scholarly journals Advances in herring biology: from simple to complex, coping with plasticity and adaptability

2009 ◽  
Vol 66 (8) ◽  
pp. 1688-1695 ◽  
Author(s):  
Audrey J. Geffen
Keyword(s):  
Life History ◽  
Population Biology ◽  
Current Knowledge ◽  
Early Stage ◽  
Basic Research ◽  
Marine Ecology ◽  
Life History Strategies ◽  
Migration Patterns ◽  
Otolith Analysis ◽  
Stock Mixing

Abstract Geffen, A. J. 2009. Advances in herring biology: from simple to complex, coping with plasticity and adaptability. – ICES Journal of Marine Science, 66: 1688–1695. At least two centuries of investigations on herring have been absorbed by scientific journals, and applied and basic research has produced groundbreaking concepts in fisheries, population biology, and marine ecology. By the 1970s, a firm understanding of herring biology formed the basis for more sophisticated research. At that point, herring populations had been delineated, and their migration patterns described. The reproduction and early stage biology were characterized in ways that could be applied to fisheries management. However, over the subsequent four decades, new approaches and technology overturned many of the earlier findings. Behavioural studies revealed a repertoire of patterns that extended the concept of schooling, and genetic analyses showed high levels of stock mixing. Application of otolith analysis to larval, juvenile, and adult fish revealed the scope of plasticity in growth and life-history strategies. Developments in physiological research have revealed that herring are not “primitive”, as once believed, but highly adaptable in their nutrition and metabolism. These advances fundamentally changed our view of herring, and the resulting challenge is to synthesize current knowledge to help explain the significance of adaptability and plasticity in its flexible life history.

scholarly journals Strontium isotopes reveal diverse life history variations, migration patterns, and habitat use for Broad Whitefish (Coregonus nasus) in Arctic, Alaska

2021 ◽  
Author(s):  
Jason C. Leppi ◽  
Daniel J. Rinella ◽  
Mark S. Wipfli ◽  
Randy J. Brown ◽  
Karen J. Spaleta ◽  
...  
Keyword(s):  
Life History ◽  
Habitat Use ◽  
Life Histories ◽  
Anthropogenic Impacts ◽  
Indigenous Communities ◽  
Life History Strategies ◽  
Time And Space ◽  
Marine Habitat ◽  
Migration Patterns ◽  
Arctic Alaska

Conservation of Arctic fish species is challenging partly due to our limited ability to track fish through time and space, which constrains our understanding of life history diversity and lifelong habitat use. Broad Whitefish ( Coregonus nasus ) is an important subsistence species for Alaska’s Arctic Indigenous communities, yet little is known about life history diversity, migration patterns, and freshwater habitat use. Using laser ablation Sr isotope otolith microchemistry, we analyzed Colville River Broad Whitefish 87 Sr/ 86 Sr chronologies (n = 61) to reconstruct movements and habitat use across the lives of individual fish. We found evidence of at least six life history types, including three anadromous types, one semi-anadromous type, and two nonanadromous types. Anadromous life history types comprised a large proportion of individuals sampled (collectively, 59%) and most of these (59%) migrated to sea between ages 0–2 and spent varying durations at sea. The semi-anadromous life history type comprised 28% of samples and entered marine habitat as larvae. Nonanadromous life history types comprised the remainder (collectively, 13%). Otolith 87 Sr/ 86 Sr data from juvenile and adult freshwater stages suggest that habitat use changed in association with age, seasons, and life history strategies. This information on Broad Whitefish life histories and habitat use across time and space will help managers and conservation planners better understand the risks of anthropogenic impacts and help conserve this vital subsistence resource.

scholarly journals State-dependent energy allocation in cod (Gadus morhua)

2006 ◽  
Vol 63 (1) ◽  
pp. 186-199 ◽  
Author(s):  
Christian Jørgensen ◽  
Øyvind Fiksen
Keyword(s):  
Life History ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Energy Allocation ◽  
Marine Ecology ◽  
Life History Strategies ◽  
Special Importance ◽  
State Dependent ◽  
Growth Energy ◽  
State Of The Environment

