bluuebunny/crossref_metadata_2025 huggingface dataset:
Dispersal potential and early growth in 14 tropical mangroves: do early life history traits correlate with patterns of adult distribution?
Authors: Clarke Peter J. , Kerrigan Raelee A. , Westphal Christine J.
Published: March 2003

We characterized the dispersal potential and early growth traits of 14 tropical mangrove species in experiments where diaspores were immersed in various solutions of seawater and subsequently stranded onto surfaces with the same salinity.

Viviparous and non‐viviparous species had similar buoyancy, seed weight and rates of root and shoot initiation, as well as early growth and salinity tolerance. This trait convergence may be related to selection against small, dormant diaspores in the unstable regeneration niche.

Differences in dispersal potential and early growth of 12 species were compared with known patterns of distribution (across the shore, along estuaries, regional occurrence and continental range size) to test if tidal sorting of diaspores could account for adult spatial patterns.

Diaspore buoyancy, orientation, lateral root initiation, shoot initiation and early shoot extension differed among species but none correlated with adult zonation across the shore or along estuaries. However, some back‐shore species had diaspores that were buoyant and were slow to initiate lateral roots and shoots. Patterns of early growth were partially related to the distribution along estuaries but salinity responses contributed to this zonation in only three species.

Regional distributions were unrelated to dispersal potential. However, the tendency of infrequent species to show slow growth in full seawater may account for the under‐saturation of species in estuaries with appropriate habitats. The range size of the tropical mangroves appears unrelated to their dispersal potential and early growth traits.

Early life history traits of 12 mangroves showed poor correlation with patterns of adult distribution across all spatial scales. Traits related to establishment were, however, stronger predictors of distribution than those associated with dispersal.
Leaf dynamics and maintenance of tree crowns in a Malaysian rain forest stand
Authors: Osada Noriyuki , Takeda Hiroshi , Furukawa Akio , Awang Muhamad
Published: March 2003

Leaf demography was examined for trees of various heights over a 3.7‐year period in a Malaysian rain forest. We compared demography between upper and lower parts of the crown and its relation to height. The results were analysed at the stand level by pooling several trees of various shade‐tolerant species, as well as three species for which multiple individuals were sampled.

 Photon flux density was generally higher in the upper than in the lower crowns. Leaf production rate and leaf loss rate were faster, and number of leaf cohorts and median leaf life span were therefore lower, in the upper crowns of most trees. Faster rates of leaf loss and shorter life spans were associated with increasing height, although leaf production rate was unaffected.

 Leaf life span and specific leaf area were plastic traits which decreased with height within several shade‐tolerant tree species, indicating functional convergence.

 Vertical distribution of leaf biomass was almost even in the stand. Because leaf life span was shorter in the upper canopy, these leaves contributed most to litter production. The vertical structure of the forest stand was therefore maintained through dynamic processes in trees of various heights over short time‐scales.
Degradation of mangrove tissues and implications for peat formation in Belizean island forests
Authors: Middleton B. A. , McKee K. L.
Published: March 2003

Macrofaunal leaf consumption and degradation of leaves, woody twigs and roots were studied in mangrove island forests on a Belizean island. Factors influencing accumulation of organic matter deposited both above and below ground in this oligotrophic, autochothonous system were assessed.

 Leaf degradation rates ofRhizophora mangle(red mangrove),Avicennia germinans(black mangrove) andLaguncularia racemosa(white mangrove) measured in mesh bags, were much faster in the lower than the upper intertidal zone. Mass loss was most rapid inA. germinansbut zonal effects were much larger than species differences.

 Exposure to invertebrates such as crabs and amphipods tripled overall rates of leaf litter breakdown. In the lower intertidal, crabs completely consumed some unbagged leaves within 23 days. Crabs also had an effect on some upper intertidal sites, where degradation of leaves placed in artificial burrows was 2.4 times faster than when placed on the soil surface.

 In contrast to leaves (27 ± 5% remaining after 230 days), roots and woody twigs were highly refractory (40 ± 2% and 51 ± 6% remaining after 584 and 540 days, respectively). Root degradation did not vary by soil depth, zone or species. Twigs ofR. mangleandA. germinansdegraded faster on the ground than in the canopy, whereas those ofL. racemosawere highly resistant to decay regardless of position.

 Peat formation at Twin Cays has occurred primarily through deposition and slow turnover of mangrove roots, rather than above‐ground tissues that are either less abundant (woody twigs) or more readily removed (leaves).
Parasitic fungus mediates change in nitrogen‐exposed boreal forest vegetation
Authors: Strengbom Joachim , Nordin Annika , Näsholm Torgny , Ericson Lars
Published: March 2003

Experimental additions of N to an old‐growth boreal forest resulted in elevated levels of free amino acids in leaves of the dominant dwarf‐shrub Vaccinium myrtillus and increased attack from a parasitic fungus, Valdensia heterodoxa.

Glutamine additions to the leaf surface of V. myrtillus increased disease incidence by an average of almost three times compared to controls and suggested a causal connection between amino acid availability and fungal infection.

Increased abundance of the grass Deschampsia flexuosa followed N addition but infection by the parasitic fungus, which causes premature leaf loss of its primary host V. myrtillus, explained four times as much of the variation in grass abundance as N did.

