bluuebunny/crossref_metadata_2025 huggingface dataset:
Abdominal wall defects in Denmark, 1970–89
Authors: Bugge M. , Holm N. V.
Published: March 2003

In the last two to three decades, increasing rates of gastroschisis but not of omphalocele have been reported from different parts of the world. The present study represents a register containing 469 children born with abdominal wall defects based on data retrieved from 20 birth cohorts (1970–89) in three nationwide registries. A tentative estimate of the completeness as regards identification of liveborn and stillborn infants is a minimum of 95% and 90% respectively. All cases were reclassified to 166 cases of gastroschisis, 258 of omphalocele and 16 of gross abdominal wall defect. The average point prevalence at birth of gastroschisis was 1.33 per 10 000 live and stillbirths. During the first decade, an increase in prevalence occurred culminating in 1976, followed by a decrease reaching its initial value in 1983 and then a new increase. Overall, no significant linear trend could be demonstrated for the entire period. The average point prevalence at birth for omphalocele was 2.07 and for gross abdominal wall defect 0.12 per 10 000 live and stillbirths with no significant change in the period. The geographical distribution of gastroschisis and omphalocele showed no difference per county.
The reproductive health of daughters of pregestational diabetic women: Medical Birth Registry of Norway
Authors: Egeland Grace M. , Skjærven Rolv , Irgens Lorentz
Published: March 2003

Maternal diabetes may have an impact upon a daughter's reproductive health through genetic influences, an altered fetal metabolic environment or both. We examined the reproductive health of daughters of diabetic women using linked generation data from the Medical Birth Registry of Norway. Among all female births between 1967 and 1982 (n = 459 182), 739 had a mother with registered pregestational diabetes, a rate of 1.6 per 1000 deliveries. A total of 142 904 daughters delivered at least one child by 1998. After taking into account differences in survival, we observed no differences in the percentage of childbearing and in the average number of children born by 1998 between daughters with and without a diabetic mother in age‐stratified analyses. In analyses limited to singleton deliveries and stratified by mothers’ and daughters’ diabetic status, we found a threefold excess stillbirth delivery rate among women who had either a mother with pregestational diabetes (2.6%) or pregestational diabetes themselves (2.6%) compared with the stillbirth delivery rate observed in non‐diabetic women with no maternal history of diabetes (0.8%). These findings were unaltered in multivariable analyses adjusting for daughters’ maternal age and registered obstetric risk factors. Our results indicate that pregestational diabetes remains a health care challenge in Norway and that further evaluation of the reproductive health of daughters of diabetic pregnancies is warranted.
Reducing the caesarean delivery risk in elective inductions of labour: a decision analysis
Authors: Bailit Jennifer L. , Downs Stephen M. , Thorp John M.
Published: March 2003

To determine whether the vaginal delivery rate is increased in nulliparous women who have positive fetal fibronectin (fFN) testing before elective induction of labour, we performed a decision analysis that tested three options: (1) spontaneous labour; (2) testing nulliparous candidates for elective induction of labour at 39 weeks gestation with fFN and inducing labour if fFN positive (women who are fFN negative are managed expectantly); (3) elective induction of labour for women who are at least 39 weeks. We found that spontaneous labour had a vaginal delivery rate of 90%, elective induction 79% and fFN screening 83%. At baseline, a mother must be willing to take an additional 7% risk of caesarean delivery to warrant fFN testing or an additional 11% risk of caesarean delivery to warrant elective induction. We conclude that spontaneous labour has the highest vaginal delivery rates. An fFN test in a nulliparous woman may help to raise her likelihood of a vaginal delivery in an elective induction.
Breast feeding and cognitive development in childhood: a prospective birth cohort study
Authors: Oddy Wendy H. , Kendall Garth E. , Blair Eve , De Klerk Nicholas H. , Stanley Fiona J. , Landau Louis I. , Silburn S. , Zubrick Stephen
Published: March 2003

The aim of this study was to examine prospectively the relation between duration of breast feeding and cognitive outcomes. A cohort study of 2860 children enrolled before birth provided data from 2393 term infants of English‐speaking mothers. Of these, complete infant feeding data in the first year of life and verbal cognitive IQ (Peabody Picture Vocabulary Test – PPVT‐R) were available for 1450 children at 6 years, and a performance subtest (Perceptual organisation WISC – Block Design) for 1375 children at 8 years. Full breast feeding was categorised as none,> 0 to < 4 months, 4–6 months and> 6 months. Associations between breast‐feeding duration and PPVT‐R at 6 years and Block Design at 8 years were estimated before and after adjustment for gender, gestational age, maternal age, maternal education, parental smoking and the presence of older siblings.

