The role of “ larval retention” in life-cycle closure of Atlantic herring (Clupea harengus) populations

2015 ◽  
Vol 172 ◽  
pp. 401-414 ◽  
Author(s):  
Mike Sinclair ◽  
Mike Power
1984 ◽  
Vol 41 (7) ◽  
pp. 1055-1065 ◽  
Author(s):  
M. Sinclair ◽  
M. J. Tremblay

Each population of Atlantic herring (Clupea harengus harengus) has its own seasonally fixed spawning period of a few weeks duration, but the mean spawning times of different populations differ substantially. The extant theory explains the population-specific timing of spawning relative to the plankton production blooms in the inferred larval distributional area. Support of this theory is evaluated, and found lacking, in the light of a recent "stock" hypothesis involving larval retention. The new hypothesis involves two constraints. First, the larvae of a discrete herring population develop within, and are thus adapted to, the specific oceanographic conditions of their larval retention area. Second, metamorphosis from the larval to juvenile form occurs primarily within a restricted period of the year (April to October). Given these two constraints, it is hypothesized that the timing of spawning of a herring population is a function of the time necessary to complete the larval phase and yet metamorphose within the acceptable seasonal envelope. Populations that have "good" larval retention areas can spawn in the spring and still metamorphose within the seasonal envelope. Populations with larval retention areas that are less "good" for larval growth have to spawn earlier to satisfy the two constraints. The implications of the hypothesis on the "match–mismatch" theory are briefly discussed.


Author(s):  
Petar Halachev ◽  
Victoria Radeva ◽  
Albena Nikiforova ◽  
Miglena Veneva

This report is dedicated to the role of the web site as an important tool for presenting business on the Internet. Classification of site types has been made in terms of their application in the business and the types of structures in their construction. The Models of the Life Cycle for designing business websites are analyzed and are outlined their strengths and weaknesses. The stages in the design, construction, commissioning, and maintenance of a business website are distinguished and the activities and requirements of each stage are specified.


2021 ◽  
Vol 22 (9) ◽  
pp. 4438
Author(s):  
Jessica Proulx ◽  
Kathleen Borgmann ◽  
In-Woo Park

The ubiquitin (Ub) proteasome system (UPS) plays a pivotal role in regulation of numerous cellular processes, including innate and adaptive immune responses that are essential for restriction of the virus life cycle in the infected cells. Deubiquitination by the deubiquitinating enzyme, deubiquitinase (DUB), is a reversible molecular process to remove Ub or Ub chains from the target proteins. Deubiquitination is an integral strategy within the UPS in regulating survival and proliferation of the infecting virus and the virus-invaded cells. Many viruses in the infected cells are reported to encode viral DUB, and these vial DUBs actively disrupt cellular Ub-dependent processes to suppress host antiviral immune response, enhancing virus replication and thus proliferation. This review surveys the types of DUBs encoded by different viruses and their molecular processes for how the infecting viruses take advantage of the DUB system to evade the host immune response and expedite their replication.


Author(s):  
Thassya C. dos Santos Schmidt ◽  
Doug E. Hay ◽  
Svein Sundby ◽  
Jennifer A. Devine ◽  
Guðmundur J. Óskarsson ◽  
...  

AbstractLife-history traits of Pacific (Clupea pallasii) and Atlantic (Clupea harengus) herring, comprising both local and oceanic stocks subdivided into summer-autumn and spring spawners, were extensively reviewed. The main parameters investigated were body growth, condition, and reproductive investment. Body size of Pacific herring increased with increasing latitude. This pattern was inconsistent for Atlantic herring. Pacific and local Norwegian herring showed comparable body conditions, whereas oceanic Atlantic herring generally appeared stouter. Among Atlantic herring, summer and autumn spawners produced many small eggs compared to spring spawners, which had fewer but larger eggs—findings agreeing with statements given several decades ago. The 26 herring stocks we analysed, when combined across distant waters, showed clear evidence of a trade-off between fecundity and egg size. The size-specific individual variation, often ignored, was substantial. Additional information on biometrics clarified that oceanic stocks were generally larger and had longer life spans than local herring stocks, probably related to their longer feeding migrations. Body condition was only weakly, positively related to assumingly in situ annual temperatures (0–30 m depth). Contrarily, body growth (cm × y−1), taken as an integrator of ambient environmental conditions, closely reflected the extent of investment in reproduction. Overall, Pacific and local Norwegian herring tended to cluster based on morphometric and reproductive features, whereas oceanic Atlantic herring clustered separately. Our work underlines that herring stocks are uniquely adapted to their habitats in terms of trade-offs between fecundity and egg size whereas reproductive investment mimics the productivity of the water in question.


2021 ◽  
Vol 22 (2) ◽  
pp. 643
Author(s):  
Xiao Li ◽  
Fen Wang ◽  
Yanyan Xu ◽  
Guijun Liu ◽  
Caihong Dong

Hydrophobins are a family of small secreted proteins found exclusively in fungi, and they play various roles in the life cycle. In the present study, genome wide analysis and transcript profiling of the hydrophobin family in Cordyceps militaris, a well-known edible and medicinal mushroom, were studied. The distribution of hydrophobins in ascomycetes with different lifestyles showed that pathogenic fungi had significantly more hydrophobins than saprotrophic fungi, and class II members accounted for the majority. Phylogenetic analysis of hydrophobin proteins from the species of Cordyceps s.l. indicated that there was more variability among the class II members than class I. Only a few hydrophobin-encoding genes evolved by duplication in Cordyceps s.l., which was inconsistent with the important role of gene duplication in basidiomycetes. Different transcript patterns of four hydrophobin-encoding genes during the life cycle indicated the possible different functions for each. The transcripts of Cmhyd2, 3 and 4 can respond to light and were related with the photoreceptors. CmQHYD, with four hydrophobin II domains, was first found in C. militaris, and multi-domain hydrophobins were only distributed in the species of Cordycipitaceae and Clavicipitaceae. These results could be helpful for further function research of hydrophobins and could provide valuable information for the evolution of hydrophobins.


2021 ◽  
Vol 9 (8) ◽  
pp. 1621
Author(s):  
Adeline Ribeiro E Silva ◽  
Alix Sausset ◽  
Françoise I. Bussière ◽  
Fabrice Laurent ◽  
Sonia Lacroix-Lamandé ◽  
...  

Kinome from apicomplexan parasites is composed of eukaryotic protein kinases and Apicomplexa specific kinases, such as rhoptry kinases (ROPK). Ropk is a gene family that is known to play important roles in host–pathogen interaction in Toxoplasma gondii but is still poorly described in Eimeria tenella, the parasite responsible for avian coccidiosis worldwide. In the E. tenella genome, 28 ropk genes are predicted and could be classified as active (n = 7), inactive (incomplete catalytic triad, n = 12), and non-canonical kinases (active kinase with a modified catalytic triad, n = 9). We characterized the ropk gene expression patterns by real-time quantitative RT-PCR, normalized by parasite housekeeping genes, during the E. tenella life-cycle. Analyzed stages were: non-sporulated oocysts, sporulated oocysts, extracellular and intracellular sporozoites, immature and mature schizonts I, first- and second-generation merozoites, and gametes. Transcription of all those predicted ropk was confirmed. The mean intensity of transcription was higher in extracellular stages and 7–9 ropk were specifically transcribed in merozoites in comparison with sporozoites. Transcriptional profiles of intracellular stages were closely related to each other, suggesting a probable common role of ROPKs in hijacking signaling pathways and immune responses in infected cells. These results provide a solid basis for future functional analysis of ROPK from E. tenella.


Sign in / Sign up

Export Citation Format

Share Document