bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular systematics and phylogeography of the Plethodon elongatus species group: combining phylogenetic and population genetic methods to investigate species history
Authors: Mahoney Meredith J. 
Published: December 2003

Abstract Plethodon elongatus and P. stormi (Caudata: Plethodontidae) are Pacific Northwest endemic species which occur in northwestern California and southwestern Oregon. Studies on these salamanders have resulted in differing taxonomic conclusions, but the underlying historical hypotheses, at both inter‐ and intraspecific levels, have never been examined in a molecular framework. Here, representatives of 81 populations from throughout the range of both taxa are sequenced. Portions of three mitochondrial protein‐coding genes (cytochrome b, NADH dehydrogenase subunit 4, and ATPase 6) were sequenced. Four haplotype groups with nonoverlapping geographical ranges were recovered in separate and combined analyses of the data. One clade corresponds to the distribution of P. stormi, while the remaining three comprise P. elongatus. Phylogenetic relationships among haplotype groups differ in separate analyses of the genes but converge on a well‐supported topology, with P. elongatus and P. stormi as monophyletic sister taxa, in combined Maximum Parsimony and Maximum Likelihood analyses. Population genetic analyses of mismatch distributions and Tajima's D‐statistic are consistent with range expansion for the largest clade within P. elongatus, covering the northern two‐thirds of the species range. In contrast, the P. stormi haplotype clade and the P. elongatus clade from the southern third of the species range may have been relatively stable. Morphological boundaries between P. elongatus and P. stormi are largely congruent with mitochondrial DNA breaks and continued treatment as sister taxa is supported. Although mitochondrial DNA haplotype groups may reflect historical separation within P. elongatus, genetic barriers are incongruent with intraspecific patterns of morphological variation.
The last common ancestor of Sarcolaenaceae and Asian dipterocarp trees was ectomycorrhizal before the India–Madagascar separation, about 88 million years ago
Authors: Ducousso M. , Béna G. , Bourgeois C. , Buyck B. , Eyssartier G. , Vincelette M. , Rabevohitra R. , Randrihasipara L. , Dreyfus B. , Prin Y. 
Published: December 2003

AbstractPhylogenetic studies comparing the Dipterocarpaceae and the Sarcolaenaceae, a tree family endemic to Madagascar, have shown that the Sarcolaenaceae share a common ancestor with Asian dipterocarps. This suggests that Asian dipterocarps drifted away from Madagascar with the India–Seychelles landmass and then dispersed through Asia. Although all dipterocarps examined so far have been found to be ectomycorrhizal, the ectomycorrhizal status of Sarcolaenaceae had not been investigated. Here we establish the ectomycorrhizal status of Sarcolaenaceae using histological and molecular methods. This indicates that the common ancestor of the Sarcolaenaceae and Asian dipterocarps was ectomycorrhizal, at least before the separation of the Madagascar–India landmass, 88 million years ago.
Genetic assignment methods for the direct, real‐time estimation of migration rate: a simulation‐based exploration of accuracy and power
Authors: Paetkau David , Slade Robert , Burden Michael , Estoup Arnaud 
Published: December 2003

AbstractGenetic assignment methods use genotype likelihoods to draw inference about where individuals were or were not born, potentially allowing direct, real‐time estimates of dispersal. We used simulated data sets to test the power and accuracy of Monte Carlo resampling methods in generating statistical thresholds for identifying F0 immigrants in populations with ongoing gene flow, and hence for providing direct, real‐time estimates of migration rates. The identification of accurate critical values required that resampling methods preserved the linkage disequilibrium deriving from recent generations of immigrants and reflected the sampling variance present in the data set being analysed. A novel Monte Carlo resampling method taking into account these aspects was proposed and its efficiency was evaluated. Power and error were relatively insensitive to the frequency assumed for missing alleles. Power to identify F0 immigrants was improved by using large sample size (up to about 50 individuals) and by sampling all populations from which migrants may have originated. A combination of plotting genotype likelihoods and calculating mean genotype likelihood ratios (DLR) appeared to be an effective way to predict whether F0 immigrants could be identified for a particular pair of populations using a given set of markers.
Stable Bacillus thuringiensis (Bt) toxin content in interspecific F1 and backcross populations of wild Brassica rapa after Bt gene transfer
Authors: Zhu B. , Lawrence J. R. , Warwick S. I. , Mason P. , Braun L. , Halfhill M.D. , Stewart C. N. 
Published: December 2003