Nitrogen deposition can have marked effects on vegetation by affecting the interaction between dominant hosts and their natural enemies. A shift in abundance of dominating species occurred within 3 years of treatment, with nitrogen loads similar to those deposited over large areas in Europe and North America, suggesting that such effects may by important for the vegetation of large areas subjected to low levels of nitrogen input.
Elevated atmospheric CO2affects structure of a model regenerating longleaf pine community
Authors: Davis Micheal A. , Pritchard Seth G. , Mitchell Robert J. , Prior Stephen A. , Rogers Hugo H. , Runion G. Brett
Published: March 2003

Differences in plant morphology, physiology, life form, and symbiotic relationships can generate differences in species responses to CO2‐enrichment, which can alter competitive interactions, thus affecting community structure and function. Here, we present data from a two‐year study, examining the species and community responses to elevated [CO2] of a model regenerating longleaf pine community. The model community was constructed from an assemblage of early successional forest species representing major functional guilds within a typical longleaf pine–wiregrass community: (1) a C3evergreen conifer (Pinus palustris); (2) a C4bunch grass (Aristida stricta); (3) a C3broadleaf tree (Quercus margaretta); (4) a C3perennial herbaceous legume (Crotalaria rotundifolia); and (5) a C3herbaceous perennial (Asclepias tuberosa). After 2 years, CO2‐enriched plots had 109% greater above‐ground biomass than ambient plots, mainly due to a 117% increase in pine biomass. Community structure was altered by CO2enrichment;CrotalariaandAsclepiashad higher mortality and less biomass in high‐CO2plots, suggesting that not all species will perform well as global [CO2] rises. Our data suggest that longleaf pine communities as a whole will perform well in a future higher CO2world, but some species may fall prey to altered competitive interactions for light and soil moisture.
Molecular determinants for the action of general anesthetics  at recombinant α2β3γ2γ‐aminobutyric acidA receptors
Authors: Siegwart Roberta , Jurd Rachel , Rudolph Uwe
Published: March 2003

General anesthetics modulate the activity of ligand‐gated ion channels including the GABAA receptor. Mutational studies mainly on the benzodiazepine‐insensitive α2β1(M286W) and α6β3(N289M)γ2 GABAA receptors revealed that a serine in transmembrane domain 2 and a methionine in transmembrane domain 3 are essential for the action of most general anesthetics. We investigated whether these residues would similarly be relevant for their action at the benzodiazepine‐sensitive GABA receptor subtype, α2β3γ2. We found that not only the N265M but also the M286W mutation nearly abolished the modulatory effect of etomidate. However, the anti‐convulsant loreclezole, a structural homologue of etomidate, was inactive on the N265M mutant, but displayed normal modulatory activity on the M286W mutant. Both mutations did not affect the modulatory action of the neurosteroid alphaxalone. The direct action of alphaxalone, however, was dramatically increased in the M286W mutant to about twice the maximal GABA current but not significantly affected in the N265M mutant. These data demonstrate that the structural requirements for modulatory and direct actions of various general anesthetics are distinct. The molecular switches induced by these mutations can be exploited to identify the molecular determinants for the action of general anesthetics.
Role of Ca2+ and calmodulin‐dependent enzymes in the regulation of glycine transport in Müller glia
Authors: Gadea Ana , López Edith , Hernández‐Cruz Arturo , López‐Colomé Ana María
Published: March 2003

Glycine (Gly) is considered an obligatory co‐agonist at NMDA receptors. Müller glia from the retina harbor functional NMDA receptors, as well as low and high affinity Gly transporters, the later identified as GLYT1. We here studied the regulation of Gly transport in primary cultures of Müller glia, as this process could contribute to the modulation of NMDA receptor activity at glutamatergic synapses in the retina. We demonstrate that neither glutamate stimulation nor the activation or inhibition of protein kinases A or C modify transport. In order to assess a function for Ca2+ and calmodulin (CaM)‐dependent processes in the regulation of Gly transport, we explored the participation of Ca2+ concentration, CaM and Ca2+/CaM‐dependent enzymes on Gly transporter activity. ATP and carbachol, known to induce Ca2+ waves in Müller cells, as well as caffeine‐induced Ca2+ release from intracellular stores stimulated transport, whereas Ca2+ chelation by BAPTA‐AM markedly reduced transport. CaM inhibitors W‐7, ophiobolin A, R‐24571 and trifluoperazine, induced a specific dose‐dependent inhibition of transport. The inhibition of CaMKII by the autocamtide‐2‐related inhibitory peptide or by KN62 caused a decrease in transport which, in the case of KN62, was due to the abolition of the high affinity component, ascribed to GLYT1. Our results further suggest that Gly transport is under cytoskeletal control, as activation of calpain by major increases in [Ca2+]i induced by ionophores, as well as actin destabilization clearly inhibit uptake. We here demonstrate for the first time the participation of CaM, CaMKII and the actin cytoskeleton in the regulation of Gly transport in glia. Ca2+ waves are induced in Müller cells by distinct neuroactive compounds released by neurons and glia, hence the regulation of [Gly] by this system may be of physiological relevance in the control of retinal excitability.
Interleukin‐1β‐induced substance P release from rat cultured primary afferent neurons driven by two phospholipase A2 enzymes: secretory type IIA and cytosolic type IV
Authors: Morioka Norimitsu , Takeda Kazumi , Kumagai Kei , Hanada Tomohiko , Ikoma Kozo , Hide Izumi , Inoue Atsuko , Nakata Yoshihiro
Published: March 2003

