bluuebunny/crossref_metadata_2025 huggingface dataset:
The catalytic direction of pyrophosphate:fructose 6‐phosphate 1‐phosphotransferase in rice coleoptiles in anoxia
Authors: Kato‐Noguchi Hisashi
Published: December 2004

The catalytic direction of pyrophosphate:fructose‐6‐phosphate 1‐phosphotransferase (PFP; EC 2.7.1.90) in coleoptiles of rice (Oryza sativa L.) seedlings subjected to anoxia stress is discussed. The stress greatly induced ethanol synthesis and increased activities of alcohol dehydrogenase (ADH; EC 1.1.1.1) and pyruvate decarboxylase (PDC; EC 4.1.1.1) in the coleoptiles, whereas the elevated PDC activity was much lower than the elevated ADH activity, suggesting that PDC may be one of the limiting factors for ethanolic fermentation in rice coleoptiles. Anoxic stress decreased concentrations of fructose 6‐phosphate (Fru‐6‐P) and glucose 6‐phosphate, and increased concentration of fructose 1,6‐bisphosphate (Fru‐1,6‐bisP) in the coleoptiles. PFP activity in rice coleoptiles was low in an aerobic condition and increased during the stress, whereas no significant increase was found in ATP:fructose‐6‐phosphate 1‐phosphotransferase (PFK; EC 2.7.1.11) activity in stressed coleoptiles. Fructose 2,6‐bisphosphate concentration in rice coleoptiles was increased by the stress and pyrophosphate concentration was above the Km for the forward direction of PFP and was sufficient to inhibit the reverse direction of PFP. Under stress conditions the potential of carbon flux from Fru‐6‐P toward ethanol through PFK may be much lower than the potential of carbon flux from pyruvate toward ethanol through PDC. These results suggest that PFP may play an important role in maintaining active glycolysis and ethanolic fermentation in rice coleoptiles in anoxia.
Genetic control over grain damage in a spring barley mapping population
Authors: Rajasekaran P. , Thomas W. T. B. , Wilson A. , Lawrence P. , Young G. , Ellis R. P.
Published: December 2004

A genetic map was constructed using DNA‐based markers in a barley mapping population derived from the cross ‘Tankard’×‘Livet’, that was developed to explore the genetic control over grain damage in spring barley cultivars. Quantitative trait loci (QTL) were located for husk skinning, gape between the lemma and palea and splitting of the fused pericarp/testa/aleurone tissues. The QTL accounted for 70% of the genetic variation in Split and 60% of the genetic variation in Gape and Skinning. The QTL were clustered on chromosomes 1H, 4H, 5H, 6H and 7H. QTL analysis indicates the possibility of transgressive segregation for grain splitting and so the breeding of lines with more extreme splitting. This is of concern to the malting industry as, without extensive phenotypic assessment, such lines could be commercialized, as was the case of Landlord, and put malting barley supplies at risk. These findings are discussed in relation to the genetic control over traits including grain length and width.
Possibility of exploiting the Yd2 resistance to BYDV in spring barley breeding
Authors: Š Ip V. , Chrpová J. , Vacke J. , Ovesná J.
Published: December 2004

The effects of the Yd2 gene on tolerance to barley yellow dwarf virus (BYDV) and other agronomically important characters in spring barley were evaluated in a set of randomly selected doubled haploid (DH) lines of an‘Igri’/‘Atlas 68’ cross and three crosses between CIMMYT Yd2 materials and the Czech malting barley ‘Akcent’. The cleaved amplified polymorphic site (CAPS) diagnostic marker Yd2 was used for identification of the Yd2 gene and this analysis showed high agreement with the results of field infection tests. Yd2 lines exhibited significantly lower symptom scores and lower reductions of some grain yield characters, but their resistance level was not consistent over the years. The presence of secondary stresses (high temperature/drought) in 2000 led to relatively higher sensitivity to BYDV infection, strengthened by the long life cycle of genotypes. In cases where secondary stresses were mild (in 2002), the longer life cycle significantly increased sensitivity to BYDV infection only in the absence of the Yd2 gene (in susceptible genotypes). The examination of different vegetative, grain yield and malting quality characters separately for groups of Yd2 and non‐ Yd2 lines did not show any evidence of adverse effect of the Yd2 gene on any character.
Inheritance of Karnal bunt‐free trait in bread wheat
Authors: Sharma I. , Bains N. S. , Nanda G. S.
Published: December 2004

A Karnal bunt (KB)‐free wheat stock (‘KBRL22’) obtained from a cross of two resistant lines (‘HD29’ and ‘W485’) was used as a donor to introgress the KB‐free trait into ‘PBW343’(an ‘Attila’ sib), the most widely grown wheat cultivar in India. The number of KB‐free and KB‐affected plants in BC 1, BC2, BC3 and BC4 as well the F2 was recorded after artificial inoculations. The segregation pattern in these generations clearly indicated two independently segregating, dominant genes which jointly confer the KB‐free attribute. The importance of the KB‐free line generated in this experiment is discussed.
Utility of AFLP markers for the assessment of genetic diversity within Brassica nigra germplasm
Authors: Negi M. S. , Sabharwal V. , Bhat S. R. , Lakshmikumaran M.
Published: December 2004