AbstractStable expression of a transgene may lead to increased fitness for wild plants after acquiring the transgene via crop–weed hybridization. Here, we investigate the stability of Bt toxin content in wild Brassica rapa acquiring the Bt gene from Bt Brassica napus. The Bt toxin content in nine Bt‐expressing B. napus lines was 0.80–1.70 µg/g leaf tissue throughout the growing season. These nine lines were crossed with three accessions of wild B. rapa and the Bt gene was successfully transferred to interspecific hybrids (F1) and successive backcross generations (BC1 to BC4). The Bt toxin level in F1 and BC progenies containing the Bt gene remained at 0.90–3.10 µg/g leaf tissue. This study indicates that the Bt gene can persist and be stably expressed in wild B. rapa.
Socio‐economic factors associated with the purchasing of insecticide‐treated nets in Afghanistan and their implications for social marketing
Authors: Howard Natasha , Chandramohan Daniel , Freeman Tim , Shafi Ahmed , Rafi Mohammed , Enayatullah Sayed , Rowland Mark 
Published: November 2003

SummaryMalaria is often a major health problem in war‐torn countries in the tropics owing to the collapse of health services and the vulnerability of displaced populations to epidemics. Insecticide‐treated nets (ITN) represent one of the few options for obtaining protection against malaria in unstable settings deficient in health infrastructure. Social marketing of subsidized ITN by a consortium of non‐governmental organizations began in Afghanistan in 1993 and has continued every year since then despite regular political turmoil. Almost 350 000 nets have been sold and approximately 1.2 million people protected. In 2000 we examined the determinants of ITN purchasing among households in Nangarhar province, eastern Afghanistan, as part of an effort to increase ITN uptake. The survey was conducted using a structured questionnaire to collect data on socio‐economic characteristics and malaria beliefs and practices among more than 400 net‐owning and non‐net‐owning households. A composite socio‐economic index was created using principal components analysis, and survey households were divided into socio‐economic quartiles. ITN were 4.5 times more likely to be purchased by families from the richest quartile and 2.3 times more likely to be purchased from the upper‐middle quartile than from the two lower quartiles. Even so, a significant minority from the lower quartiles did prioritize and buy ITN. In conflict affected countries where livelihoods are compromised, it is necessary to target subsidies at the most impoverished to make ITN affordable and to improve overall coverage.
Ubiquitination of TMV Coat Protein Aggregates in Infected Tobacco Leaves
Authors: Hamacher J. , Wettern M. , Schulz M. 
Published: November 2003

AbstractProtein extracts from Tobacco mosaic virus (TMV) infected young tobacco leaves exhibiting strong symptoms contain higher amounts of ubiquitin conjugates in comparison with non‐infected control plants presumably due to stress reactions of host cells. Western blots with antibodies against TMV indicate as well an increase in coat protein or in ubiquitinated coat protein subunits. Immunogold labelling of infected leaf material revealed the accumulation of large amounts of coat protein in opaque inclusions which also reacted strongly with ubiquitin antibodies. These inclusions appear in close vicinity to chloroplasts in chlorotic areas of the leaf. It is concluded that most of the ubiquitin conjugates found in Western blots are due to ubiquitinated coat protein. As a consequence, a considerable amount of coat protein cannot be used for correct capsid construction as the stabilizing lysine residues are blocked by ubiquitination.
Delphacodes haywardi Muir, a New Natural Vector of Mal de Río Cuarto virus in Argentina
Authors: Velázquez P. D. , Arneodo J. D. , Guzmán F. A. , Conci L. R. , Truol G. A. 
Published: November 2003

Abstract Mal de Río Cuarto virus (MRCV; Fijivirus) causes one of the principal diseases of maize in Argentina and also infects a wide range of cultivated and wild species of the Gramineae. Its spread in the Argentine maize‐growing area coincides largely with the geographical distribution of Delphacodes kuscheli, its only previously known vector. Nevertheless, the presence of MRCV in regions where D. kuscheli has not been detected, or is found only infrequently, led to the study of another delphacid species (D. haywardi) as a possible transmitter of the virus. Specimens of D. haywardi were collected from crops and pastures in the province of Entre Ríos (Argentina). MRCV was transmitted by naturally infected individuals from the field, and also in experimental transmission trials with laboratory‐reared populations of the same species. Virus in the D. haywardi samples was detected and identified with molecular hybridization probes, and in infected plants by observation of symptomatology, serological tests, electrophoresis of dsRNA and electron microscopy. The vector capacity of D. haywardi has very important implications in the epidemiology of this disease.
Vector Transmission of Eggplant Mottled Dwarf Virus in Iran
Authors: Babaie Gh. , Izadpanah K. 
Published: November 2003