We previously described that recombinant interleukin‐1β (IL‐1β) induced the significant release of substance P (SP) via a cyclooxygenase (COX) pathway in primary cultured rat dorsal root ganglion (DRG) cells. In the present study, we examined the involvement of two types of phospholipase A2 (PLA2) enzymes, which lie upstream of COX in the prostanoid‐generating pathway, in the IL‐1β‐induced release of SP from DRG cells. The expression of type ΙΙΑ secretory PLA2 (sPLA2‐IIA) mRNA was undetectable by ribonuclease protection assay in non‐treated DRG cells, while in DRG cells incubated with 1 ng/mL of IL‐1β, the expression was induced in a time‐dependent manner. On the other hand, type IV cytosolic PLA2(cPLA2) mRNA was constitutively expressed in the non‐treated DRG cells, and treatment with 1 ng/mL of IL‐1β for 3 h significantly increased the levels of cPLA2mRNA. The IL‐1β‐induced SP release was significantly inhibited by the sPLA2inhibitor, thioetheramide phosphorylcholine (TEA‐PC), and the cPLA2inhibitor, arachidonyl trifluoromethyl ketone (AACOCF3). Furthermore AACOCF3suppressed the induction of sPLA2‐IIA mRNA expression induced by IL‐1β. These observations suggested that two types of PLA2, sPLA2‐IIA and cPLA2, were involved in the IL‐1β‐induced release of SP from DRG cells, and that the functional cross‐talk between the two enzymes might help to control their activity in the prostanoid‐generating system in DRG cells. These events might be key steps in the inflammation‐induced hyperactivity in primary afferent neurons of spinal cord.
N‐Glycans on the receptor for advanced glycation end products influence amphoterin binding and neurite outgrowth
Authors: Srikrishna Geetha , Huttunen Henri J. , Johansson Lena , Weigle Bernd , Yamaguchi Yu , Rauvala Heikki , Freeze Hudson H.
Published: March 2003

In this study we show that embryonic neurite growth‐promoting protein amphoterin binds to carboxylated N‐glycans previously identified on mammalian endothelial cells. Since amphoterin is a ligand for the receptor for advanced glycation end products (RAGE), and the ligand‐binding V‐domain of the receptor contains two potential N‐glycosylation sites, we hypothesized that N‐glycans on RAGE may mediate its interactions with amphoterin. In support of this, anti‐carboxylate antibody mAbGB3.1 immunoprecipitates bovine RAGE, and PNGase F treatment reduces its molecular mass by 4.5 kDa, suggesting that the native receptor is a glycoprotein. The binding potential of amphoterin to RAGE decreases significantly in presence of soluble carboxylated glycans or when the receptor is deglycosylated. Oligosaccharide analysis shows that RAGE contains complex type anionic N‐glycans with non‐sialic acid carboxylate groups, but not the HNK‐1 (3‐sulfoglucuronyl β1–3 galactoside) epitope. Consistent with the functional localization of RAGE and amphoterin at the leading edges of developing neurons, mAbGB3.1 stains axons and growth cones of mouse embryonic cortical neurons, and inhibits neurite outgrowth on amphoterin matrix. The carboxylated glycans themselves promote neurite outgrowth in embryonic neurons and RAGE‐transfected neuroblastoma cells. This outgrowth requires full‐length, signalling‐competent RAGE, as cells expressing cytoplasmic domain‐deleted RAGE are unresponsive. These results indicate that carboxylated N‐glycans on RAGE play an important functional role in amphoterin‐RAGE‐mediated signalling.
Elevated atmospheric CO2 improved Sorghum plant water status by ameliorating the adverse effects of drought
Authors: Wall G. W. , Brooks T. J. , Adam N. R. , Cousins A. B. , Kimball B. A. , Pinter P. J. , LaMorte R. L. , Triggs J. , Ottman M. J. , Leavitt S. W. , Matthias A. D. , Williams D. G. , Webber A. N.
Published: March 2003

The interactive effects of atmospheric CO2 concentration and soil‐water content on grain sorghum (Sorghum bicolor) are reported here.

Sorghum plants were exposed to ambient (control) and free‐air CO2 enrichment (FACE; ambient + 200 µmol mol−1), under ample (wet, 100% replacement of evapotranspiration) and reduced (dry, postplanting and mid‐season irrigations) water supply over two growing seasons.

FACE reduced seasonal average stomatal conductance (gs) by 0.17 mol (H2O) m−2 s−1 (32% and 37% for dry and wet, respectively) compared with control; this was similar to the difference between dry and wet treatments. FACE increased net assimilation rate (A) by 4.77 µmol (CO2) m−2 s−1 (23% and 9% for dry and wet, respectively), whereas dry decreased A by 10.50 µmol (CO2) m−2 s−1 (26%) compared with wet. Total plant water potential (ψw) was 0.16 MPa (9%) and 0.04 MPa (3%) less negative in FACE than in the control treatment for dry and wet, respectively. Under dry, FACE stimulated final shoot biomass by 15%.

By ameliorating the adverse effects of drought, elevated atmospheric CO2 improved plant water status, which indirectly caused an increase in carbon gain.
The cytoskeleton in plant cell growth: lessons from root hairs
Authors: Ketelaar Tijs , Emons Anne Mie C.
Published: March 2003

In this review, we compare expansion of intercalary growing cells, in which growth takes place over a large surface, and root hairs, where expansion occurs at the tip only. Research that pinpoints the role of the cytoskeleton and the cytoplasmic free calcium in both root hairs and intercalary growing cells is reviewed. From the results of that research, we suggest experiments to be carried out on intercalary growing cells to test our hypotheses on plant cell expansion. Our main hypothesis is that instability of the cortical actin cytoskeleton determines the location where expansion takes place and the amount of expansion.