Genetic diversity of 18 Brassica nigra accessions was estimated using amplified fragment length polymorphism (AFLP) marker technology. Two B. rapa and two B. juncea accessions were selected as outliers in the study. Eight AFLP primer combinations generated a total of 426 bands, of which 79% were polymorphic. The UPGMA method was employed to construct a dendrogram based on the Jaccard's similarity coefficient. The accessions of B. rapa separated from those of B. nigra at a genetic similarity coefficient of 0.27 while those of B. juncea did so at 0.5. The genetic similarity coefficients within the B. nigra accessions ranged from 0.58 to 0.86. Based on these coefficients it was concluded that the B. nigra accessions show high levels of genetic variation. These results have significant implications in the crop improvement programmes for the agronomically important crop B. juncea, an amphidiploid of B. nigra and B. rapa. Two incorrectly labelled B. nigra accessions were also identified. These accessions were found to cluster with those of B. juncea accessions. This result demonstrates the great value of AFLP markers in the management of genebanks.
Dose‐related efficacy and safety of formoterol (Oxis®) Turbuhaler® compared with salmeterol Diskhaler® in children with asthma
Authors: Pohunek Petr , Matulka Milan , Rybníček Ondřej , Kopřiva František , Honomichlová Helena , Svobodová Tamara
Published: December 2004

To compare the dose‐related bronchodilator efficacy and tolerability of formoterol (Oxis®) Turbuhaler® with salmeterol Diskhaler® and placebo in children with asthma. A single‐dose, randomized, double‐blind, incomplete crossover study of 68 children (7–17 years), with moderate‐to‐severe asthma, 82% receiving inhaled corticosteroids. Patients received four of six treatments [4.5, 9, 18, or 36 μg formoterol (6, 12, 24 or 48 μg metered doses), 50 μg salmeterol (metered dose) or placebo] at 12‐h visits, separated by ≥3 days. Forced expiratory volume in 1 s (FEV1), pulse, blood pressure, electrocardiogram, adverse events and urine formoterol were assessed. The therapeutic ratio of formoterol vs. salmeterol was estimated from the efficacy and systemic effects results. All active treatments significantly improved FEV1 compared with placebo. Formoterol 9–36 μg provided dose‐related increases over salmeterol in lung function: average 12‐h FEV1 (increases of 4.9–8.7%, p < 0.001) and FEV1 at 12 h post‐dose (7.0–12.2%, p < 0.001). The onset of effect of formoterol was also significantly faster than salmeterol for doses ≥9 μg. Salmeterol 50 μg was estimated to be equieffective to 3.3 μg formoterol for 12‐h average FEV1 and the estimated equieffective dose for a variety of systemic effects was 7.8–13.5 μg formoterol. All treatments were well tolerated. Formoterol (Oxis) Turbuhaler 4.5–36 μg provided dose‐related improvements in bronchodilator efficacy in children with asthma. Formoterol ≥9 μg provided superior bronchodilator efficacy over 12 h compared with salmeterol Diskhaler 50 μg with no increase in systemic effects.
A Hazard Model of the Probability of Medical School Drop-Out in the UK
Authors: Arulampalam Wiji , Naylor Robin A. , Smith Jeremy P.
Published: December 2004

From individual level longitudinal data for two entire cohorts of medical students in UK universities, we use multilevel models to analyse the probability that an individual student will drop out of medical school. We find that academic preparedness—both in terms of previous subjects studied and levels of attainment therein—is the major influence on withdrawal by medical students. Additionally, males and more mature students are more likely to withdraw than females or younger students respectively. We find evidence that the factors influencing the decision to transfer course differ from those affecting the decision to drop out for other reasons.
The Impact of Denial‐of‐Service Attack Announcements on the Market Value of Firms
Authors: Hovav Anat , D'Arcy John
Published: December 2004

Abstract

The increase in security breaches in the last few years and the need to insure information assets has created an intensified interest in information risk within organizations and for insurance companies. Risk assessment is an important component in the establishment of security policies. However, very little is known of the financial impact and the risk associated with security breaches. This article reports the impact of Denial‐of‐Service (DOS) attack announcements on the market over a period of 4.5 years. The study was conducted using event study methodology. The results show that in general the market does not penalize companies that experience such an attack. However, there is an indication that the market penalizes “Internet‐specific” companies more than other companies. Our results indicate that large companies who are not “Internet‐specific” might be overreacting to the media hype and may be investing resources to prevent a problem that has marginal impact on their shareholder value.
The Value of Personal Contact in Marketing Insurance: Client Judgments of Representativeness and Mental Availability
Authors: Theil Michael
Published: December 2004

Abstract

Much previous research in decision analyses has focused on the processes of simplification that the decision maker applies in order to obtain a reduced set of alternatives. In the present work, we show how the principles of judgment by representativeness and mental availability can be applied to insurance decisions. We extend this view by considering interaction between these two heuristics and by analyzing the effect of the longer time horizon typical for insurance problems. The results of such simplification are shown to be inherently unstable. Nevertheless, it is possible to explain on the basis of our analysis why certain marketing practices dominate insurance markets.
Ectoparasite ticks and chewing lice of red‐legged partridge,Alectoris rufa, in Spain
Authors: Calvete C. , Estrada R. , Lucientes J. , Estrada A.
Published: December 2004

