bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnosis of Severe Acute Respiratory Syndrome (SARS) by Detection of SARS Coronavirus Nucleocapsid Antibodies in an Antigen-Capturing Enzyme-Linked Immunosorbent Assay
Authors: Shi Yuling , Yi Yanping , Li Ping , Kuang Tieji , Li Linhai , Dong Mei , Ma Qingjun , Cao Cheng
Published: December 2003

Recombinant severe acute respiratory syndrome (SARS) coronavirus nucleocapsid protein was employed to establish an antigen-capturing enzyme-linked immunosorbent assay (ELISA). Antinucleocapsid protein antibodies could be detected in 68.4% of probable SARS patients 6 to 10 days after illness and in 89.6% of the patients 11 to 61 days after illness. No false-positive results were observed in 20 non-SARS fever patients, 24 non-SARS respiratory illness patients, and 20 health care workers. Among 940 other non-SARS clinical serum samples, only 1 was found to be weakly positive. This method provides a new, sensitive, and specific approach for SARS diagnosis.
First Report of Capsule Replacement among Electrophoretic Type 37
Neisseria meningitidis
Strains in Italy
Authors: Stefanelli Paola , Fazio Cecilia , Neri Arianna , Sofia Tonino , Mastrantonio Paola
Published: December 2003

This report describes the C-to-B capsular switching in four
Neisseria meningitidis
strains belonging to the electrophoretic type 37 (ET-37) complex. In particular, one strain belonged to the new sequence type 1860, which was first detected in the year 2000 in Italy and is now frequently isolated. The presence of switched serogroup B strains deserves special attention if they prove as able to spread as their serogroup C progenitors belonging to the hypervirulent ET-37 complex.
Dissemination of Macrolide-Resistant
Streptococcus pneumoniae
Isolates Containing Both
erm
(B) and
mef
(A) in South Korea
Authors: Waites Ken B. , Jones Kellie E. , Kim Kyung Hyo , Moser Stephen A. , Johnson Crystal N. , Hollingshead Susan K. , Kang Eun-Suk , Hong Ki Sook , Benjamin William H.
Published: December 2003

Macrolide resistance was detected in 64 of 77 (83.1%)
Streptococcus pneumoniae
isolates from South Korea. Seven (10.9%) isolates contained only
mef
(A), 32 (50%) contained only
erm
(B), and 25 (39.1%) contained
mef
(A) and
erm
(B). Nineteen isolates containing
mef
(A) and
erm
(B) belonged to serotype 19F, and seven isolates were identical to the Taiwan
19F
-14 clone.
Expression of Plasma Coagulase among Pathogenic
Candida
Species
Authors: Rodrigues Acácio Gonçalves , Pina-Vaz Cidália , Costa-de-Oliveira Sofia , Tavares Christina
Published: December 2003

Candida
coagulase production was assessed by the classical tube test. All
Candida krusei
strains were coagulase negative, but most
C. albicans
and
C. tropicalis
strains can produce coagulase. Some strains agglutinated the Pastorex Staph-Plus reagent, probably because of antigen similarities to coagulase produced by
Staphylococcus aureus
that may cause mistakes in clinical laboratories.
Extraintestinal Pathogenic
Escherichia coli
as a Cause of Invasive Nonurinary Infections
Authors: Johnson James R. , Gajewski Abby , Lesse Alan J. , Russo Thomas A.
Published: December 2003

Multiple
Escherichia coli
isolates from four adults with extraintestinal infections underwent molecular phylotyping and virulence profiling. A patient with secondary peritonitis had two low-virulence
E. coli
strains from phylogenetic groups A and D. In contrast, three patients with invasive extraurinary infections (septic arthritis/pyomyositis, nontraumatic meningitis/hematogenous osteomyelitis, and pneumonia) each had a single high-virulence phylogenetic group B2 strain resembling typical isolates causing urinary infection and/or sepsis, i.e., extraintestinal pathogenic
E. coli
.
Tracheopulmonary Myiasis Caused by a Mature Third-InstarCuterebraLarva: Case Report and Review
Authors: Cornet Muriel , Florent Martine , Lefebvre Aurélie , Wertheimer Christophe , Perez-Eid Claudine , Bangs Michael J. , Bouvet Anne
Published: December 2003

Myiasis is the infestation of vertebrate tissues with fly larvae (Diptera). Most human cases in North America are subcutaneous forms due toDermatobia hominisimported from Central and South America. Human cases of myiasis acquired in North America are rare and are primarily subdermal or ophthalmologic forms of infestation caused by early stages ofCuterebralarvae. We report an unusual case of tracheopulmonary myiasis, resulting from the in situ development of a mature cuterebrine larva associated with high eosinophilia. Only two other cases of tracheopulmonary cuterebrid myiasis have been reported in humans, and they are reviewed herein.Cuterebramyiasis (cuterebrosis) remains a rare and aberrant cause of tracheopulmonary disease and is a newly described cause of eosinophilia in humans.
Molecular Detection and Identification of Agents of Eumycetoma: Detailed Report of Two Cases
Authors: Ahmed Abdalla O. A. , Desplaces Nicole , Leonard Philippe , Goldstein Fred , De Hoog Sybren , Verbrugh Henri , van Belkum Alex
Published: December 2003