The early cessation of full breast feeding was associated with reduced verbal IQ and the performance subtest. In unadjusted analysis, mean standardised PPVT‐R scores were 6.44 points greater (P < 0.0001) in children fully breast fed for> 6 months compared with those never breast fed. After adjustment, mean PPVT‐R scores were 3.56 points higher in children fully breast fed for> 6 months compared with those children never breast fed (P = 0.003). Similarly, Block Design scores were higher in those fully breast fed for> 6 months compared with those never breast fed in unadjusted (P = 0.001) but not adjusted analyses (P = 0.223). Interactions between maternal education (four levels) and breast feeding demonstrated a positive association of maternal education on verbal IQ (F = 2.64; P = 0.005) in children breast fed for longer but not on performance (F = 0.74; P = 0.67). The early introduction of milk other than breast milk was associated with reduced verbal IQ after adjustment for social and perinatal confounders. Although these effects were interacting with maternal education, they may act through undefined mechanisms in human milk.
Variability of the intestinal immunoglobulin E response of rats to infection with Trichinella spiralis, Heligmosomoides polygyrus or Nippostrongylus brasiliensis
Authors: NEGRAO‐CORREA DEBORAH , S.ADAMS LINCOLN , G.BELL ROBIN
Published: March 2003

Total intestinal IgE level increased in rats infected with Trichinella spiralis or Heligmosomoides polygyrus (peak levels of 2.6 μg and 3.7 μg, respectively), but not in rats infected with Nippostrongylus brasiliensis. Intestinal implantation of young adult N. brasiliensis did not stimulate an intestinal immunoglobulin (Ig)E response, suggesting that mucosal penetration may be required for local intestinal IgE responses in rats. During a T. spiralis infection, total IgE levels in the intestinal lumen were consistently higher in LEWIS and LOU rats (rat strains that eliminate T. spiralis worms earlier in the infection) than in PVG, AO and WKA/H strain rats. There was no correlation in either the total level of serum IgE and IgA, or of intestinal IgA with differences between strains in the rate of worm elimination from the gut. Furthermore, the intestinal IgE immunoprecipitated from LEWIS rats 12 days after infection reacted with T. spiralis adult worm metabolic antigens, while intestinal IgE from PVG rats only became reactive with adult worm metabolic antigens from 14 days after infection. These data emphasize the significance of the intestinal IgE response and its unique features by comparison with serum IgE and IgA or intestinal IgA.
Serological responses of Gambian children to immunization with the malaria vaccine SPf66
Authors: METZGER  , HAYWOOD  , D'ALESSANDRO  , DRAKELEY  , WEISS  , BOJANG  , TARGETT  , GREENWOOD
Published: March 2003

Antibody responses to the malaria vaccine SPf66 and to its constituent peptides were measured over a period of 2 years in Gambian children who had been immunized with SPf66 or with a control vaccine (inactivated polio vaccine). Three hundred and six of 308 children (99%) who had received three doses of SPf66 vaccine had antibodies to SPf66 at a level above that found in European controls who had not been exposed to malaria. Responses to the constituent peptides derived from 35.1, 55.1 and 83.1‐kDa proteins were found in 88%, 97% and 97% of children, respectively; 26% had an antibody response to the NANP repeat peptide of circumsporozoite protein which is also included in the SPf66 vaccine. A response to SPf66 was found in 22% of children who had received the control vaccine. Antibody responses to NANP, 35.1, 55.1 and 83.1‐kDa peptide were found in 3%, 33%, 49% and 33% of these children. Overall, no significant correlation was found between the level of anti‐SPf66 antibody at the beginning of the malaria transmission season following vaccination and the subsequent risk of malaria. However, further analysis showed that among the control children who had acquired antibodies to SPf66 as a result of natural exposure to malaria, those with high levels of anti‐SPf66 were less at risk of malaria, perhaps reflecting their greater previous exposure and thus immunity. In contrast, among children who had received three doses of SPf66, those with high antibody levels were at greater risk of have malaria during the subsequent malaria transmission season.
The human hookworm pathogen Necator americanus induces apoptosis in T lymphocytes
Authors: Chow Sek C. , Brown Alan , Pritchard David
Published: March 2003

In the present study, we demonstrate that Jurkat T cells undergo apoptosis when cocultured with the human hook‐worm Necator americanus. Pro‐apoptotic activity was dose‐dependent and readily detectable in hookworm secretions. This pro‐apoptotic effect appears to be specific to cells of T lineage since the monocytic cell line, THP‐1, the erythroleukaemic cell line, K562, and the basophil cell line, KU812, were unaffected. The induction of apoptosis in Jurkat T cells by the hookworm secretions did not involve cell activation or the Fas/Fas ligand interaction. In addition, the pro‐apoptotic effect of the hookworm, or its secretions, was observed with activated human T cells but not with resting peripheral blood lymphocytes. These findings support the hypothesis that the hookworms' ability to recurrently infect humans is due to the parasite creating a site of ‘immune privilege’ around itself. This strategy promptly induces any reactive host leucocytes infiltrating the site of parasite colonization to undergo apoptosis, which reduces inflammation and renders the infection relatively asymptomatic.
Cytokine responses of C3H/HeN mice infested with Ixodes scapularis or Ixodes pacificus nymphs
Authors: Schoeler George B. , Manweiler Stephen A. , Wikel Stephen K.
Published: March 2003

Lyme borreliosis, caused by Borrelia burgdorferi, is transmitted by Ixodes scapularis in the eastern and midwestern United States and by Ixodes pacificus in the far‐Western United States. Studies have shown that infestation with I. scapularis nymphs modulates host cytokine production; however, the influence of I. pacificus infestation on host cytokines remains uninvestigated. This study demonstrated how repeated infestations with pathogen‐free I. scapularis or I. pacificus nymphs affects the production of the macrophage cytokines IL‐1β, IL‐6 and tumour necrosis factor‐α and the T lymphocyte cytokines IL‐2, IL‐4, IL‐5, IL‐6, IL‐10 and IFN‐γ by C3H/HeN mice. Female mice were infested once or twice with pathogen‐free I. scapularis or I. pacificus nymphs, with a 14‐day tick‐free period between exposures. After each infestation, tick biology parameters were assessed and macrophage and T lymphocyte cytokine production measured by antigen capture ELISA. Acquired resistance to tick feeding did not develop after infestation with either tick species. Differences in cytokine production were observed between infested and noninfested mice, and between mice infested with either I. scapularis or I. pacificus nymphs. Infestations polarized cytokine production towards a Th2 cytokine profile, with suppression of pro‐inflammatory Th1 cytokines. This pattern of cytokine production is more pronounced for I. pacificus infested mice.
Cellular responses to Loa loa experimental infection in mandrills (Mandrillus sphinx) vaccinated with irradiated infective larvae
Authors: Ungeheuer  , Elissa  , Morelli  , Georges  , Deloron  , Debre  , Bain  , Millet
Published: March 2003

