bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of the interferon‐γ‐inducible chemokines IP‐10 and Mig and their receptor, CXCR3, in multiple sclerosis lesions
Authors: Simpson J. E. , Newcombe J. , Cuzner M. L. , Woodroofe M. N.
Published: March 2003

The recruitment of leucocytes to sites of inflammation is an important feature of multiple sclerosis (MS) pathology. Chemokines are involved in the activation and specific directional migration of monocytes and T‐lymphocytes to sites of inflammation. Using immunocytochemistry, the expression of the α‐chemokines, interferon (IFN)‐γ‐inducible protein‐10 (IP‐10) and monokine induced by IFN‐γ (Mig), and their receptor CXCR3 have been examined in post‐mortem central nervous system (CNS) tissue from MS cases at different stages of lesion development. In actively demyelinating lesions both IP‐10 and Mig protein were predominantly expressed by macrophages within the plaque and by reactive astrocytes in the surrounding parenchyma. CXCR3 was expressed by T cells and by astrocytes within the plaque. Interferon‐γ may stimulate glial cells to express IP‐10 and Mig, which continue the local inflammatory response by selectively recruiting activated T‐lymphocytes into the CNS.
Alterations in neurofilaments associated with reactive brain changes and axonal sprouting following acute physical injury to the rat neocortex
Authors: King C. E. , Canty A. J. , Vickers J. C.
Published: March 2003

In order to study the changes in axons related to acute localized physical trauma, a 25 gauge needle was inserted into the somatosensory cortex of anaesthetized adult rats. Animals were examined over 11 time points, from 30 min to 14 days postinjury. Initially, the central needle tract was surrounded by ‘reactive’ abnormal axons characterized by their bulb‐ or ring‐like immunoreactivity for neurofila ments. Quantification demonstrated that these structures reached a peak density at 24 h postinjury, followed by a gradual decrease over 2 weeks. By 5 days postinjury, long axons showing high levels of neurofilament labelling were localized to the lesion area, either aligned parallel to the tract edges or extending into the bridge of tissue forming between the tract edges. Double‐labelling demonstrated a close association between sprouting axons and ferritin‐labelled microglia. Immunolabelling for GAP43 also demonstrated the presence of sprouting axons within this tissue bridge. Ultrastuctural examination showed that sprouting axons contained a high density of neurofilaments, with a leading edge lacking these filaments. Injury to the adult neocortex is associated with reactive and sprouting changes within axons, coordinated with the proliferation of microglia and wound healing. These data also support a role for neurofilaments in axonal sprouting following brain injury.
Abnormal ubiquitination of axons in normally myelinated white matter in multiple sclerosis brain
Authors: Giordana M. T. , Richiardi P. , Trevisan E. , Boghi A. , Palmucci L.
Published: March 2003

The hallmark of the lesions in multiple sclerosis (MS) is inflammatory demyelination with sparing of axons. Recent neuropathological and neuroradiological investigations show that structural changes of the axons occur, both in plaques and in the normal appearing white matter. A better understanding of the axonal damage in MS is important, since this may be responsible for permanent disability. We have investigated the immunoreactivity for ubiquitin, a sensitive method to detect axonal dystrophy and accumulation of abnormal proteins in pathological conditions of the nervous system, in the brains of six cases of MS (age range 39–66 years). Tissue blocks were fixed in formalin and embedded in paraffin. A panel of antibodies was used: anti‐ubiquitin, anti‐neurofilament (SMI‐31 + SMI‐32), anti‐amyloid precursor protein and anti‐PGP9.5. We focused our attention on chronic plaques, recognized by the absence of Luxol Fast Blue B‐positive inclusions in macrophages. SMI‐31 + SMI‐32 showed the presence of a variable amount of axons within the plaques; the axonal network within the plaques was looser than outside. No ubiquitin reactivity was present in chronic plaques. In the normally myelinated white matter surrounding the plaques, a dense granular ubiquitin immunoreactivity was found both near and far from the plaque edge. No similar staining was found in control brains. Ubiquitination is the first step of a non‐lysosomal degradation pathway of proteins. The present findings suggest a derangement of this proteolytic pathway in the axons outside the plaques, possibly as a consequence of chronic absence of myelin in the axonal segment inside the plaque. The spectrum of axonal changes in MS appears to be wider than expected and involves the apparently normal white matter.
Expression of excitatory amino acid transporter‐2 (EAAT‐2) and glutamine synthetase (GS) in brain macrophages and microglia of SIVmac251‐infected macaques
Authors: Chrétien F. , Vallat‐Decouvelaere A.‐V. , Bossuet C. , Rimaniol A.‐C. , Le Grand R. , Le Pavec G. , Créminon C. , Dormont D. , Gray F. , Gras G.
Published: March 2003

Na+‐dependent transporters for glutamate (excitatory amino acid transporters, EAATs) clear extracellular glutamate in the brain and prevent excitotoxic neuronal damage. Glutamine synthetase (GS) provides metabolic support for neurones by producing the neurotrophic amino acid glutamine. EAAT and GS expression has recently been demonstrated in macrophages and microglial cells in vitro, and in two models of acute inflammation in vivo. This observation might modify our current understanding of brain inflammation, which considers activated microglia and brain macrophages as the main neurotoxic cells through their production of a variety of neurotoxins, including glutamate. EAAT and GS expression by these cells would entail neuroprotective and neurotrophic properties, counterbalancing the deleterious consequences of microglial activation.

