bluuebunny/crossref_metadata_2025 huggingface dataset:
Hepatitis B vaccine – do we need boosters?
Authors: Banatvala J. E. , Van Damme P.
Published: March 2003

summary. This review analyses the cumulated data from a number of long‐term follow‐up studies among infants, children and adults vaccinated against hepatitis B in industrialised and developing countries. Despite low or undetectable antibody responses years ater vaccination, the development of HBsAg was a rarity and, if present, only transient. Some vaccinees developed anti‐HBc responses but none developed an HB carrier state or clinical manifestations of disease. Studies demonstrating anamnestic responses among those with low or undetectable anti‐HBs levels following challenge with HB vaccine, together with the production of anti‐HBs in circulating B‐cells by spot ELISA, confirmed the presence of immune memory among vaccinees. Anamnestic anti‐HBs responses all correlate close in kinetics and magnitude with proliferative T‐cell responses. The accumulated data from studies assessed in this Review indicate that protection is dependent on immune memory, rather than declining anti‐HBs responses and add additional weight to the European Consensus recommendations (12) that following a complete course of vaccination, booster doses are unnecessary in immunocompetent persons. If implemented, this recommendation will have considerable cost benefits world‐wide.
The impact of predation risk from small mustelids on prey populations
Authors: Norrdahl Kai , KorpimÄki Erkki
Published: March 2003

Small mustelids are ‘snake‐like’ mammals adapted to hunt small rodents, which are their principal prey, in tunnels leaving practically no refuge for the prey. Prey rodents have adaptive behaviours to situations where the predation risk from mustelids is high, including reduced activity and escape by climbing. Small mustelids may affect prey population dynamics directly through killing (increased mortality) and/or indirectly through behavioural changes in prey as a response to the presence of mustelids (predation risk). The Predator‐Induced Breeding Suppression hypothesis (PIBS) states that a trade‐off between survival and reproduction should lead to delayed breeding under temporarily high predation risk, so that the mere presence of predators may reduce reproductive output. Current results suggest that small mustelids mainly affect prey population growth rate directly through killing. In many cyclic rodent populations, small mustelid predation is a major mortality factor, and experimental evidence supports the hypothesis that these predators drive prolonged summer declines in prey. In contrast, the evidence for PIBS is controversial. Experimental evidence shows that the indirect effects of small mustelids on prey populations are negligible during the best breeding season. However, in other seasons, the presence of predators may indirectly affect prey populations, although this has not been studied experimentally. Prey rodents may decrease mobility as a response to high predation risk by small mustelids, and this reduction in mobility decreases feeding. Reduced feeding affects the energy reserves of voles, and may delay maturation or lower the size of the first litter.
Mass treatment with ivermectin for filariasis control in Papua New Guinea: impact on mosquito survival
Authors: Bockarie M. J. , Hii J. L. K. , Alexander N. D. E. , Bockarie F. , Dagoro H. , Kazura J. W. , Alpers M. P.
Published: March 2003

Field studies were carried out to determine the impact of mass human treatment with ivermectin on the survival of anthropophagic mosquitoes of the Anopheles punctulatus complex (Diptera: Culicidae), the vectors of lymphatic filariasis and malaria in Papua New Guinea. In a village where mass treatment had been given, using 400 μg/kg ivermectin plus 6 mg/kg diethylcarbamazine citrate (DEC), we performed pre‐ and post‐treatment collections of freshly blood‐engorged mosquitoes from the same nine bedrooms. All blood‐fed mosquitoes collected less than 4 days after mass treatment died within 9 days, whereas 67% of those collected before treatment survived for > 9 days. Comparison (using the log‐rank test) of the survival curves for mosquitoes collected (i) before treatment, (ii) < 4 days after treatment, and (iii) 28 days after treatment, showed the survival rate of group (ii) to be significantly lower than the other two (χ2 = 176, df = 2, P < 0.0001). Pre‐ and post‐treatment all‐night landing catches showed no reduction in human biting rates in the experimental village. In another village, where people were mass treated with ivermectin (400 μg/kg) only, the survival rates of freshly blood‐engorged An.punctulatus collected from bedroom resting‐sites less than 1 day after treatment, were compared to similar collections carried out at the same time in a nearby village where people were not treated with ivermectin. The 48‐h survival rate for the ivermectin‐treated village was 31% compared to 94% for the other; this difference was highly significant (χ2 = 32.42, df = 1, P < 0.0001). Mosquitoes fed 2 months post‐treatment with DEC or collected 38 days post‐treatment with ivermectin had normal survival rates. We conclude that the duration of the systemic lethal effect of ivermectin on mosquitoes is insufficient to be of epidemiological significance in filariasis control programmes that are based on biannual and annual single‐dose treatments, but might reduce vectorial capacity sufficiently to block epidemics of dengue or even malaria.
Survival, ovarian development and bloodmeal size for the horn fly Haematobia irritans irritans reared in vitro
Authors: Kuramochi K.
Published: March 2003