Contents

Summary
409

I.
How do plant cells expand their surface?
409

II.
Immunolocalization of epitopes in fixed root hairs for light‐microscopy
410

III.
The cytoskeleton in growing root hairs
412

1. Microtubules
412

2. Actin filaments
413

3. Free cytoplasmic calcium concentration
413

IV.
The role of cytoskeletal elements and cytoplasmic free alcium in intercalary expanding root cells
414

1. Microtubules
414

2. Actin filaments
415

3. Free cytoplasmic calcium concentration
416

Acknowledgements
416

References
416
Following the dynamics of strobilurin resistance in Blumeria graminis f.sp. tritici using quantitative allele‐specific real‐time PCR measurements with the fluorescent dye SYBR Green I
Authors: Fraaije B. A. , Butters J. A. , Coelho J. M. , Jones D. R. , Hollomon D. W.
Published: March 2003

Strobilurin‐resistant isolates of Blumeria (Erysiphe) graminis f.sp. tritici, the cause of wheat powdery mildew, were more than 10‐fold less sensitive to azoxystrobin than sensitive isolates. In all resistant isolates, a mutation resulting in the replacement of a glycine by an alanine residue at codon 143 (G143A) in the mitochondrial cytochrome b gene was found. Allele‐specific primers were designed to detect this point mutation in infected wheat leaves. Using quantitative fluorescent allele‐specific real‐time polymerase chain reaction (PCR) measurements, strobilurin‐resistant A143 alleles could be detected amongst strobilurin‐sensitive G143 alleles at a frequency of at least 1 in 10 000, depending on the amount of target and nontarget DNA. Most isolates tested were dominant homoplasmic for either the A143 or G143 allele, although mixed populations of alleles could be detected in some isolates. In some of these isolates, strobilurin resistance was not always stable when they were maintained for many generations in the absence of selection. The allele‐specific real‐time PCR assay was also used to follow the dynamics of A143 alleles in field populations of B. graminis f.sp. tritici before and after application of fungicides. As expected, the A143 allele frequency only increased under selection pressure from a strobilurin fungicide. After three sprays of azoxystrobin, a pronounced selection for the strobilurin‐resistant allele, with an increase in average frequency from 2·2 to 58%, was measured. The use of quantitative real‐time PCR diagnostics for early detection of fungicide resistance genes at low frequency, coupled with risk evaluation, will be invaluable for further resistance risk assessment and validation of antiresistance strategies.
Possibilities of avoidance and control of bacterial plant diseases when using pathogen‐tested (certified) or ‐treated planting material
Authors: Janse J. D. , Wenneker M.
Published: March 2003

Testing of planting material for freedom from phytopathogenic bacteria is an important, although not exclusive, method for control of bacterial diseases of plants. Ideally, pathogen‐free or pathogen‐/disease‐resistant planting material is desirable, but this situation is not always possible on a practical basis. For most bacterial pathogens, resistance is not available in cultivated hosts, and production of pathogen‐free planting material requires strict certification schemes via several routes. These include (i) indexing, with subsequent removal of infected/contaminated material from the production chain; (ii) meristem and other tissue culture production systems; (iii) thermo‐ or chemotherapy; (iv) plant or seed surface disinfection for epiphytic bacterial pathogens; (v) avoidance or decontamination of contaminated production factors such as substrate, soil or irrigation water. These methods cannot guarantee 100% freedom from the pathogen or disease during crop multiplication from certified planting material, because of factors such as sampling error, experimental error, test sensitivities, limitations of therapies (e.g. phytotoxicity or insufficient penetration), re‐introduction of the pathogen, insufficient hygiene or decontamination during planting and multiplication of clean propagating material, and manipulations during trade and production. These factors are discussed with reference to several bacterial plant diseases, in particular control of bacterial brown rot and ring rot of potato in Europe and North America. The most efficient control of bacterial diseases can be expected through a combination of the use of healthy/tested planting material and good cultivation practice, including strict crop and storage hygiene.
P–T modelling of the andalusite–kyanite–andalusite sequence and related assemblages in high‐Al graphitic pelites. Prograde and retrograde paths in a late kyanite belt in the Variscan Iberia
Authors: Martinez F. J. , Reche J. , Arboleya M. L.
Published: March 2003

The exceptional andalusite–kyanite–andalusite sequence occurs in Al‐rich graphitic slates in a narrow pelite belt on the hangingwall of a ductile normal fault in NW Variscan Iberia. Early chiastolite is replaced by Ky–Ms–Pg aggregates, which are overgrown by pleochroic andalusite near granites intruded along the fault. Slates plot in AKFM above the chloritoid‐chlorite tie‐line. Their P–T grids are modelled with Thermocalc v2.7 and the 1998 databases in the NaKFMASH and KFMASH systems. The univariant reaction Ctd + And/Ky = St + Chl + Qtz + H2O ends at progressively lower pressure as F/FM increases and A/AFM decreases, shrinking the assemblage Cld–Ky–Chl, and opening a chlorite‐free Cld–Ky trivariant field on the low temperature reaction side. This modelling matches the observed absence of chlorite in high F/FM rocks, which is restricted to low pressure in the andalusite stability field.

