bluuebunny/crossref_metadata_2025 huggingface dataset:
Negotiating Workplace Equality: A Systemic Approach
Authors: Sturm Susan
Published: January 2009

Negotiations can operate as powerful engines of inequality, often because of the institutional and social context placing women and people of color at a systemic disadvantage. Yet, negotiation literature and practice has paid little attention to the question of how to reshape the context within which negotiations proceed. This article provides an approach for connecting individual level negotiations with institutional interventions that reshape the context for those negotiations, so that women and people of color can fully and fairly participate in the interactions and decisions so crucial to their advancement. It first lays out the systemic underpinnings of negotiated inequality, identifying structural disparities in information, networks, cognitive frames, and ground rules. It then identifies the role of organizational catalysts in reshaping the contours within which negotiations occur, and learning from the successes and failures of negotiations aggregated over time and place. Finally, it identifies a set of strategies for tackling the systemic underpinnings of inequality in the negotiation process, including (1) critical reframing through root cause analysis, (2) generating and mobilizing information, (3) developing social capital needed for effective negotiation, (4) creating and connecting opportunity networks, and (5) developing constituencies of accountability.
Role of RFLP using TspRI for carrier detection in Glanzmann’s thrombasthenia: a report on two families
Authors: KANNAN M. , YADAV B. K. , AHMAD F. , SAXENA R.
Published: January 2009

Glanzmann’s thrombasthenia (GT) was diagnosed in two patients who presented with bleeding manifestations accompanied by absent platelet aggregation, secondary to adenosine‐5'‐diphosphate, adrenaline, arachidonic acid and collagen. Flow cytometry analysis for GPIIb/IIIa expression was done using CD61 and CD41 markers in these patients and their family members including siblings. The patients were sub typed as Type I as he had absent glycoproteins (GP) IIb/IIIa. Family studies by flow cytometry showed reduced GPII/IIIa expression in both the parents and one sibling. However, western blot showed abnormal GPIIb protein in all the family members including siblings. It is possible that abnormal GPIIb protein by western blot in family members may reflect their carrier status. Patients’ DNA was analyzed for mutation in both the GPIIb and GPIIIa genes by conformational sensitive gel electrophoresis (CSGE), followed by sequencing. CSGE showed defect in exon 12 and the promoter region of GPIIb. By sequence, it was confirmed that both the mutations were homozygous one was c.1028T>C and the other one was M33320.1:g.951G>A. For one of these mutations, restriction fragment length polymorphism (RFLP) was developed to look for the same mutation in all the family members. RFLP was developed using a restriction enzyme (TspRI) against the patient’s mutation, c.1028T>C in exon 12 of GPIIb gene. RFLP followed by gel electrophoresis revealed that the mutation was heterozygous in all the family members. The findings by RFLP were double confirmed by direct DNA sequencing of the exon 12 in all the family members. Thus, TspRI marker may be used as a RFLP marker to predict the carriers in GT families, if the patients’ mutation status is identified.
In vitro studies with ‘acatalasemic‐like’ erythrocytes and hydrogen peroxide: attention to the formation of lysis resistant erythrocytes
Authors: NASCIMENTO H. , BELO L. , FERNANDES J. , ROCHA S. , QUINTANILHA A. , SANTOS‐SILVA A.
Published: January 2009

Hemolysis assays, using hydrogen peroxide as an oxidant injury agent and sodium azide as a catalase inhibitor, were performed to evaluate how assay conditions affect the development of lysis resistant erythrocytes. The concentration of hydrogen peroxide should be carefully selected for use in hemolysis assays, as it was found to affect the number of water resistant erythrocytes.
The utility of immature reticulocyte fraction as an indicator of erythropoietic response to altitude training in elite cyclists
Authors: NADARAJAN V. S. , OOI C. H. , STHANESHWAR P. , THOMPSON M. W.
Published: January 2009

Altitude training is sometimes employed by elite endurance athletes to improve their sea level performance. This improvement results from the increased red cell mass consequent upon the boost in erythropoietin (EPO) level that occurs as a response to the relatively hypoxic environment at high altitudes. We measured serum EPO levels together with various red cell and reticulocyte parameters including immature reticulocyte fraction (IRF) in eight national track‐endurance cyclists, resident at sea‐level, prior to and upon return from an altitude of approximately 1905 m. Reticulocytes and soluble transferrin receptor (sTfR) were significantly increased with reduction in ferritin levels immediately on return from high altitude indicating increased erythropoietic activity. IRF in particular showed a significant peak immediately on return but decline to sub‐baseline levels by day 9, and recovery to baseline by day 16. Our results indicate that IRF is a sensitive marker of erythropoietic status in athletes undergoing altitude training and subsequent loss of EPO stimuli on return to sea level.
CTLA4 and generalized vitiligo: two genetic association studies and a meta‐analysis of published data
Authors: Birlea Stanca A. , LaBerge Greggory S. , Procopciuc Lucia M. , Fain Pamela R. , Spritz Richard A.
Published: January 2009