Horn flies, Haematobia irritans irritans (Linneaus) (Diptera: Muscidae) were reared in vitro using cattle, pig, horse, rabbit, sheep, goat or chicken blood. The highest survival, bloodmeal size and rate of ovarian development were recorded for both female and male flies fed cattle blood. Flies fed pig, rabbit, sheep and goat blood showed intermediate survival. Flies fed chicken blood showed the lowest survival rates, ingested the smallest bloodmeals and did not develop ovaries. The relationship between dietary factors and host specificity of the horn fly, and the efficiency of vertebrate blood source of several animals for laboratory colonization of horn fly are discussed.
Feeding behaviour of Glossina pallidipes and G. morsitans centralis on Boran cattle infected with Trypanosoma congolense or T. vivax under laboratory conditions
Authors: Moloo S. K. , Sabwa C. L. , Baylis M.
Published: March 2003

In field studies, tsetse flies (Diptera: Glossinidae) feed more successfully on cattle infected with Trypanosoma congolense Broden (Kinetoplastida: Trypanosomatidae) than on cattle infected with T. vivax Ziemann or uninfected cattle. Here we describe the first laboratory investigation of this phenomenon. In the first experiment, caged Glossina pallidipes Austen were fed for 1 and 5 min on a Boran steer infected with T. congolense clone IL 1180 and on an uninfected steer. Feeding success was recorded in this way five times over several weeks. The same protocol was subsequently used in three additional experiments with the following combinations: G. pallidipes and a steer infected with T. vivax stock IL 3913, G. morsitans centralis Machado and a steer infected with T. congolense, and G. morsitans centralis and a steer infected with T. vivax. The four experiments were replicated once, making eight experiments in total. In three experiments there was increased tsetse feeding success, measured at 1 min, after a steer became infected (T. congolense, two experiments and T. vivax, one experiment). Analysis of all data combined found no significant differences in tsetse feeding success on the different groups of cattle prior to infection, but after infection tsetse feeding success was significantly greater on the infected cattle (P < 0.001). Trypanosoma congolense infection led to a greater increase in tsetse feeding success than T. vivax infection. The increase in feeding success was not related to changes in the level of anaemia, skin surface temperature or parasitaemia. A possible explanation is the effects of trypanosome infection on cutaneous vasodilation and/or blood clotting in infected cattle. When allowed to feed for 5 min, nearly all tsetse engorged successfully and effects of cattle infection on feeding success were not found.
Disappearance of malaria vector Anopheles sundaicus from Chilika Lake area of Orissa State in India
Authors: Dash A. P. , Hazra R. K. , Mahapatra N. , Tripathy H. K.
Published: March 2003

Malaria has declined around Chilika Lake (85°20′ E, 19°40′ N) in Orissa State, India, from hyperendemicity in the 1930s to hypoendemicity during recent decades. Six decades ago, 21 spp. of Anopheles mosquitoes (Diptera: Culicidae) were recorded from this area, including the well known Indian malaria vectors An. culicifacies Giles, An. fluviatilis James, An. maculatus Theobald, An. stephensi Liston and An. sundaicus (Rodenwaldt), the last formerly regarded as the main vector locally. Surveys of Chilika area during 1995–96 found 8 spp. of culicine plus 14 spp. of anopheline mosquitoes, the latter comprising An. subpictus Grassi sensu lato, An. hyrcanus (Pallas) s.l., An. vagus Dönitz, An. annularis van der Wulp s.l., An. culicifacies Giles s.l., An. aconitus Dönitz, An. varuna Iyengar, An. barbirostris van der Wulp s.l., An. philippinensis Ludlow, An. ramsayi Covell, An. jeyporiensis James, An. pallidus Theobald, An. tessellatus Theobald and An. karwari James in decreasing order of abundance. Among indoor‐resting female mosquitoes, the anthropophilic index was 4–7% and some species (An. culicifacies, An. subpictus, An. vagus) tended to enter houses for resting after blood‐feeding outside. Females of potentially infective age (three‐parous) were obtained for An. culicifacies (11%) and An. annularis (< 2%), the more abundant established vector in this coastal area, but not for small samples of An. subpictus and An. vagus. Anophelines reported previously but not found in our survey were An. fluviatilis, An. jamesii Theobald, A. maculatus, An. splendidus Koidzumi, An. stephensi, An. theobaldi Giles and the former main vector An. sundaicus.
Zoophily of Anopheles arabiensis and An. gambiae in Madagascar demonstrated by odour‐baited entry traps
Authors: Duchemin J. ‐B. , Tsy J. ‐M. Leong Pock , Rabarison P. , Roux J. , Coluzzi M. , Costantini C.
Published: March 2003