In order to shed light on the mechanisms of antifilarial protective immunity, we investigated the course of experimental loaiosis after vaccination in a nonhuman primate host, Mandrillus sphinx. Six vaccinated (V) mandrills received 50 irradiated L3 while six nonvaccinated (NV) received saline solution on days −60, −30 and −15. All animals were challenged with 100 intact L3 (day 0). Parasitological and immunological status were followed for 9 months. Vaccination delayed the appearance and mean peak of microfilaraemia. Five mandrills (Mf–) were never microfilaraemic (one V mandrill) or microfilaraemic on only one occasion (2 V and 2 NV), the other seven having stable microfilaraemia (Mf+). The cytokine response of peripheral blood mononuclear cells to L3 (L3 Ag) was Th2 dominated, while microfilariae (Mf Ag) elicited a Th0‐like response. During vaccination, Th2 cytokine production significantly increased in V mandrills against L3 Ag, as well as Mf Ag, whereas Th1 cytokines decreased. On day 60 postinoculation, cellular proliferation was higher in V mandrills in response to L3 and Mf Ags and PHA‐L mitogen. At the end of prepatency (on day 130), mandrills with delayed appearance of microfilaraemia exhibited a high, transient IL‐2 and IL‐4 secretion in response to L3 Ag. Finally, high anti‐Mf Th2 cytokine levels characterized Mf–mandrills not only during prepatency, but also (for IL‐5) before immunization. However, the presence of a balanced Th1 anti‐L3 response during prepatency in the amicrofilaraemic mandrill suggests its importance in protective immunity. Taken together, our data suggest that Th2 cells and also Th1 components of the antifilarial response, especially to larval antigen, may contribute to parasite elimination.
Apoptosis: a mechanism of immunoregulation during human schistosomiasis mansoni
Authors: Carneiro‐Santos Patricia , Martins‐Filho Olindo , Alves‐Oliveira Lucia F. , Silveira Alda M.S. , Coura‐Filho Pedro , Viana Iramaya R.C. , Wilson Robert A. , Correa‐Oliveira Rodrigo
Published: March 2003

People infected with schistosomes may present with a variety of clinical manifestations ranging from the relatively asymptomatic intestinal (INT) form to the hepatointestinal (HI) or hepatosplenic (HS) forms characterized by hepatomegaly and hepatosplenomegaly with severe portal hypertension, respectively. Flow cytometry analyses were used to evaluate the contribution of apoptosis in specific cell populations from schistosomiasis patients to the development of the different clinical forms of the disease. The results showed that cell death induced by combinations of specific antigen and cytokines corresponds with specific clinical presentations. It was shown that soluble egg antigen (SEA) increased the level of apoptosis only in T cells from INT patients. Stimulation with soluble lung worm antigen preparation (SLAP) did not induce significant differences in the levels of apoptosis in T cells from the patients with the different clinical forms of schistosomiasis. These results suggest for the first time that apoptosis plays an important role in the modulation of the anti‐SEA response in INT patients.
A new standard for the assessment of disease progression in murine cutaneous leishmaniasis
Authors: J.roberts Lynden , J.foote Simon , Handman Emanuela
Published: March 2003

Infection of mice with Leishmania major has been used both as a model for the cutaneous disease in humans and as a model for the more general control and function of helper T cells in immunity. In both cases, disease patterns and disease progression have been assessed by two complementary methods, lesion size and parasite burden in the draining lymph nodes. We propose a much improved method for the graphical representation of lesion development which conveys more information with better accuracy. We also describe a polymerase chain reaction method for determining parasite burden, which is faster and allows the analysis of larger numbers of experimental animals than the current limiting dilution analysis. Moreover, these methods are equally applicable to other infectious diseases, an obvious one being schistosomiasis.
Cutaneous and systemic responses during primary and challenge infestations of sheep with the sheep scab mite, Psoroptes ovis
Authors: Van Den Broek  , Huntley  , Machell  , Taylor  , Bates  , Groves  , Miller
Published: March 2003

Lesional area was estimated and lesional mast cells and eosinophils were counted during primary and challenge infestations of sheep with Psoroptes ovis. In addition, circulating basophils and eosinophils and serum P. ovis‐specific immunoglobulin IgE antibody were quantified. Expansion of lesional area was significantly less and serum IgE titres significantly greater in challenge than primary infestations. Lesional mast cell hyperplasia and massive eosinophil infiltration accompanied by raised titres of P. ovis antigen‐specific IgE antibody were compatible with an IgE‐mediated Type‐1 allergic reaction, while detection of lesional basophils was suggestive of cutaneous basophil hypersensitivity. The temporal pattern of lesional mastocytosis and eosinophil infiltration and the role of these cells and serum IgE in the immune response is discussed.
Mercury enhances susceptibility to murine leishmaniasis
Authors: Bagenstose Lee M. , Mentink‐Kane Margaret M. , Brittingham Andrew , Mosser David M. , Monestier Marc
Published: March 2003