Growth and maturation are processes that are tuned to the external environment that an individual is likely to experience, where food availability, the mortality regime, and events necessary to complete the life cycle are of special importance. Understanding what influences life history strategies and how changes in life history in turn influence population dynamics and ecological interactions are crucial to our understanding of marine ecology and contemporary anthropogenic induced change. We present a state-dependent model that optimises life-long energy allocation in iteroparous fish. Energy can be allocated to growth or reproduction and depends in the individual's age, body length, and stored energy and the state of the environment. Allocation and the physiological processes of growth, energy storage, and reproduction are modelled mechanistically. The model is parameterised for Atlantic cod (Gadus morhua), more specifically the Northeast Arctic cod stock. Growth and maturation predicted by the model fit well with field observations, and based on a further investigation of cod reproduction in the model, we conclude that the model has the ability to recapture complex life history phenomena, e.g., indeterminate growth and skipped spawning, and therefore provides an important tool that can improve our understanding of life history strategies in fish.

scholarly journals Ecological biomechanics of benthic organisms: life history, mechanical design and temporal patterns of mechanical stress

1999 ◽  
Vol 202 (23) ◽  
pp. 3469-3476 ◽  
Author(s):  
M.A. Koehl
Keyword(s):  
Life History ◽  
Population Biology ◽  
Mechanical Performance ◽  
Mechanical Design ◽  
Temporal Distribution ◽  
Life History Strategies ◽  
Ecological Interactions ◽  
Individual Change ◽  
Benthic Organisms ◽  
Biomechanical Tests

We can gain biomechanical insights if we couple knowledge of the environments, ecological roles and life history strategies of organisms with our laboratory analyses of their mechanical function or fluid dynamics, as illustrated by studies of the mechanical design of bottom-dwelling marine organisms. Obviously, measurements of the spatial and temporal distribution of loads on an organism in nature reveal the magnitudes and rates at which biomechanical tests should be performed in the laboratory. Furthermore, knowledge of the population biology and ecological interactions of the organisms being studied is crucial to determine when during the life of an individual particular aspects of mechanical performance should be measured; not only can the size, shape and material properties of an individual change during ontogeny, but so can its habitat, activities and ecological role. Such ecological information is also necessary to determine whether the aspects of mechanical performance being studied are biologically important, i.e. whether they affect the survivorship or fitness of the organisms. My point in raising these examples is to illustrate how ecological studies can enhance or change our understanding of biomechanical function.

scholarly journals Costs of migratory decisions: A comparison across eight white stork populations

2016 ◽  
Vol 2 (1) ◽  
pp. e1500931 ◽  
Author(s):  
Andrea Flack ◽  
Wolfgang Fiedler ◽  
Julio Blas ◽  
Ivan Pokrovsky ◽  
Michael Kaatz ◽  
...  
Keyword(s):  
Life History ◽  
Life History Strategies ◽  
Complete Suppression ◽  
Migratory Species ◽  
Ecological Processes ◽  
Migration Patterns ◽  
White Storks ◽  
Specific Species ◽  
Migration Costs ◽  
Migratory Movements

Annual migratory movements can range from a few tens to thousands of kilometers, creating unique energetic requirements for each specific species and journey. Even within the same species, migration costs can vary largely because of flexible, opportunistic life history strategies. We uncover the large extent of variation in the lifetime migratory decisions of young white storks originating from eight populations. Not only did juvenile storks differ in their geographically distinct wintering locations, their diverse migration patterns also affected the amount of energy individuals invested for locomotion during the first months of their life. Overwintering in areas with higher human population reduced the stork’s overall energy expenditure because of shorter daily foraging trips, closer wintering grounds, or a complete suppression of migration. Because migrants can change ecological processes in several distinct communities simultaneously, understanding their life history decisions helps not only to protect migratory species but also to conserve stable ecosystems.

scholarly journals Fitness of Herbicide-Resistant Weeds: Current Knowledge and Implications for Management

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 469 ◽  
Author(s):  
Vila-Aiub
Keyword(s):  
Life History ◽  
Herbicide Resistance ◽  
Management Practices ◽  
Current Knowledge ◽  
Resistance Management ◽  
Fitness Cost ◽  
Plant Fitness ◽  
Resistance Mutations ◽  
Fitness Costs ◽  
Wide Range