In Madagascar we used odour‐baited entry traps (OBETs) for host choice tests of wild female anopheline mosquitoes (Diptera: Culicidae) at representative localities on the East and West sides of the island (villages Fenoarivo and Tsararano, respectively) and at the southern margin of the central plateau (Zazafotsy village, 800 m altitude). No insecticide house‐spraying operations have been undertaken at these villages. Odours from a man and a calf of similar mass, concealed in different tents, were drawn by fans into separate OBETs set side by side. Traps were alternated to compensate for position effects, and different pairs of individual baits were employed for successive replicates. Totals of 266 An. funestus Giles sensu stricto and 362 An. gambiae Giles sensu lato were collected in 48 trap nights during March–June 1999. For each mosquito species the ‘index of anthropophily’ was defined as the proportion of females caught in the human‐baited trap. For An. funestus this index was found to be consistently greater than 0.5 (value for random choice between traps/hosts), indicating that this species ‘preferred’ human to calf odour (index = 0.83). Conversely, the index of anthropophily for An. gambiae s.l. indicated they ‘chose’ calf in preference to human odour (index = 0.26). No significant differences of relative preference for calf or man were detected between villages; geographical variance accounted for < 8% of the total experimental variance. Molecular identifications of 181 specimens of the An. gambiae complex (≈ 50% of the samples) revealed only An. arabiensis Patton at Tsararano and Zazafotsy, but > 97% An. gambiae Giles sensu stricto at Fenoarivo, in accordance with prior knowledge of the differential distributions of these sibling species on the island. Predominant zoophily (i.e. intrinsic ‘preference’ for cattle odours) by both An. arabiensis and An. gambiae s.s. in Madagascar contrasts with their greater anthropophily in continental Africa.
Vector potential of houseflies for the bacterium Aeromonas caviae
Authors: Nayduch D. , Pittman Noblet G. , Stutzenberger F. J.
Published: March 2003

Abstract Houseflies, Musca domestica Linnaeus (Diptera: Muscidae), have been implicated as vectors or transporters of numerous gastrointestinal pathogens encountered during feeding and ovipositing on faeces. The putative enteropathogen Aeromonas caviae (Proteobacteria: Aeromonadaceae) may be present in faeces of humans and livestock. Recently A. caviae was detected in houseflies by PCR and isolated by culture methods. In this study, we assessed the vector potential of houseflies for A. caviae relative to multiplication and persistence of the bacterium in the fly and to contamination of other flies and food materials. In experimentally fed houseflies, the number of bacteria increased up to 2 days post‐ingestion (d PI) and then decreased significantly 3 d PI. A large number of bacteria was detected in the vomitus and faeces of infected flies at 2–3 d PI. The bacteria persisted in flies for up to 8 d PI, but numbers were low. Experimentally infected flies transmitted A. caviae to chicken meat, and transmissibility was directly correlated with exposure time. Flies contaminated the meat for up to 7 d PI; however, a significant decrease in contamination was observed 2–3 d PI. In the fly‐to‐fly transmission experiments, the transmission of A. caviae was observed and was apparently mediated by flies sharing food. These results support houseflies as potential vectors for A. caviae because the bacterium multiplied, persisted in flies for up to 8 d PI, and could be transmitted to human food items.
Anticoagulant activities in salivary glands of tabanid flies
Authors: KAZIMÍROVÁ M. , ŠULANOVÁ M. , TRIMNELL A. R. , KOZÁNEK M. , VIDLIČKA L. , LABUDA M. , NUTTALL P. A.
Published: March 2003

AbstractTabanid flies are telmophages (pool feeders), taking frequent and rapid bloodmeals from many different individual hosts. To investigate how they accomplish this intermittent feeding strategy, we examined the anticoagulant activities in salivary gland extracts (SGE) from 19 species representing six genera:Atylotus,Chrysops,Haematopota,Heptatoma, HybomitraandTabanus(Diptera: Tabanidae).Standard coagulation screen assays were used to determine thrombin time, prothrombin time and activated partial thromboplastin time. Chromogenic substrate assays were performed for thrombin and factor Xa activity. SGE of most species (exceptChrysopsspp.) considerably prolonged human plasma clotting time in a dose‐dependent manner, and showed potent and specific antithrombin activity in the chromogenic substrate assay.Heptatoma pellucensdisplayed the strongest anticoagulant activity. Specific anti‐factor Xa activity in tabanid SGE was not detected. Electrophoretic profiles of SGE proteins differed between genera and species. Overall, the results suggest that tabanids have evolved at least two antihaemostatic strategies.
Development and validation of a simulation model for blowfly strike of sheep
Authors: Wall R. , Cruickshank I. , Smith K. E. , French N. P. , Holme A. S.
Published: March 2003

Abstract A comprehensive simulation model for sheep blowfly strike due to Lucilia sericata (Meigen) (Diptera: Calliphoridae), which builds on previously published versions but also incorporates important new empirical data, is used to explain patterns of lamb and ewe strike recorded on 370 farms in south‐west, south‐east and central England and Wales. The model is able to explain a significant percentage of the variance in lamb strike incidence in all four regions, and ewe strike in three of the four regions. The model is able to predict the start of seasonal blowfly strike within one week in three of the four regions for both ewes and lambs, and within 3 weeks in the fourth region. It is concluded that the accuracy of the model will allow it to be used to assess the likely efficacy of new control techniques and the effects of changes in existing husbandry practices on strike incidence. The model could also be used to give sheep farmers advance warning of approaching strike problems. However, the ability to forecast future strike patterns is dependent on the accuracy of the weather projections; the more long‐term the forecast, the more approximate the prediction is likely to be. When applied on a regional basis, model forecasts indicate expected average patterns of strike incidence and may not therefore be appropriate for individual farmers whose husbandry practices differ substantially from the average.
An update on British medical students' lifestyles
Authors: Webb E , Ashton C H , Kelly P , Kamali F
Published: March 2003