The genetic background of mice infected with Leishmania major determines the response to infection, resulting in a resistant or susceptible phenotype. Susceptible mice develop a T‐helper type 2 (Th2)‐type immune response following infection distinguished by the development of interleukin (IL)‐4 secreting T cells in the lymph node and spleen. In SJL mice, which normally heal L. major lesions, subtoxic doses of mercury induce an autoimmune syndrome characterized by an expansion of Th2 cells. In this study, we examined the effect of mercury administration on the outcome of L. major infection in SJL mice. We show that subtoxic doses of mercuric chloride (HgCl2) exacerbate disease outcome in SJL mice resulting in increased footpad swelling and increased parasite burdens. Furthermore, the effects of HgCl2 treatment on resistance to L. major are time‐dependent. The nonhealing phenotype was observed only if mice had been treated with HgCl2 prior to L. major infection for at least 1 week, a timepoint at which mice treated with HgCl2 alone had increased splenocyte IL‐4 production. HgCl2 treatment also increased production of serum immunoglobulin (Ig)E and IgG1, two IL‐4 dependent isotypes. These results show that HgCl2 treatment enhances the susceptibility to L. major in SJL mice, consistent with the induction of host Th2 parameters. These findings have implications for the role of mercury contamination in areas of endemic leishmaniasis.
Social influences on nymphal development in the cockroach, Diploptera punctata
Authors: HOLBROOK GLENN , SCHAL COBY
Published: March 2003

Solitary male nymphs of the cockroach Diploptera punctata (Eschscholtz) (Blattaria: Blaberidae) took significantly longer to reach adulthood than males paired with either a male or female nymph or grouped with four other male nymphs since birth. When isolated throughout nymphal development, 15.8% of males passed through 3 stadia before adult eclosion, and the remainder went through 4 stadia. In contrast, 61.3% of paired males became adults in 3 stadia. Males need not, however, be isolated or paired for the entire nymphal period to express isolated or paired patterns of development. About 60% of males paired in just the first stadium or its initial 9 days became adults in 3 stadia, and only 20.4% of males isolated in the first stadium and the first 3 days of the second reached adulthood within 3 stadia. Although the first stadium was a critical period in which social condition determined the course of future development, analyses of covariance showed that isolated males gained less weight than paired ones, not only in the first stadium, but in the second as well. Moreover, the degree of growth of a male in the second stadium, measured as either weight gain or relative growth rate, did not depend on the male’s social condition in the first stadium, because isolated second‐instar males grew less than paired ones, even when both sets of insects had been paired in the first stadium. Female nymphal development, unlike that of males, was not greatly affected by social factors.
Electrophysiological response to herbivore‐induced host plant volatiles in the moth Spodoptera littoralis
Authors: Jönsson M. , Anderson P.
Published: March 2003

In cotton, Gossypium hirsutum (Malvacae), the volatiles emitted from the plant change in response to herbivory. Ovipositing females of the Egyptian cotton leaf worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) can discriminate between cotton plants subjected to larval feeding and undamaged plants during oviposition. In this study we investigate whether females of this moth can detect the herbivore‐induced cotton volatiles. The response of female S. littoralis antennae to volatiles collected from cotton plants subjected to larval feeding was studied using GC‐EAD (coupled gas chromatography electroantennographic‐detection). By GC‐EAD, responses to over 10 different cotton volatiles were observed. Using single sensillum technique the responses of short sensilla trichodea on the antennae of S. littoralis females to 19 cotton volatiles and 12 general plant volatiles were investigated. Responses to these volatiles were recorded from 108 receptor neurones. Several neurones activated by herbivore‐induced cotton volatiles were recorded. For example, a neurone type responding to two homoterpenes [(E,E)‐4,8,12‐trimethyl‐1,3,7,11‐tridecatetraene and (E)‐4,8‐dimethyl‐1,3,7‐nonatriene] and (E,E)‐α‐farnesene was frequently found. We also observed sensitive neurones responding specifically to the herbivore‐induced volatiles (+/–)‐linalool and indole. In general, a stimulus load of less than 1 ng was needed to activate these neurones. In addition, specific neurones were found for constitutive cotton volatiles released in connection with damage to the plant. An abundant neurone type responded to β‐caryophyllene and α‐humulene. Another neurone type responded specifically to the non‐induced cotton volatile (Z)‐jasmone. These results show that females of S. littoralis have receptor neurones that would make it possible to discriminate between damaged and undamaged plants using volatile signals.
An analysis of the pattern of feeding in the Costa Rican weevil, Exopthalmus jekelianus, on the tropical tree, Cedrela odorata
Authors: Wright G. A. , Raubenheimer D. , Simpson S. J.
Published: March 2003