We describe two cases of eumycetoma in the legs. The infections could not be adequately diagnosed by classical mycology, but the causative agents were successfully identified asMadurella mycetomatisby species-specific PCR and DNA sequencing.
Case of Keratitis Caused by an Uncommon
Fusarium
Species
Authors: Guarro Josep , Rubio Carmen , Gené Josepa , Cano Josep , Gil Joaquina , Benito Rafael , Moranderia M. José , Miguez Enrique
Published: December 2003

Fusarium polyphialidicum
caused a corneal ulcer in a Spanish man. Diagnosis was established by a histopathological study and repeated cultures. The isolate was clearly resistant in vitro to the antifungal agents tested. This is the first case of human or animal mycosis by this rare fungus.
Trichosporon inkin
Peritonitis Treated with Caspofungin
Authors: Madariaga Miguel G. , Tenorio Allan , Proia Laurie
Published: December 2003

Trichosporon inkin
is one of six pathogenic species of the genus
Trichosporon
and the etiologic agent of pubic white piedra.
Trichosporon
species have been reported as a cause of disseminated infections, particularly among immunosuppressed patients. We describe the third reported case of
T. inkin
peritonitis associated with peritoneal dialysis and the first to be treated with caspofungin.
Fatal Case of
Salmonella enterica
subsp.
arizonae
Gastroenteritis in an Infant with Microcephaly
Authors: Mahajan Rakesh Kumar , Khan Shoeb Akhtar , Chandel Dinesh Singh , Kumar Navin , Hans Charoo , Chaudhry Rama
Published: December 2003

Salmonella enterica
subsp.
arizonae
is a common gut inhabitant of reptiles, with snakes as the most common reservoir. Though human cases due to this organism are exceedingly rare, it may infect young infants and immunocompromised individuals with a history of intimate associations with reptiles. Gastroenteritis is the most common presentation; others include peritonitis, pleuritis, osteomyelitis, meningitis, and bacteremia. We report a fatal case of
S. enterica
subsp.
arizonae
gastroenteritis in a 3-month-old child with microcephaly, with a review of earlier cases and problems encountered in identification of this rare human pathogen.
Use of assisted reproductive technology to reduce the risk of transmission of HIV in discordant couples wishing to have their own children where the male partner is seropositive with an undetectable viral load: Table 1
Authors: Baker H W G , Mijch A , Garland S , Crowe S , Dunne M , Edgar D , Clarke G , Foster P , Blood J
Published: December 2003

The advances in treatment of HIV and the introduction of polymerase chain reaction assay for the virus now make it acceptable for HIV discordant couples where the male partner is seropositive to attempt to conceive through artificial insemination by husband (AIH) or via in vitro fertilisation. With undetectable viral load and washed sperm, there is minimal risk of transmission of HIV to the female partner, children, other patients, or staff. We describe the development of a programme of AIH for HIV discordant couples and the reasoning behind offering such a programme.
The physician as an accessory in the parental project of HIV positive people
Authors: Pennings Guido
Published: December 2003

The question of the moral acceptability of infertility treatment to HIV positive persons raises a number of interesting ethical points regarding the responsibility of the infertility specialist for the outcome of his or her actions. The analysis of the physician’s responsibility is conducted within the framework of accomplice liability. The physician is a collaborator in the parental project of the principals—that is, the intentional parents. Both causal contribution and intention are considered as elements of complicity. It is concluded that a two per cent risk of vertical transmission when the woman is HIV positive is insufficient to blame the infertility specialist who helps her to conceive. Helping an infertile HIV positive infertile couple to have a child does not constitute reckless behaviour. When the couple is fertile, infertility treatment is directed at risk reduction and falls under the physician’s obligation to act in the best interests of his patients.
Should HIV discordant couples have access to assisted reproductive technologies?
Authors: Spriggs M , Charles T
Published: December 2003

In this paper we identify and evaluate arguments for and against offering assisted reproductive technologies (ART), specifically IVF, to HIV discordant couples (male partner HIV positive, female partner HIV negative). The idea of offering ART to HIV discordant couples generates concerns about safety and public health and raises questions such as: what is an acceptable level of risk to offspring and should couples who want this assistance be subject to selection criteria; should they undergo scrutiny about their suitability as parents when those who are able to conceive naturally face no such scrutiny and people with other illnesses are given access to ART? We conclude that offering ART to HIV discordant couples is likely to produce more benefit than harm and violates no ethical principles. Nevertheless, a decision to deny treatment need not constitute unjustified discrimination.
When is physician assisted suicide or euthanasia acceptable?
Authors: Frileux S , Lelièvre C , Muñoz Sastre M T , Mullet E , Sorum P C
Published: December 2003

Objectives:To discover what factors affect lay people’s judgments of the acceptability of physician assisted suicide and euthanasia and how these factors interact.

Design:Participants rated the acceptability of either physician assisted suicide or euthanasia for 72 patient vignettes with a five factor design—that is, all combinations of patient’s age (three levels); curability of illness (two levels); degree of suffering (two levels); patient’s mental status (two levels), and extent of patient’s requests for the procedure (three levels).

Participants:Convenience sample of 66 young adults, 62 middle aged adults, and 66 older adults living in western France.