Macaque infection by the simian immunodeficiency virus (SIV) is considered the most relevant model for human acquired immunodeficiency syndrome (AIDS), including chronic inflammation of the brain at the early asymptomatic stage of the infection, followed by an AIDS‐like disease where neuronal death occurs. We studied the expression of EAAT‐2 and GS in the brains of three SIVmac251‐infected and two noninfected cynomolgus macaques. We found that both microglia and brain macrophages expressed EAAT‐2 and GS in infected primates, suggesting that these cells might, like astrocytes, clear extracellular glutamate and provide glutamine to neurones. Microglia and macrophages could thus have neuroprotective and neurotrophic properties in addition to their production of neurotoxins. This finding might explain the contrast between early intense microglial activation and the late occurrence of neuronal apoptotic cell death, which is mainly observed at the terminal stage of the disease.
Profound loss of GABAergic interneurons in the PPT1 knockout mouse model of infantile neuronal ceroid lipofuscinosis
Authors: Cooper J. D. , Gupta P. , Bible E. , Hofmann S. ,   introduced by, Lantos) P.
Published: March 2003

Introduction:  The neuronal ceroid lipofuscinoses (NCL) are progressive neurodegenerative disorders with onset from infancy to adulthood that are manifested by blindness, seizures and dementia. In infantile NCL (INCL), a mutation in the palmitoyl protein thioesterase (PPT1) gene results in loss of PPT1 activity and lysosomal accumulation of autofluorescent proteolipid in the brain and other tissues. We have generated a PPT1 knockout mouse model of INCL (PPT1–/–) and characterized pathological changes in the CNS of these mice, which die by 8 months of age.

Results:  7‐month‐old PPT1–/– exhibited NCL‐like pathology with prominent accumulation of autofluorescent lipopigment throughout the CNS, together with pronounced cerebral atrophy. Staining for phenotypic markers normally present in subpopulations of interneurons in the cortex and hippocampus revealed progressive loss of staining in the cortex and hippocampus, with persisting interneurons exhibiting pronounced hypertrophy and abnormal dendritic morphology.

Conclusions:  Taken together with our findings in the other mouse models of NCL and preliminary data from NCL patient derived tissue, these results provide further substantive evidence for the involvement of interneurons in the NCLs.

Acknowledgements:  Supported by The Batten's Disease Support and Research Association, The Natalie Fund, The Remy Fund; Batten's Disease Family Association.
Cerebrospinal fluid brain‐derived proteins in the diagnosis of Alzheimer's disease and Creutzfeldt–Jakob disease
Authors: Green A. J. E.
Published: March 2003

The differential diagnosis of dementia can be difficult in the early stages of disease, and with the emergence of new therapeutic agents for Alzheimer's disease (AD) there is an increasing need for reliable and accurate diagnostic tests. The concept of brain‐specific proteins was first proposed in the 1960s and, since that time, methods have developed to measure these proteins in the cerebrospinal fluid (CSF). The concentration of individual brain‐specific proteins can be altered in disease, and these changes are thought to reflect the underlying pathology. CSF tau protein and amyloid peptide Aβ42 concentrations are altered in AD and have been proposed as early diagnostic tests for this disease. The data from a number of studies suggest that these proteins may be of value, but are less specific than previously thought and further studies with neuropathological confirmation are required before these tests can be introduced into clinical practice. The detection of 14‐3‐3 in the CSF is an accurate test for sporadic Creutzfeldt–Jakob disease (CJD) and this accuracy has lead the World Health Organization to revise the clinical criteria for probable sporadic CJD to include a positive CSF 14‐3‐3. However, CSF 14‐3‐3 is less useful in the diagnosis of variant CJD, where studies are underway investigating the value of other CSF proteins.
Determinants of participation in an epidemiological study of preterm delivery
Authors: Savitz  , Dole  , Williams  , Thorp  , McDonald  , Carter  , Eucker
Published: March 2003

We describe the study design and patterns of participation for a cohort study of preterm delivery, focused on genital tract infections, nutrition, tobacco use, illicit drugs and psychosocial stress. Women are recruited at 24–29 weeks’ gestation from prenatal clinics at a teaching hospital and a county health department. We recruited 57% of the first 1843 eligible women; 29% refused and 8% could not be contacted. White women were somewhat more likely to participate than African‐American women (61% vs. 54% respectively). More notable differences were found comparing teaching hospital and health department clinics (71% vs. 47% participation respectively), with the health department clinic having a greater proportion refuse (24% vs. 33%) and more women who could not be contacted (4% vs. 11%). Participation was affected only minimally by day or timing of recruitment, but inability to contact diminished substantially as the study continued (13–0%). Refusals were largely unrelated to patient attributes. Lower education predicted inability to contact. Risk of preterm delivery was 14% among recruited women, 10% among women who refused, and 15% among women whom we were not able to contact, demonstrating that, overall, risk status was not lower among recruited women.
Participation in a mail survey: role of repeated mailings and characteristics of nonrespondents among recent mothers
Authors: Larroque  , Kaminski  , Bouvier‐Colle  , Hollebecque
Published: March 2003