During the 1992–1993 and 1993–1994 shooting seasons, 212 wild red‐legged partridge,Alectoris rufa(Galliformes: Phaisanide) were captured in 18 Spanish provinces and examined for chewing lice and ticks. Three tick species and six species of chewing lice were found. Ticks (Acari: Ixodidae)Haemaphysalis punctataCanestrini & Fanzago,Hyalomma lusitanicumKoch andIxodes frontalisPanzer were found at the lowest prevalence (1.4% overall tick prevalence). The louse (Mallophaga) species,Goniodes disparBurmeister (Goniodidae) (52.8%) andCuclotogaster obscuriorHopkins (Philopteridae) (28.8%) were the most prevalent, whileGoniocotes obscurusGiebel (Philopteridae) (10.8%),Menopon pallensClay (Menoponidae) (7.5%) andMenacanthus lyaliRodriguezet al. (Menoponidae) (3.3%) were found at medium to low prevalence.Columbicola columbae columbaeLinnaeus (Philopteridae) was found at the lowest prevalence (0.5%). The intensity ofC. obscuriorand overall intensity of all lice species were directly related to the environmental mean temperature and the Normalized Difference Vegetation Index (NDVI), whereas intensity ofG. disparwas directly related to NDVI only. The intensity ofG. dispar,C. obscurior, all louse intensity, and louse species richness were higher in male than female birds. Intensity of each louse species, all louse intensity and louse species richness were inversely associated with the nutritional index. No relationship was observed between bird age and louse intensity or species richness.
Tick infestation of dogs in Thessaloniki, northern Greece
Authors: Papazahariadou M. G. , Saridomichelakis M. N. , Koutinas A. F. , Papadopoulos E. G. , Leontides L.
Published: December 2004

Abstract. Ticks were collected from 249 dogs, admitted over a one‐year period (1996–1997) to a Veterinary Teaching Hospital and four private veterinary practices located in the county of Thessaloniki, Greece. A total of 2812 ticks (Acari: Ixodidae) were collected, of which 2511 (89.3%) were Rhipicephalus sanguineus (Latreille) adults (1070 males, 1441 females), 156 (5.5%) R. turanicus Pomerantsev adults (35 males, 121 females), 100 (3.6%) Rhipicephalus spp. nymphs and 45 (1.6%) Rhipicephalus spp. larvae. Dogs living outdoors, in rural areas and in close proximity to farm animals, were infested with higher numbers of ticks than dogs living indoors. Tick attachment sites were recorded on 237 dogs, harbouring a total of 1711 ticks. The most heavily infested sites were, in decreasing frequency, the ear pinnae, neck, interdigital skin folds, trunk, head, ventrum, extremities and the tail. Cutaneous lesions at the attachment sites were noticed in 129 dogs and then mainly in the more severely infested animals.
Presence in the Balearic Islands (Spain) of the midges Culicoides imicola and Culicoides obsoletus group
Authors: Miranda M. A. , Borràs D. , Rincón C. , Alemany A.
Published: December 2004

An outbreak of the livestock viral disease bluetongue (BT) was detected during September and October 2000 in the Balearic Islands, Spain. Due to the lack of information about the species of Culicoides (Diptera: Ceratopogonidae) reported in the affected area, six farms in Majorca, four in Minorca and one in Ibiza were selected to carry out surveillance of Culicoides adults using light traps. Here, for the first time, we report the presence in the Balearic Islands of Culicoides imicola Keiffer, the main vector of BT, and the Culicoides obsoletus Meigen group.
Cannibalism and predation among larvae of the Anopheles gambiae complex
Authors: Koenraadt C. J. M. , Takken W.
Published: December 2004

Among the aquatic developmental stages of the Anopheles gambiae complex (Diptera: Culicidae), both inter‐ and intra‐specific interactions influence the resulting densities of adult mosquito populations. For three members of the complex, An. arabiensis Patton, An. quadriannulatus (Theobald) and An. gambiae Giles sensu stricto, we investigated some aspects of this competition under laboratory conditions. First‐instar larvae were consumed by fourth‐instar larvae of the same species (cannibalism) and by fourth‐instar larvae of other sibling species (predation). Even when larvae were not consumed, the presence of one fourth‐instar larva caused a significant reduction in development rate of first‐instar larvae. Possible implications of these effects for population dynamics of these malaria vector mosquitoes are discussed.
Control of phlebotomine sandflies
Authors: Alexander B. , Maroli M.
Published: December 2004

Abstract. Phlebotomine sandflies (Diptera: Psychodidae) transmit many zoonotic diseases (arboviruses, bartonelloses and especially leishmaniases) of importance to human health in at least 80 countries. Measures used to control adult sandflies (Lutzomyia and Phlebotomus) include the use of insecticides (mostly pyrethroids) for residual spraying of dwellings and animal shelters, space‐spraying, insecticide‐treated nets, impregnated dog‐collars and personal protection through application of repellents/insecticides to skin or fabrics. Because the breeding‐sites of sandflies are generally unknown, control measures that act specifically against immatures are not feasible, although the effectiveness of a few biological and chemical agents has been demonstrated in laboratory evaluations. Reports of insecticide‐resistance refer to only three sandfly species (P. papatasi, P. argentipes and S. shorttii) against DDT in one country (India), although there are reports of DDT‐tolerance in several countries. Current knowledge of sandfly susceptibility to various insecticides is summarized. Constraints and advantages of different compounds, formulations and delivery methods for sandfly control under different environmental conditions are discussed.
Does gestational age in combination with birthweight provide better statistical adjustment of neonatal mortality rates than birthweight alone?
Authors: Coory Michael
Published: December 2004