Main measurements:In accordance with the functional theory of cognition of N H Anderson, main effects, and interactions among patient factors and participants’ characteristics were investigated by means of both graphs and ANOVA.

Results:Patient requests were the most potent determinant of acceptability. Euthanasia was generally less acceptable than physician assisted suicide, but this difference disappeared when requests were repetitive. As their own age increased, participants placed more weight on patient age as a criterion of acceptability.

Conclusions:People’s judgments concur with legislation to require a repetition of patients’ requests for a life ending act. Younger people, who frequently are decision makers for elderly relatives, place less emphasis on patient’s age itself than do older people.
Absent virtues: the poacher becomes gamekeeper
Authors: Koch T
Published: December 2003

Since its inception, bioethics’ principled stance has been to argue against paternalism and elitism, and for an inclusive ethical perspective. But at least in North America, the growth of bioethics as a special area of applied ethics has created conflicts within the field itself. Those who, a generation earlier, argued against paternalism and for both professional and public accountability in medical decision making are now part of the decision making process. Too often, it is argued in this paper, their allegiance is to the employer, or to a view of medicine that is institutionally based. As a result, it is suggested by this review, medical ethicists have adopted the perspective that, in the early 1970s, they most criticised. The answer, it is argued here, is to revisit a lexicographical ordering of responsibility in bioethics, one that recognises professionals as individuals with responsibilities, as citizens with a public posture, and finally, as professionals involved in the process of medical decision making.
Stored human tissue: an ethical perspective on the fate of anonymous, archival material
Authors: Jones D G , Gear R , Galvin K A
Published: December 2003

The furore over the retention of organs at postmortem examination, without adequate consent, has led to a reassessment of the justification for, and circumstances surrounding, the retention of any human material after postmortem examinations and operations. This brings into focus the large amount of human material stored in various archives and museums, much of which is not identifiable and was accumulated many years ago, under unknown circumstances. Such anonymous archival material could be disposed of, used for teaching, used for research, or remain in storage. We argue that there are no ethical grounds for disposing of the material, or for storing it in the absence of a teaching or research rationale. Nevertheless, with stringent safeguards, it can be used even in the absence of consent in research and teaching. Regulations are required to control the storage of all such human material, along the lines of regulations governing anatomy body bequests.
The utilitarian argument for medical confidentiality: a pilot study of patients’ views
Authors: Jones C
Published: December 2003

Objectives:To develop and pilot a questionnaire based assessment of the importance patients place on medical confidentiality, whether they support disclosure of confidential information to protect third parties, and whether they consider that this would impair full disclosure in medical consultations.

Design:Questionnaire administered to 30 consecutive patients attending a GP surgery.

Results:Overall patients valued confidentiality, felt that other patients might be deterred from seeking treatment if it were not guaranteed, but did not think that they would withhold information for this reason themselves.

Conclusions:When presented with brief details of five clinical situations in which a breach of confidentiality might be considered, a clear majority of subjects believed that doctors should disclose information in two of the situations, but subjects were not confident that doctors would do so. In three situations, about half felt that disclosure was justified—these included the only scenario in which disclosure was clearly mandated by statute. There was little change in patients’ general attitude to confidentiality after considering the scenarios. However, the views expressed were often inconsistent with responses to the clinical scenarios, suggesting that complex opinions were not accurately reflected in the responses. The format of the questionnaire has been amended, and the study will be repeated with other groups of patients.
Priority setting in cardiac surgery: a survey of decision making and ethical issues
Authors: Ridderstolpe L , Collste G , Rutberg H , Åhlfeldt H
Published: December 2003

Objectives:The aim of this study was to examine priority setting for coronary artery bypass surgery, and to provide an overview of decisions and rationales used in clinical practice.

Method:Questionnaires were sent to all permanently employed cardiologists, cardiothoracic surgeons, and anaesthesiologists at nine Swedish hospitals performing adult cardiothoracic surgery.

Results:A total of 208 physicians responded (a 44% return rate). There was considerable agreement concerning the criteria that should be used to set priorities for coronary artery bypass interventions (clusters of factors in synthesis). However, there was a lack of accord regarding the use of national guidelines for priority setting and risk indexes.

Conclusions:Basic training and the strong support of ethical principles in priority setting are lacking. The respondents indicated a need for clearer guidelines and an open dialogue or discussion. The lack of generally acknowledged plans and guidelines for priority setting may result in unequal, conditional, and unfair treatment.
Researching medicine in context: the Arts and Humanities Medical Scholars Program
Authors: Meites E , Bein S , Shafer A
Published: December 2003

In 2000, the Arts and Humanities Medical Scholars Program at Stanford University School of Medicine issued its first grants to medical students interested in researching an area of the medical arts or humanities in depth. To date, 34 projects have been funded, including renewals. The projects encompass a range of genres and topics, from a website on Asian American health and culture to an ethnographic study of women physicians in training in Spain. Two projects are highlighted here: an online history of medicine course and a poetry project. Students are mentored by faculty from a wide array of university departments and centres and submit completion documents to the committee overseeing the programme. Students are encouraged to present their work at conferences, such as the programme’s annual symposium, as well as in publication or other appropriate formats. Future directions include integration with the scholarly concentrations initiative at the medical school.
Parallel experience: how art and art theory can inform ethics in human research
Authors: Schwartz L
Published: December 2003

