They emit an induced volatile blend that is highly detectable to the carnivores from a distance. Such detectable signals that indicate herbivore presence are important for the carnivores because herbivores themselves are under strong selection not to expose themselves. In addition, carnivores would benefit from a specificity of the induced plant volatiles. Whether herbivore‐induced plant volatiles are reliable indicators of herbivore identity, however, has not been resolved unambiguously. Some studies support the reliability of herbivore‐induced plant volatiles, while others do not. Different approaches have been used such as chemical analysis, behavioural analysis or a combination of the two. Based on the total of chemical studies one might conclude that in most cases herbivore‐induced plant volatiles are not very specific for the herbivore that damages the plant. However, arthropod chemosensors are much more sensitive than the detectors of analytical instruments. Therefore, chemical analyses are not suitable to demonstrate whether or not herbivore‐induced plant volatiles are reliable indicators of herbivore identity to carnivores. Behavioural studies should provide this information. In analysing carnivore behaviour it should be realised, however, that arthropod behaviour can be highly variable. Arthropod foraging decisions are affected by external and internal factors such as (a) abiotic environmental factors, (b) presence of competitors or enemies, (c) deprivation of food or oviposition sites, (d) specific deprivation of certain nutrients or (e) learning. In this paper their effect on discrimination of carnivores between volatile blends emitted by plants infested by different herbivores is reviewed. This provides testable hypotheses of why discrimination was not found in some studies. The ability of carnivores to discriminate is likely to be more common than is clear to date, which should invoke functional studies of the conditions that influence the occurrence of this discrimination.
Induction of cotton extrafloral nectar production in response to herbivory does not require a herbivore‐specific elicitor
Authors: Wäckers F.L. , Wunderlin R.
Published: October 2003

The production of extrafloral nectar is thought to represent an indirect plant defense, as it allows plants to recruit natural enemies which can protect the plant against herbivore attacks. In previous work we demonstrated that plants may show a strong increase in extrafloral nectar secretion in response to herbivory. Here we address the question of whether this induction is herbivory‐specific, or simply a general response to tissue damage. We compared the level of induction in Gossypium herbaceum (L.) (Malvaceae) following either herbivory by Spodoptera littoralis (Boisduval) (Lepidoptera; Noctuidae) or mechanical damage with and without the addition of S. littoralis regurgitate. Both herbivore feeding and mechanical damage significantly raised nectar production. No difference in volume or pattern of nectar secretion was found between natural and mechanical damage, nor between artificially damaged plants treated with regurgitate or water. Our findings indicate that the induction of extrafloral nectar secretion constitutes a general response by the plant to tissue damage, rather than representing a herbivory‐specific mechanism. The costs and benefits of such a non‐specific strategy for the plant are discussed.
Wound‐induced increases in the glucosinolate content of oilseed rape and their effect on subsequent herbivory by a crucifer specialist
Authors: Bartlet Elspeth , Kiddle Guy , Williams Ingrid , Wallsgrove Roger
Published: October 2003

Damage to the oilseed rape plant (Brassica napus L.) by the cabbage stem flea beetle, Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae) induces systemic changes to the glucosinolate profile, most noticeably an increase in the concentration of indole glucosinolates. When jasmonic acid was applied to the cotyledons of the plant, a similar effect was observed. Feeding tests with artificial substrates compared a glucosinolate fraction from jasmonic acid‐treated plants with a similar fraction from untreated plants. In these tests, alterations to the glucosinolate profile increased the feeding of a crucifer‐specialist feeder (P. chrysocephala). However, in whole plant tests, P. chrysocephala did not feed more on the jasmonic acid treated plants than on the controls. This implies that other aspects of the damage response are being induced by the jasmonic acid treatment and having a negative effect on subsequent herbivory.
Pyrrolizidine alkaloid distribution in Senecio jacobaea rosettes minimises losses to generalist feeding
Authors: de Boer Nico J.
Published: October 2003

The within‐plant distribution of pyrrolizidine alkaloids (PAs) was determined in the shoots of vegetative Senecio jacobaea L. Asteraceae plants. Also the distributions of feeding stimulants, soluble sugars and total nitrogen, were determined. PAs were found to decrease with leaf age, sugars were constant, and nitrogen decreased with leaf age. These results were compared with the within‐plant distribution of feeding damage by the generalist herbivores Spodoptera exigua Hübner and Mamestra brassicae L. Both generalists showed a strong preference for older leaves. It was concluded, that the herbivores were forced to feed on sub‐optimal parts of the plant.
A galling aphid furnishes its home with a built‐in pipeline to the host food supply
Authors: Wool David , Aloni Roni , Ben‐Zvi Ofra , Wollberg Miriam
Published: October 2003

Galling insects modify the developmental pathways of their host plants and create a protected and favourable microhabitat for their offspring. Galling aphids reproduce in their galls and the resulting clones often comprise hundreds of individuals. We followed the histological changes in the host Pistacia palaestina (Anacardiaceae) induced by the galling aphid Geoica wertheimae (Aphidoidea, Pemphigidae: Fordinae). We showed that the leaf tissues are altered in the gall in a way that gives the aphids easy access to the vascular system from which they obtain their nourishment. Specifically, the cuticle that lines the normal leaf epidermal cells is absent on the surface of the inner gall cavity, and the normal palisade cells are replaced by parenchymatous tissue with numerous wide latex ducts. Associated with these ducts, many new sieve tubes (phloem elements) are formed just a few cell layers below the inner gall surface. This arrangement enables the hundreds of aphids to feed simultaneously and continuously in the gall throughout the summer.
Ostrinia spp. in Japan: their host plants and sex pheromones
Authors: Ishikawa Yukio , Takanashi Takuma , Kim Choong‐gon , Hoshizaki Sugihiko , Tatsuki Sadahiro , Huang Yongping
Published: October 2003

To contribute to the understanding of the genus Ostrinia (Lepidoptera; Pyralidae) in Japan, we collected larvae of Ostrinia spp. from known host plants and plants not recorded as hosts, and we examined the morphology and sex pheromones of the adults obtained. Consequently, the host plant ranges of the 7 Ostrinia spp. in Japan were clarified, and the sex pheromones of the 5 species O. scapulalis, O. zealis, O. zaguliaevi, O. palustralis and O. latipennis were identified in addition to that of the Asian corn borer O. furnacalis. The phylogenetic relationships of Japanese Ostrinia spp., with reference to the European corn borer O. nubilalis, are discussed based on these findings and results of molecular phylogenetic analyses.