The P–T path deduced from modelling shows a first prograde event in the andalusite field followed by retrogression into the kyanite field, most likely coupled with a slight pressure increase. The final prograde evolution into the andalusite field can be explained by two different prograde paths. Granite intrusion caused the first prograde part of the path with andalusite growth. The subsequent thermal relaxation, together with aH2O decrease, generated the retrograde andalusite–kyanite transformation, plus chlorite consumption and chloritoid growth. This transformation could have been related to folding in the beginning, and aided later by downthrowing due to normal faulting. Heat supplied by syntectonic granite intrusion explains the isobaric part of the path in the late stages of evolution, causing the prograde andalusite growth after the assemblage St–Ky–Chl. Near postectonic granites, a prograde path with pressure decrease originated the assemblage St–And–Chl.
Improving access to the international coverage of reports of controlled trials in electronic databases: a search of the Australasian Medical Index
Authors: McDonald Steve
Published: March 2003

Introduction: Locating reports of trials from journals not indexed in the major databases presents difficulties to systematic reviewers, and may be a factor in improving the reliability of the reviews.

Objectives: To identify and make available reports of controlled trials from the Australasian Medical Index (AMI). To measure the quality of indexing of trials in AMI.

Methods: Using a highly sensitive search strategy consisting of methodology indexing and free‐text terms, records from AMI were read for reports of controlled trials. Trials meeting the criteria were submitted for inclusion in The Cochrane Controlled Trials Register (CCTR) and assessed for the quality of their indexing.

Results: 3621 records were downloaded, of which 512 were identified as reports of controlled trials (317 RCTs; 195 CCTs) and submitted to CCTR. The precision of methodology indexing terms was 60%, but sensitivity just 18%. The quality of indexing of trials was generally poor with only 50 tagged with the RCT/CCT publication type term. 453 reports (88%) were not previously available in CCTR.

Conclusions: The large proportion of trials found to be unique to the AMI database increases the pool of studies available to systematic reviewers, and helps ensure CCTR remains the most comprehensive source of trials.
Different for girls? Feminism, health information and librarianship*
Authors: Ilett Rosie
Published: March 2003

This paper focuses on the provision and organization of health information materials in women’s health centres in UK and Ireland in the late 20th century. Such centres sprung from the work of feminist activists and health workers from the late 1960s onwards, promoting health information and other interventions to counteract women’s devalued status within society, and the stereotypes perpetuated by health care and other systems. Centres that developed were (and still are) typically within the voluntary sector, have a strong feminist perspective and are run by lay workers.

This paper will draw on research into information provision in these centres, its scope, organization and who provides it. It will argue that this work is of interest to mainstream librarianship, but there are minimal linkages as feminist thinking within librarianship has been unable overall to make common cause with the work of these, and other such agencies, which has inhibited potential developments of mutual benefit. This paper draws on ongoing research into feminism and librarianship, and findings that have been presented in a number of settings.
Computer access and student achievement in the early school years
Authors: Owston R.D. , Wideman H.H.
Published: March 2003

AbstractThis study examines the assumption that optimal learning occurs in classrooms where every child has access to their own computer. Grades 1 to 4 classrooms in seven schools of an urban school district were given laptop computers in three different student‐to‐computer ratios (1 : 1, 2 : 1, 4 : 1). Throughout the school year three samples of student writing were taken at equal intervals and classrooms were regularly observed. Writing samples were also collected from control classrooms in the same schools that did not have access to computers. Amancovaanalysis of holistic ratings of writing samples revealed that by the end of the school year students in the 2 : 1 ratio classrooms improved significantly more than their counterparts in the other groups; the control group students demonstrated the least improvement, while the 1 : 1 and 4 : 1 groups showed intermediate levels of improvement. The study concludes by questioning the long‐range efforts at equipping schools with one computer for every student.
Qualitative case studies of innovative pedagogical practices using ICT
Authors: Kozma R.B. , Anderson R.E.
Published: March 2003

Abstract The Second Instructional Technology in Education Study: Module 2 (SITES M2) is a series of qualitative studies that identify and describe innovative pedagogical practices in 28 participating countries that use technology. The project resulted in 174 case study reports of innovative practice that are currently being analysed. This paper describes the goals, research questions, and methodology for this study and provides a context for the other papers that are published in this issue. Given the large number of case studies, a combined qualitative and quantitative approach to the research is described.
School experience course with multimedia in teacher education
Authors: Asan A.
Published: March 2003

Abstract This paper describes an interactive and self‐paced multimedia tutorial programme that provides pre‐service teachers with a complete range of school system and teaching strategies. Situated learning has been used as the theoretical framework to produce the multimedia tutorial for a pre‐service teachers' School Experience course. The programme allows pre‐service teachers to implement approaches appropriate for teaching a K‐12 curriculum. Two methods of information delivery were investigated: traditional lecturing and multimedia. The results show that using the multimedia tutorial leads to a positive difference in the School Experience course over participants in traditional lecturing. Pre‐service teachers who participated in the multimedia group responded positively to a multimedia approach. This study concludes that using multimedia in teacher education enriches pre‐service teachers' learning and provides them with an opportunity to view and critique various teaching methods and classroom activities collectively.
Establishment of the cat flea (Ctenocephalides felis felis) on the ferret (Mustela putorius furo) and its control with imidacloprid
Authors: Hutchinson M. J. , Jacobs D. E. , Mencke N.
Published: March 2003