Between‐area comparisons of neonatal mortality rates should be adjusted for differences in the underlying mortality risk. The traditional approach to this problem is to adjust neonatal mortality rates statistically for between‐area differences in the birthweight distributions. However, in other types of perinatal research, birthweight is usually considered in combination with gestational age. For between‐area comparisons of neonatal mortality rates, some researchers have argued that adjustment by gestational age in addition to birthweight might not be necessary. This present study used graphical methods based on a non‐parametric version of Poisson regression to underline the importance of examining neonatal mortality rates by both gestational age and birthweight. Six years of data from a whole‐population database (Queensland Perinatal Data Collection) were used. The analysis also illustrates the value of non‐parametric modelling in perinatal epidemiology.
Twenty‐year birth prevalence of Down syndrome in Cape Town, South Africa
Authors: Molteno Christopher , Smart Ron , Viljoen Denis , Sayed Rauf , Roux Amanda
Published: December 2004

The 20‐year birth prevalence of Down syndrome in Cape Town, South Africa, was determined. All cases delivered to mothers in Cape Town, plus terminations following prenatal diagnosis, between 1 January 1974 and 31 December 1993 were ascertained. There were 784 Down syndrome pregnancies, of which 95% were trisomies. The 32 terminations comprised 18.3% of the white, 5.8% of the coloured (mixed race) and 1.4% of the black cases. The overall prevalence rate was 1.49 per 1000 (white 1.88, coloured 1.54 and black 1.29 per 1000). Analysis for linear trends showed a significant decline in rates for the total population and for whites, a downward trend for coloureds, but no decline for blacks. Over the last 5‐year period the prevalence rates in all three population groups were 1.3 per 1000. An increasing risk with advancing maternal age was confirmed, but no maternal age‐specific differences in rates by race were demonstrated.
Excessive volume expansion and neonatal death in preterm infants born at 27–28 weeks gestation
Authors: Ewer Andrew K. , Tyler Wendy , Francis Andre , Drinkall Donna , Gardosi Jason O.
Published: December 2004

Volume expansion is used commonly in preterm infants to treat presumed hypovolaemia. However, the amount that should be given is uncertain. We present data that were obtained from anonymised regional case notes of Project 27/28, a national case–controlled study run by the Confidential Enquiry into Stillbirths and Deaths in Infancy. Various clinical parameters were analysed, including the volume expansion administered during the first 48 h of life. All deaths in the first year of the study in the West Midlands (cases, n = 22) and matched regional controls (survivors, n = 29) were included. The primary outcome was death within 28 days. Sixteen of the 22 deaths were considered ‘not inevitable’ on the basis of the neonates’ condition at birth. These newborns received on average more than twice the volume expansion compared with controls in the first 48 h of life (38.2 vs. 18.2 mL/kg, P = 0.007). There were no significant differences between the groups in lowest blood pressure or base deficit within the first 12 h of life. Newborns who received ≥ 30 mL/kg volume expansion in the first 48 h of life were more likely to die than those who received < 30 mL/kg (OR 4.5 [95% CI 1.2, 17.2]). Our data suggest that administration of ≥ 30 mL/kg volume expansion is associated with increased mortality in neonates of 27–28 weeks’ gestation. Unless there is clear evidence of hypovolaemia, clinicians should exercise caution when prescribing volume expansion.
Talipes equinovarus in Western Australia
Authors: Carey Mary , Bower Caroline , Mylvaganam Arul , Rouse Ian
Published: December 2004

In Western Australia (WA), talipes equinovarus is a notifiable birth defect and, since 1980, has been ascertained by the population‐based Birth Defects Registry (BDR). Talipes equinovarus deformities were classified as two distinct and distinguishable types, viz. isolated talipes equinovarus (no other birth defects present) and associated talipes equinovarus (other birth defects present). The birth prevalence of associated talipes in WA between 1980 and 1994 was 0.90 per 1000 births, and of isolated talipes was 1.25 per 1000 births. The rate of the isolated deformity was higher in Aboriginal infants (3.49 per 1000 births) than in Caucasian infants (1.11 per 1000 births) and non‐Aboriginal non‐Caucasian infants (0.73 per 1000 births). The sex differential in the rate of the isolated deformity was greatest among Aboriginal infants, with the rate in males being almost four times that in females. The birth prevalence of both types of the deformity remained stable over the 15‐year study period. The rate of caesarean and breech deliveries and the proportion of bilaterally affected feet was greater among infants with associated talipes equinovarus deformity. An accurate and complete identification of cases of isolated talipes equinovarus in the 1980–94 WA birth cohort provides a basis for furthering the understanding of the epidemiology and hence the aetiology of the deformity.
T‐cell activity associated with secondary infections and implanted cysts of Echinococcus granulosus in BALB/c mice
Authors: Rogan M.T.
Published: December 2004

Selected cytokine profiles of lymphocytes were assessed in BALB/c mice infected with protoscoleces of Echinococcus granulosus. Late stages of the infection (three months +) were characterized by more dominant Th2 activity with elevated IL‐4 and IL‐10 and reduced IFN‐γ output by Con‐A and antigen stimulated splenocytes. Circumparasitic leucocytes produced mainly IL‐10 by five months post infection. A peak in IFN‐γ production in the first month of infection may suggest Th1 or Th0 activity at this time and this may be correlated with initial protoscolex death. In addition, cytokine profiles from mice implanted with intact hydatid cysts were also assessed. At two weeks post implantation all cysts were still viable and cytokine production was characterized mainly by elevated IL‐10 production. However, at four months post implantation, some of the cysts from two mice had been killed whilst all cysts in the remaining mouse remained viable. In the mice where dead cysts were present, elevated levels of IFN‐γ were detected from splenocytes and circumparasitic cells. Elevated IL‐4 was also evident with the splenocytes. In the mouse with viable cysts IFN‐γ production was reduced. Results indicate that IFN‐γ (Th1) activity may be correlated with killing of both protoscoleces and established cysts of E. granulosus.
Plasma levels of interleukin‐18 and interleukin‐12 in Plasmodium falciparum malaria
Authors: Malaguarnera Lucia , Pignatelli Salvatore , Musumeci Maria , Simporè Jacques , Musumeci Salvatore
Published: December 2004