This study analysed the characteristics of respondent and nonrespondent mothers at each stage of a survey procedure, from a initial questionnaire to a reminder letter and two repeated mailings. Of 938 mothers of liveborn children who, while maternity inpatients, received a questionnaire and information about a mail survey to follow 2 months later, 828 completed and returned the initial questionnaire, 708 agreed to participate in the mail survey and were sent the mail questionnaire, and 612 finally completed and returned the questionnaire at 2 months. There were differences between respondents and non‐respondents for socio‐demographic factors at each stage of the process. The final response rate to the mail questionnaire was higher among mothers who were younger, were breast feeding, and had more education, an occupation and fewer children. The characteristics of late respondents were intermediate between those of early to middle re‐spondents and nonrespondents for age, educational level, breast feeding and occupation. Maternal and infant health varied only slightly according to response status. Repeated mailings increased response and diminished selection. A mail questionnaire after contact in a matern‐ity ward is a cost‐effective means of gathering data about a large sample of recent mothers and their children.
Assessing number‐specific error in the recall of onset of last menstrual period
Authors: Waller D.K. , Spears W.D. , Gu Y. , Cunningham G.C.
Published: March 2003

The goal of this investigation was to determine whether women who did not report preferred numbers for their last menstrual period (LMP) may be a group of women who are particularly careful in keeping track of their menstrual cycles and therefore have more accurate LMP dating – based on a comparison with ultrasound examinations. We also sought to estimate the frequency with which preferred numbers are reported in different sources of data and for different subgroups of women. First, we examined the 1987 California birth certificates in which LMP was collected at the time of birth (n = 504 853). We also examined the records of 43 880 women participating in the California Alpha‐fetoprotein (AFP) Screening Program between 1986 and 1987, for whom gestational ages based on both early ultrasound examination and LMP were collected before 20 weeks of gestation. In the 1987 California birth certificates, seven numbers–1, 5, 10, 15, 20, 25 and 28–were recorded more frequently than expected. An estimated 12.9% of these records had preferred numbers. The most frequently recorded number was 15, occurring 2.5 times more often than expected (P < 0.01). In the data of the AFP Screening Program, the same seven numbers were preferred, and approximately 7.9% of records were affected by number preference. Comparisons with measurements of gestational age based on ultrasound demonstrated that LMP‐based gestational ages in which non‐preferred numbers are reported for the LMP are slightly more accurate than those in which preferred numbers are reported (P < 0.01). In most cases, number preference appears to introduce small errors into measurements of gestational age, probably as a result of rounding. Thus, the effect of number preference may be primarily of interest to research studies in which small errors in the measurement of gestational age will have a significant impact on findings.
Identification of a differentially expressed Echinococcus multilocularis protein Em6 potentially related to antigen 5 of Echinococcus granulosus
Authors: SILES‐LUCAS  , GOTTSTEIN  , FELLEISEN
Published: March 2003

By a strategy of differential immunological screening of an expression library constructed from adult Echinococcus multilocularis parasites, a partial cDNA sequence encoding a protein termed Em6 was isolated. This molecule displayed high sequence homology to the recombinant antigen ‘Eg6’ which was previously described as an immunogenic epitope of antigen 5 of E. granulosus. Further Em6 sequences and the corresponding sequences from a cattle isolate of E. granulosus were obtained by a PCR approach. By immunoblot analyses using affinity purified antibodies, expression of Em6 in fertile cysts producing protoscoleces of the E. multilocularis metacestode stage was observed. However, Em6 was absent in non‐fertile metacestodes. The demonstration of a protein in E. multilocularis displaying identities to ‘antigen 6’ of E. granulosus could potentially contribute to the future elucidation of the relationship between antigen 5 and ‘antigen 6’ in the genus Echinococcus, and shed some lights on the performance of serodiagnostic assays for hydatid disease based on the respective antigens.
Echinococcus granulosus human infection stimulates low avidity anticarbohydrate IgG2 and high avidity antipeptide IgG4 antibodies
Authors: STERLA SILVIA , SATO HIROSHI , NIETO ALBERTO
Published: March 2003

Total IgG and IgG subclasses recognizing carbohydrate and peptidic epitopes from native and periodate treated partially purified hydatid cyst fluid (ppHCFA) and protoscolex somatic antigens (PSA) were tested by ELISA in hydatid patients sera. Binding of the major cross‐reactive antiphosphorylcholine antibodies was inhibited with free reagent. A predominant anticarbohydrate antibody response against ppHCFA and PSA is shown. Although the main contributing IgG subclass to the antipeptide response against both antigens was IgG4, IgG1 also significantly contributed to the anti‐PSA peptidic epitopes response. Western blot showed that IgG1 antibodies strongly recognized in ppHCFA a periodate susceptible 38 kDa antigen. The IgG4 antibodies mainly recognized the periodate‐resistant 12, 16 and 24 kDa antigens. In addition, IgG2 antibodies recognized three strongly periodate‐susceptible broad bands (116, 55 and 24 kDa antigens). PSA‐specific IgG1 and IgG4 antibodies showed similar patterns of antigen recognition as well as no significant reduction of reactivity after periodate treatment while the IgG2 antibody recognition was strongly affected by this treatment. Furthermore, IgG2 showed significantly lower avidities than IgG1 and IgG4 antibodies recognizing both antigens. In conclusion, hydatid patients showed an enhanced production of low avidity anticarbohydrate IgG2 as well as high avidity antipeptide IgG4 antibodies.
HLA degenerate T‐cell epitopes from Plasmodium falciparum liver stage‐specific antigen 1 (LSA‐1) are highly conserved in isolates from geographically distinct areas
Authors: Ravichandran Manickam , Doolan Denise L. , Cox‐Singh Janet , Hoffman Stephen L. , Singh Balbir
Published: March 2003