Abstract.As the ferret,Mustela putorius furoL. (Carnivora: Mustelidae), is becoming increasingly popular as a pet animal and as it is susceptible to the cat‐flea,Ctenocephalides felis felisBouché (Siphonaptera: Pulicidae), an experimental model was established for evaluating insecticidal treatments on this host. A high establishment rate (76.7–91.8%) was recorded when 60 unfed adultC. feliswere placed on ferrets. This provided an adequate infestation for chemotherapeutic evaluation without causing undue discomfort to the host. Twelve ferrets were allocated to two groups matched for sex and individual ability to sustain a flea population. One group was treated topically with an imidacloprid spot‐on formulation at a dose rate of 10 mg/kg body‐weight on Day 0. All ferrets were infested withC. felison Days − 1, 7, 14, 21 and 28, and flea counts were performed 8 and 24 h post‐treatment and one day after each subsequent infestation. Fleas were removed at all but the 8 h count (when they were returned to their host). Flea burdens were reduced by 95.3% (P < 0.001) within 8 h of treatment and 100% efficacy was recorded at 24 h. At 1, 2, 3 and 4 weeks post‐treatment, protection against re‐infestation was 92.9% (P < 0.001), 55.7% (P < 0.02), 18.3% (NS) and 7.4% (NS), respectively. Thus, at this dose rate, imidacloprid gave excellent efficacy against a residentC. felispopulation and provided a high level of residual activity for at least one week after treatment.
Laboratory and field evaluation of insect repellents as oviposition deterrents against the mosquito Aedes albopictus
Authors: Xue R.‐D. , Barnard D. R. , Ali A.
Published: March 2003

Abstract. Three experimental approaches were used to evaluate the oviposition deterrency of three insect repellents, AI3‐35765, AI3‐37220 (piperidine compounds), and the standard N,N‐diethyl‐3‐methylbenzamide (deet) to the mosquito Aedes albopictus Skuse (Diptera: Culicidae). Against laboratory‐reared Ae. albopictus gravid females, the EC50 values of AI3‐37220, AI3‐35765 and deet were 0.004%, 0.008% and 0.011% in laboratory cages and 0.004%, 0.01% and 0.009% in an outdoor screened cage. For a natural population of Ae. albopictus tested in the field, the EC50 values were determined as 0.004%, 0.008% and 0.001%, respectively. Ageing concentrations of 0.1% of each repellent provided > 50% effective oviposition deterrency against the laboratory population of Ae. albopictus for 13 days in laboratory cages, for 15 days in the outdoor cage, and for 21 days against field population of Ae. albopictus in Florida. These topical skin repellents are effective oviposition deterrents for Ae. albopictus when employed at relatively low application rates.
Phlebotomine sandflies and leishmaniasis risks in Colombian coffee plantations under two systems of cultivation
Authors: Alexander B , Agudelo L. A. , Navarro F. , Ruiz F. , Molina J. , Aguilera G. , Quiñones M. L.
Published: March 2003

Abstract. The phlebotomine sandfly fauna of traditional (shaded) and intensified (unshaded) coffee plantations in Colombia was sampled by a variety of methods and the species composition and density under the two systems compared. Twenty species of Lutzomyia sandflies (Diptera: Psychodidae: Phlebotominae) were collected, of which eight were found only in the ‘Coffee Axis’ (‘Eje Cafetero’) of the departments of Caldas, Risaralda and Quindio, six were exclusive to the department of Norte de Santander and six occurred in both regions. Four species were collected only in traditional plantations and two exclusively in intensified ones. At least 13 species occurred in both plantation types. Fifteen species are opportunistic man‐biters and eight are suspected vectors of leishmaniasis caused by Le. braziliensis, Le. panamensis or Le. mexicana. Seven species were collected inside houses and may be involved in intradomiciliary transmission of Leishmania. The dominant species in Norte de Santander was Lu. spinicrassa, which made up 93.8% of all the sandflies collected in this department. This species was absent from the Eje Cafetero and a number of others among the 15 recorded there might be responsible for Leishmania transmission in this region, including Lu. trapidoi, Lu. yuilli, Lu. gomezi, L. hartmanni and Lu. ovallesi. Sandfly population densities were significantly higher in traditional plantations than in intensified ones. Residents of traditional plantations were able to describe sandflies in significantly more detail than those of intensified plantations, based on seven basic characteristics related to the appearance and biting behaviour of the insects.
Development of an exposure‐free bednet trap for sampling Afrotropical malaria vectors
Authors: Mathenge E. M. , Killeen G. F. , Oulo D. O. , Irungu L. W. , Ndegwa P. N. , Knols B. G. J.
Published: March 2003