Information about medical students' lifestyles was obtained from 785 second‐year students from seven medical schools in Great Britain by a personally administered questionnaire. Fifteen per cent of the students were non‐drinkers. Among those who drank, 48% of the men and 38% of the women exceeded sensible weekly limits of alcohol consumption, and high‐risk levels of consumption were reported by 12% of men and 7% of women. Cannabis had been used at least once or twice by more than half the men and 40% of the women, and 10% reported regular use (weekly or more often). Experience with other illicit drugs was also reported: amphetamines (8% of students), LSD (7%), ecstasy (4%), amyl/butyl nitrate (10%) and magic mushrooms (7%). Nineteen per cent of the students had used two or more different drugs. Experience with illicit drugs started before entering university in more than a third of those who used them. Comparison of the results with other student surveys suggests that the lifestyles of medical students differ little from those of other student groups, but that alcohol and illicit drug consumption is increasing in university students generally. Prospective studies are under way to establish whether medical students change their lifestyles at later stages of their course and after qualification.
Doctors who qualified in the UK between 1974 and 1993: age, gender, nationality, marital status and family formation
Authors: Lambert Trevor W , Goldacre Michael J , Parkhouse James
Published: March 2003

We report on some demographic characteristics of junior doctors in the United Kingdom, studied in six national cohorts of qualifiers between 1974 and 1993. Over the 20 years covered by the data, the percentage of qualifiers who were women increased substantially (from 27% in 1974 to 47% in 1993). Between 1983 and 1993, the number of women qualifiers rose by 242 (a 17% rise) and the number of men fell by 430 (a fall of 18%). Of all doctors, 52% were aged 23 years or less when they qualified and there was no increase over time in mature qualifiers. We report on increases in the percentage of doctors who qualified in the UK but who were born outside it (from 11% to 16%). The percentage of respondents who were married at the end of the first year after qualification declined from 45% in 1974 to 15% in 1993. At 25 years of age, 2% of the women doctors who qualified in 1983 had children compared with 45% of women aged 25 in the general population. Two‐thirds of the women doctors had children by their mid‐30s.
Assessing medical student effectiveness from the psychiatric patient's perspective: The Medical Student Interviewing Performance Questionnaire
Authors: Black Aaron E , Church Marcy
Published: March 2003

This study sought to develop and pilot‐test a patient‐completed rating scale of medical student effectiveness while training in psychiatry. Specifically, the study focused on: (1) examining the statistical reliability and validity of a new scale; (2) using the measure to assess patient satisfaction with medical student care during the psychiatry clerkship; and (3) providing some experience‐based recommendations about utilizing patient feedback when training medical students in psychiatry. Data were collected over an entire academic year and involved 35 third‐year medical students and ratings of their performance provided by 102 psychiatric inpatients. Participants were recruited from three inpatient units and the rate of participation was 62·5%. Principle components analyses of the Medical Student Interviewing Performance Scale (MSIPQ) showed that the overall scale consisted of two, theoretically relevant subscales called `Rapport' and `Treatment Feedback.' Each subscale had adequate reliability. In addition, the two subscales were shown to each account for unique variance in two separate questions assessing the patient's overall ratings of rapport and treatment helpfulness. Finally, patients' mean ratings of medical student effectiveness were examined and showed very high levels of satisfaction with the student–patient relationship and the quality of care received. This study is among the first to examine patient satisfaction with medical student providers among a general population of psychiatric inpatients. Recommendations are made about the ways in which the MSIPQ can be used to strengthen the training of medical students in psychiatry.
Teaching on gender‐related issues; a survey of psychiatry faculty and residents
Authors: Rosiers Pascale Des , Charney Dara A , Russell Ruth C , Du Fort Guillaume Galbaud , Boothroyd Lucy J
Published: March 2003

A survey was distributed to 299 members of the McGill Department of Psychiatry regarding the teaching of gender‐related issues. The response rate was 62·5%. The majority of respondents indicated that they were moderately or very knowledgeable about, and moderately or very interested in gender issues. Current teaching was rated as less than adequate, while future teaching was rated as very important. Women rated personal interest and importance of future teaching higher than men, but rated adequacy of current teaching lower. Residents rated personal interest higher than certified psychiatrists, but rated self‐assessed knowledge lower, and tended to rate adequacy of current teaching lower.
Problem‐based learning versus lecture‐based learning in a course of basic pharmacology: a controlled, randomized study
Authors: Antepohl Wolfram , Herzig Stefan
Published: March 2003