Several lines of evidence have implicated the gene encoding cytotoxic T lymphocyte antigen 4 (CTLA4) in susceptibility to various autoimmune diseases. However, published studies of genetic association between CTLA4 polymorphisms and vitiligo have yielded conflicting results. Here, we describe two new genetic association studies of CTLA4 single‐nucleotide polymorphisms (SNPs) and generalized vitiligo in two independent Romanian Caucasian (CEU) case‐control cohorts. The first study, of SNPs rs1863800, rs231806, rs231775, rs3087243, rs11571302, rs11571297, and rs10932037, showed no allelic, genotypic, or haplotypic association with generalized vitiligo. The second study, of SNP rs231775, likewise showed no significant association. To enhance statistical power over that of any individual study, we carried out a meta‐analysis that incorporated these two new studies and all other published genetic association studies of CTLA4 SNPs and vitiligo in CEU populations. While there was no association with vitiligo overall, the meta‐analysis showed significant association of SNP rs231775 in that subgroup of vitiligo patients who also had other concomitant autoimmune diseases. Similarly, there was near‐significant association in this same patient subgroup with several other CTLA4 SNPs that are in linkage disequilibrium with rs231775. Our results indicate that the association of CTLA4 with vitiligo is weak, and indeed may be secondary, driven by primary genetic association of CTLA4 with other autoimmune diseases that are epidemiologically associated with vitiligo.
BI‐69A11‐mediated inhibition of AKT leads to effective regression of xenograft melanoma
Authors: Gaitonde Supriya , De Surya K , Tcherpakov Marianna , Dewing Antimone , Yuan Hongbin , Riel‐Mehan Megan , Krajewski Stan , Robertson Gavin , Pellecchia Maurizio , Ronai Ze’ev
Published: January 2009

The AKT/PKB pathway plays a central role in tumor development and progression and is often up‐regulated in different tumor types, including melanomas. We have recently reported on the in silico approach to identify putative inhibitors for AKT/PKB. Of the reported hits, we selected BI‐69A11, a compound which was shown to inhibit AKT activity in in vitro kinase assays. Analysis of BI‐69A11 was performed in melanoma cells, a tumor type that commonly exhibits up‐regulation of AKT. Treatment of the UACC903 human melanoma cells, harboring the PTEN mutation, with BI‐69A11 caused efficient inhibition of AKT S473 phosphorylation with concomitant inhibition of AKT phosphorylation of PRAS40. Treatment of melanoma cells with BI‐69A11 also reduced AKT protein expression, which coincided with inhibition of AKT association with HSP‐90. BI‐69A11 treatment not only caused cell death of melanoma, but also prostate tumor cell lines. Notably, the effect of BI‐69A11 on cell death was more pronounced in cells that express an active form of AKT. Significantly, intra‐peritoneal injection of BI‐69A11 caused effective regression of melanoma tumor xenografts, which coincided with elevated levels of cell death. These findings identify BI‐69A11 as a potent inhibitor of AKT that is capable of eliciting effective regression of xenograft melanoma tumors.
Lentivirus‐mediated bifunctional cell labeling for in vivo melanoma study
Authors: Day Chi‐Ping , Carter John , Bonomi Carrie , Esposito Dominic , Crise Bruce , Ortiz‐Conde Betty , Hollingshead Melinda , Merlino Glenn
Published: January 2009

Lentiviral vectors (LVs) are capable of labeling a broad spectrum of cell types, achieving stable expression of transgenes. However, for in vivo studies, the duration of marker gene expression has been highly variable. We have developed a series of LVs harboring different promoters for expressing reporter gene in mouse cells. Long‐term culture and colony formation of several LV‐labeled mouse melanoma cells showed that promoters derived from mammalian house‐keeping genes, especially those encoding RNA polymerase II (Pol2) and ferritin (FerH), provided the highest consistency for reporter expression. For in vivo studies, primary B16BL6 mouse melanoma were infected with LVs whose luciferase–green fluorescence protein fusion gene (Luc/GFP) was driven by either Pol2 or FerH promoters. When transplanted into syngeneic C57BL/6 mice, Luc/GFP‐labeled B16BL6 mouse melanoma cells can be monitored by bioluminescence imaging in vivo, and GFP‐positive cells can be isolated from the tumors by fluorescence‐activated cell sorter. Pol2‐Luc/GFP labeling, while lower in activity, was more sustainable than FerH‐Luc/GFP labeling in B16BL6 over consecutive passages into mice. We conclude that Pol‐2‐Luc/GFP labeling allows long‐term in vivo monitoring and tumor cell isolation in immunocompetent mouse melanoma models.
Physiological role and regulation of glutamate dehydrogenase inProchlorococcussp. strain MIT9313
Authors: Rangel Oriol Alberto , Gómez‐Baena Guadalupe , López‐Lozano Antonio , Diez Jesús , García‐Fernández Jose Manuel
Published: January 2009