Abstract Eggplant mottled dwarf virus (EMDV) is a plant rhabdovirus whose natural means of transmission has remained unknown. In the present study various arthropods including two mite, one psyllid, one thrips, five aphid, four planthopper and 14 leafhopper species were examined for their competence to vector EMDV. Healthy eggplant seedlings were inoculated by arthropods either from naturally infested EMDV infected plants or after having access to source plants and subsequent incubation on rearing host. Transmission was achieved only by the agallian leafhopper Agallia vorobjevi. Symptoms began to appear 20 days after inoculation. Viruliferous leafhoppers were also captured in the field. Symptomatic plants and vector leafhoppers reacted positively with EMDV antiserum in enzyme linked immunosorbent assay. This is the first report on the identification of EMDV vector in Iran.
A Study on Pathogenicity of Bacteria Carried by Pine Wood Nematodes
Authors: Han Z. M. , Hong Y. D. , Zhao B. G. 
Published: November 2003

AbstractThree bacterial strains Njh, Njt and Njw, have been isolated with a high frequency from the xylem of the wilted black pine (Pinus thuntergii) and from the surface of the pine wood nematodes (Bursaphelenchus xylophilus). These bacteria have been identified as Pseudomonas fluorescens biotype I, P. fluorescens biotype II and a species of the genus Pantoea respectively. To determine pathogenicity, callus and aseptic black pine seedlings were inoculated as follows: aseptic nematodes only (each of B. xylophilus and B. mucronatus); bacterium only (each of bacterial strain Njh, Njt, Njw) and aseptic nematodes plus bacterium (each of B. xylophilus and B. mucronatus in combination with each of Njh, Njt, Njw). The results showed that inoculation with either aseptic B. xylophilus or B. mucronatus did not lead to browning of the callus or wilt of aseptic black pine seedlings. But those inoculated with aseptic nematodes plus any one of Njh, Njt, Njw showed some wilting or browning symptoms. The combination of nematodes plus either Njh or Njt caused severe symptoms but the combination of nematodes plus Njw had fewer symptoms. The bacteria carried by pine wood nematodes played an important role in pathogenicity. In addition, bacteria were cultured in liquid media through shaking. The filtered liquid was directly applied to the callus and the ability of each kind of bacterium to induce browning was determined. The results showed that Njh and Njt caused severe browning but Njw did not. It is suspected that this is due to wilt related toxins in the bacterial culture fluid. Therefore, it's suggested that the disease was caused by co‐infection of both pine wood nematodes and bacteria and possible toxic effect of bacteria.
Relationship between Management Practices, Fungal Infection and Aflatoxin for Stored Maize in Benin
Authors: Hell K. , Cardwell K. F. , Poehling H.‐M. 
Published: November 2003

AbstractThis study relates preharvest and harvest practises to postharvest quality of maize in Benin, West Africa. Fungal infection and aflatoxin levels were evaluated in 300 farmers’ stores in four agro‐ecological zones over 2 years (1993–1995), at the beginning of storage (sample A) and 6 months later (sample B). Aspergillus flavus infected 10–20% of the kernels in sample A (1993–1994). In sample B, 54–79% of the kernels were infected with A. flavus. In 1994–1995, A. flavus infection was higher in sample A (27–47%) than B (8–26%). Fusarium species were found in 38–58% of the kernels in sample A in both years, but decreased slightly to 29–51% in sample B. Significant agroecozonal effects existed within sampling, but were not consistent between samplings and years. Of the total number of samples collected (744), 38.8% were found to be aflatoxin‐positive, with an average of 105 parts per billion (ppb) and 60% of the aflatoxin‐positive samples having a contamination approximately 20 ppb, the intervention level recommended by the World Health Organization. Factors associated with increased aflatoxin were: planting local maize varieties in southern Benin, intercropping with cowpea, groundnut, or cassava, use of urea‐fertilizer, damage to maize in the field, prolonged harvesting, long drying periods in the field, and winnowing. Practices that reduced aflatoxin contamination were: planting improved varieties in northern Benin, mixed cropping with vegetables, use of NPK‐fertilizer, drying of harvested cobs for 60–90 days, drying ears without the husk, sorting out of poor quality ears.
Long‐term efficacy of mycophenolate mofetil in the control of severe intraocular inflammation
Authors: Lau Chun H , Comer Marie , Lightman Susan 
Published: November 2003