Trends in ethical research involving humans emphasise the importance of collaboration, of involving research subjects, alongside the researchers in the construction and implementation of research. This paper will explore parallels derived from another tradition of investigation of the human: art and art theory. An artist’s inquiry into the problems of human research will be described, followed by the application of arguments from art theory to research practice. Recently artist Christine Borland has provided examples in which the lack of collaboration in research has caused injustice. Borland’s work reflects these ethical dilemmas and questions the procedures and assumptions involved. In most cases the value of subject anonymity is called into question because it reduces the subjects’ control over themselves. The application of art theory, which has already considered these problems, helps question and explore the ways in which the subject turned object of artistic or scientific interpretation can maintain some control and dignity.
Principlism or narrative ethics: must we choose between them?
Authors: McCarthy J
Published: December 2003

This paper addresses a current debate in the bioethics community between principlists, who consider that principles are at the heart of moral life, and narrativists, who see communication at its core. Using a case study entitled “The forgetful mourner” to introduce the tensions between each of these positions, I go on to explain the central tenets of both principlism and narrative ethics. Rather than focus on their respective weaknesses, which many theorists do, I emphasise instead, the contribution that each approach can make to understanding moral life and the process of ethical decision making in health care situations. My ultimate aim is to identify the, sometimes overlapping, skills that both principlism and narrative ethics require on the part of health professionals who deploy them. I conclude that a good principlist has narrativist tendencies and a good narrativist is inclined toward principlism.
Mortality and medicine: forms of silence and of speech
Authors: Rowe M
Published: December 2003

Silence can be harmful to patients, their loved ones, and doctors within the contexts of illness and bereavement. I draw from my experience with my son’s illness and death to discuss five forms of silence—the silence around the experience of critical illness; the silence between life and death; the silence of doctors; the silence of the dead, and the silence of the ill—and of speech that may emerge in response to these silences.
Medicine and the humanities—theoretical and methodological issues
Authors: Puustinen R , Leiman M , Viljanen A M
Published: December 2003

Engel’s biopsychosocial model, Cassell’s promotion of the concept “person” in medical thinking and Pellegrino’s and Thomasma’s philosophy of medicine are attempts to widen current biomedical theory of disease and to approach medicine as a form of human activity in pursuit of healing. To develop this approach further we would like to propose activity theory as a possible means for understanding the nature of medical practice. By “activity theory” we refer to developments which have evolved from Vygotsky’s research on socially mediated mental functions and processes. Analysing medicine as activity enforces the joint consideration of target and subject: who is doing what to whom. This requires the use of historical, linguistic, anthropological, and semiotic tools. Therefore, if we analyse medicine as an activity, humanities are both theoretically and methodologically “inbound” (or internal) to the analysis itself. On the other hand, literature studies or anthropological writings provide material for analysing the various forms of medical practices.
Philosophy for medical students—why, what, and how
Authors: Louhiala P
Published: December 2003

In this paper the author’s biographical choices and experiences of both medicine and philosophy are first described. Then, the concept of philosophy is briefly examined with special reference to medical education. Finally, various ways of teaching philosophy to medical students are illustrated in the light of examples from the author’s own teaching. It is argued that, whatever the form of teaching, somehow the content must be linked to the everyday medical world of the students.
Itinerary: Concerning the professional and spiritual objectives of my life
Authors: van Praag H M
Published: December 2003

In this paper I look back on my life, on what have I tried to achieve professionally, and on what trends and theories I have opposed. Next I discuss the convictions and considerations that constituted the building blocks for the spiritual foundation of my life. I reach the conclusion that the building blocks were derived from Judaism and explain why that is so. Finally, I conclude that the scientific and the theological ingredients of my life relate reciprocally and do not exist independently.
The differing crustacean zooplankton communities of Canadian Shield lakes with and without the nonindigenous zooplanktivore Bythotrephes longimanus
Authors: Boudreau Stephanie A , Yan Norman D
Published: December 2003

The nonindigenous predatory cladoceran Bythotrephes longimanus is spreading rapidly among Canadian Shield lakes, but only one case study of its impacts exists. In Harp Lake, the abundances of several cladoceran and one cyclopoid species fell after the invasion, and far fewer species benefited. To determine if Harp Lake provides typical results, we compared the summer crustacean zooplankton communities of 17 invaded and 13 noninvaded (reference) lakes in Ontario. The communities of the two lake groups differed. Average species richness was 30% higher in the reference (15.3 species) vs. the invaded lakes (11.8 species). Total zooplankton biomass was significantly lower in the invaded lakes, mainly because of lower abundances of all common epilimnetic cladoceran species. As these results were quite similar to those of Harp Lake, it is apparent that current summer zooplankton communities of Canadian Shield lakes with Bythotrephes differ substantially from noninvaded lakes.
Zooplankton biomass enhances growth, but not survival, of first-feeding Pomoxis spp. larvae
Authors: Bunnell David B , González María J , Stein Roy A
Published: December 2003