Abstract An exposure‐free bednet trap (the ‘Mbita trap’) for sampling of Afrotropical malaria vectors was developed during preliminary studies of mosquito behaviour around human‐occupied bednets. Its mosquito sampling efficiency was compared to the CDC miniature light‐trap and human landing catches under semi‐field conditions in a screen‐walled greenhouse using laboratory‐reared Anopheles gambiae Giles sensu stricto (Diptera: Culicidae). When compared in a competitive manner (side by side), the Mbita trap caught 4.1 ± 0.5 times as many mosquitoes as the CDC light‐trap, hung beside an occupied bednet (P < 0.0001) and 43.2 ± 10% the number caught by human landing catches (P < 0.0001). The ratio of Mbita trap catches to those of the CDC light trap increased with decreasing mosquito density. Mosquito density did not affect the ratio of Mbita trap to human‐landing catches. In a non‐competitive comparison (each method independent of the other), the Mbita trap caught 89.7 ± 10% the number of mosquitoes caught by human landing catches (P < 0.0001) and 1.2 ± 0.1 times more mosquitoes than the CDC light trap (P = 0.0008). Differences in Mbita trap performance relative to the human landing catch under non‐competitive vs. competitive conditions were explained by the rate at which each method captured mosquitoes. Such bednet traps do not expose people to potentially infectious mosquito bites and operate passively all night without the need for skilled personnel. This trap is specifically designed to catch host‐seeking mosquitoes only and may be an effective, sensitive, user‐friendly and economic alternative to existing methods for mosquito surveillance in Africa.
Expression of poly(ADP‐ribose) polymerase and distribution of poly(ADP‐ribosyl)ation in glioblastoma and in a glioma multicellular tumour spheroid model
Authors: Wharton S. B. , McNelis U. , Bell H. S. , Whittle I. R.
Published: March 2003

Development of necrosis is a characteristic feature of glioblastoma but its pathogenesis remains poorly understood. The process of poly(ADP‐ribosyl)ation in response to DNA damage is mediated by poly(ADP‐ribose) polymerase (PARP) and results in NAD+ depletion. The consequent ATP and energy depletion may result in cell necrosis. Therefore PARP activation is a potential candidate for a regulatory role in the pathogenesis of necrosis in glioblastoma. This study investigated whether there might be a relationship between both PARP expression and poly(ADP‐ribosyl)ation, and necrosis in glioblastoma. The pattern of expression of PARP and of poly(ADP‐ribose) groups in an archival series of glioblastoma was examined using immunohistochemistry. These parameters were also studied in multicellular tumour spheroids, derived from human glioma cell lines in which central necrosis develops with increasing spheroid diameter. Poly(ADP‐ribose) groups were expressed in peri‐necrotic tumour cells in glioblastoma. In the spheroid model poly(ADP‐ribosyl)ation was seen centrally in pre‐necrotic and necrotic cells with increasing spheroid diameter. PARP was widely expressed in viable tumour cells in the glioblastoma sections. In the spheroids, PARP expression, which was initially diffuse, became confined to the outer proliferative zone with increasing diameter. The pattern of expression of poly(ADP‐ribose) groups in the spheroids and in glioblastoma raises the possibility that poly(ADP‐ribosyl)ation may play a role in the development of necrosis in glioma. The high basal PARP expression in both glioblastoma and the spheroids suggests that this enzyme may have additional roles in glioma cell biology.
Trypanosoma brucei brucei crosses the blood–brain barrier while tight junction proteins are preserved in a rat chronic disease model
Authors: Mulenga C. , Mhlanga J. D. M. , Kristensson K. , Robertson B.
Published: March 2003

African trypanosomiasis, sleeping sickness in humans, is caused by the systemic infection of the host by the extracellular parasite, the African trypanosome. The pathogenetic mechanisms of the severe symptoms of central nervous system involvement are still not well understood. The present study examined the routes of haematogenous spread of Trypanosoma brucei brucei (Tbb) to the brain, in particular on the question whether parasites can cross the blood–brain barrier, as well as their effect on tight junction proteins. Rats were infected with Tbb and at various times post‐infection, the location of the parasite in the central nervous system was examined in relation to the brain vascular endothelium, visualized with an anti‐glucose transporter‐1 antibody. The tight junction‐specific proteins occludin and zonula occludens 1, and the possible activation of the endothelial cell adhesion molecules ICAM‐1 and VCAM‐1 were also studied. At 12 and 22 days post‐infection, the large majority of parasites were confined within blood vessels. At this stage, however, some parasites were also clearly observed in the brain parenchyma. This was accompanied by an upregulation of ICAM‐1/VCAM‐1. At later stages, 42, 45 and 55 days post‐infection, parasites could still be detected within or in association with blood vessels. In addition, the parasite was now frequently found in the brain parenchyma and the extravasation of parasites was more prominent in the white matter than the cerebral cortex. A marked penetration of parasites was seen in the septal nuclei. In spite of this, occludin and zonula occludens 1 staining of the vessels was preserved. The results indicate that the Tbb parasite is able to cross the blood–brain barrier in vivo, without a generalized loss of tight junction proteins.
Trigeminal neuralgia due to multiple sclerosis: ultrastructural findings in trigeminal rhizotomy specimens
Authors: Love Seth , Gradidge Terry , Coakham Hugh B.
Published: March 2003

Trigeminal neuralgia is a well‐recognized complication of multiple sclerosis. In patients with neuralgia not responding to medical treatment or transcutaneous ablative procedures, the pain can often be treated successfully by partial rhizotomy of the trigeminal sensory root. We have examined partial trigeminal rhizotomy specimens from six multiple sclerosis patients, aged between 34 and 77 years, with intractable trigeminal neuralgia lasting between 18 months and 11 years. The rhizotomy specimens were placed in buffered glutaraldehyde immediately after resection, and subsequently processed for electron microscopy. In all cases, this revealed demyelination in the proximal (CNS) part of the nerve root, with associated gliosis and variable inflammation. A consistent feature was the presence of clusters of juxtaposed axons without intervening glial processes. Similar juxtaposition of axons was previously observed in trigeminal neuralgia due to vascular compression of the nerve root. Experimental studies indicate that this arrangement of demyelinated axons is conducive to both spontaneous impulse activity and ephaptic spread of excitation. The demyelination and associated juxtaposition of axons may therefore account for key aspects of the pathogenesis of trigeminal neuralgia.
Mast cells and multiple sclerosis: a quantitative analysis
Authors: Krüger P. G.
Published: March 2003