Considerable effort is directed at the development of a malaria vaccine that elicits antigen‐specific T‐cell responses against pre‐erythrocytic antigens of Plasmodium falciparum. Genetic restriction of host T‐cell responses and polymorphism of target epitopes on parasite antigens pose obstacles to the development of such a vaccine. Liver stage‐specific antigen‐1 (LSA‐1) is a prime candidate vaccine antigen and five T‐cell epitopes that are degenerately restricted by HLA molecules common in most populations have been identified on LSA‐1. To define the extent of polymorphism within these T‐cell epitopes, the N‐terminal non‐repetitive region of the LSA‐1 gene from Malaysian P. falciparum field isolates was sequenced and compared with data of isolates from Brazil, Kenya and Papua New Guinea. Three of the T‐cell epitopes were completely conserved while the remaining two were highly conserved in the isolates examined. Our findings underscore the potential of including these HLA‐degenerate T‐cell epitopes of LSA‐1 in a subunit vaccine.
The 14‐3‐3 protein is secreted by the adult worm of Echinococcus granulosus
Authors: Siles‐Lucas M. , Nunes C.P. , Zaha A. , Breijo M.
Published: March 2003

The 14‐3‐3 protein, already described in the metacestode of Echinococcus multilocularis, has been characterized in the Echinococcus granulosus adult worm. Immunolocalization studies show the presence of the 14‐3‐3 protein in the periphery of testes and externally associated with the apical rostellum and adjacent worm tegument. The alcian blue staining in consecutive parasite sections gave similar reactivity patterns, suggesting that the 14‐3‐3 protein is produced and secreted by rostellar glands. Immunoblot analysis showed the presence of the 14‐3‐3 protein in somatic and excretory‐secretory worm products with higher and smaller apparent molecular masses, respectively, than those detected in E. multilocularis or E. granulosus metacestode tissues. Conversely, the 14‐3‐3 protein was not detected in metacestode secretory products. Detection of anti‐E. granulosus 14‐3‐3 reactivity in sera of experimentally infected dogs was achieved at early stages of infection. Specific antibody titres decreased during the course of infection. The possible origin and functions of the 14‐3‐3 protein produced by the adult worm are discussed.
Immune mechanisms in Onchocerca volvulus‐mediated corneal disease (river blindness)
Authors: Pearlman Eric , Hall Laurie R.
Published: March 2003

Infection with the parasitic nematode Onchocerca volvulus can lead to severe visual impairment and blindness. In an effort to characterize the molecular basis for the inflammatory response in the cornea, we have developed a murine model for O. volvulus‐mediated keratitis in which parasite antigens are injected into the corneal stroma of sensitized mice. This model reproduces the two main clinical features of human disease, corneal opacification and neovascularization. Histological analysis of corneas from these mice reveals a biphasic recruitment of neutrophils and eosinophils to the central cornea, along with a small, but persistent number of CD3+ cells. In this review, we present evidence that production of antigen‐specific T cell and antibody responses are essential for development of O. volvulus keratitis, and we propose a sequence of molecular and cellular events that lead to migration of inflammatory cells to the cornea and to loss of corneal clarity.
Characterization of two monoclonal antibodies raised in Btkxid mice that recognize phosphorylcholine‐bearing antigens from Trichinella and other helminths
Authors: Romarís F. , Escalante M. , Valiñas B. , Seoane R. , Wang Z.Q. , Leiro J. , Ubeira F.M.
Published: March 2003

This study investigated the binding properties of two monoclonal antibodies (mAbs US1 and US2) raised in (CBA/n × BALB/c)F1 (NBF1) Btkxid male mice. Both mAbs show unusual specificity for phosphorylcholine (PC)‐containing TSL4 antigens of Trichinella. Specifically, and in contrast to mAbs raised in normal mice, US1 and US2 mAbs do not bind to artificial PC‐protein conjugates and are not inhibited by either free PC or NPPC, although US2 was partially inhibited by NPPC at high concentration (10−2 m). However, both mAbs completely abrogate the binding to Trichinella antigens of other anti‐PC mAbs (e.g. BH8 and Mab‐2). These results suggest that both US1 and US2 recognize complex PC‐containing epitopes. The patterns of recognition of PC‐bearing antigens from different helminths by US1, US2, Mab‐2 and BH8 were broadly correlated with phylogenetic proximity. The closest similarities were observed between the members of the Trichinelloidea superfamily (Trichinella spiralis and Trichuris muris) and among the ascarids (Toxocara canis, Anisakis simplex, Hysterothylacium aduncum and Ascaris lumbricoides). However, US1 did not react with the filarial nematode Onchocerca volvulus and reacted only weakly with Onchocerca gibsoni, while US2 reacted only weakly with both species. Only BH8 recognized PC‐bearing antigens from the trematode Fasciola hepatica and the cestode Bothriocephalus scorpii. These results suggest that PC is attached to identical or very similar structures on most different nematode species, although major differences exist with respect to helminth species from groups such as the trematodes and cestodes that are phylogenetically distant from the nematodes.
Interleukin‐10 does not contribute to the pathogenesis of a virulent strain of Toxoplasma gondii
Authors: Wille Ulrike , Villegas Eric N. , Striepen Boris , Roos David S. , Hunter Christopher A.
Published: March 2003