Glutamate dehydrogenase is an enzyme catalysing a reaction for ammonium assimilation, alternative to those performed by glutamine synthetase and glutamate synthase. In the genusProchlorococcus, genomic studies have shown the presence of thegdhAgene (encoding glutamate dehydrogenase) in only four of the sequenced strains, including MIT9313. We studied the physiological regulation of glutamate dehydrogenase in this strain, by measuring the expression ofgdhA, the intracellular concentration of the enzyme and its activity. Our goal was to clarify the physiological role of glutamate dehydrogenase, in order to understand why it has been selectively conserved in certain strains. Studies performed in cultures under nitrogen starvation, or with inhibitors of the nitrogen assimilation, suggest that the main role of glutamate dehydrogenase is not the assimilation of ammonium. Glutamate dehydrogenase activity andgdhAexpression increased along the growth of cultures. Besides, we found a significant upregulation in gene expression when cultures were grown on glutamate as nitrogen source. We suggest that the main physiological role of glutamate dehydrogenase inProchlorococcusMIT9313 is the utilization of glutamate to produce ammonium and 2‐oxoglutarate, and amino acid recycling, thus enabling to use amino acids as nitrogen source. Therefore we propose that glutamate dehydrogenase is present in the genome of strains for whom the utilization of amino acids is most important.
A Multi‐Level Approach for Investigating Socio‐Economic and Agricultural Risk Factors Associated with Rates of Reported Cases of Escherichia coli O157 in Humans in Alberta, Canada
Authors: Pearl D. L. , Louie M. , Chui L. , Doré K. , Grimsrud K. M. , Martin S. W. , Michel P. , Svenson L. W. , McEwen S. A.
Published: January 2009

Using negative binomial and multi‐level Poisson models, the authors determined the statistical significance of agricultural and socio‐economic risk factors for rates of reported disease associated with Escherichia coli O157 in census subdivisions (CSDs) in Alberta, Canada, 2000–2002. Variables relating to population stability, aboriginal composition of the CSDs, and the economic relationship between CSDs and urban centres were significant risk factors. The percentage of individuals living in low‐income households was not a statistically significant risk factor for rates of disease. The statistical significance of cattle density, recorded at a higher geographical level, depended on the method used to correct for overdispersion, the number of levels included in the multi‐level models, and the choice of using all reported cases or only sporadic cases. Our results highlight the importance of local socio‐economic risk factors in determining rates of disease associated with E. coli O157, but their relationship with individual risk factors requires further evaluation.
The Methodological Soundness of Literature Reviews Addressing Three Potential Zoonotic Public Health Issues
Authors: Waddell L. , Rajić A. , Sargeant J. , Parker S. , Deckert A. , McEwen S.
Published: January 2009

Literature reviews are important information sources for multiple stakeholders in zoonotic public health with limited time to keep up with the rapid increase in primary research in this field. However, their validity depends on their methodological soundness. The study purpose was to evaluate the methodological soundness of literature reviews in zoonotic public health. Relevant reviews (n = 132) published between January 2000 and August 2006 were identified on three issues:Mycobacterium aviumsspparatuberculosisas a potential cause of Crohn’s disease in humans (30 reviews); antimicrobial use in animals as a risk factor for antimicrobial resistance in human pathogens (36); and the zoonotic potential of transmissible spongiform encephalopathies (66). The zoonotic aspect of the issue was the focus of 59 reviews and a subsection of 73 reviews. Two independent reviewers evaluated reviews using 13 criteria: 10 previously validated in the medical field, and three applicable to aetiology research. No review met more than eight of 13 criteria for methodological soundness; two articles met only one criterion. Two reviews described methods for identifying relevant primary research. In only two and four reviews respectively, authors conducted quantitative syntheses of research evidence or reported summarized measures of effect for the zoonotic risk to humans. Recommendations for future research and economic impact were provided in 64 and 10 reviews respectively. In 14 reviews, conclusions exceeded evidence presented. The various review authors’ position on the evidence for the zoonotic association and the zoonotic risk to public health were inconsistent for all three issues. Reviews addressing potential zoonotic public health issues lack structured and transparent methodology preventing the end user from assessing the review’s validity. These reviews should adhere to structured scientific principles similar to what is used for primary research articles.
Serovars ofSalmonellafrom captive reptiles
Authors: Pedersen K. , Lassen‐Nielsen A.‐M. , Nordentoft S. , Hammer A. S.
Published: January 2009

The distribution on serovars of 60Salmonellaisolates from reptiles kept in captivity in Denmark during the period 1995–2006 was investigated. The isolates were all recovered from clinical specimens submitted to the National Veterinary Institute. A majority of the samples were from reptiles in zoological gardens or similar, while a minor number was from reptiles kept in private homes. A total of 43 serovars were detected, most of them being what is usually called exotic serotypes, and many not having a trivial name, while a few isolates belonged to well‐known human pathogenic serovars, such asS. Enteritidis,S. Typhimurium,S. Bovismorbificans. One isolate was rough and two were non‐typeable. Isolates from turtles belonged to the subspeciesenterica, while many isolates from both sauria and snakes belonged to other subspecies. The findings underline the potential zoonotic risk by handling reptiles in zoological garden or other public settings, or keeping pet reptiles in private homes.
Vaccination with Mycobacterium bovis BCG Strains Danish and Pasteur in White‐tailed Deer (Odocoileus virginianus) Experimentally Challenged with Mycobacterium bovis
Authors: Palmer M. V. , Thacker T. C. , Waters W. R.
Published: January 2009