Interleukin (IL)‐18 produced primarily by mononuclear phagocytes synergizes with IL‐12 for interferon‐γ production from T, B and natural killer cells. It has been also demonstrated that, in Plasmodium falciparum malaria, IL‐18 could have an immunoregulatory function. The aim of this study was to detect the plasma levels of IL‐12 and IL‐18, using an enzyme‐linked immunosorbent assay, in 105 African children affected by mild and severe Plasmodium falciparum malaria to correlate the production of these cytokines with the severity of the disease. The levels of IL‐18 and IL‐12 were higher (25·7 ± 7·6 pg/ml and 17·1 ± 7·8 pg/ml, respectively) in children with mild malaria than in children with a severe form of the disease (21·5 ± 10 pg/ml and 13·2 ± 5·5 pg/ml, respectively). A positive correlation was observed between IL‐18 and IL‐12. This finding suggests that the production of these two cytokines (IL‐18 and IL 12) may be coregulated and both have an immunoregulatory effect on the immune response in Plasmodium falciparum infection.
C‐reactive protein‐mediated phagocytosis of Leishmania donovani promastigotes does not alter parasite survival or macrophage responses
Authors: Bodman‐Smith Katherine B. , Mbuchi Margaret , Culley Fiona J. , Bates Paul A. , Raynes John G.
Published: December 2004

C‐reactive protein (CRP) is an acute phase protein that binds to surface structures of a number of different organisms. Leishmania donovani express CRP ligand when first entering the mammalian host and CRP has been shown to alter macrophage function. The aim of this study was to investigate the functional significance of CRP‐mediated uptake of L. donovani on survival of the parasite within human macrophages and macrophage cell responses to the infection. CRP opsonized L. donovani uptake was inhibitable by including excess CRP in the fluid phase, suggesting Fc receptor usage rather than indirect complement‐mediated uptake. Comparing equivalent initial infection loads, parasite survival over 72 h within peripheral blood derived macrophages (PBMs) and differentiated U937 cells was unaltered by CRP. Whereas CRP increased macrophage responses to phosphorylcholine coated erythrocytes, no significant alteration in tumour necrosis factor‐α, interleukin (IL)‐10 or IL‐12 production from PBMs was observed between CRP opsonized or unopsonized L. donovani promastigotes. Thus, in contrast to other systems, where CRP opsonization results in macrophage activation, Leishmania can use CRP to improve infection without inducing detrimental macrophage activation.
In vivo inhibition of inducible nitric oxide synthase decreases lung injury induced by Toxocara canis in experimentally infected rats
Authors: Espinoza Elsa Y. , Pérez‐Arellano José L. , Carranza Cristina , Collía Francisco , Muro Antonio
Published: December 2004

The direct effect of nitric oxide (NO) on the viability of Toxocara canis larvae was studied. We observed that the nitric oxide donors, SIN‐1 and SNOG, exert no cytotoxic effect on the in vitro viability of T. canis larvae. In addition, we developed a model in rats to elucidate the role of NO during T. canis infection. We evaluated different indicators in four experimental groups: morphological parameters, the total number cells and cell types recovered, nitrite and protein concentration, lactate dehydrogenase and alkaline phosphatase enzymatic activity in the bronchoalveolar lavage fluid, lung index and detection of anti‐T. canis specific antibodies. We observed significant differences between non‐infected and infected groups. The infected animals treated with the inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine were less damaged than infected, non‐treated animals. Our results suggest that the in vivo inhibition of the synthesis of NO triggered by iNOS diminishes the deleterious effects of the parasite upon the host, especially the vascular alterations in the lungs. We could show that in vivo production of NO induced by infection with T. canis results in direct host damage. Thus, this induction may constitute an evasion/adaptation mechanism of the parasite.
Cellular responses and cytokine profiles in Ascaris lumbricoides and Trichuris trichiura infected patients
Authors: Geiger Stefan M. , Massara Cristiano L. , Bethony Jeffrey , Soboslay Peter T. , Carvalho Omar S. , Corrêa‐Oliveira Rodrigo
Published: December 2004