Interleukin (IL)‐10 is an inhibitor of cell mediated immunity and an antagonist of the development of protective immune responses associated with resistance to T. gondii. These observations led to the hypothesis that the production of IL‐10 could contribute to the ability of T. gondii to replicate and survive in an immune competent host. To determine whether the production of IL‐10 affects the ability of the RH strain of T. gondii to cause a lethal infection in mice, we compared the immune response to RH in IL‐10+/+ and IL‐10−/– BALB/c mice. Both groups of mice produced comparable amounts of IL‐12 and interferon (IFN)‐γ and had similar mortality curves and parasite burdens. The use of green fluorescent protein‐labelled parasites allowed us to infect IL‐10+/+ and IL‐10−/− mice and use a fluorescence‐activated cell sorter to distinguish infected and uninfected populations of macrophages and compare their expression of CD80, CD86 and major histocompatibility complex (MHC) class II. Although infected cells expressed higher overall levels of these molecules than uninfected cells, there were no differences between cells isolated from IL‐10+/+ and IL‐10−/– mice. Taken together, these results indicate that IL‐10 is not required for the virulence of the RH strain of T. gondii, nor is it involved in the regulation of the CD80, CD86 and MHC class II molecules during RH‐infection.
The influence of protein supplementation on the immune response to Haemonchus contortus
Authors: Strain S.A.J. , Stear M.J.
Published: March 2003

A major protective mechanism in lambs against the abomasal parasite Ostertagia (Teladorsagia) circumcincta appears to be the immunoglubulin (Ig)A‐mediated suppression of worm growth and fecundity. The present study indicates that IgA may play a similar role in the control of another abomasal parasite Haemonchus contortus. Hampshire Down lambs were offered one of two diets: (i) a basal diet and (ii) a diet supplemented with additional protein. Lambs were then ‘trickle’ infected with H. contortus and killed 10 weeks after the start of infection. Those lambs on the supplemented diet had shorter adult worms and produced significantly more antiparasite IgA. There was a significant association between reduced female adult worm length and increased IgA against third‐stage larvae. Most of the difference between the two groups in worm length could be accounted for by differences in IgA responses. Therefore, IgA may be the major mechanism controlling fecundity of H. contortus and the magnitude of the IgA response is influenced by the quality of the diet.
Identification of an antigen from the sheep scab mite, Psoroptes ovis, homologous with house dust mite group I allergens
Authors: Lee A. J. , Machell J. , Van Den Broek A. H. M. , Nisbet A. J. , Miller H. R. P. , Isaac R. E. , Huntley J. F.
Published: March 2003

Infestation of sheep with the ectoparasitic mite Psoroptes ovis, results in a severe allergic dermatitis. Currently, little is known about the allergens/antigens that stimulate the allergic response. We have isolated an 836‐bp cDNA from a P. ovis cDNA library which displays strong homology to cysteine proteases and, in particular, to the group I house dust mite allergens Der p 1, Der f 1 and Eur m 1. The cDNA was expressed in Escherchia coli, fused to a hexahistidine tag and the recombinant protein (Pso o 1) purified using a nickel‐affinity column. The recombinant Pso o 1 was tested for recognition by immunoglobulin (Ig)G and IgE in serum from P. ovis naïve and P. ovis infested sheep. Using Western blots, both classes of antibody to Pso o 1 were detected in postinfestation serum. In enzyme‐linked immunosorbent assays, a pronounced IgG‐antibody response to Pso o 1 was detected in five of five sheep 3 weeks postinfestation. The IgE‐antibody response to whole mite extract was poor in four of five animals. However, a marked IgE response occurred in the fifth animal, and IgE anti Pso o 1 was detected in the serum.
Activation in vitro of vitellogenin uptake by the oocytes of the mosquito, Aedes aegypti
Authors: SAPPINGTON THOMAS , HELBLING PAUL , KOLLER C. , RAIKHEL ALEXANDER
Published: March 2003

A blood meal stimulates the ovaries of the mosquito, Aedes aegypti, to internalize vitellogenin from the haemolymph for storage as yolk. The nature of the stimulation is biphasic, with a pulsed factor from the head released within the first 5 min of feeding stimulating the first phase of uptake, and the continuous release of another head factor initiating the second phase. Using an in vitro assay of [35S]‐vitellogenin uptake by ovaries, we sought to determine the intracellular signalling pathways utilized by the ovaries during stimulation of both phases of uptake. The adenylate cyclase activators forskolin and ethanol produced a statistically significant increase in rate of uptake in previtellogenic ovaries to levels characteristic of first‐phase activated ovaries. Forskolin also induced the second phase of uptake in ovaries that had been arrested in the first phase of uptake by decapitation of the mosquito within 5 min of ingesting blood. Initiation and up‐regulation of the rate of vitellogenin uptake does not depend on new protein synthesis.
Variation in pit size of antlion (Myrmeleon carolinus) larvae: the importance of pit construction
Authors: Hauber MarK. E.
Published: March 2003

Abstract.Larvae of several antlions build pits that vary in size across and within species. The influence of food limitation and pit building experience on variation in pit size of the larvae of Myrmeleon carolinus was investigated in the laboratory. Unfed larvae that were allowed to build pits had smaller pit diameters than fed larvae. However, fed antlions that had been previously prevented from pit building, initially did not build larger pits than unfed antlion larvae that, too, had been prevented from pit building. Therefore, physiological constraints associated with food limitation alone are not sufficient to explain the reduction in pit size of food limited antlions of this species.
Upwind anemotaxis in response to cue‐lure by the Queensland fruit fly, Bactrocera tryoni
Authors: Meats A. , Hartland C. L.
Published: March 2003