Wildlife reservoirs of Mycobacterium bovis represent serious obstacles to the eradication of tuberculosis in domestic livestock and the cause for many faltering bovine tuberculosis eradication programmes. One approach in dealing with wildlife reservoirs of disease is to interrupt inter‐species and intraspecies transmission through vaccination of deer or cattle. To evaluate the efficacy of BCG vaccination in white‐tailed deer, 35 deer were assigned to one of three groups; one s.c. dose of 107 CFU of M. bovis BCG Pasteur (n = 12); 1 s.c. dose of 107 CFU of M. bovis BCG Danish (n = 11); or unvaccinated deer (n = 12). After vaccination, deer were inoculated intratonsilarly with virulent M. bovis. Lesion severity scores of the medial retropharyngeal lymph node, as well as all lymph nodes combined, were reduced in vaccinated deer compared to unvaccinated deer. BCG Danish vaccinated deer had no late stage granulomas characterized by coalescent caseonecrotic granulomas containing numerous acid‐fast bacilli compared to BCG Pasteur vaccinated or unvaccinated deer where such lesions were present. Both BCG strains were isolated as late as 250 days after vaccination from deer that were vaccinated but not challenged. In white‐tailed deer, BCG provides protection against challenge with virulent M. bovis. Issues related to vaccine persistence, safety and shedding remain to be further investigated.
Direct Detection of Mycobacterium bovis in Bovine Lymph Nodes by PCR
Authors: Cardoso M. A. , Cardoso R. F. , Hirata R. D. C. , Hirata M. H. , Leite C. Q. F. , Santos A. C. B. , Siqueira V. L. D. , Okano W. , Rocha N. S. , Lonardoni M. V. C.
Published: January 2009

Thirty‐five lymph node samples were taken from animals with macroscopic lesions consistent with Mycobacterium bovis infection. The animals were identified by postmortem examination in an abattoir in the northwestern region of state of Paraná, Brazil. Twenty‐two of the animals had previously been found to be tuberculin skin test positive. Tissue samples were decontaminated by Petroff’s method and processed for acid‐fast bacilli staining, culture in Stonebrink and Lowenstein‐Jensen media and DNA extraction. Lymph node DNA samples were amplified by PCR in the absence and presence (inhibitor controls) of DNA extracted from M. bovis culture. Mycobacterium bovis was identified in 14 (42.4%) lymph node samples by both PCR and by culture. The frequency of PCR‐positive results (54.5%) was similar to that of culture‐positive results (51.5%, P > 0.05). The percentage of PCR‐positive lymph nodes increased from 39.4% (13/33) to 54.5% (18/33) when samples that were initially PCR‐negative were reanalysed using 2.5 μl DNA (two samples) and 1 : 2 diluted DNA (three samples). PCR sensitivity was affected by inhibitors and by the amount of DNA in the clinical samples. Our results indicate that direct detection of M. bovis in lymph nodes by PCR may be a fast and useful tool for bovine tuberculosis epidemic management in the region.
The phenology and impact of Caliciopsis arceuthobii on lodgepole pine dwarf mistletoe, Arceuthobium americanumThis article is one of a collection of papers based on a presentation from the Stem and Shoot Fungal Pathogens and Parasitic Plants: the Values of Biological Diversity session of the XXII International Union of Forestry Research Organization World Congress meeting held in Brisbane, Queensland, Australia, in 2005.
Authors: Ramsfield Tod D. , Shamoun Simon F. , van der Kamp Bart J.
Published: January 2009

Arceuthobium americanum Nuttal ex Engelmann in Gray (lodgepole pine dwarf mistletoe) causes significant losses to the timber industry. The fungus Caliciopsis arceuthobii (Peck) Barr shows high specificity to Arceuthobium spp., and therefore infection of A. americanum was monitored for 4 years to determine the effect of this fungus on fruit production. The contribution of stand-level and locally produced inoculum in the infection process was also studied to better understand the epidemiology of the pathogen. Over the period of the study, C. arceuthobii caused an average annual fruit reduction of 58%. When the contribution of local and stand-level inoculum was modelled, the results suggested that on A. americanum infections with ≥ 4 ascospore-producing immature fruit, more than half of the new C. arceuthobii infections on the same plant are derived from locally produced ascospores. The effect of the fungus on the host suggests that it has potential as a biological control agent for A. americanum, and further studies are needed to attempt to induce inoculum production in culture.
Mistletoe ecophysiology: host–parasite interactionsThis review is one of a collection of papers based on a presentation from theStem and Shoot Fungal Pathogens and Parasitic Plants: the Values of Biological Diversitysession of the XXII International Union of Forestry Research Organization World Congress meeting held in Brisbane, Queensland, Australia, in 2005.
Authors: Glatzel G. , Geils B. W.
Published: January 2009

Mistletoes are highly specialized perennial flowering plants adapted to parasitic life on aerial parts of their hosts. In our discussion on the physiological interactions between parasite and host, we focus on water relations, mineral nutrition, and the effect of host vigour. When host photosynthesis is greatest, the xylem water potential of the host is most negative. To maintain a flux gradient and avoid stomatal closure and wilting, the mistletoe must tolerate a more negative water potential than the host. Succulent leaves enhance water storage and allow mistletoes to rehydrate before their hosts rehydrate. Mistletoe infections may disrupt the host stomatal control system, causing early and oscillating closure of host stomata, thereby diminishing host photosynthetic gain. Mistletoes lack the active uptake of minerals of a typical plant root system and rely upon the haustorium to connect with the host for the essentially one-way flow of photosynthates and nutrients from host to parasite. Modest growth rates, tolerance, succulence, and rapid leaf turnover are some means by which mistletoes avoid mineral deficiency or excess. We propose high concentrations of some mobile elements in the mistletoe by comparison with the host result not from active uptake, but from the inevitable accumulation by a parasite that utilizes host phloem sap. The relationship between host condition and mistletoe performance varies by situation and over time. In some cases, the host can outgrow the mistletoe, but favorable host status can also accelerate mistletoe growth. A better understanding of the mistletoe–host interaction can be utilized in improved management of infested forest plantations for resource production as well as for conservation of biodiversity and endangered species.
Host responses in the xylem of trees after inoculation with six wood-decay fungi differing in invasivenessThis article is one of a collection of papers based on a presentation from the Stem and Shoot Fungal Pathogens and Parasitic Plants: the Values of Biological Diversity session of the XXII International Union of Forestry Research Organization World Congress meeting held in Brisbane, Queensland, Australia, in 2005.
Authors: Deflorio Giuliana , Franz Erwin , Fink Siegfried , Schwarze Francis Willis Mathew Robert
Published: January 2009