The impact of intestinal helminth infection, i.e. Ascaris lumbricoides and Trichuris trichiura, on cellular responsiveness and cytokine production was investigated in young adults. Ascaris‐specific cellular responsiveness was higher in parasite‐free endemic controls than in patients infected with T. trichiura, or A. lumbricoides, or patients co‐infected with both parasites. Also, mitogen‐induced tumour necrosis factor (TNF)‐α, interleukin (IL)‐12 and interferon (IFN)‐γ secretion by peripheral blood mononuclear cells (PBMC) was higher in negative endemic controls than in infected individuals. Ascaris antigen‐specific production of TNF‐α, IL‐12 and IFN‐γ was low in singly Ascaris as well as in co‐infected patients, whereas secretion of IL‐10 and IL‐13 was elevated and similarly high in all patient groups. The detection of Trichuris‐specific and Ascaris‐specific IgG4 revealed significantly higher serum antibody levels in Trichuris or Ascaris patients when compared to endemic controls (P < 0·05), whereas parasite‐specific IgE antibody levels were similarly high in infected individuals and in endemic controls. In summary, chronically infected Ascaris and Trichuris patients with a high parasite load presented reduced cellular reactivity and lower type 1 TNF‐α, IFN‐γ and IL‐12 responses when compared with endemic controls, whereas type 2 IL‐10 and IL‐13 productions were similar in all groups from the endemic area. The former may support parasite persistence, whereas substantial type 2 cytokine release may promote protective immunity, suggesting an adaptation of the host to control the parasite burden while minimizing immune‐mediated host self‐damage.
Immune rejection of Trichostrongylus colubriformis in sheep; a possible role for intestinal mucus antibody against an L3‐specific surface antigen
Authors: Harrison G. B. L. , Pulford H. D. , Hein W. R. , Barber T. K. , Shaw R. J. , Mcneill M. , J WAKEFIELD St. , Shoemaker C. b
Published: December 2004

Sheep that have been immunized by multiple truncated infections with the parasitic nematode Trichostrongylus colubriformis contain anti‐larval activity in their intestinal mucus and high‐speed mucus supernatants. This activity induces T. colubriformis L3 to clump in vitro and causes a significant reduction in larval establishment in naive sheep after infusion of larvae and mucus into the intestinal lumen via a duodenal cannula. In this report, we provide evidence that one factor contributing to the anti‐larval activity of immune mucus is antibody against a 35‐kDa L3‐specific cuticular antigen. The anti‐larval activity in mucus is > 100 kDa by membrane filtration, is heat labile and sensitive to either protease digestion or reduction with DTT. Immunoblotting showed that mucus and supernatants of ultracentrifuged mucus from immune sheep contained IgG1 and IgA antibodies that recognized predominantly a larval antigen with an estimated molecular weight of 35 kDa on SDS‐PAGE. Antibodies eluted from the surface of washed larvae that had been incubated in immune mucus also reacted specifically with the 35 kDa antigen on blots of larval homogenate. Immunofluorescence and immunogold electron microscopy showed that the 35 kDa antigen is present on the epicuticle of L3 and is shed during the moult to L4. The antigen is not present in eggs, L1, L2, L4 or adult worms and is found only in extracts of sheaths and L3 before infection and up to 4 days after infection. We hypothesize that the binding of antibody to the larval surface prevents larvae from establishing at their preferred site, causing them to be eliminated from the intestine. Monoclonal antibody PAB‐1 recognizes the 35 kDa T. colubriformis larval antigen and also cross‐reacts with antigens of similar molecular weight on blots of L3 extracts of the parasitic nematodes Haemonchus contortus and Ostertagia circumcincta; and with a 22‐kDa antigen on blots of L3 extracts from Cooperia curticei and Nematodirus spathiger. This indicates that an antigenically related surface antigen with immunizing potential is present on several nematode species and can be identified by mAb PAB‐1. The 35 kDa T. colubriformis larval antigen and related molecules in other nematodes are potential novel targets for stimulating host‐protective immunity against nematode infections.
Partial characterization and post‐feeding activity of midgut aminopeptidase in the human body louse,Pediculus humanus humanus
Authors: Ochanda James O. , Oduor Eva A. C. , Galun Rachel , Imbuga Mabel O. , Mumcuoglu Kosta Y.
Published: December 2004

Abstract.A leucine aminopeptidase was found in the midgut of the human body louse, Pediculus humanus humanus L. (Anoplura: Pediculidae). The enzyme is activated by the bloodmeal with a pH optimum at 8. The enzyme is soluble in both aqueous and detergent‐containing solutions. The two forms of the enzyme had the same Km but exhibited different catalytic activities with regard to Vmax values in these solutions. The enzyme is inhibited competitively by a substrate analogue 1,10‐phenanthroline and by Mn2+ ions in the presence and absence of detergent.
A rhythm underlying feeding behaviour in a highly polyphagous caterpillar
Authors: Bernays E. A. , Singer M. S.
Published: December 2004

Abstract.Behavioural mechanisms of food mixing were studied in the polyphagous caterpillar Grammia geneura (Strecker) (Lepidoptera, Arctiidae) in arenas with different plant foods. Combinations of food plants, including single and multiple plant species were used. Behavioural observations on individuals of similar age were undertaken for 4 h. Foraging and feeding behaviour were monitored in detail. It was found that feeding was generally initiated during short intervals that represented the peaks of an endogenous activity rhythm. Feeding was not initiated on all peaks but at times that represented multiples of the oscillatory period. The oscillation fitted to each individual varied between 10 and 13 min. The possible significance of the oscillation is discussed.
Interactions of temperature and dietary protein concentration in growth and feeding ofManduca sextacaterpillars
Authors: Kingsolver J. G. , Woods H. A.
Published: December 2004