Movements of mature male Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) were observed individually in a wind tunnel under conditions of ‘cue‐lure with wind’, ‘cue‐lure with no wind’, ‘wind only’ and ‘no wind or cue‐lure’. Further observations were made using a dense foliage array in the wind tunnel and a structured plume of cue‐lure. Patterns of walking or flying were essentially the same in all of the first four treatments except that in the ‘cue‐lure with wind’ treatment, over half of the flies moved in a consistent track upwind for at least 400 mm at some time during the first 5 min of observation. With clean wind, only 10% of the flies did this. The result was that mean net upwind displacement after 5 min in the ‘cue‐lure with wind’ treatment significantly exceeded that in the other three treatments, the results of which did not differ significantly from each other. The upwind tracks were accomplished by either walking or flying (with or without stops) or by a combination of both. When the wind tunnel was filled with a dense foliage array, the results with cue‐lure laden wind were similar to those obtained with the equivalent treatment without foliage, except that upwind tracks were predominantly in short stages. When flies were exposed to a structured plume of cue‐lure odour (without foliage present), they did not apparently alter their behaviour on leaving or entering the plume, but some did make consistent upwind tracks while they were in the plume.
Copula duration and sperm storage in Mediterranean fruit flies from a wild population
Authors: Taylor P.H.illip W. , Kaspi R.O.Y. , Yuval B.O.A.Z.
Published: March 2003

In the Mediterranean fruit fly (Ceratitis capitata Weidemann, ‘medfly’), a lekking tephritid, evidence from laboratory studies of flies from laboratory strains suggests that copulation is shorter, and sperm storage more abundant, if males are large or protein‐fed, and that copulation is longer when females are large. In addition, sperm tend to be stored asymmetrically between the female’s two spermathecae and this asymmetry declines with abundance of stored sperm. The primary objective of this study was to investigate whether these trends persist in other experimental contexts that bear closer resemblance to nature. Accordingly, we carried out experiments in a field‐cage using males derived as adults from a wild population and virgin females reared from naturally infested fruit. The results of this study were consistent with laboratory studies in that copula duration increased with female size, that sperm were stored asymmetrically between the females’ spermathecae, and that this asymmetry declined with number of sperm stored. However, we also found some previously unreported effects of female size; large females stored more sperm and stored sperm more asymmetrically between their two spermathecae than did small females. Unlike the laboratory studies, copula duration and sperm storage patterns were unaffected by male size and diet. This may be due to overwhelming variation from other sources in the wild‐collected males used, as well as environmental variability in the semi‐natural setting.
Abdominal movements, heartbeats and gas exchange in pupae of the Colorado potato beetle, Leptinotarsa decemlineata
Authors: Tartes Urmas , Kuusik Aare , Hiiesaar KÜlli , Metspalu Luule , Vanatoa Alo
Published: March 2003

The rhythms of abdominal movements, heartbeats and gas exchange in the pupae of Leptiontarsa decemlineata (Say) were recorded simultaneously using an electrolytic respirometer and infrared gas analyser, both combined with contact thermography.

Abdominal pulsations and heartbeat occurred periodically with little variance among individuals. The abdominal pulsations and heartbeat pauses varied individually within large limits, with the frequency of abdominal pulsations being six to seven times lower than that of the heart pulses.

A proportion of the pupae (20%) showed discontinuous gas exchange with large, actively ventilated CO2 bursts, whereas others (≈ 25%) exhibited continuous regular microcycles (flutter) with abrupt intake of air into the tracheae before discrete microbursts of carbon dioxide. The abdominal pulsations exerted only a minor influence on ventilation during the microcycles.

More than 90% of the bursts of abdominal movement coincided with a series of forward directed heartbeats, but interspersed between the bouts of abdominal movement commonly two to three heartbeat pulses were observed that were not associated with abdominal movements. A period of abdominal movement associated with a heartbeat pulse was commonly initiated by one or two vigorous strokes of abdominal rotation.
Novel case of a tenebrionid beetle using discontinuous gas exchange cycle when dehydrated
Authors: Duncan Frances D. , Krasnov Boris , McMaster Megan
Published: March 2003

Abstract In this study we show a link between the respiratory method and state of hydration in an arid dwelling tenebrionid beetle (Pimelia grandis). Dehydrated beetles use discontinuous gas exchange cycles with a flutter period consisting of several discrete bursts of CO2 release, whereas beetles given access to food and water showed a form of continuous CO2 release. These data give support to the respiratory water conservation hypothesis for the discontinuous gas exchange cycle.
Adaptation to high CO2 concentration in an optimal environment: radiation capture, canopy quantum yield and carbon use efficiency
Authors: Monje O. , Bugbee B.
Published: March 2003