Since its first implementation in a medical programme at McMaster University, Canada, problem‐based learning (PBL) has become a well‐established means of teaching and learning medicine. Extensive research has been conducted and a number of strengths of the method are well supported. Several items, however, remain unclear1 although there is evidence that no relevant difference exists in factual knowledge among students from PBL and traditional curricula, a controlled, randomized study has not been conducted to address this issue. The Medical Faculty of the University of Cologne is in the process of integrating elements of PBL into its curriculum. In the spring term of 1997, after seven semesters of experience with PBL supplementing the traditional course of basic pharmacology, we did for the first time use PBL instead of the lecture‐based course (LBL) and conducted a controlled prospective study to determine the effects of this intervention. One‐hundred and twenty‐three students were randomly assigned to either PBL (n = 63), with tutorial groups of up to nine students, or to the traditional, lecture‐based course (n = 60). Analysis of the results of both groups in the examination of basic pharmacology, consisting of multiple‐choice and short‐essay questions, revealed similar scores with a tendency favouring PBL students in the category of short‐essay questions. Hence, it seems clear that PBL does not imply a disadvantage in terms of factual knowledge. Students considered PBL to be an effective learning method and favoured it over the lecture format. Furthermore, students reported positive effects of PBL in terms of use of additional learning resources, inter‐disciplinarity, team work and learning fun.
Service Increment for Teaching (SIFT): a review of its origins, development and current role in supporting undergraduate medical education in England and Wales
Authors: Clack Gillian B , Bevan Gwyn , Eddleston Adrian L W F
Published: March 2003

Objectives

To describe the ways in which total resources available for the Service Increment for Teaching (SIFT) have been determined and related to numbers of undergraduate medical students; and the development and current arrangements for allocating SIFT to the providers of service support for teaching.

Design

The derivation of SIFT from excess costs of teaching hospitals over general hospitals is described. The official principles of organizing SIFT to reimburse the service costs of teaching undergraduate medical students are explained. The crucial development that is examined is the change from SIFT being a global subsidy to being related to educational contracts. This development has facilitated both the specification of standards and innovative uses of SIFT. These are illustrated with examples.

Setting

Hospital and Community Health Services and Primary Care in the National Health Service (NHS) in England and Wales.

Subjects

Medical students.

Results

There is often confusion caused by SIFT being intended to cover the service costs of teaching but not having been derived in this way. This causes problems in deciding what providers should be paid through contracts for teaching of different kinds.

Conclusions

The new contractual basis has enabled medical schools to use contracts to improve the clinical teaching of undergraduate medical students in the NHS. These developments may offer useful models for other countries.
Are professional attitudes related to gender and medical specialty?
Authors: Batenburg V , Smal J A , Lodder A , Melker R A de
Published: March 2003

Objectives

The importance of professional attitudes in medical care has long been recognized; however, medical training has not stressed attitude development until recently. In previous studies among medical students, we found that gender and specialty preference are important factors in attitudes. In this study, patient‐centredness of trainees in general practice and surgery and of final‐year clerks preferring one of these specialties was assessed in one medical school in The Netherlands. The effect of gender, specialty and training level on attitude was investigated.

Design

In 1995, attitudes of 37 general practice trainees, 31 surgery trainees and 120 clerks were measured anonymously using questionnaires containing the Doctor–Patient Scale. This attitude scale measures patient‐centredness vs. doctor‐centredness. Response rates were 78%, 58% and 84%, respectively.

Setting

University of Utrecht.

Subjects

Medical students.

Results

Attitudes were related to specialty. General practice trainees showed more patient‐centredness than surgery trainees. In accordance with previous findings among younger students, no differences were found between final‐year clerks and vocational trainees. In contrast to previous studies, gender was not related to patient‐centredness.

Conclusions

Professional attitudes, in particular patient‐centredness, seem to be related to specialty preference in the final year of graduate medical training and specialty as a career choice. It remains unclear whether professional socialization reinforces existing attitudes or whether existing attitudes result in specialty preference.
A study of genetic diversity in Populus nigra subsp. betulifolia in the Upper Severn area of the UK using AFLP markers
Authors: WINFIELD M. O. , ARNOLD G. M. , COOPER F. , LE RAY M. , WHITE J. , KARP A. , EDWARDS K.J.
Published: March 2003

A survey of amplified fragment length polymorphism (AFLP) was conducted to examine genetic diversity in 146 individuals of British, native black poplar (Populus nigra subsp. betulifolia) and three individuals considered by collectors to be non‐betulifolia poplars. Using two primer pairs, a total of 147 bands were detected of which 82 (56%) were polymorphic in at least one individual. Cluster analysis and principal coordinates analysis of the calculated similarity matrix revealed a low level of genetic diversity, although a loose clustering into five groups could be identified, one of which contained the non‐betulifolia individuals. Examination of the spatial distribution of the other four groups (all betulifolia) revealed a general correlation between geographic proximity and genetic similarity. On the basis of the polymorphism observed, it was possible to identify a small number of individual plants which exhibit maximum diversity and might therefore be suitable for inclusion in a replanting programme designed to maintain at least the existing low level of polymorphism observed within British black poplar.
Molecular genetic analysis of black poplar (Populus nigra L.) along Dutch rivers
Authors: ARENS P. , COOPS H. , JANSEN J. , VOSMAN B.
Published: March 2003