Herbicide resistance is the ultimate evidence of the extraordinary capacity of weeds to evolve under stressful conditions. Despite the extraordinary plant fitness advantage endowed by herbicide resistance mutations in agroecosystems under herbicide selection, resistance mutations are predicted to exhibit an adaptation cost (i.e., fitness cost), relative to the susceptible wild-type, in herbicide untreated conditions. Fitness costs associated with herbicide resistance mutations are not universal and their expression depends on the particular mutation, genetic background, dominance of the fitness cost, and environmental conditions. The detrimental effects of herbicide resistance mutations on plant fitness may arise as a direct impact on fitness-related traits and/or coevolution with changes in other life history traits that ultimately may lead to fitness costs under particular ecological conditions. This brings the idea that a “lower adaptive value” of herbicide resistance mutations represents an opportunity for the design of resistance management practices that could minimize the evolution of herbicide resistance. It is evident that the challenge for weed management practices aiming to control, minimize, or even reverse the frequency of resistance mutations in the agricultural landscape is to “create” those agroecological conditions that could expose, exploit, and exacerbate those life history and/or fitness traits affecting the evolution of herbicide resistance mutations. Ideally, resistance management should implement a wide range of cultural practices leading to environmentally mediated fitness costs associated with herbicide resistance mutations.

scholarly journals Molecular Mechanisms of Insulin Resistance in Polycystic Ovary Syndrome: Unraveling the Conundrum in Skeletal Muscle?

2019 ◽  
Vol 104 (11) ◽  
pp. 5372-5381 ◽  
Author(s):  
Nigel K Stepto ◽  
Alba Moreno-Asso ◽  
Luke C McIlvenna ◽  
Kirsty A Walters ◽  
Raymond J Rodgers
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Polycystic Ovary Syndrome ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Polycystic Ovary ◽  
Evidence Synthesis ◽  
Basic Research ◽  
Future Research ◽  
Ovary Syndrome

Abstract Context Polycystic ovary syndrome (PCOS) is a common endocrine condition affecting 8% to 13% of women across the lifespan. PCOS affects reproductive, metabolic, and mental health, generating a considerable health burden. Advances in treatment of women with PCOS has been hampered by evolving diagnostic criteria and poor recognition by clinicians. This has resulted in limited clinical and basic research. In this study, we provide insights into the current and future research on the metabolic features of PCOS, specifically as they relate to PCOS-specific insulin resistance (IR), that may affect the most metabolically active tissue, skeletal muscle. Current Knowledge PCOS is a highly heritable condition, yet it is phenotypically heterogeneous in both reproductive and metabolic features. Human studies thus far have not identified molecular mechanisms of PCOS-specific IR in skeletal muscle. However, recent research has provided new insights that implicate energy-sensing pathways regulated via epigenomic and resultant transcriptomic changes. Animal models, while in existence, have been underused in exploring molecular mechanisms of IR in PCOS and specifically in skeletal muscle. Future Directions Based on the latest evidence synthesis and technologies, researchers exploring molecular mechanisms of IR in PCOS, specifically in muscle, will likely need to generate new hypothesis to be tested in human and animal studies. Conclusion Investigations to elucidate the molecular mechanisms driving IR in PCOS are in their early stages, yet remarkable advances have been made in skeletal muscle. Overall, investigations have thus far created more questions than answers, which provide new opportunities to study complex endocrine conditions.

scholarly journals Hidden Host Plant Associations of Soilborne Fungal Pathogens: An Ecological Perspective

2013 ◽  
Vol 103 (6) ◽  
pp. 538-544 ◽  
Author(s):  
Glenna M. Malcolm ◽  
Gretchen A. Kuldau ◽  
Beth K. Gugino ◽  
María del Mar Jiménez-Gasco
Keyword(s):  
Host Plant ◽  
Population Biology ◽  
Fungal Pathogens ◽  
Current Knowledge ◽  
Vascular Plant ◽  
Disease Symptoms ◽  
Nonhost Plant ◽  
Plant Associations ◽  
Definition Of ◽  
Forest Plants

Much of the current knowledge on population biology and ecology of soilborne fungal pathogens has been derived from research based on populations recovered from plants displaying disease symptoms or soil associated with symptomatic plants. Many soilborne fungal pathogens are known to cause disease on a large number of crop plants, including a variety of important agronomical, horticultural, ornamental, and forest plants species. For instance, the fungus Verticillium dahliae causes disease on >400 host plants. From a phytopathological perspective, plants on which disease symptoms have not been yet observed are considered to be nonhosts for V. dahliae. This term may be misleading because it does not provide information regarding the nature of the plant–fungus association; that is, a nonhost plant may harbor the fungus as an endophyte. Yet, there are numerous instances in the literature where V. dahliae has been isolated from asymptomatic plants; thus, these plants should be considered hosts. In this article, we synthesize scattered research that indicates that V. dahliae, aside from being a successful and significant vascular plant pathogen, may have a cryptic biology on numerous asymptomatic plants as an endophyte. Thus, we suggest here that these endophytic associations among V. dahliae and asymptomatic plants are not unusual relationships in nature. We propose to embrace the broader ecology of many fungi by differentiating between “symptomatic hosts” as those plants in which the infection and colonization by a fungus results in disease, and “asymptomatic hosts” as those plants that harbor the fungus endophytically and are different than true nonhosts that should be used for plant species that do not interact with the given fungus. In fact, if we broaden our definition of “host plant” to include asymptomatic plants that harbor the fungus as an endophyte, it is likely that the host ranges for some soilborne fungal pathogens are much larger than previously envisioned. By ignoring the potential for soilborne fungal pathogens to display endophytic relationships, we leave gaps in our knowledge about the population biology and ecology, persistence, and spread of these fungi in agroecosystems.