The effect of elevated [CO2] on wheat (Triticum aestivum L. Veery 10) productivity was examined by analysing radiation capture, canopy quantum yield, canopy carbon use efficiency, harvest index and daily C gain. Canopies were grown at either 330 or 1200 μmol mol–1[CO2] in controlled environments, where root and shoot C fluxes were monitored continuously from emergence to harvest. A rapidly circulating hydroponic solution supplied nutrients, water and root zone oxygen. At harvest, dry mass predicted from gas exchange data was 102·8 ± 4·7% of the observed dry mass in six trials. Neither radiation capture efficiency nor carbon use efficiency were affected by elevated [CO2], but yield increased by 13% due to a sustained increase in canopy quantum yield. CO2 enrichment increased root mass, tiller number and seed mass. Harvest index and chlorophyll concentration were unchanged, but CO2 enrichment increased average life cycle net photosynthesis (13%, P < 0·05) and root respiration (24%, P < 0·05). These data indicate that plant communities adapt to CO2 enrichment through changes in C allocation. Elevated [CO2] increases sink strength in optimal environments, resulting in sustained increases in photosynthetic capacity, canopy quantum yield and daily C gain throughout the life cycle.
PR‐10 protein is induced by copper stress in roots and leaves of a Cu/Zn tolerant clone of birch, Betula pendula
Authors: Utriainen M. , Kokko H. , Auriola S. , Sarrazin O. , Kärenlampi S.
Published: March 2003

The response of a Cu‐ and Zn‐tolerant birch (Betula pendula) clone to copper stress was investigated. The plants were exposed to control and EC50 concentrations of Cu (0·3 and 30 μM CuSO4, respectively) for 7 d in hydroponic culture. Total proteins were extracted from the roots and leaves and separated by two‐dimensional polyacrylamide gel electrophoresis. The differences in protein patterns on silver‐ or Coomassie‐stained gels were analysed. The most apparent quantitative difference was the increase in the amount of a 17 kDa polypeptide caused by Cu stress in both roots and leaves. The protein was identified as Bet v 1‐Sc3 (according to the current nomenclature PR‐10c) using N‐terminal amino acid sequencing and on‐line high‐performance liquid chromatography/electrospray ionization/ion trap mass spectrometry. The present results indicate that PR‐10 is not only activated by pathogens but also by excessive amounts of copper ions. PR‐10 proteins in birch have been reported earlier not to be induced by Ag, Li or Cd in birch suspension culture, but Cu has not been previously tested.
The mechanism of floral heliotropism in the snow buttercup, Ranunculus adoneus
Authors: Sherry R. A. , Galen C.
Published: March 2003

We designed field experiments using solar‐tracking Ranunculus adoneus flowers to determine where photoreception occurred, which organs responded, and how movement was achieved. Flower peduncles bend eastward in the morning and gradually unbend over the course of the day. Peduncles were found to bend significantly more frequently in the middle region near the floral bracts, 1–3 cm below the flower, than elsewhere on the peduncle. Because the peduncle tip continued to track the sun even after the flower itself was removed, our experiments concentrated on shielding (or conversely, exposing) various portions of peduncles from (or to) sunlight. Photoreception occurred primarily in the portion of the stem just beneath the floral receptacle. By following the position of landmarks applied to the stem, we found that 40% more growth occurred on the shaded side of bent peduncles, compared to the sunlit side. In contrast, top‐shielded peduncles did not solar track well and grew only 25% more on the shaded side than on the sunlit side. This growth differential corresponded to differences in cell length on the two sides of bent peduncles, with significantly longer epidermal cells occurring on the shaded side than on the sunlit side.
Why do fast‐ and slow‐growing grass species differ so little in their rate of root respiration, considering the large differences in rate of growth and ion uptake?
Authors: Scheurwater I. , Cornelissen C. , Dictus F. , Welschen R. , Lambers H.
Published: March 2003

Herbaceous plants grown with free access to nutrients exhibit inherent differences in maximum relative growth rate (RGR) and rate of nutrient uptake. Measured rates of root respiration are higher in fast‐growing species than in slow‐growing ones. Fast‐growing herbaceous species, however, exhibit lower rates of respiration than would be expected from their high rates of growth and nitrate uptake. We investigated why the difference in root O2 uptake between fast‐ and slow‐growing species is relatively small. Inhibition of respiration by the build‐up of CO2 in closed cuvettes, diurnal variation in respiration rates or an increasing ratio of respiratory CO2 release to O2 uptake (RQ) with increasing RGR failed to explain the relatively low root respiration rates in fast‐growing grasses. Furthermore, differences in alternative pathway activity can at most only partly explain why the difference in root respiration between fast‐ and slow‐growing grasses is relatively small. Although specific respiratory costs for maintenance of biomass are slightly higher in the fast‐growing Dactylis glomerata L. than those in the slow‐growing Festuca ovina L., they account for 50% of total root respiration in both species. The specific respiratory costs for ion uptake in the fast‐growing grass are one‐third of those in the slow‐growing grass [0·41 versus 1·22 mol O2 mol (NO3–)–1]. We conclude that this is the major cause of the relatively low rates of root respiration in fast‐growing grasses.
Exogenously supplied glycine betaine in spinach and rapeseed leaf discs: compatibility or non‐compatibility?
Authors: Sulpice R. , Gibon Y. , Bouchereau A. , Larher F.
Published: March 2003