Feeding patterns were recorded and analysed for adult female weevils, Exopthalmus jekelianus (White) (Coleoptera: Curculionidae), feeding on Central American mahogany, Cedrela odorata L., in the field in Costa Rica. The study forms part of an investigation into the relationship between feeding patterns and the fine‐scale variation in leaf chemistry occurring within the host plant. The weevils’ feeding patterns were the simplest in temporal structure of any reported to date for an insect herbivore. Weevils spent an average of only 3% of their time feeding during the 10‐h observation periods. Meals lasted an average of 2.8 min and occurred at a mean intermeal interval of 84 min. The feeding patterns gave the appearance of a short‐term rhythm underlying the onset of feeding (as has been found in locusts and caterpillars), although there were insufficient meals taken by individuals over the 10‐h period to test this suggestion. Meals were notable in apparently lacking intrameal pauses and also commencing without preliminary sampling behaviours, such as palpating or biting. Whether the combination of short, infrequent meals, ingested without pauses and not preceded by sampling behaviour, represents an adaptation reducing apparency to natural enemies, or else simply reflects low nutritional needs, is discussed. Correlations between meal durations and following and preceding intermeal intervals suggested that variation in intermeal intervals stemmed largely from variation in meal duration, not vice versa, with variation in meal duration resulting from an external influence such as leaf nutritional and/or allelo‐chemistry. The latter suggestion is currently being tested.
Relationship between sex pheromone elicited behaviour and response of single olfactory receptor neurones in a wind tunnel
Authors: Valeur Peter G. , Hansson Bill S. , Markebo Kristin , Löfstedt Christer
Published: March 2003

Responses from pheromone‐specific receptor neurones in male Agrotis segetum (Denis & Schiffermüller) (Lepidoptera: Noctuidae) were recorded in a laboratory wind tunnel. Stimuli were: (1) rubber septum dispensers loaded with single components or a four‐component pheromone blend, (2) excised glands from female A. segetum, (3) constrained A. segetum females with extruded glands. Dose–response curves for three neurone‐types with different specificity were established. The neurones were specifically tuned to respond to either one of the two pheromone components (Z)‐5‐decenyl acetate and (Z)‐7‐dodecenyl acetate, or to the behavioural antagonist (Z)‐5‐decenol. In parallel, a behavioural dose–response curve with males flying upwind to a four‐component pheromone blend was established. There was a clear correlation between behavioural arrestment of upwind flight and maximum spiking activity in Z5–10:OAc‐specific neurones.

The pheromone release rates of individual females and synthetic dispensers were compared. A load of 50–200 ng of Z5–10:OAc on a rubber septum elicited approximately the same neural response as one female gland.
The structure and function of songs emitted by southern green stink bugs from Brazil, Florida, Italy and Slovenia
Authors: Cˇokl Andrej , Virant‐Doberlet Meta , Stritih Natasˇa
Published: March 2003

Nezara viridula (L.) (Pentatomidae: Heteroptera) from Brazil, Florida, Italy and Slovenia, communicate by vibratory songs associated with long‐range calling and close‐range courting, rivalry and repelling. Each song is composed of spectrally and temporally different units. Spectrally different pulses of duration less than 300 ms are present in the male calling song. The female calling song is characterized by pulse trains composed of pulses shorter than 150 ms and pulse trains composed of a longer (> 700 ms) and shorter (< 250 ms) pulse. Shorter and longer pulses have different spectral characteristics. The male and female courtship songs are characterized by fusion of shorter (< 150 ms) pulses into a pulse train usually followed by a shorter (< 200 ms) postpulse in the case of the male courtship song. The female repelling song is a several seconds long vibration of irregular temporal structure. The short (< 400 ms) male rival song pulses are frequency modulated. The dominant frequency peaks of the songs investigated lie between 70 and 130 Hz. The dominant frequency and the microstructure of song spectra show no population specificity. The average duration varies more in calling than in courtship songs. The repetition time varies extensively in songs of different populations. Normal communication followed by copulation was observed between mates from Slovenia and Brazil and between mates from Florida and Italy. The potential role of different temporal and spectral parameters for species recognition and mate location is discussed in view of the expected distortion of the characteristic signal structure during transmission through plants.
Temperature and the hygropreference of the Arctic CollembolanOnychiurus arcticusand miteLauroppia translamellata
Authors: Hayward S. A. L. , Worland M. R. , Bale J. S. , Convey P.
Published: March 2003

The hygropreference of adultOnychiurus arcticus(Tullberg) was investigated over 2 h at 0, 10 and 20°C, along humidity gradients (12–98% RH) established using different salt solutions. At all temperaturesO. arcticuspreferred the highest humidity (98% RH). At 0 and 20°C, saturated conditions were preferred to 98% RH. The hygropreference of the miteLauroppia translamellata(Willmann) was also assessed at 20°C, and no clear RH preference was observed. This species survived the loss of 24.9 ± 2.1% of its initial water content when held for 24 h at 20°C and 12% RH. A range of assays designed to eliminate the influence of thigmotactic behaviour and population clumping permit exclusion of these factors as being responsible for the observed results. The mean initial water content ofO. arcticussamples (71.7 ± 10.9, 73.4 ± 4.0 and 73.8 ± 23.5% at 0, 10 and 20°C, respectively) did not differ significantly between temperatures, indicating that the results were not influenced by differences in initial hydrated state. The percentage water loss of individuals within the gradient increased with temperature, and differed significantly between regimes. The ecological significance of the observed humidity preferences are discussed.
Identification of feeding attractants in oak sap for adults of two nymphalid butterflies, Kaniska canace and Vanessa indica
Authors: Ômura Hisashi , Honda Keiichi , Hayashi Nanao
Published: March 2003