Host responses, i.e., formation of reaction and barrier zones, were studied in the xylem of Douglas-fir, beech, oak, and sycamore trees, after wounding and artificial inoculation with brown-, soft-, and white-rot fungi. The objective of this study was to determine whether strongly invasive wood-decay fungi trigger a higher magnitude of host response than weakly invasive fungi. Differences in active host response, observed microscopically, depended on wood anatomy. Restriction of discoloration and decay by reaction zones was primarily influenced by the content and distribution of parenchyma cells within the sapwood of each host. By contrast, barrier-zone anatomy showed similarities to the basic xylem structure of each host, except for some cell types that were either reduced in number or absent. Regardless of the decay fungus inoculated, individual trees of each host responded differently. With the exception of beech trees inoculated with the soft-rot fungus Kretzschmaria deusta (Hoffm.: Fr.) P. Martin and the white-rot fungus Trametes versicolor (L.: Fries) Pilát, host response appeared to be nonspecific, as the degree of fungal invasiveness did not influence the magnitude of host response within the xylem of investigated trees.
Interactive effects of carbon dioxide concentration and light on the morphological and biomass characteristics of black spruce and white spruce seedlings
Authors: Marfo Jacob , Dang Qing-Lai
Published: January 2009

CO2–light interactions can influence the competition among boreal plants, but are poorly understood. We investigated the effect of such interactions on the growth and biomass of 1-year-old black spruce (Sb) ( Picea mariana (Mill.) BSP) and white spruce (Sw) ( Picea glauca (Moench) Voss) grown with CO2 concentrations ([CO2]) of 360 and 720 µmol·mol–1 under 30%, 50%, and 100% light, in greenhouses. There were significant two-way and three-way interactions. Root collar diameter (RCD) of Sw decreased with decreasing light, while in Sb, there was no significant difference in RCD for plants grown under 50% or 30% light. Height was greater for plants grown under 100% light than if the plants were shaded. Elevated [CO2] increased RCD by 33% and enhanced stem volume by 67%, 98%, and 84% under 100%, 50%, and 30% light, respectively. The CO2 enhancement of total biomass was relatively higher under lower light, and greater for Sb than Sw. Elevated [CO2] decreased specific leaf area under 50% light only. Root mass was generally higher under 100% light than when shaded. Elevated [CO2] increased the root mass of Sb under 100% light, but decreased it under 30% light. Elevated [CO2] decreased the shoot/root ratio under 100% light, but increased it under 30% light. Our data suggest that raising [CO2] will likely increase species competitiveness under low light conditions, and that the increase will be greater in species that are relatively shade tolerant.
Intracanopy variation in leaf morphology and physiology in dominant shrubs of Florida’s xeric uplands
Authors: Stephens Elizabeth L. , Saha Sonali , Menges Eric S.
Published: January 2009

The variation in morphological traits and photosynthetic potentials associated with light conditions in the canopy can determine whole-plant function. However, leaf structure–function relationships are poorly studied in ecosystems experiencing nominal light attenuation. We examined morphological leaf traits (area, specific leaf area, thickness, revoluteness, length–width) and photosynthetic traits estimated from rapid light curves (PARsat, ETRmax, light harvesting efficiency α) in seven shrub species in two xeric upland ecosystems of Florida: rosemary scrub and sandhill. Across species and ecosystem types, shade leaves had greater specific leaf area, were thinner, and less revolute than sun leaves. Surprisingly, shade leaves had smaller areas than sun leaves. Three out of six species showed a tight relationship between morphological and photosynthetic traits. Species common to both sandhill and rosemary scrub ecosystems showed similar photosynthetic traits but greater sclerophylly in the scrub ecosystem. Overall, greater leaf thickness and greater leaf area of upper canopy leaves yielded higher photosynthetic capacities and saturation at higher photon flux densities compared with lower canopy leaves. Our results suggest that variation in leaf morphological traits governed by patterns in light availability have functional significance; however, ecosystem properties such as nutrient availability might also impact light-driven structure-function relationships.
Viability of Neotyphodium endophytic fungus and endophyte-infected and noninfected Lolium multiflorum seeds
Authors: Gundel Pedro E. , Martínez-Ghersa M. Alejandra , Garibaldi Lucas A. , Ghersa Claudio M.
Published: January 2009