Abstract.Temperature and the protein content of food affect rates of consumption and growth in herbivorous insects in different ways: reduced temperature typically reduces both consumption and growth rates, whereas reduced dietary protein typically increases consumption rate but either reduces or has no effect on growth rate. The interactions between temperature and dietary protein concentration in affecting consumption, growth and efficiency in fifth‐instar caterpillars of Manduca sexta were studied, using both short‐term (4 h) and long‐term (duration of fifth stadium) experiments. The short‐term experiments examined constant temperatures between 14 and 42°C, whereas the long‐term experiments examined constant temperatures between 18 and 34°C; both experiments considered two levels of dietary protein. In both experiments, caterpillars had significantly higher consumption and frass production rates on low‐protein compared with high‐protein diets at each test temperature between 18 and 34°C, thereby compensating for the lower diet quality. In contrast, at more extreme temperatures (14 and 42°C) in the short‐term studies, consumption and frass production rates were lower on low‐protein compared with high‐protein diets. As a result, there were substantial interactions between temperature and dietary protein for consumption and frass production rates in the short‐term experiments, but not in the long‐term experiments. These results suggest that interactions between temperature and dietary protein may emerge because of the failure of compensatory feeding responses at low and high temperatures. It is hypothesized that the failure of compensatory responses is more likely to occur under diurnally fluctuating temperatures than under a constant temperature with the same mean, and it is proposed that interactions between temperature and dietary protein for consumption are relevant to M. sexta and other caterpillars that experience wide diurnal fluctuations in temperature in the field.
Relations between stomatal closure, leaf turgor and xylem vulnerability in eight tropical dry forest trees
Authors: BRODRIBB T. J. , HOLBROOK N. M. , EDWARDS E. J. , GUTIÉRREZ M. V.
Published: December 2004

This study examined the linkage between xylem vulnerability, stomatal response to leaf water potential (ΨL), and loss of leaf turgor in eight species of seasonally dry tropical forest trees. In order to maximize the potential variation in these traits species that exhibit a range of leaf habits and phenologies were selected. It was found that in all species stomatal conductance was responsive to ΨL over a narrow range of water potentials, and that ΨL inducing 50% stomatal closure was correlated with both the ΨL inducing a 20% loss of xylem hydraulic conductivity and leaf water potential at turgor loss in all species. In contrast, there was no correlation between the water potential causing a 50% loss of conductivity in the stem xylem, and the water potential at stomatal closure (ΨSC) amongst species. It was concluded that although both leaf and xylem characters are correlated with the response of stomata to ΨL, there is considerable flexibility in this linkage. The range of responses is discussed in terms of the differing leaf‐loss strategies exhibited by these species.
Relationship between growth rates and xylem hydraulic characteristics in young, mature and old‐growth ponderosa pine trees
Authors: DOMEC J‐C. , GARTNER B. L.
Published: December 2004

The first objective of the present study was to quantify the effects of tree age and stem position on specific conductivity (ks), vulnerability to embolism and water storage capacity (capacitance) in trunks of young, mature and old‐growth ponderosa pine. The second objective was to determine relationships between hydraulic characteristics and radial and height growth rates to increase the understanding of possible tradeoffs. Within sapwood at all heights and in all ages of trees, outer sapwood had 25–60% higherksthan inner sapwood. The water potential at which embolism started (air entry point) was 1.3 MPa lower in inner sapwood than outer sapwood within the mature trees, but there was no difference in the other trees. There was no significant difference in capacitances between the tops of the old growth trees, the mature trees and the young trees. Taking all data together, the capacitances increased sharply with an increase inksand an increase in vulnerability to embolism. The hydraulic characteristics of the three age classes were correlated with the height growth rate but not with the diameter growth rate. Within these age classes, highkswas associated with the slowest yearly increase in sapwood area and with a low percentage of latewood, whereas high vulnerability to embolism and high capacitance were more closely associated with high height growth rates.
Responses to UV‐B radiation in Trifolium repens L. – physiological links to plant productivity and water availability
Authors: HOFMANN R. W. , CAMPBELL B. D. , BLOOR S. J. , SWINNY E. E. , MARKHAM K. R. , RYAN K. G. , FOUNTAIN D. W.
Published: December 2004

This study used comparisons across nine populations of Trifolium repens (white clover) in conjunction with drought to examine physiological responses to ultraviolet‐B radiation (UV‐B). Plants were exposed for 12 weeks to supplementation with 13.3 kJ m−2 d−1 UV‐B, accompanied by 4 weeks of drought under controlled environmental conditions. UV‐B increased the levels of UV‐B‐absorbing compounds and of flavonol glycosides and this effect was synergistically enhanced by water stress. These changes were more pronounced for the ortho‐dihydroxylated quercetin, rather than the monohydroxylated kaempferol glycosides. UV‐B increased leaf water potential (ψL) by 16% under drought and proline levels by 23% under well‐watered conditions. The intraspecific comparisons showed that higher UV‐B‐induced levels of UV‐B‐absorbing compounds, of quercetin glycosides and of ψL were linked to lower plant productivity and to higher UV‐B tolerance under well‐watered conditions. These findings suggest that: (1) slow‐growing T. repens ecotypes adapted to other stresses have higher capacity for physiological acclimation to UV‐B; and (2) that these attributes also contribute to decreased UV‐B sensitivity under drought.
Rubisco expression in rice leaves is related to genotypic variation of photosynthesis under elevated growth CO2 and temperature
Authors: GESCH R. W. , KANG I.‐H. , GALLO‐MEAGHER M. , VU J. C. V. , BOOTE K. J. , H. ALLEN L. , BOWES G.
Published: December 2004