The active compounds of oak‐sap odour in attracting adults of two butterflies, Kaniska canace (L.) and Vanessa indica (Herbst) (Lepidoptera: Nymphalidae), were identified by chemical analyses, electroantennogram (EAG) and two behavioural assays: proboscis extension reflex (PER) and attraction to artificial tree models. Fourteen compounds were identified from two sap samples collected in 1997 and 1998, of which the major volatiles were ethanol and acetic acid (≈ 900 p.p.m. and 500 p.p.m. in sap, respectively). However, the chemical composition of the minor volatiles varied considerably between the two samples. Among 13 chemicals tested, V. indica showed strong PER to five aliphatic acids (acetic, propionic, butyric, isobutyric and isovaleric), 2‐methylpropan‐1‐ol and 3‐hydroxybutan‐2‐one, whereas the PER‐active compounds for K. canace were these seven compounds and also ethanol, 3‐methylbutan‐1‐ol and 1‐hydroxypropan‐2‐one. In two‐choice behavioural bioassays, the model scented with a sap‐odour mimic, which was an aqueous mixture of the PER‐active compounds, was more attractive to the two butterflies than an unscented control. These results demonstrated that the sap odour stimulates foraging behaviour of the butterfly. Although EAG responses of both butterflies to 3‐methylbutan‐1‐ol and that of V. indica to 2‐methylpropan‐1‐ol were positively dose‐dependent, responses to other compounds were not strong and not dose‐dependent at 1–100 μg doses. These EAG responsiveness suggests that the olfactory receptors for these compounds might be few in the antenna and that the butterflies have enough olfactory sensitivity to the dose of 1 μg.
Reproductive allocation by the blow fly Lucilia sericata in response to protein limitation
Authors: Wall R. , Wearmouth V. J. , Smith K. E.
Published: March 2003

Adult females of the anautogenous blow fly Lucilia sericata (Meigen) (Diptera: Calliphoridae) were fed standardized meals of liquidized liver, in quantities shown to range around the minimum required to initiate yolk deposition. Females from each feeding regime were dissected at daily intervals between 4 and 11 days of age; the number and stage of development of all oöcytes were recorded. Once an initial threshold quantity of protein was ingested, yolk deposition was initiated in all available oöcytes. Subsequently, one of two distinct developmental pathways was followed: arrested development in all oöcytes at an early stage of yolk deposition, or more extensive yolk deposition followed by progressive oösorbtion and the maturation of small batches of eggs. The proportion of females showing oösorbtion relative to arrested follicular development increased with increasing protein meal size, suggesting that the difference in response may be triggered by a second protein threshold, either side of which the arrested development or oösorbtion pathways are followed. The behaviour observed may reflect strategies to maximize reproductive output in this short‐lived, resource‐limited insect species. Flies that display arrested development may have sufficient protein to mature few if any complete eggs, but may subsequently be able to mature a full egg‐batch if they obtain further protein meals; this possibility is offset by the risk of death before finding such a meal. Flies that show oöcyte development and oösorbtion produce smaller egg batches more quickly and hence have a higher probability of achieving at least some reproductive output. By initiating yolk deposition in all oöcytes, female L. sericata retain the potential to adopt either developmental pathway, depending on subsequent protein intake.
Can source–sink relations explain responses of tobacco to infection by the root holoparasitic angiospermOrobanche cernua?
Authors: Hibberd J. M. , Quick W. P. , Press M. C. , Scholes J. D.
Published: March 2003

The achlorophyllous holoparasitic angiospermOrobanche cernuareduced biomass accumulation of its tobacco host, such that 73‐d‐old plants achieved 29% of the biomass of control plants. The difference in biomass between infected and uninfected tobacco could be accounted for directly by diversion of dry matter to the parasite. Thus, the smaller infected plants were responsible for the production of as much dry matter in host and parasite as their larger uninfected counterparts. The productivity of the infected system was maintained by: (a) sustained production of leaf area (a greater leaf area ratio); (b) increased specific leaf area, and (c) delayed senescence. When tobacco was inoculated with different densities of the parasite, the amount of dry matter accumulated by the parasite was not changed, suggesting that a finite amount of resource was available to the parasite. The response of the host to infection can be explained by simple source–sink interactions and the data are discussed with respect to other parasitic angiosperm–host systems which show different types of responses.
Elevated atmospheric [CO2] promotes frost damage in evergreen tree seedlings
Authors: Lutze J. L. , Roden J. S. , Holly C. J. , Wolfe J. , Egerton J. J. G. , Ball M. C.
Published: March 2003

Growth under elevated [CO2] promoted spring frost damage in field grown seedlings of snow gum (Eucalyptus pauciflora Sieb. ex Spreng.), one of the most frost tolerant of eucalypts. Freezing began in the leaf midvein, consistent with it being a major site of frost damage under field conditions. The average ice nucleation temperature was higher in leaves grown under elevated [CO2] (– 5·7 °C versus – 4·3 °C), consistent with the greater incidence of frost damage in these leaves (34% versus 68% of leaves damaged). These results have major implications for agriculture, forestry and vegetation dynamics, as an increase in frost susceptibility may reduce potential gains in productivity from CO2 fertilization and may affect predictions of vegetation change based on increasing temperature.
Soybean nodulation and N2 fixation response to drought under carbon dioxide enrichment
Authors: Serraj R. , Sinclair T. R. , Allen L. H.
Published: March 2003