We used otoliths to estimate growth and survival of white (Pomoxis annularis) and black (Pomoxis nigromaculatus) crappie larvae in five Ohio reservoirs. Because Pomoxis spp. larvae are among the smallest freshwater larvae and competition with gizzard shad larvae (Dorosoma cepedianum) is likely, we hypothesized that first-feeding Pomoxis spp. larvae would be susceptible to slow growth and starvation. We estimated survival by comparing proportional weekly cohort distributions of Pomoxis spp. larvae and juveniles. When distributions differed, a cohort survival index was evaluated against density of appropriately sized zooplankton biomass (crustaceans and rotifers), as well as temperature, turbidity, and density of all limnetic larvae that occurred during hatch week, when exogenous feeding began. Growth of first-feeding larvae (<10 days old) increased with total zooplankton biomass (r2 = 0.64); growth of larvae aged 10–16 days was unrelated to all measured variables. Survival was positively correlated with zooplankton biomass in only one of four reservoirs, and other variables did not correlate as expected. This result casts doubt on whether zooplankton contributes to survival of freshwater larvae.
The effect of acute changes in temperature and light on the aerobic metabolism of embryos and yolk-sac larvae of turbot (Scophthalmus maximus)
Authors: Finn Roderick Nigel , Rønnestad Ivar
Published: December 2003

The effect of acute changes of temperature and light on the rates of oxygen consumption and ammonia excretion of developing embryos and yolk-sac larvae of turbot (Scophthalmus maximus) reared at 15 °C were studied. Short-term temperature adjustments of ±2 °C gave a mean Q10of 2.6 for the rate of oxygen consumption. Neither the presence nor the absence of light significantly influenced this response to acute temperature changes, despite light causing a significantly higher rate of oxygen consumption in the yolk-sac larvae between 9 and 12 days after fertilisation. This elevated metabolic rate in the presence of light occurred after pigmentation of the eyes and was probably due to activity associated with food-searching behaviour of this visual feeder. Similarly, for most development, the presence or absence of light and acute temperature adjustments did not cause any significant shift in the relative fraction of amino acids catabolised at 15 °C. However, on day 10 after fertilisation when peak rates of oxygen consumption occurred in the yolk-sac larvae exposed to light, the significantly elevated apparent nitrogen quotients indicated that greater amounts of amino acids were utilised for catabolic substrate oxidation.
The role of sewage in a large river food web
Authors: deBruyn Adrian M.H , Marcogliese David J , Rasmussen Joseph B
Published: December 2003

We evaluated the role of sewage as a resource for the littoral food web of the fluvial St. Lawrence River near Montreal, Quebec. Stable isotope analysis indicated that macroinvertebrate primary consumers were feeding on local epiphytic production at sites outside the sewage plume, but shifts in δ15N of primary and secondary consumers revealed a substantial uptake of sewage-derived resources within the plume, up to 10 km from the outfall. Daily secondary production of macroinvertebrates was 1.8- to 4.1-fold higher at sewage-enriched sites, and the fraction of this production attributable to larval Chironomidae increased from 46% (outside the plume) to 85% (at sewage-enriched sites). Sewage enrichment also stimulated increases in daily fish production based on algivory-detritivory (1.3- to 4.4-fold), invertivory (1.7- to 10-fold), and piscivory (11- to 73-fold). We estimate a daily flux of 13 tonnes of sewage-derived particulate matter, 184 kg of total nitrogen, and 13 kg of total phosphorus into the food web over 1.2 km2 of the littoral zone within 10 km of the outfall. These values represent no more than a few percent of the total daily discharge of sewage-derived resources but were sufficient to support an overall fivefold increase in secondary production relative to sites outside the plume.
Sexual size dimorphism of walleye (Stizostedion vitreum vitreum)
Authors: Henderson Bryan A , Collins Nicholas , Morgan George E , Vaillancourt Andre
Published: December 2003

Sexual size dimorphism of walleye (Stizostedion vitreum vitreum) is achieved by females having higher growth rates than males before and after maturation, resulting in females with greater asymptotic sizes. Mercury (Hg) concentrations in epaxial muscle by age and weight for 31 populations of walleye were used to evaluate the relative importance of differences in consumption and activity in generating sexual size dimorphism. Growth efficiency by sex, age, and maturity is estimated by a ratio of annual increments in weight (g) to annual increments of Hg (mg), using the pooled changes in weight and Hg loadings of males and females from all lakes. The higher growth rates of females arise from greater consumption and higher growth efficiency. Growth efficiency of both sexes is similar before maturity, but the growth efficiency of mature males is substantially lower than that of either immature males or mature females. We propose that the inferior growth efficiency of males is a function of the greater activity of males, particularly during the spawning season when scramble competition for fertilization is likely to produce substantial increases in male fitness as a result of increased efforts to find and spawn with females.
Indirect effects of zebra mussels (Dreissena polymorpha) on the planktonic food web
Authors: Noonburg Erik G , Shuter Brian J , Abrams Peter A
Published: December 2003