Abstract Purpose: To assess whether the previously demonstrated short‐term efficacy of the immunosuppressant mycophenolate mofetil (MMF; CellCept, Roche) is maintained in the long‐term management of refractory uveitis. Methods: The study was an open‐label, non‐comparative retrospective series of 14 patients with refractory uveitis and treated with MMF for a mean of>33 months. Mycophenolate mofetil was given at a dosage of 1 g (oral) twice daily. Indications included prednisolone reduction, additive agent with cyclosporin, or replacement therapy (azathioprine or methotrexate). The intraocular inflammatory response, side‐effects, and toxicity were monitored. Results: Intraocular inflammation remained under control in 10 patients, unchanged in three and deteriorated in one patient. Transient side‐effects included tiredness, headache and dizziness (one patient each, lasting less than 2 weeks from the time of MMF introduction). Mycophenolate mofetil was stopped in one patient because of absence of prolonged clinical improvement. Vision improved in 25% (7 eyes), did not change in 50% (14 eyes), but was reduced in 25% (7 eyes). Conclusions: Mycophenolate mofetil is safe for long‐term usage and is recommended for treatment of refractory panuveitis or posterior uveitis with uncontrolled inflammation despite high prednisolone maintenance dosage (>15 mg/day) or toxicity or lack of efficacy of other immuno­suppressive agents. However, MMF is less effective for refractory uveitis unresponsive to azathioprine.
In vivo effects of fluoroquinolones on rabbit corneas
Authors: Pollock Graeme A , McKelvie Penelope A , McCarty Daniel J , White Jacinta F , Mallari Peter LT , Taylor Hugh R 
Published: November 2003

Abstract Purpose: The use of topical fluoroquinolones to treat microbial keratitis is associated with an increased incidence of corneal perforation compared to other standard treatments. This study examined the effects of topical fluoro­quinolones on corneal collagen and keratocytes in intact rabbit corneas and corneas with an epithelial defect. Methods: Studies consisted of one group of intact corneas and one group of corneas where a 6‐mm epithelial defect was created with a surgical scrape. Within each group, eyes were randomly assigned to one of four topical medications (0.3% ciprofloxacin, 0.3% ofloxacin, fortified antibiotics (1.36% tobramycin, 5% cefrazolin) or Tears Naturale (Alcon Laboratories, Frenchs Forest, NSW, Australia). Two drops were instilled hourly for 48 h and then 2‐hourly for an additional 48 h. At 96 h the corneas were removed and processed for light microscopy, immunohistology for collagen IV, V and VI, and apoptosis staining. Results: In intact rabbit corneas there was no demonstrable difference between treatment groups. In corneas with an epithelial defect, both fluoroquinolones delayed epithelial healing when compared to fortified antibiotics or tears. Keratocyte loss was seen in all groups and was greatest in the ofloxacin group. Median stromal thickness with keratocyte loss were: ofloxacin 30%; ciprofloxacin 10%; fortified antibiotics 7.5%; and tears 15% (ofloxacin vs tears, Mann−Whitney = 16.0, P = 0.09). Keratocyte loss did not correlate with the amount of demonstrable apoptosis. Collagens IV, V and VI showed no differences between treatments. Conclusions: These results suggest that ofloxacin is potentially cytotoxic to corneal keratocytes. Such an effect could lead to the observed increased incidence of corneal per­foration in microbial keratitis.
Serum melatonin levels following enucleation and transpupillary thermotherapy in patients with choroidal melanoma
Authors: Kiratli Hayyam , Gedik Sansal , Us Dürdal , Bilgiç Sevgül 
Published: November 2003

Abstract Purpose: To study serum melatonin levels in patients with choroidal melanoma preoperatively and following enucleation and transpupillary thermotherapy. Methods: Forty patients with preoperative choroidal melanoma were included in the study. Of these, 15 patients underwent enucleation (group 1) and 25 patients received transpupillary thermotherapy (group 2). A further 20 patients without melanoma acted as age‐matched controls. Serum melatonin levels were determined 1 day preoperatively, and at the first and sixth months postoperatively using ELISA. Results: Preoperative serum melatonin levels were highest in group 2 followed by group 1, but this was not statistically significant compared to controls. Postoperatively, a constant decrease of serum melatonin was observed in both groups after the first month, which reached statistical significance at the sixth month (P = 0.003). Also, a significant regression in tumour thickness was documented in group 2 (P = 0.003). Three patients in group 1 developed hepatic metastases. Conclusions: Patients with choroidal melanomas had higher levels of serum melatonin compared to individuals without tumours. Smaller tumours were associated with more elevated melatonin levels compared to larger tumours. Serum melatonin levels fell considerably following enucleation and transpupillary thermotherapy.
Corneal endothelial status in the subtypes of primary angle closure glaucoma
Authors: Sihota Ramanjit , Lakshmaiah N Chinna , Titiyal Jawahar S , Dada Tanuj , Agarwal Harish C 
Published: November 2003