The genetic structure of remaining black poplar (Populus nigra) trees on the banks of the Dutch Rhine branches was investigated using the AFLP technique. In total, 143 trees, including one P. deltoides and some P. x euramericana, were analysed using six AFLP primer combinations which generated 319 polymorphic bands. The AFLP patterns showed that some of the trees sampled as P. nigra were clearly different. These deviating patterns were also observed for the P. deltoides tree and all trees already identified as hybrid P. x euramericana. Hybrids between the two species are morphologically sometimes difficult to distinguish from the species itself. Two important possible source populations for recolonization of the riverbanks of the river Rhine, consisting of mature flowering P. nigra trees, appeared to consist of only a few genotypes each. In contrast, young black poplar trees growing alone or in small groups downstream of the possible source populations appeared to be predominantly generatively derived because no clones of mature trees were found among them. Therefore vegetative propagation seems a very local strategy whereas colonization of new areas appears to occur through generative propagation. Whether the genetic diversity within these black poplars is sufficient for recolonization of river banks and survival of the metapopulation is a question for further research.
The postfire discomycete Geopyxis carbonaria (Ascomycota) is a biotrophic root associate with Norway spruce (Picea abies) in nature
Authors: VRÅLSTAD T. , HOLST‐JENSEN A. , SCHUMACHER T.
Published: March 2003

The hypothesis that the postfire discomycete Geopyxis carbonaria (Ascomycota, Pezizales, Pyronemataceae) has a biotrophic association with roots of Norway spruce (Picea abies) in nature was tested by isolation of fungal strains from fresh, brown, smooth mycorrhiza‐like root tips of Norway spruce collected from below the depth of detrimental heat penetration in a postfire site. The morphology of seven culture isolates originating from the smooth mycorrhiza‐like root tips of two different spruce trees was congruent with the morphology of axenic culture isolates obtained from ascospores of G. carbonaria. DNA sequences of the nuclear ribosomal internal transcribed spacers ITS1 and ITS2 from these root‐derived cultures and the ascosporic G. carbonaria culture isolates were found to be identical, further supporting the conclusion that the isolates were conspecific. The extensive ascocarp and ascospore formation of G. carbonaria which succeeds a forest fire may be explained in terms of a fungal escape from a moribund tree associate. Possible ecological adaptations of G. carbonaria to the pre‐ and postfire community are discussed.
The history and purview of phylogeography: a personal reflection
Authors: AVISE JOHN C.
Published: March 2003

Last year marked the 10th anniversary of the birth of phylogeography as a formal discipline. However, the field’s gestation began in the mid‐1970s with the introduction of mitochondrial (mt) DNA analyses to population genetics, and to the profound shift toward genealogical thought at the intraspecific level (now formalized as coalescent theory) that these methods prompted. This paper traces the early history and explosive growth of phylogeography, and closes with predictions about future challenges for the field that centre on several facets of genealogical concordance.
Genetic affinities of an introduced predator: Nile perch in Lake Victoria, East Africa
Authors: HAUSER L. , CARVALHO G. R. , PITCHER TONY J. , OGUTU‐OHWAYO RICHARD
Published: March 2003

Although the introduction of Nile perch, Lates niloticus, to Lake Victoria has received intense global attention, especially in relation to its impact on endemic cichlid species and on fishery yields, fundamental information on its taxonomy and population genetics is lacking. Most importantly, the introduced fish originated from two lakes (Lakes Albert and Turkana) containing three Lates species, and it has never been entirely clear which of these became established in Lake Victoria, or indeed whether the Lake Victoria population is derived from hybridization between Lates species. In addition, genetic drift caused by the relatively small founder population (≈ 400), the initially slow population increase followed by a period of explosive population growth, and selection pressures in the new environment may have resulted in substantial genetic changes. Allozyme data indicated that the introduced Nile perch of Lake Victoria were mainly L. niloticus from Lake Albert, although maximum likelihood estimates of stock contributions (GSI) suggested the presence of L. macrophthalmus. In contrast, introduced Nile perch in adjacent smaller lakes (Lakes Kyoga and Nabugabo) appeared to be entirely L. niloticus. The effect of the introductions on allozyme diversity varied among lakes and appeared to be uncorrelated to the number of fish introduced.
A hierarchical analysis of minisatellite DNA diversity in Gambel oak (Quercus gambelii Nutt.; Fagaceae)
Authors: KUMAR A. , ROGSTAD S. H.
Published: March 2003

Gambel oak is a short shrub to medium‐sized tree of southwest North America for which the potential to grow in large clonal stands has been proposed. Here we use three different multilocus VNTR DNA probes (synthesized via PCR) to demonstrate that clones growing together can be identified, but individual clones exceeding 50 m in diameter do not commonly occur in the study population of Quercus gambelii. Further, using a hierarchical sampling scheme (three circular transects with diameters of 9, 1100, and 28 000 m), we estimate that for nonclonal individuals: (i) mean number of bands analysed per individual = 22.92; (ii) mean similarity (band sharing) between individuals = 0.322; (iii) mean probability that two randomly chosen individuals share all bands = 4.93 × 10–11; and (iv) mean estimated heterozygosity = 0.796. FST calculated for the two nonclonal levels of the sampling hierarchy was 0.023, indicating that little genetic differentiation exists between them. These results support previous findings that, due to life‐history traits of the genus and this species (out‐crossing, wind‐pollinated, animal‐dispersed, long‐lived woody perennials), gene flow is high and genetic subdivision of populations is low in oaks. At this study site, the clonal nature demonstrated for Gambel oak appears to have little detectable effect on these population genetic characteristics.
Consequences of a catadromous life‐strategy for levels of mitochondrial DNA differentiation among populations of the Australian bass, Macquaria novemaculeata
Authors: JERRY D. R. , BAVERSTOCK P. R.
Published: March 2003