Genetic modifications of agronomic crops will likely be necessary to cope with global climate change. This study tested the hypotheses that genotypic differences in rice (Oryza sativa L.) leaf photosynthesis at elevated [CO2] and temperature are related to protein and gene expression of Rubisco, and that high growth temperatures under elevated [CO2] negatively affect photosystem II (PSII) photochemical efficiency. Two rice cultivars representing an indica (cv. IR72) and japonica type (cv. M103) were grown in 350 (ambient) and 700 (elevated) µmol CO2 mol−1 at 28/18, 34/24 and 40/30 °C sinusoidal maximum/minimum, day/night temperatures in outdoor, sunlit, environment‐controlled chambers. Leaf photosynthesis of IR72 favoured higher growth temperatures more than M103. Rubisco total activity and protein content were negatively affected in both genotypes by high temperatures and elevated CO2. However, at moderate to high growth temperatures, IR72 leaves averaged 71 and 39% more rbcS transcripts than M103 under ambient and elevated CO2, respectively, and likewise had greater Rubisco activity and protein content. Expression of psbA (D1 protein of PSII) in IR72 leaves increased with temperature, whereas it remained constant for M103, except for a 20% decline at 40/30 °C under elevated CO2. Even at the highest growth temperatures, PSII photochemical efficiency was not impaired in either genotype grown under either ambient or elevated CO2. Genotypic differences exist in rice for carboxylation responses to elevated CO2 and high temperatures, which may be useful in developing genotypes suited to cope with global climate changes.
Calcium‐dependent K current in plasma membranes of dermal cells of developing bean cotyledons
Authors: ZHANG W.‐H. , WALKER N. A. , PATRICK J. W. , TYERMAN S. D.
Published: December 2004

In developing seeds of bean (Phaseolus vulgaris L.), phloem‐imported assimilates (largely sucrose and potassium) are released from coats to seed apoplasm and subsequently retrieved by the dermal cell complexes of cotyledons. To investigate the mechanisms of K+ uptake by the cotyledons, protoplasts of dermal cell complexes were isolated and whole‐cell currents across their plasma membranes were measured with the patch‐clamp technique. A weakly rectified cation current displaying a voltage‐dependent blockade by external Ca2+ and acidic pH, dominated the conductance of the protoplasts. The P haseolus v ulgaris Cotyledon Dermal‐cell pH and Calcium‐dependent Cation Conductance (Pv‐CD‐pHCaCC) was highly selective for K+ over Ca2+ and Cl–. For K+ current through Pv‐CD‐pHCaCC a sigmoid shaped current–voltage (I–V) curve was observed with negative conductance at voltages between −200 and −140 mV. This negative K+ conductance was Ca2+ dependent. With other univalent cations (Na+, Rb+, NH4+) the currents were smaller and were not Ca2+ dependent. Reversal potentials remained constant when external K+ was substituted with these cations, suggesting that Pv‐CD‐pHCaCC channels were non‐selective. The Pv‐CD‐pHCaCC would provide a pathway for K+ and other univalent cation influx into developing cotyledons. These cation influxes could be co‐ordinated with sucrose influx via pH and Ca2+dependence.
Relationships between stem canker, stolon canker, black scurf (Rhizoctonia solani) and yield of potato (Solanum tuberosum) under different agronomic conditions
Authors: SIMONS S. A. , GILLIGAN C. A.
Published: December 2004

Relationships between diseases caused by Rhizoctonia solani on different parts of potato plants (Solanum tuberosum) at different stages of crop growth were investigated under selected agronomic conditions. The effects of different densities of tuber‐borne inoculum, date of planting, irrigation, size of seed tubers and their interactions on the incidence of stem and stolon canker during crop growth, the incidence and severity of black scurf and the yield of progeny tubers at harvest were quantified in a multifactorial experiment. Differences in the incidence of stem canker, stolon canker and black scurf were dominated by the effect of density of inoculum on seed tubers at planting. Highly positive correlations between the disease variables indicated a close relationship between the incidence of disease at each stage of crop growth although the degree of association between variables measured at an early growth stage and those measured at progressively later stages of crop growth weakened as the time interval increased. Total yield of progeny tubers was not affected by the density of tuber‐borne inoculum although there was a shift in the size distribution, with a decrease in the yield of main‐sized tubers and an increase in the yield of baker‐ and oversized tubers at the higher density of inoculum. Of the remaining factors, the effect of season tended to be more pronounced than any of the agronomic treatments although the use of irrigation and later dates of planting did influence the incidence of infection to a limited extent.
Characterization and occurrence of Zucchini Yellow Mosaic Virus in Sudan
Authors: MAHGOUB H. A. , DESBIEZ C. , WIPF‐SCHEIBEL C. , DAFALLA G. , LECOQ H.
Published: December 2004

Zucchini yellow mosaic potyvirus (ZYMV) was isolated in 1993 from a squash plant (Cucurbita pepo cv. Eskandrani) showing severe leaf and fruit distortions, collected in the Gezira region (Sudan). This isolate (ZYMV‐Su) was found to be very closely serologically related if not identical to the type strain from Italy. The host range was mostly limited to Cucurbitaceae but systemic infection was found to occur on sesame (Sesamum indicum), an important cultivated crop in Sudan. ZYMV‐Su induced mosaic symptoms on the resistant melon accession PI 414723, indicating that it belongs to pathotype 2, but did not cause wilting of melon cv. Doublon. ZYMV‐Su was efficiently transmitted by Myzus persicae and Aphis gossypii in a non‐persistent manner. Surveys conducted from 1993 to 1995 revealed that ZYMV occurred in the major cucurbit growing areas in Sudan, in a diversity of crops and agroecosystems.