Neotyphodium endophyte fungi are vertically transmitted symbionts of cool-season grasses. The seed phase of the grass’ life cycle appears to be critical for the persistence of the fungus. Endophyte viability decreases faster than seed viability, but little is known of the effects of this endophyte on seed viability. The endophyte could affect seed viability through changes in water content. Here, we assessed the effects of the endophyte on seed viability, the differential survival of endophyte and seed, and the effects of infection on seed water content. Viability of endophyte-infected and noninfected seeds and endophyte were evaluated over a period of 729 d under 12 controlled environmental conditions. Seed viability was reduced by the infection at high temperature and high relative humidity, but not under other conditions. Moreover, endophyte viability decreased faster than seed viability only under high humidity or high temperature. Seed water content was not affected by endophyte presence. The proportion of viable infected seeds was mainly affected by the loss in endophyte viability and secondly by the differential survival of infected and noninfected seeds. Knowledge on the relative importance of these processes is critical to understand the factors affecting the efficiency of endophyte vertical transmission and the frequency of endophyte-infected plants.
Molecular studies of animal systems/Études au niveau moléculaire des systèmes animaux: Introduction
Authors: Pasternak J. J.
Published: January 2009

The 26th annual meeting of the Canadian Society of Zoologists, held in May 1987, included a symposium entitled Molecular Studies of Animal Systems. Certainly, a recent and pervasive research thrust in the study of animals has been the accessibility of molecular biology techniques to complement existing research strategies. In organizing this session, Dr. Marilyn Scott had two major objectives: first, to demonstrate how studies at the molecular level facilitate an understanding of the biology of animals and second, to use examples of research programmes that would be of interest to zoologists, in particular those concerned with insect and fish physiology, parasitology, and evolutionary biology. An attempt was made to provide some breadth without being too divergent. The specific research topics derived from the original lectures and included in this issue of the Canadian Journal of Zoology describe and discuss (i) molecular commonality of cuticular and genomic structures between a free-living nematode and a parasitic one, (ii) regulation of vitellogenesis in the locust, and (iii) characterization at the molecular level of fish antifreeze proteins. These papers illustrate how various molecular biology methodologies can be used to resolve problems of biological interest.
Molecular biology of nematodes: some recent studies on Panagrellus and Ascaris
Authors: Pasternak J. J.
Published: January 2009

Nematodes have a number of biological attributes that make them amenable for molecular studies. In our laboratory, attention has focused on (i) determining the polypeptide composition of cuticles, (ii) using monoclonal antibodies to identify epitopes among the cuticular proteins, (iii) visualizing the sites of collagenous components within the cuticle of Ascaris by immunolocalization, and (iv) sequencing a moderately repetitive DNA element that is found, with extensive similarity, in the genomes of Ascaris and Panagrellus. The role of these and other molecular studies in understanding the biology of nematodes is discussed.
Vitellogenin synthesis and the analysis of juvenile hormone action in locust fat body
Authors: Wyatt G. R.
Published: January 2009

Juvenile-hormone-dependent synthesis of vitellogenin in the fat body of migratory locusts is being studied for insight into subcellular modes of action of juvenile hormone (JH). Vitellogenin (Vg), a dimeric glycolipoprotein assembled from polypeptide subunits of 185 kDa, is produced in females from day 6–8 of adult life. Locusts deprived of corpora allata produce no Vg, but synthesis can be induced by administration of JH or an active analog such as methoprene. Vg synthesis could not be induced in male adults, but did occur in male larvae given high doses of methoprene, so that sex-limited cell programming must occur at metamorphosis. Adult fat body of both sexes responds to JH by DNA replication and enhanced protein synthesis. In stimulated female fat body, Vg mRNA of 6300 nucleotides is abundant. From locust genomic DNA libraries, clones making up two genes, VgA and VgB, have been isolated and shown to be the locust's only genes for Vg. Both are on the X chromosome and both contain introns. No cross-hybridization between them could be obtained for most of the coding regions, but similarity in their N-terminal amino acid sequences and those of chicken, Xenopus, and nematode Vgs suggests that these all belong to a gene superfamily. Repetitive sequences, including an Alu-like family, occur near the locust Vg genes. Assays with unique-sequence probes showed that, after a lag of about 24 and 12 h for primary and secondary stimulation, respectively, VgA and VgB mRNAs accumulate coordinately. Within 500 base pairs (bp) upstream from the transcription start sites, the sequences flanking VgA and VgB show several blocks of similarity; two of these, which are matched by 12-bp units upstream from JH-regulated cockroach oothecin genes, may represent JH-response elements. Locust Vg sequences transferred into Drosophila were integrated but not expressed. The data are consistent with a steroid-like model for control of gene transcription by JH, but many particulars remain to be established.
Population dynamics of Psocoptera in farm-stored grain and oilseed
Authors: Sinha R. N.
Published: January 2009

Population fluctuation and spatial distribution patterns of five species of Psocoptera were determined during 1959–1979 in 12 cereal and oilseed bulks stored for 2–6 years in granaries on Manitoba farms. Lepinotus reticulatus, Liposcelis bostrychophilus, Liposcelis liparus, Liposcelis rugosus, Liposcelis subfuscus, and other Liposcelis spp. naturally infested wheat, oats, and barley initially stored at 10.3–14.0% moisture content and rapeseed stored at 6.3–11.6% moisture content. Generally, psocids were sparsely distributed and occurred in all parts of the granaries throughout the year, but they were most common and abundant during late summer and autumn. Only one serious outbreak of psocids in general was observed during 1963–1964 involving L. reticulatus in two adjacent 13.6-tonne wheat bulks in one granary. Application of Iwao's mean density and mean crowding regression method revealed a clumped spatial distribution for this species; an analysis of variance of the data showed that insect number per sample varied significantly (P < 0.01) among samples from 3-, 30-, 61-, 91-, and 152-cm depths after 24, 36, 47, and 48 months of storage. Principal component analyses and stepwise multiple regression analyses of the data for these sampling dates indicated that the large population rise of L. reticulatus resulted from significant (P < 0.01) interaction among several variables including moisture content, fungi, and mites. L. bostrychophilus occurred regularly in low numbers in patches in wheat and rapeseed bulks during 31–65 months of storage; the maximum number per sample was 126, in rapeseed in September. Liposcelis liparus and L. subfuscus also occurred in low numbers in patches in barley and wheat bulks; their maximum number was 42 per sample, in wheat in October. Association of the psocid species with other stored-grain insects and mites is discussed.
The problematic phylogenetic analysis of interlocus heteropolymer isozyme characters: a case study from sea snakes and cobras
Authors: Murphy Robert W.
Published: January 2009