scholarly journals EU FP7 research funding for an orphan drug (Orfadin®) and vaccine (Hep C) development: a success and a failure?

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
L. Schmidt ◽  
O. Sehic ◽  
C. Wild
Keyword(s):  
Hepatitis C ◽  
Late Stage ◽  
Research Funding ◽  
Early Stage ◽  
Basic Research ◽  
Pharmaceutical Products ◽  
Clinical Development ◽  
Clinical Indication ◽  
Market Authorisation ◽  
Risk Capital

Abstract Background We considered the extent of the contribution of publicly funded research to the late-stage clinical development of pharmaceuticals and medicinal products, based on the European Commission (EC) FP7 research funding programme. Using two EC FP7-HEALTH case study examples—representing two types of outcomes—we then estimated wider public and charitable research funding contributions. Methods Using the publicly available database of FP7-HEALTH funded projects, we identified awards relating to late-stage clinical development according to the systematic application of inclusion and exclusion criteria, classified them according to product type and clinical indication, and calculated total EC funding amounts. We then identified two case studies representing extreme outcomes: failure to proceed with the product (hepatitis C vaccine) and successful market authorisation (Orfadin® for alkaptonuria). Total public and philanthropic research funding contributions to these products were then estimated using publicly available information on funding. Results 12.3% (120/977) of all EC FP7-HEALTH awards related to the funding of late-stage clinical research, totalling € 686,871,399. Pharmaceutical products and vaccines together accounted for 84% of these late-stage clinical development research awards and 70% of its funding. The hepatitis C vaccine received total European Community (FP7 and its predecessor, EC Framework VI) funding of €13,183,813; total public and charitable research funding for this product development was estimated at € 77,060,102. The industry sponsor does not consider further development of this product viable; this now represents public risk investment. FP7 funding for the late-stage development of Orfadin® for alkaptonuria was so important that the trials it funded formed the basis for market authorisation, but it is not clear whether the price of the treatment (over €20,000 per patient per year) adequately reflects the substantial public funding contribution. Conclusions Public and charitable research funding plays an essential role, not just in early stage basic research, but also in the late-stage clinical development of products prior to market authorisation. In addition, it provides risk capital for failed products. Within this context, we consider further discussions about a public return on investment and its reflection in pricing policies and decisions justified.

scholarly journals Natural variation in plant telomere length is associated with flowering time

2021 ◽  
Author(s):  
Jae Young Choi ◽  
Liliia R Abdulkina ◽  
Jun Yin ◽  
Inna B Chastukhina ◽  
John T Lovell ◽  
...  
Keyword(s):  
Life History ◽  
Telomere Length ◽  
Flowering Time ◽  
Dna Sequences ◽  
Genome Wide Association Study ◽  
Genomic Analysis ◽  
Life History Strategies ◽  
Length Variation ◽  
Chromosomal Structure ◽  
Chromosome Integrity

Abstract Telomeres are highly repetitive DNA sequences found at the ends of chromosomes that protect the chromosomes from deterioration during cell division. Here, using whole genome re-sequencing and terminal restriction fragment assays, we found substantial natural intraspecific variation in telomere length in Arabidopsis thaliana, rice (Oryza sativa), and maize (Zea mays). Genome-wide association study (GWAS) mapping in A. thaliana identified 13 regions with GWAS-significant associations underlying telomere length variation, including a region that harbors the telomerase reverse transcriptase (TERT) gene. Population genomic analysis provided evidence for a selective sweep at the TERT region associated with longer telomeres. We found that telomere length is negatively correlated with flowering time variation not only in A. thaliana, but also in maize and rice, indicating a link between life history traits and chromosome integrity. Our results point to several possible reasons for this correlation, including the possibility that longer telomeres may be more adaptive in plants that have faster developmental rates (and therefore flower earlier). Our work suggests that chromosomal structure itself might be an adaptive trait associated with plant life history strategies.

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