The combined effects of carbon dioxide (CO2) enrichment and water deficits on nodulation and N2 fixation were analysed in soybean [Glycine max (L.) Merr.]. Two short‐term experiments were conducted in greenhouses with plants subjected to soil drying, while exposed to CO2 atmospheres of either 360 or 700 μmol CO2 mol–1. Under drought‐stressed conditions, elevated [CO2] resulted in a delay in the decrease in N2 fixation rates associated with drying of the soil used in these experiments. The elevated [CO2] also allowed the plants under drought to sustain significant increases in nodule number and mass relative to those under ambient [CO2]. The total non‐structural carbohydrate (TNC) concentration was lower in the shoots of the plants exposed to drought; however, plants under elevated CO2 had much higher TNC levels than those under ambient CO2. For both [CO2] treatments, drought stress induced a substantial accumulation of TNC in the nodules that paralleled N2 fixation decline, which indicates that nodule activity under drought may not be carbon limited. Under drought stress, ureide concentration increased in all plant tissues. However, exposure to elevated [CO2] resulted in substantially less drought‐induced ureide accumulation in leaf and petiole tissues. A strong negative correlation was found between ureide accumulation and TNC levels in the leaves. This relationship, together with the large effect of elevated [CO2] on the decrease of ureide accumulation in the leaves, indicated the importance of ureide breakdown in the response of N2 fixation to drought and of feedback inhibition by ureides on nodule activity. It is concluded that an important effect of CO2 enrichment on soybean under drought conditions is an enhancement of photoassimilation, an increased partitioning of carbon to nodules and a decrease of leaf ureide levels, which is associated with sustained nodule growth and N2 rates under soil water deficits. We suggest that future [CO2] increases are likely to benefit soybean production by increasing the drought tolerance of N2 fixation.
Elevated atmospheric CO2 does not affect per se the preference for symbiotic nitrogen as opposed to mineral nitrogen of Trifolium repens L.
Authors: Zanetti S. , Hartwig U.A. , Nösberger J.
Published: March 2003

The objective of this investigation was to examine the effect of an elevated atmospheric CO2 partial pressure (pCO2) on the N‐sink strength and performance of symbiotic N2 fixation in Trifolium repens L. cv. Milkanova. After initial growth under ambient pCO2 in a nitrogen‐free nutrient solution, T. repens in the exponential growth stage was exposed to ambient and elevated pCO2 (35 and 60 Pa) and two levels of mineral N (N‐free and 7·5 mol m–3 N) for 36 d in single pots filled with silica sand in growth chambers. Elevated pCO2 evoked a significant increase in biomass production from day 12 after the start of CO2 enrichment. For plants supplied with 7·5 mol m–3 N, the relative contribution of symbiotically fixed N (%Nsym) as opposed to N assimilated from mineral sources (15N‐isotope‐dilution method), dropped to 40%. However, in the presence of this high level of mineral N, %Nsym was unaffected by atmospheric pCO2 over the entire experimental period. In plants fully dependent on N2 fixation, the increase in N yield reflects a stimulation of symbiotic N2 fixation that was the result of the formation of more nodules rather than of higher specific N2 fixation. These results are discussed with regard to physiological processes governing symbiotic N2 fixation and to the response of symbiotic N2 fixation to elevated pCO2 in field‐grown T. repens.
Modifications of the leaf surface structures of Quercus ilex L. in open, naturally CO2‐enriched environments
Authors: Paoletti E. , Nourrisson G. , Garrec J. P. , Raschi A.
Published: March 2003

Two Italian CO2 springs allowed us to study the long‐term effect of a 350–2600 μmol mol–1 increase in CO2 concentrations on the surface structures of leaves of Quercus ilex L. Carbon dioxide increased the quantity of cuticular waxes, above an apparent threshold of 750 μmol mol–1 CO2. Leaf wettability was not modified by CO2 concentrations. Reduction in stomatal frequency was observable up to 750 μmol mol–1 CO2, the slope being almost the same as that estimated for the increase in CO2 concentration from pre‐industrial times to the present. At higher concentrations, CO2 seemed to exert no more impact on stomatal frequency.
Application of transgenic plants in understanding responses to atmospheric change
Authors: HEINEKE D. , KAUDER F. , FROMMER W. , KÜHN C. , GILLISSEN B. , LUDEWIG F. , SONNEWALD U.
Published: March 2003

Acclimation of plants to an increase in atmospheric carbon dioxide concentration is a well described phenomenon. It is characterized by an increase in leaf carbohydrates and a degradation of ribulose 1, 5‐bisphosphate carboxylase protein (Rubisco) leading in the long term to a lower rate of CO2 assimilation than expected from the kinetic constants of Rubisco. This article summarizes studies with transgenic plants grown in elevated pCO2 which are modified in their capacity of CO2 fixation, of sucrose and starch synthesis, of triosephosphate and sucrose transport and of sink metabolism of sucrose. These studies show that a feedback accumulation of carbohydrates in leaves play only a minor role in acclimation, because leaf starch synthesis functions as an efficient buffer for photoassimilates. There is some evidence that in elevated pCO2, plants grow faster and senescence is induced earlier.
Expression of Vp1 and water channel proteins during seed germination
Authors: FUKUHARA T. , KIRCH H.‐H. , BOHNERT H. J.
Published: March 2003