Multiple cases of parallel advancement (isozyme silencing) of L-lactate dehydrogenase heterotetramer isozymes are encountered when the observed isozyme patterns are superimposed on a well-corroborated cladogram depicting the phylogenetic relationships of some sea snakes, cobras, and coral snakes. This finding may be common among similar data sets because of parallel evolution and the inability to discern transformation sequences. Thus, the utility of this isozyme character in phylogenetic investigations may be severely limited, depending on the taxonomic group or level of universality being investigated.
Variation in developmental biology of pink salmon (Oncorhynchus gorbuscha) in British Columbia
Authors: Beacham T. D. , Murray C. B.
Published: January 2009

Pink salmon stocks in British Columbia spawning from August through October were surveyed for variation in developmental biology from 1983 to 1985. Pink salmon in the even-year broodline tended to have higher embryonic survival and proportionately better embryonic and alevin growth at a low incubation temperature (4 °C) than did those in the odd-year broodline. Within a broodline, late-spawning stocks had slightly faster fry emergence timing than did early spawning stocks. Stocks within broodlines had different trends in alevin and fry size with respect to incubation temperature. Pink salmon in the even-year broodline appeared to be better adapted to a colder environment than those in the odd-year broodline. This may reflect a different recent origin of the two broodlines.
Behavioral temperature regulation by aquatic ectotherms during hypoxia
Authors: Dupré R. Keith , Wood Stephen C.
Published: January 2009

Terrestrial animals lower their body temperature by behavioral and (or) physiological means in response to environmental or anemic hypoxia. Because hypoxia is common in some aquatic environments, temperature selection by two aquatic ectotherms, paedomorphic tiger salamanders (Ambystoma tigrinum) and crayfish (Procambarus simulans), was examined during environmental hypoxia in an aquatic thermal gradient. Both species selected lower temperatures when exposed to an environment with a [Formula: see text] of about 37 Torr (4.9 kPa). These data suggest that the lowering of body temperature, and thus oxygen demand, in the face of a low oxygen availability may be an adaptive response in heterothermal aquatic environments. The available data for diverse species show that the hypothermic response to hypoxia is a taxonomically widespread phenomenon occurring in both water- and air-breathing animals.
Trill rate dialects in the Rufous-collared Sparrow, Zonotrichia capensis, in northwestern Argentina
Authors: Handford Paul
Published: January 2009

Geographical variation in trill rate of Zonotrichia capensis was assessed in a sample of about 2300 individuals from nearly 600 sites distributed throughout northwestern Argentina, from 22 to 34°S. The variation was partitioned among the following site characteristics: original (natural) vegetation, contemporary vegetation structure, latitude, longitude, and altitude. About 45% of the variation was attributable to the original vegetation (p < 0.0001): the other site characteristics explained a further 4%. Thus the geographical distribution of trill rate closely paralleled that of the natural vegetation, even where this vegetation has been long (80–200 years) replaced by various forms of agriculture. These results were interpreted as the consequence of vocal learning influenced by the vocalizations of dominant elements in the local avifauna of each habitat, together with factors affecting the unambiguous propagation of acoustic signals through given kinds of vegetation.
Fatty acid binding proteins in teleost fish
Authors: Stewart J. M. , Driedzic W. R.
Published: January 2009

A fatty acid binding protein of low molecular weight (12 800) was detected in the white heart muscle of ocean pout (Macrozoarces americanus) and the myoglobin-rich heart muscle of sea raven (Hemitripterus americanus), but not the glycolytic white skeletal muscle of ocean pout. The interaction of isolated ocean pout fatty acid binding protein with potassium [1-14C]palmitate was examined. Data indicate two binding sites for palmitate with an apparent dissociation constant, Kd, of 0.69 ± 0.03 × 10−6 M. The amount of bound palmitate was influenced by pH and by calcium ion concentration.
Epizootics of thyroid hyperplasia in Lake Superior and Lake Erie pink salmon (Oncorhynchus gorbuscha (Walbaum))
Authors: Noltie Douglas B. , Leatherland John F. , Keenleyside Miles H. A.
Published: January 2009