The influence of a catadromous life‐strategy on levels of spatial genetic structuring in fish is poorly understood. In an effort to gain a better appreciation of how this specialized life‐strategy determines population genetic structuring, we assessed variation in the mitochondrial DNA (mtDNA) control region in a catadromous perciform, the Australian bass Macquaria novemaculeata. Nineteen putative haplotypes were resolved using temperature gradient gel electrophoresis from 10 geographically distinct populations. Significant heterogeneity was revealed in haplotype frequencies and their spatial distributions among many locales. Gene partitioning statistics (AMOVA) for both raw haplotype frequency data and frequency data with sequence divergences were concordant, indicating that M. novemaculeata populations were moderately genetically structured (ΦST = 0.05, 0.06; P < 0.001, respectively). Isolation by distance seems to be a strong structuring force in M. novemaculeata, culminating in no detectable phylogeographic structuring among haplotypes. Low sequence divergences were observed among many haplotypes and it is suggested that these are the result of pruning of maternal lineages by cyclical variations in female reproductive success. This study highlights the importance of life‐history patterns and, in particular, spawning locality, in determining spatial structuring of mtDNA variation in catadromous species.
New epidemiological features on animal trypanosomiasis by molecular analysis in the pastoral zone of Sideradougou, Burkina Faso
Authors: LEFRANÇOIS T. , SOLANO P. , BENGALY S. DE LA ROCQUE*† Z. , REIFENBERG J. M. , KABORE I. , CUISANCE D.
Published: March 2003

A multidisciplinary work was undertaken in the agropastoral zone of Sidéradougou, Burkina Faso to try to elucidate the key factors determining the presence of tsetse flies. In this study the PCR was used to characterize trypanosomes infecting the vector (Glossina tachinoides and Glossina palpalis gambiensis) and the host, i.e. cattle. A 2‐year survey involved dissecting 2211 tsetse of the two Glossina species. A total of 298 parasitologically infected tsetse were analysed by PCR. Trypanosoma vivax was the most frequently identified trypanosome followed by the savannah type of T. congolense and, to a lesser extent, the riverine forest type of T. congolense, and by T. brucei. No cases of T. simiae were found. From the 107 identified infections in cattle, the taxa were the same, but T. congolense savannah type was more frequent, whereas T. vivax and T. congolense riverine forest types were found less frequently. A correlation was found between midgut infection rates of tsetse, nonidentified infections and reptile bloodmeals. These rates were higher in G.p. gambiensis, and in the western part of the study area. T. vivax infections were related to cattle bloodmeals, and were more frequent in G. tachinoides and in the eastern study area. The PCR results combined with bloodmeal analysis helped us to establish the relationships between the vector and the host, to assess the trypanosome challenge in the two parts of the area, to elucidate the differences between the two types of T. congolense, and to suspect that most midgut infections were originating from reptilian trypanosomes.
Genetic variability, population size and isolation of distinct populations in the freshwater fish Cottus gobio L.
Authors: HÄNFLING B. , BRANDL R.
Published: March 2003

Analysis of allozyme data of the European freshwater fish Cottus gobio showed marked genetic differentiation across drainage basins in northeastern Bavaria, which points to the existence of at least two cryptic taxa. Genetic variability within populations differed significantly between these two taxa, which could be due to historical (bottlenecks) or ecological reasons (population size). To distinguish between these two hypotheses we sampled 12 distinct populations from Rhine, Elbe and Danube drainages. Using allozyme data we examined the influence of population size and isolation on genetic variability within populations. We used spatial extent of populations (patch size) as a measure for population size. To estimate isolation we calculated a compound measure which took into account patch size and distance to all neighbouring populations. Both patch size and isolation were highly correlated with genetic variability, explaining ≈95% of the variance of genetic variability within populations. Furthermore, analysis of covariance suggests that the difference in genetic variability between taxa may be explained by differences in population size.
Microsatellite loci in eelgrassZostera marinareveal marked polymorphism within and among populations
Authors: STAM THORSTEN B. H. REUSCH, WYTZE T. , OLSEN JEANINE L.
Published: March 2003

Using an enriched genomic library, we developed seven (CT)n/(GA)nmicrosatellite loci for eelgrassZostera marinaL. Enrichment is described and highly recommended for genomes in which microsatellites are rare, such as in many plants. A test for polymorphism was performed on individuals from three geographically separated populations (N= 15/population) and revealed considerable genetic variation. The number of alleles per locus varied between five and 11 and the observed heterozygosities for single loci ranged from 0.16 to 0.81 within populations. Mean allele lengths were markedly different among populations, indicating that the identified loci will be useful in studying population structure inZ. marina. As the frequency of the most abundant multilocus genotype within populations was always < 1%, these loci have sufficient resolving power to address clone size in predominantly vegetatively reproducing populations.
Reliable noninvasive genotyping based on excremental PCR of nuclear DNA purified with a magnetic bead protocol
Authors: Flagstad  , Røed  , Stacy  , Jakobsen
Published: March 2003