ABA, abscisic acid Cdc2, transcript for a cell‐cycle related protein Mip/MIP, transcript/protein for aquaporins (AQP) or water channels (WCH) Vp1/VP1, transcript/protein for transcriptional activator VP1.  Germination of seeds from individual seed capsules of Mesembryanthemum crystallinum (common ice plant) is spread out over time with some seeds germinating within 1 d (early, E) and others germinating up to more than 4 weeks after imbibition (late, L). L‐seeds are characterized by a lack of expression of Cdc2‐related transcripts and an increase of Vp1‐transcripts after water uptake, while Cdc2‐related transcripts increase early and Vp1 decline early in E‐seeds. Maintenance of Vp1 transcription, which can be disrupted by abolishing translation activity, seems to be at the basis of prolonged dormancy in L‐seeds. We have in addition characterized the expression of several MIP (water channel) proteins during germination and in organs of adult plants. Using probes specific for individual ice plant Mip, we observed differences during germination that are not exclusively due to water uptake. Mip transcripts increase before L‐seeds begin to germinate. Gene‐specific probes indicate that the expression of all Mip is high in germinating seedlings, but differences in expression exist in the root, hypocotyl and cotyledon. In adult plants, all Mip‐transcripts are expressed at a significantly lower rate than in seedlings, and organ‐specific expression of individual Mip transcripts is observed. Their expression, measured by MIP‐specific antibodies, indicates developmental specificity of MIP in different organs and highest amounts in actively growing tissues.
CO2 enrichment in a maturing pine forest: are CO2 exchange and water status in the canopy affected?
Authors: ELLSWORTH D. S.
Published: March 2003

A
net, leaf net CO2 assimilation ca, CO2 concentration of air surrounding a leaf ci, leaf intercellular CO2 concentration Δ, 13C isotope discrimination δ13C, relative stable carbon isotope content ɛ, ratio of Anet at ca = 560μmol mol–1 to Anet at ca = 360 μmol mol–1 FACE, free‐air CO2 enrichment gw, stomatal conductance to water vapour Πi, initial leaf osmotic potential Rt, relative water content at incipient turgor loss Ψl, xylem water potential of leaves Ψm, soil matric potential  Elevated CO2 is expected to reduce forest water use as a result of CO2‐induced stomatal closure, which has implications for ecosystem‐scale phenomena controlled by water availability. Leaf‐level CO2 and H2O exchange responses and plant and soil water relations were examined in a maturing loblolly pine (Pinus taeda L.) stand in a free‐air CO2 enrichment (FACE) experiment in North Carolina, USA to test if these parameters were affected by elevated CO2. Current‐year foliage in the canopy was continuously exposed to elevated CO2 (ambient CO2+200μmol mol–1) in free‐air during needle growth and development for up to 400 d. Photosynthesis in upper canopy foliage was stimulated by 50–60% by elevated CO2 compared with ambient controls. This enhancement was similar in current‐year, ambient‐grown foliage temporarily measured at elevated CO2 compared with long‐term elevated CO2 grown foliage. Significant photosynthetic enhancement by CO2 was maintained over a range of conditions except during peak drought.

There was no evidence of water savings in elevated CO2 plots in FACE compared to ambient plots under drought and non‐drought conditions. This was supported by evidence from three independent measures. First, stomatal conductance was not significantly different in elevated CO2 versus ambient trees of P. taeda. Calculations of time‐integrated ci/ca ratios from analysis of foliar δ13C showed that these ratios were maintained in foliage under elevated CO2. Second, soil moisture was not significantly different between ambient and elevated CO2 plots during drought. Third, pre‐dawn and mid‐day leaf water potentials were also unaffected by the seasonal CO2 exposure, as were tissue osmotic potentials and turgor loss points. Together the results strongly support the hypothesis that maturing P. taeda trees have low stomatal responsiveness to elevated CO2. Elevated CO2 effects on water relations in loblolly pine‐dominated forest ecosystems may be absent or small apart from those mediated by leaf area. Large photosynthetic enhancements in the upper canopy of P. taeda by elevated CO2 indicate that this maturing forest may have a large carbon sequestration capacity with limiting water supply.
Gas exchange and carbon isotope composition of Ananas comosus in response to elevated CO2 and temperature
Authors: Zhu  , Goldstein  , Bartholomew
Published: March 2003

Ananas comosus L. (Merr.) (pineapple) was grown at three day/night temperatures and 350 (ambient) and 700 (elevated) μmol mol–1 CO2 to examine the interactive effects of these factors on leaf gas exchange and stable carbon isotope discrimination (Δ,‰). All data were collected on the youngest mature leaf for 24 h every 6 weeks. CO2 uptake (mmol m–2 d–1) at ambient and elevated CO2, respectively, were 306 and 352 at 30/20 °C, 175 and 346 at 30/25 °C and 187 and 343 at 35/25 °C. CO2 enrichment enhanced CO2 uptake substantially in the day in all environments. Uptake at night at elevated CO2, relative to that at ambient CO2, was unchanged at 30/20 °C, but was 80% higher at 30/25 °C and 44% higher at 35/25 °C suggesting that phosphoenolpyruvate carboxylase was not CO2‐saturated at ambient CO2 levels and a 25 °C night temperature. Photosynthetic water use efficiency (WUE) was higher at elevated than at ambient CO2. Leaf Δ‐values were higher at elevated than at ambient CO2 due to relatively higher assimilation in the light. Leaf Δ was significantly and linearly related to the fraction of total CO2 assimilated at night. The data suggest that a simultaneous increase in CO2 level and temperature associated with global warming would enhance carbon assimilation, increase WUE, and reduce the temperature dependence of CO2 uptake by A. comosus.