All Lake Superior and Lake Erie pink salmon (Oncorhynchus gorbuscha (Walbaum)) collected exhibited thyroid hyperplasia. Samples from British Columbia, however, were unaffected. In fish from Lake Superior, lesion sizes increased through a graded series and were correlated with increased body size. In contrast, almost all Lake Erie fish exhibited extreme hyperplasia regardless of body size. Pink salmon lesion histopathology differed markedly from that shown by Great Lakes coho (Oncorhynchus kisutch (Walbaum)) and chinook (Oncorhynchus ishawytscha (Walbaum)) salmon. Among Great Lakes populations, males and females were equally afflicted. Greater proportions of females entered their spawning streams with immature gonads in Lake Erie, where fish exhibited larger lesions. Indications are that males showed poorer secondary sexual character development there as well. Gonad weights in Lake Erie males were proportionally smaller than in Lake Superior males, and liver weights in Lake Superior fish were smaller than in British Columbia specimens. Thyroid hormone levels and lesion sizes were negatively correlated, providing evidence of hypothyroidism. These findings warn of potential water quality problems in Lake Superior, and suggest a useful means of assessing the goitrogenic potential of Great Lakes systems. Despite its negative effects, however, thyroid hyperplasia has not prevented the increase of pink salmon numbers and distribution in the Great Lakes.
Differences in breeding Lake Superior pink salmon (Oncorhynchus gorbuscha (Walbaum)) associated with variation in thyroid hyperplasia
Authors: Noltie Douglas B.
Published: January 2009

Pink salmon (Oncorhynchus gorbuscha (Walbaum)) from eastern Lake Superior exhibit various degrees of thyroid hyperplasia. A link between goitrogenesis and growth is suggested by the increased prevalence of large lesions among large fish of both sexes. Despite males being larger than females, however, lesion prevalence did not differ between the sexes. More large lesions occurred among late migrants, especially males, indicating a seasonal increase in hyperplasticity. Delayed stream entry occurred in overtly lesioned fish of both sexes, evidence of a possible inhibition of maturation. Males and females differed in condition (weight-at-length) with lesion severity. Females with overt lesions showed reduced secondary sexual character development, more so than males. The pre- and post-spawning testis characteristics of males generally did not differ with lesion size, although the testes of spawned-out males with large lesions did have higher water contents. In females, the reduced water content of eggs in severely lesioned individuals was evidence of delayed maturation. Enlarged livers occurred in badly lesioned females, but not in males. In neither sex did severely lesioned fish exhibit shorter breeding life-spans. In overview, this study demonstrates that a wide range of effects is associated with differences in the severity of thyroid hyperplasia exhibited by Lake Superior pink salmon, these also being mediated by apparent differences in physiology between the sexes.
Effects of habitat on development, fecundity, and susceptibility to parasites in Parameletus chelifer and Parameletus minor (Ephemeroptera)
Authors: Söderström Olle , Johansson Anita
Published: January 2009

Life history parameters of two mayflies were studied for 4 years in two habitats in northern Sweden: a river margin and a seasonal stream. Water temperature before river peak flood was higher and the C/N ratio of the dominating food fraction was lower in the seasonal stream than at the river margin. Over the entire season, the growth rate of Parameletus chelifer nymphs was higher in the seasonal stream than at the river margin, whereas that of Parameletus minor nymphs was similar in both habitats in 2 out of 4 years. Because of desiccation, emergence success of P. chelifer in the seasonal stream was low in some years while almost no specimens emerged successfully from the river. Emergence success was always high in P. minor, and in some years emergence was further advanced in the seasonal stream than at the river margin. Subimagoes of both species were larger in the seasonal stream than at the river margin. Males of both species were larger than females in the seasonal stream, as were males of P. minor at the river margin. The fecundity of P. chelifer females was higher in the seasonal stream than at the river margin, while no difference could be found in P. minor between the two habitats. Only P. chelifer specimens were infested by mermithid nematodes; in some years as many as 21% of the female subimagoes were infested. Such females were unable to reproduce.
Caractéristiques écologiques et épidémiologiques de l'Echinococcus multilocularis au cours d'un cycle complet des populations d'un hôte intermédiaire (Microtus arvalis)
Authors: Delattre Pierre , Pascal Michel , Pesteur Marie-Hélène Le , Giraudoux Patrick , Damange Jean-Pierre
Published: January 2009

This study, carried out in a medium altitude mountain ecosystem (Doubs, France), was devoted to the analysis of spatial and temporal variations of the infestation rate of Echinococcus multilocularis Leuckart in a microtine secondary host (Microtus arvalis Pallas) during a complete population cycle of the rodent. This analysis, combined with a structural study of the landscape, showed that contaminated rodents were located only in or near ploughed fields. The age structure of the rodent population showed that infestation occurred only during winter (from October to April in the studied area). These results suggest new ways of research for elucidating the mechanisms responsible for the perenniality of the parasite.
Mate retention in Giant Canada Geese
Authors: Raveling Dennis G.
Published: January 2009

Of 73 pairs of Giant Canada Geese (Branta canadensis maxima) in which both members of the pair were marked with individually identifiable neckbands, 68 (93%) remained together for as long as both members were alive or retained their markers. Collectively, these data represent 183 years of pair histories (sum of pairs × years of records). One pair that had raised a brood in the summer they were captured and marked separated during the next breeding season; neither re-paired with another bird, and then they rejoined the following autumn and remained together for five consecutive breeding seasons (and winters). Members of four (5.5%) pairs obtained new mates while their former mates were still alive. Of 17 surviving members of pairs in which the mate died (or disappeared) over winter, 15 (88%) re-paired. Data on reproductive success of 4 of these new pairs were not obtained, but 10 of 11 of the other new pairs successfully reared broods.