The exotic zebra mussel (Dreissena polymorpha) has caused dramatic reductions in phytoplankton density in lakes with dense mussel populations. However, the indirect effects of this invader on other trophic groups have been inconsistent and difficult to interpret. In some lakes, zebra mussels appear to have had little effect on zooplankton density, despite decreasing the abundance of their phytoplankton prey. We analyze food web models to test hypothesized mechanisms for the absence of a strong effect of dreissenids on zooplankton. Our results suggest that neither reduced inedible algal interference with zooplankton filtering nor reduced phytoplankton self-shading is sufficient to explain the insensitivity of zooplankton populations to dreissenid competition. Instead, we show how the impact of benthic filter feeders can be influenced by the rate of mixing within a basin, which limits phytoplankton delivery to the benthos. We explore the predictions of a simple spatially structured model and demonstrate that differences in abiotic factors that control mixing can result in large differences in direct and indirect effects of zebra mussel filtering.
Migration patterns, ambient temperature, and growth of Icelandic cod (Gadus morhua): evidence from storage tag data
Authors: Pálsson Ólafur K , Thorsteinsson Vilhjálmur
Published: December 2003

Sixty data storage tags were analysed with respect to depth and ambient temperature and for relationships between depth, ambient temperature, and growth. The fish were tagged and released in April 1996–1999 on the spawning grounds at the southwest coast of Iceland. Profiles of depth and ambient temperature suggest that cod (Gadus morhua L.) that spawn in the study area select between two alternatives in foraging strategies, i.e., deep- or shallow-water migrations. The shallow-water fish appear to follow the seasonal trend in temperature characteristic for the shelf waters. The deep-water fish, however, migrate to deeper and cooler waters outside the spawning season and increase their vertical movement. A significant positive relationship between depth and ambient temperature was observed for the shallow-water fish, and a significant negative relationship was observed for the deep-water fish. Daily variation in depth and ambient temperature showed increasing trends with increase in depth, in particular for deep-water fish. Growth was negatively related to depth and positively related to ambient temperature. This indicates higher growth rate of cod that forage in shallow waters versus deeper waters. Supply of food, for which depth may be a reasonable proxy, offers a more likely explanation for this growth pattern than environmental temperature.
The effect of cloud cover on the development of habitat quality indices for juvenile Atlantic salmon (Salmo salar)
Authors: Girard Philippe , Boisclair Daniel , Leclerc Michel
Published: December 2003

We tested the validity of the predictions made by a habitat probabilistic index (HPI) developed using a description of the physical conditions (depth, flow velocity, grain size) used and avoided by parrs during days of different cloudiness. Thirteen surveys were designed to estimate the number and the distribution of parrs actively foraging within a 300-m reach of a river. During these surveys, the number of parrs actively foraging ranged from 12 to 118, cloud cover ranged from 5% to 100%, and water temperature ranged from 16.5 °C to 21.7 °C. The number of parrs actively foraging was negatively related to cloud cover (r2 = 0.44 to 0.88) but was independent of water temperature. HPI models developed under low (<33%) and intermediate (34–67%) cloud cover explained 82% to 98% of the local variations of fish density. The HPI model developed under high cloud cover (67–100%) was unable to predict fish distribution observed during cloudy days. Our results suggest that HPI models developed when cloudiness is >67% may have a limited predictive power.
Partitioning of dissolved thallium by seston in Lakes Erie and Ontario
Authors: Twiss Michael R , Twining Benjamin S , Fisher Nicholas S
Published: December 2003

The fate of thallium (Tl) was traced in the epipelagic and coastal waters of Lake Erie (in 2000) and Lake Ontario (in 2001) sampled during the summer period of thermal stratification. Fractionation of 204Tl bound to particulate matter was conducted to trace the scavenging potential of various seston size ranges (0.22 µm, 220 µm, and 20210 µm,). Added [204Tl]-Tl(I) scavenged by seston over 13 days was 0.344.05 % in Lake Erie and 0.090.21 % in Lake Ontario, where scavenging was correlated with suspended particulate matter content and chlorophyll a concentration. There was no consistent trend with respect to Tl scavenging by a particular size fraction, except at coastal sites in Lake Erie where most Tl was scavenged by the 220 µm seston. Partition coefficients (Kd) of Tl scavenging by seston in Lake Ontario were 9381483 L·kg1. At the same pelagic site in Lake Ontario, [204Tl]-dimethylthallium partitioned into seston (Kd = 807 ± 258) to a lesser degree than added Tl(I) (Kd = 998 ± 297), a finding consistent with laboratory assays of these two Tl species. These results suggest that the plankton food web plays a role in the geochemical cycle of this toxic metal in the water column of the lower Great Lakes.
Anthropogenic introduction of the etiological agent of withering syndrome into northern California abalone populations via conservation efforts
Authors: Friedman Carolyn S , Finley Carl A
Published: December 2003

Populations of abalone have precipitously declined in California over the past several decades, largely as a result of fishing pressure and disease. Because of these declines, farmed seed abalone have been planted in an attempt to research and restore dwindling populations. Withering syndrome is a chronic disease responsible for mass mortalities of wild black abalone, Haliotis cracherodii, in southern and central California and is caused by the bacterium "Candidatus Xenohaliotis californiensis". This bacterium has been observed in wild populations of black and red (Haliotis rufescens) abalone south of Carmel and in farmed red abalone throughout the state. In an effort to elucidate the distribution and source of the bacterium in northern California, the presence or absence of the disease and bacterium was verified at 15 locations north of Carmel. This research revealed that both the bacterium and withering syndrome are present in abalone populations south of San Francisco. In addition, the bacterium (but not withering syndrome) is present at two locations in northern California, both associated with outplants of hatchery-reared abalone, suggesting a link between restoration efforts and the present distribution of this pathogen. These data highlight the need for careful assessment of animal health before restocking depleted populations.
Movement patterns of the tropical shad hilsa (Tenualosa ilisha) inferred from transects of 87Sr/86Sr isotope ratios in their otoliths
Authors: Milton David A , Chenery Simon R
Published: December 2003