CMS, cell membrane stability GB, glycine betaine PEG, polyethylene glycol TTC, 2,3,5‐triphenyltetrazolium chloride  When leaf discs of spinach (Spinacia oleracea cv. Junius) and rapeseed (Brassica napus var. oleifera cv. Samourai) were incubated in the light in the presence of glycine betaine (GB), they accumulated GB at a very high level. In comparison with the spinach leaf explants, the uptake of GB by rapeseed tissues was restricted, probably by the destabilizing effects exerted by GB in this plant material. In contrast, the viability of spinach leaf discs, as assessed by their capacity to reduce 2,3,5‐triphenyltetrazolium chloride (TTC), was not affected, suggesting that the GB taken up was compatible in the leaf tissues of the GB accumulator. In rapeseed leaf discs treated with GB, chlorophyll loss as well as significant changes in polyamine content were induced, leading to a dramatic increase of the putrescine/(spermidine + spermine) ratio. In contrast, this ratio remained constant in the GB treated spinach explants, suggesting that spinach has the capacity to stabilize polyamine metabolism in the presence of high amounts of GB. The treatment of spinach leaf discs with GB prior to application of osmotic or salt shocks provided protection from stress. A weak capacity to accumulate proline under stress conditions was partially suppressed. The protein content decreased while the free amino acid level increased independently of the presence of GB. It is concluded that GB behaves as a true compatible solute in spinach, which is a typical GB accumulator, and that GB is damaging when loaded into the leaf tissues of rapeseed, which do not normally accumulate GB.
Competitive strategies for water availability in two Mediterranean Quercus species
Authors: NARDINI A. , LO GULLO M. A. , SALLEO S.
Published: March 2003

Competition for water availability was studied in a mixed natural stand of Quercus suber L. and Quercus cerris L. growing in Sicily by measuring diurnal changes of leaf conductance to water vapour (gL), water potential (ΨL) and relative water content (RWC) in April, July and October 1997 as well as the seasonal changes in root hydraulic conductance per unit leaf surface area (KRL). Quercus cerris behaved as a drought‐tolerant species, with strong reductions of KRL, ΨL, and RWC in the summer. By contrast, Q. suber appeared to withstand summer drought by an avoidance strategy based on reducing gL, maintaining ΨL and RWC high and KRL at the same level as that measured in the spring. A ‘conductance ratio’ (CR) was calculated in terms of the ratio of gL to KRL. Seasonal changes of this ratio contrasted in the two species, thus suggesting that Q. suber and Q. cerris did not really compete for available water. In the summer, when Q. suber was extracting water from the soil to maintain high leaf hydration, Q. cerris had restricted water absorption, thus suffering drought but tolerating its effects. The possibility that cohabitation of drought‐tolerant with drought‐avoiding species can be generalized is also discussed.
Effects of nitrogen deprivation on cell division and expansion in leaves of Ricinus communis L.
Authors: ROGGATZ U. , McDONALD A. J. S. , STADENBERG I. , SCHURR U.
Published: March 2003

The effects of nitrogen deprivation on leaf extension, cell numbers and epidermal cell size were followed in leaves of Ricinus communis L. The extent to which reductions in final cell number or final epidermal cell size contributed to the reduction in final leaf size depended on the developmental stage of the leaf at the time of N deprivation. In leaves which already had their full complement of cells (leaf 2), the reduction in final leaf size following nitrogen deprivation was associated with a reduction in final cell size. In leaves that were at earlier stages of development at the onset of N deprivation (leaves 3 and 4), the reduction in final leaf size was greater than in leaf 2. In these younger leaves, the final cell size was even smaller than in leaf 2, but the greatest contribution to reduced final leaf size was a reduction in the number of cells produced. This accounted for approximately 80% of the reduction in final leaf size in leaf 4. During leaf development, the contribution from different tissue layers to the total cell number changed. In the smallest leaf sizes, the contribution from upper and lower epidermis and spongy parenchyma was greater than that from palisade parenchyma. As the leaf size increased, cells in the palisade parenchyma continued to divide for longer than in the other layers. At final leaf size, the contribution from the different tissue layers to total cell number was the same for leaves 2, 3 and 4, irrespective of N treatment. In these final leaf structures, palisade parenchyma contributed 60% of the total cell number. Thus, although nitrogen deprivation affected leaf size variously through cell division and cell expansion, depending on leaf developmental stage at the time of nitrogen deprivation, the ratio of cell numbers and sizes in different tissue layers, at final leaf size, was unaffected.
Silicon reduces sodium uptake in rice (Oryza sativa L.) in saline conditions and this is accounted for by a reduction in the transpirational bypass flow
Authors: YEO A. R. , FLOWERS S. A. , RAO G. , WELFARE K. , SENANAYAKE N. , FLOWERS T. J.
Published: March 2003

Rice is relatively sensitive to salinity and is classified as a silicon accumulator. There have been reports that silicon can reduce sodium uptake in crop grasses in saline conditions, but the mechanism by which silicon might alleviate salinity damage is unclear. We report on the effects of silicon on growth, gas exchange and sodium uptake in rice genotypes differing in salt tolerance. In non‐saline media there were no effects of supplementary silicate upon shoot fresh or dry weight or upon root dry weight, indicating that the standard culture solution was not formally deficient with respect to silicon. Plants grown with supplementary silicate had slightly, but significantly, shorter leaves than plants grown in a standard culture solution. Salinity reduced growth and photosynthetic gas exchange. Silicate supplementation partly overcame the reduction in growth and net photosynthesis caused by salt. This amelioration was correlated with a reduction in sodium uptake. Silicate supplementation increased the stomatal conductance of salt‐treated plants, showing that silicate was not acting to reduce sodium uptake via a reduction in the transpiration rate. Silicate reduced both sodium transport and the transport of the apoplastic tracer trisodium‐8‐hydroxy‐1,3,6‐pyrenetrisulphonic acid (PTS). This implies that the mode of action of silicate was by partial blockage of the transpirational bypass flow, the pathway by which a large proportion of the uptake of sodium in rice occurs. Mechanisms by which silicate might reduce the transpirational bypass flow directly are discussed.