Abstract Purpose: To study the corneal endothelium and pachy­metry in eyes with different subtypes of primary angle closure glaucoma (PACG), as compared to controls. Methods: A cross‐sectional study was conducted on 30 consecutive patients in each subtype of PACG, subacute, acute and chronic, and 30 age and refraction matched controls. The parameters recorded included gonioscopy, optic disc evaluation, applanation tonometry, specular microscopy and central ultrasonic pachymetry. Results: The mean endothelial cell counts in the four groups were as follows: subacute PACG 2396 ± 271 cells/mm2, acute PACG 1597 ± 653 cells/mm2, chronic PACG 2229 ± 655 cells/mm2 and controls 2461 ± 321 cells/mm2. The mean endothelial cell count in the fellow eyes of subacute PACG, acute PACG and chronic PACG patients was 2294 ± 305 cells/mm2, 2388 ± 226 cells/mm2 and 2108 ± 203 cells/mm2, respectively (NS). The acute PACG patients had significantly lower endothelial cell counts (P < 0.001) as compared to the other three groups. Eyes in which the acute attack of angle closure persisted for less than 72 h had a mean endothelial cell count of 2016 ± 306 cells/mm2, as compared to 759 ± 94.4 cells/mm2 in eyes with an attack lasting for 72 h or more (P < 0.001). The endothelial count was also significantly lower in eyes with chronic PACG as compared to control eyes (P < 0.001). There was increased pleomorphism and polymegathism of the corneal endothelial cells seen in eyes with resolved acute and chronic PACG. The mean central corneal thickness was 531.4 ± 25.3 µm in eyes with subacute PACG, 567.9 ± 37.3 µm in eyes with acute PACG, 526.4 ± 31.9 µm in eyes with chronic PACG and 525 ± 12.6 µm in control eyes. The acute PACG eyes had a significantly higher corneal thickness (P < 0.001) when compared to all the other groups. Conclusion: There is a significant decrease in the corneal endothelial cell density in eyes that have had an acute attack of angle closure glaucoma and in eyes with chronic PACG. The endothelial cell population in eyes with sub­acute PACG and in the fellow eyes of all subtypes of PACG is not significantly different from the normal population.
Iris colour, ethnic origin and progression of age‐related macular degeneration
Authors: Nicolas Caroline M , Robman Luba D , Tikellis Gabriella , Dimitrov Peter N , Dowrick Adam , Guymer Robyn H , McCarty Catherine A 
Published: November 2003

Abstract Aim: To investigate the relationship between iris colour, ethnic origin and the progression of age‐related macular degeneration (AMD). Methods: Participants were recruited from the population‐based Melbourne Visual Impairment Project or the prospective, randomized, double‐masked Vitamin E, Cataract and Age‐Related Macular Degeneration study. From these two cohorts, 171 participants aged between 52 and 93 years who were identified as having early AMD features at their baseline examination (1992−1995) were followed for an average of 6.8 years (until 2001) to determine the progression rate of early AMD. The participants’ iris colour was categorized as light, intermediate or dark. Ethnic origin was categorized as Anglo‐Saxon or non‐Anglo‐Saxon, according to the participants’ grandparents’ country of birth. Results: In total, 53 (31%) of the 171 participants showed signs of AMD progression. Participants with light iris colour had twofold the risk of AMD progression of those with dark or intermediate iris colours, although the age‐adjusted and multivariate‐adjusted associations were not significant (both P = 0.13). Age‐adjusted and multivariate comparisons of Anglo‐Saxon ethnic origin to non‐Anglo‐Saxon ethnic origin showed a noticeable but non‐significant association with progression of AMD (P= 0.22 and P= 0.14, respectively). Conclusion: Individuals with light iris colour or of Anglo‐Saxon ethnic origin had a strong tendency to greater progression of AMD. A larger sample is required to confirm these clinically important, but statistically non‐significant, associations.