We examine 87Sr/86Sr isotope ratios in transects across the otoliths of the diadromous tropical shad hilsa, Tenualosa toli, to assess the extent of movement of fish within the large Meghna (Ganges) River system and adjacent coastal waters. Hilsa collected from marine, estuarine, and freshwater habitats were born in all main rivers in Bangladesh. All fish moved widely, entering water of marine 87Sr/86Sr isotope ratio by 1 year of age. Most returned to fresh water after they reached sexual maturity, but not necessarily to their natal region. Comparison of the 87Sr/86Sr isotope and Sr/Ca ratios of hilsa showed that in the Meghna River, 87Sr/86Sr isotope ratios can only distinguish fish from waters when the salinity was less than 5. Sr/Ca ratios were more useful for interpreting fish movements at higher salinities. To assess whether whole-otolith 87Sr/86Sr isotope ratios reflected the ratios of the water of natal origin, we compared the 87Sr/86Sr ratios of otolith cores with the mean 87Sr/86Sr isotope ratio of the whole transect. We found major differences between the two measurements, suggesting that 87Sr/86Sr isotope ratios from whole-otolith assays may not accurately reflect the natal origin of the fish.
Different patterns of gene silencing in position-effect variegation
Authors: Lloyd Vett K , Dyment David , Sinclair Donald A.R , Grigliatti Thomas A
Published: December 2003

Position-effect variegation (PEV) results when a fully functional gene is moved from its normal position to a position near to a broken heterochromatic-euchromatic boundary. In this new position, the gene, while remaining unaltered at the DNA level, is transcriptionally silenced in some cells but active in others, producing a diagnostic mosaic phenotype. Many variegating stocks show phenotypic instability, in that the level of variegation is dramatically different in different isolates or when out crossed. To test if this phenotypic instability was due to segregation of spontaneously accumulated mutations that suppress variegation, four different and well-characterized strains showing PEV for the white+gene (wm4, wmMc, wm51b, and wmJ) and representing both large and small spot variegators were repeatedly out crossed to a strain free of modifiers, and the phenotypes of these variegators were monitored for 30 generations. Once free of modifiers, these variegating strains were then allowed to reaccumulate modifiers. The spontaneous suppressors of variegation were found to include both dominant and recessive, autosomal and X-linked alleles selected to reduce the detrimental effects of silencing white+and adjacent genes. The time of peak sensitivity to temperature during development was also determined for these four variegators. Although large and small spot variegators have previously been attributed to early and late silencing events, respectively, the variegators we examined all shared a common early period of peak sensitivity to temperature. Once free of their variegation suppressors, the different variegating strains showed considerable differences in the frequency of inactivation at a cellular level (the number of cells showing silencing of a given gene) and the extent of variegation within the cell (the number of silenced genes). These results suggest that large and small spot variegation may be a superficial consequence of spontaneous variegation suppressors. The nature and number of these spontaneous variegation suppressors depends on the number of genes silenced in a given variegating rearrangement. These results are interpreted in the context of a model that proposes that the different underlying patterns of gene silencing seen in PEV can be attributed directly to the formation of heterochromatin domains possessing different properties of propagation during cell division.Key words: Drosophila melanogaster, position-effect variegation, spontaneous suppressors of variegation.
DNA polymorphism in the stem nematode Ditylenchus dipsaci: development of diagnostic markers for normal and giant races
Authors: Esquibet Magali , Grenier Eric , Plantard Olivier , Andaloussi Fouad Abbad , Caubel Georges
Published: December 2003

DNA polymorphism in the Ditylenchus dipsaci complex was investigated using amplified fragment length polymorphism (AFLP) to determine the relationships among populations growing mainly on Vicia faba and to develop diagnostic markers. Twenty-two populations of D. dipsaci originating from different geographical areas and one population of Ditylenchus myceliophagus were used. AFLP proved to be a powerful method to reveal intraspecific polymorphism even within the giant type. The analysis showed a clear distinction between the giant and normal populations, with genetic distances similar to those observed between normal populations and D. myceliophagus or giant populations and D. myceliophagus, strengthening the hypothesis that these two nematode types could be considered distinct species. Two specific AFLP markers differentiating the two types were converted into sequenced characterized amplified region (SCAR) markers. Used in a multiplex PCR, the SCAR primers proved to be a rapid and efficient tool to identify the giant and the normal types of D. dipsaci.Key words: Ditylenchus dipsaci, Vicia faba, giant type, AFLP, SCAR.
SNP-based codominant markers for a recessive gene conferring resistance to corky root rot (Rhizomonas suberifaciens) in lettuce (Lactuca sativa)
Authors: Moreno-Vázquez Santiago , Ochoa Oswaldo E , Faber Nanne , Chao Shiaoman , Jacobs Jeanne M.E , Maisonneuve Brigitte , Kesseli Richard V , Michelmore Richard W
Published: December 2003