The average number of mast cells observed in multiple sclerosis (MS) plaques from four patients, was 0.35 mast cells per mm2. This number represents 1/100 of the amount found in normal human skin. Most mast cells were observed in the border zones of the MS plaques and were clustered in restricted areas along venules and capillaries, which represent the main area of oedema formation in the brain. This cell type may be considered as a contributor to the pathogenesis of oedema formation and subsequent myelin destruction in MS.
Cellular stress and injury responses in the brains of adult Vietnamese patients with fatal Plasmodium falciparum malaria
Authors: Medana I. M. , Mai N. T. H. , Day N. P. J. , Hien T. T. , Bethell D. , Phu N. H. , Farrar J. , White N. J. , Turner G. D. H.
Published: March 2003

Immunohistochemical techniques have been used to investigate specific patterns of potentially reversible cellular injury, DNA damage, and apoptosis in the brainstems of Vietnamese patients who died of severe Plasmodium falciparum malaria. The degree and pattern of neuronal and glial stress responses were compared between patients with cerebral and non‐cerebral malaria (CM), and appropriate non‐malaria infected controls. The following markers were examined: (i) heat shock protein 70 (HSP70), for reversible injury; (ii) heme oxygenase‐1, for oxidative stress; (iii & iv) two DNA‐repair proteins, poly(ADP) ribose polymerase (PARP) and DNA‐dependent protein kinase catalytic subunit; (v) poly(ADP) ribose, an end‐product of PARP activity; and (vi) caspase‐3‐active, for apoptosis. Stress responses were found in a range of cell types as reflected by the widespread expression of HSP70. Oxidative stress predominated in the vicinity of vessels and haemorrhages. Some degree of DNA damage was found in the majority of malaria patients, but the distribution and frequency of the damage was much less than that observed in controls with irreversible neuronal injury. Similarly, caspase‐3‐active expression, as a measure of apoptosis, was no higher in the majority of malaria patients than the negative control cases, although 40% of CM cases expressed caspase‐3‐active in a small number of neurones of the pontine nuclei or within swollen axons of the pontocerebellar and corticospinal tracts. In conclusion, cells within the brainstem of all patients who died from severe malaria showed staining patterns indicative of considerable stress response and reversible neuronal injury. There was no evidence for a specific pattern of widespread irreversible cell damage in those patients with cerebral malaria.
Summer decline in populations of the yellow dung fly: diapause or quiescence?
Authors: Blanckenhorn Wolf U. , Henseler Cornelia , Burkhard Dieter U. , Briegel Hans
Published: March 2003

Abstract. Yellow dung fly (Scathophaga stercoraria (L.)) populations on cow pastures in Central Europe usually show a characteristic summer decline in fly numbers. This has been related to their sensitivity to hot temperatures, but where and in what state the flies spend the summer has remained unclear. Field enclosure experiments revealed no evidence for survival over summer in the pupal stage, as adults never emerged in early autumn from eggs laid in late spring. Laboratory and field evidence shows instead that adults acclimatize physiologically by suppressing reproduction in favour of accumulating lipid (but not glycogen) reserves. Apparently they spend the summer in cooler, forested areas close to the pastures. As reproduction is not entirely shut down, it is suggested that this represents quiescence rather than diapause. Presumably this increases the survival of the flies during the hottest time of the season, and appears to be a flexible life‐history strategy, particularly for late‐born spring generation individuals.
Statistical modelling of insect behavioural responses in relation to the chemical composition of test extracts
Authors: Hern Alan , Dorn Silvia
Published: March 2003

Abstract. The use of generalized linear models (GLM) for relating changes in insect behaviour to changes in the chemical composition of a plant extract is presented and applied to data from an experimental study of the olfactory response of Cydia pomonella L. (Lepidoptera: Tortricidae) to apple volatiles. The volatiles were collected from healthy apples, artificially damaged apples or apples infested with C. pomonella larvae (either instar I, IV or V). These treatments produced a blend of 23 major components and the chemical composition of the blends differed substantially amongst the treatments.

A statistically significant relationship was found between the concentration of hexyl hexanoate and 2‐methylbutyl acetate in each extract and the number of moths moving upwind. Statistically significant models were developed which suggested that a relationship exists between the concentration of Z,E‐α‐farnesene, hexyl hexanoate and 2‐methylbutyl acetate and the number and duration of movements made by the moths.

Subsequently Y‐tube assays were carried out to validate the predictions made with respect to the orientation of mated female C. pomonella. The results of these assays confirm hexyl hexanoate as an attractant. There were indications that 2‐methylbutyl acetate acted as a repellent although differences were not statistically significant. Previous bioassays have shown that C. pomonella displays a statistically significant negative linear dose–response to α‐farnesene (Hern & Dorn, 1999).

The statistical methods employed are very flexible and fairly easy to implement, offering the potential to screen plant extracts for bioactive compounds with a minimum of biological constraints. Their general applicability has yet to be demonstrated and as such these analyses only offer evidence of statistical relationships; the results must be validated by additional bioassays before conclusions can be drawn.