A new protocol for extraction of DNA from faeces is presented. The protocol involves gentle washing of the surface of the faeces followed by a very simple DNA extraction utilizing the wash supernatant as the source of DNA. Unlike most other protocols, it does not involve the use of proteinase K and/or organic extraction, but is instead based on adsorption of the DNA to magnetic beads. The protocol was tested by microsatellite genotyping across six loci for sheep and reindeer faeces. Comparison with DNA extracted from blood demonstrated that the protocol was very reliable, even when used on material stored for a long time. The protocol was compared with another simple, solid‐phase DNA‐binding protocol, with the result that the bead‐based protocol gave a slightly better amplification success and a lower frequency of allelic drop‐outs. Furthermore, our experiments showed that the surface wash prior to DNA extraction is a crucial step, not only for our protocol, but for other solid‐phase protocols as well.
Host use evolution in Chrysochus milkweed beetles: evidence from behaviour, population genetics and phylogeny
Authors: Dobler Susanne , Farrell Brian D
Published: March 2003

In two sister species of leaf beetles with overlapping host associations, Chrysochus auratus and C. cobaltinus, we established diet breadth and food preference of local populations for evaluation together with genetic differentiation between populations. While C. auratus turned out to be monophagous on the same plant wherever we collected the beetles, the studied populations of C. cobaltinus fed on three different plant species in the field. Plant preference and ranking of the potential host plants significantly differed between these populations. The amount of genetic differentiation between populations was measured by a polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) assay of a 1300 bp mitochondrial DNA (mtDNA) sequence. In addition, the dominant genotypes of all populations were sequenced. No genetic differentiation between the populations of C. auratus could be detected in the RFLP assay and sequence divergence was low (= 0.3%). In C. cobaltinus, on the other hand, genetic differentiation between populations was high, revealing a lack of gene flow over a much smaller scale and a maximum of 1.3% sequence divergence. C. cobaltinus thereby has the prerequisites for host race formation on different plants from the original host spectrum. Our sequence‐based phylogeny estimate allows us to reconstruct historical diet evolution in Chrysochus. Starting from an original association with Asclepiadaceae, the common ancestor of C. auratus and C. cobaltinus included Apocynaceae in its diet. The strict specialization on Apocynum and the loss of acceptance of Asclepiadaceae observed in C. auratus could have resulted from a process similar to that displayed by C. cobaltinus populations.
Genetic divergence and phylogeographic relationships among European perch (Perca fluviatilis) populations reflect glacial refugia and postglacial colonization
Authors: Nesbø C. L. , Fossheim T. , Vøllestad L. A. , Jakobsen K. S.
Published: March 2003

We used the widely distributed freshwater fish, perch (Perca fluviatilis), to investigate the postglacial colonization routes of freshwater fishes in Europe. Genetic variability within and among drainages was assessed using mitochondrial DNA (mtDNA) D‐loop sequencing and RAPD markers from 55 populations all over Europe as well as one Siberian population. High level of structuring for both markers was observed among drainages and regions, while little differentiation was seen within drainages and regions. Phylogeographic relationships among European perch were determined from the distribution of 35 mtDNA haplotypes detected in the samples. In addition to a distinct southern European group, which includes a Greek and a southern Danubian population, three major groups of perch are observed: the western European drainages, the eastern European drainages including the Siberian population, and Norwegian populations from northern Norway, and western side of Oslofjord. Our data suggest that present perch populations in western and northern Europe were colonized from three main refugia, located in southeastern, northeastern and western Europe. In support of this, nested cladistic analysis of mtDNA clade and nested clade distances suggested historical range expansion as the main factor determining geographical distribution of haplotypes. The Baltic Sea has been colonized from all three refugia, and northeastern Europe harbours descendants from both eastern European refugia. In the upper part of the Danube lineages from the western European and the southern European refugia meet. The southern European refugium probably did not contribute to the recolonization of other western and northern European drainages after the last glaciation. However, phylogenetic analyses suggest that the southern European mtDNA lineage is the most ancient, and therefore likely to be the founder of all present perch lineages. The colonization routes used by perch probably also apply to other freshwater species with similar distribution patterns.
Discordant patterns of morphological and molecular change in broadtail madtoms (genus Noturus)
Authors: Bennetts R. Q. , Grady J. M. , Rohde F. C. , Quattro J. M.
Published: March 2003

Two morphologically distinct forms of an undescribed madtom catfish (Noturus sp.) occur in the rivers and lakes of southeastern USA. ‘Lake’ broadtail madtoms are endemic to Lake Waccamaw and are probably related to nearby ‘river’ broadtail populations. To investigate phylogenetic relationships, we surveyed mitochondrial DNA (mtDNA) sequence variation in ‘lake’ and ‘river’ broadtails and other members of the genus Noturus. Mitochondrial rDNA data suggest a sister group relationship between broadtail madtoms and N. insignis, not N. leptacanthus as posited previously. Population‐level analyses using additional mtDNA characters (NADH dehydrogenase subunit 2 (ND2) and cytochrome b (Cytb)) identified two highly divergent genetic lineages within broadtail madtoms that do not correspond to the morphological designations ‘river’ and ‘lake’.