The analysis of F2progeny and derived F3families of Lactuca sativa segregating for resistance to corky root rot caused by Rhizomonas suberifaciens permitted the identification of restriction fragment length polymorphism (RFLP) and single nucleotide polymorphism (SNP) markers linked to the recessive resistance gene cor. PCR-based markers were identified by bulked segregant analysis (BSA). Allele-specific primers were generally designed with the 3´ terminal base coinciding with an SNP, matching one of the alleles and mismatching the other, and with an additional subterminal 3´ base mismatching both alleles. Codominant, robust, and inexpensive molecular markers were obtained that used standardized PCR conditions. Some of the markers could be analyzed in multiple Lactuca mapping populations that did not segregate for disease resistance allowing the cor locus to be located on several maps. The consistent low density of markers around cor in these maps suggests that cor may be in an area with an elevated rate of recombination. Evaluation of these markers in a large sample of cultivars and landraces identified pairs of flanking polymorphic markers that can be used for marker-assisted selection of corky root resistance.Key words: single nucleotide polymorphism (SNP), sequence characterized amplified region (SCAR), marker-assisted selection (MAS), genetic map, resistance gene.
Relationships in Ananas and other related genera using chloroplast DNA restriction site variation
Authors: Duval M F , Buso G S.C , Ferreira F R , Noyer J L , d'Eeckenbrugge G Coppens , Hamon P , Ferreira M E
Published: December 2003

La phylogénie du genre Ananas et de ses apparentés a été étudiée sur la base de la diversité de l'ADN chloroplastique. Le polymorphisme de restriction de huit fragments d'ADN chloroplastique a été analysé sur un large échantillon de 91 accessions représentant les sept espèces du genre Ananas. Vingt accessions appartenant à sept autres genres de la sous-famille des Bromelioideae, dont Pseudananas considéré très proche d'Ananas, une Tillandsoideae et deux Pitcairnioideae représentant les deux autres sous-familles des Bromeliaceae complètent l'échantillon. La restriction par 18 endonucléases des huit fragments amplifiés a produit 255 fragments variables et mis en évidence 35 haplotypes différents. L'indice de Sokal et Michener a été utilisé pour le calcul des dissimilarités analysées par la méthode du « neighbor joining ». La reconstruction phylogénétique a été tentée par l'application du principe de parsimonie. Les analyses phénétiques et cladistiques donnent des résultats concordants. La précédence du genre Bromelia dans la sous-famille des Bromelioideae est confirmée. Les genres Ananas et Pseudananas forment un groupe monophylétique dans lequel trois sous-groupes sont mis en évidence. Deux d'entre eux correspondent à des unités géographiques cohérentes : l'un, restreint aux bassins du Rio Negro et de l'Orénoque, comprend la majorité des accessions d' Ananas parguazensis ; l'autre, au sud du continent Sud-américain, joint le tétraploïde Pseudananas sagenarius et le diploïde Ananas fritzmuelleri. Le troisième et le plus important sous-groupe comprend des accessions des cinq autres espèces, quelques accessions d' Ananas parguazensis et quelques accessions de phénotype intermédiaire non classées. Il présente la distribution géographique la plus large dont des zones de recouvrement avec les deux sous-groupes précédents. L'espèce sauvage Ananas ananassoides montre la variation la plus élevée et partage des haplotypes avec les trois espèces cultivées. La comparaison des données obtenues dans cette étude et des résultats obtenus précédemment à l'aide de marqueurs à transmission bi-parentale met en évidence l'existence de flux de génes, fréquents dans ce sous-groupe et plus rares avec les deux premiers. Un scénario d'évolution basé sur l'hypothèse des refuges est proposé pour expliquer la structure et la distribution de la diversité. L'application possible de ces résultats dans la réforme de la taxinomie du genre proposée est discutée.Mots clés : Ananas, diversité génétique, Amérique du Sud, ADN chloroplastique, PCR-RFLP, évolution, taxinomie.
Transmission of alien chromosomes from selfed progenies of a complete set of Allium monosomic additions: the development of a reliable method for the maintenance of a monosomic addition set
Authors: Shigyo M , Wako T , Kojima A , Yamauchi N , Tashiro Y
Published: December 2003

Selfed progeny of a complete set of Allium fistulosum  Allium cepa monosomic addition lines (2n = 2x + 1 = 17, FF+1AFF+8A) were produced to examine the transmission rates of respective alien chromosomes. All eight types of the selfed monosomic additions set germinable seeds. The numbers of chromosomes (2n) in the seedlings were 16, 17, or 18. The eight extra chromosomes varied in transmission rate (%) from 9 (FF+2A) to 49 (FF+8A). The complete set of monosomic additions was reproduced successfully by self-pollination. A reliable way to maintain a set of Allium monosomic additions was developed using a combination of two crossing methods, selfing and female transmission. FF+8A produced two seedlings with 18 chromosomes. Cytogenetical analyses, including GISH, showed that the seedlings were disomic addition plants carrying two entire homologous chromosomes from A. cepa in an integral diploid background of A. fistulosum. Flow cytometry analysis showed that a double dose of the alien 8A chromosome caused fluorescence intensity values spurring in DNA content, and isozyme analysis showed increased glutamate dehydrogenase activity at the gene locus Gdh-1.Key words: Allium cepa, Allium fistulosum, monosomic addition, disomic addition, transmission rate.