scholarly journals Sperm performance under hypoxic conditions in the intertidal fish Porichthys notatus

2009 ◽  
Vol 87 (5) ◽  
pp. 464-469 ◽  
Author(s):  
John L. Fitzpatrick ◽  
Paul M. Craig ◽  
Carol Bucking ◽  
Sigal Balshine ◽  
Chris M. Wood ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Swimming Speed ◽  
Fertilization Success ◽  
Reproductive Hormones ◽  
Reproductive Capacity ◽  
Low Oxygen ◽  
Hypoxic Conditions ◽  
Porichthys Notatus ◽  
Sperm Swimming Speed ◽  
Plainfin Midshipman

Hypoxia (low oxygen) exposure generally leads to decreased reproductive capacity, exhibited by reductions in testicular mass, reproductive hormones, and sperm swimming speed. However, in many fish species, reproduction occurs either periodically or exclusively under hypoxic conditions. In this study we assessed how hypoxia influences sperm performance in the plainfin midshipman ( Porichthys notatus Girard, 1854), a species that lives in intertidal nests that become hypoxic during low tides. We exposed sperm from the same male to normoxic or hypoxic conditions and compared sperm characteristics and oxygen consumption between treatments. Sperm exposed to hypoxic water swam faster and consumed more oxygen than sperm swimming in normoxic conditions. Sperm swimming speed was positively related with oxygen consumption. For each male, the percentage of motile spermatozoa did not differ between treatments, suggesting that the same number of sperm were active but their performance was dependent on the dissolved oxygen content in the water. We discuss the implications of our results in the context of sperm competition and fertilization success under hypoxic conditions.

Reduced sperm performance in backcross hybrids between species pairs of whitefish (Coregonus clupeaformis)

2009 ◽  
Vol 87 (7) ◽  
pp. 566-572 ◽  
Author(s):  
A. R. Whiteley ◽  
K. N. Persaud ◽  
N. Derome ◽  
R. Montgomerie ◽  
L. Bernatchez
Keyword(s):  
Sperm Competition ◽  
Swimming Speed ◽  
Fertilization Success ◽  
F1 Hybrids ◽  
Coregonus Clupeaformis ◽  
External Fertilization ◽  
Isolating Mechanisms ◽  
Species Pairs ◽  
Backcross Hybrids ◽  
Sperm Swimming Speed

Previous work has demonstrated that genomic incompatibilities work together with ecologically divergent selection to promote and maintain reproductive isolation between incipient species (dwarf and normal) of lake whitefish ( Coregonus clupeaformis (Mitchill, 1818)). Whitefish spawn in groups with external fertilization, which creates conditions for strong sperm competition. In this study, we asked whether reduced sperm performance in hybrids from whitefish species-pair matings might contribute to postzygotic isolating mechanisms between these taxa. We examined two sperm traits, sperm swimming speed and flagellum length, in pure dwarf and normal whitefish and in their F1 and backcross hybrids. We observed significantly reduced sperm swimming speed in backcross but not in F1 hybrids. Sperm flagellum length was not significantly correlated with sperm swimming speed. These results demonstrate that F1 hybrids formed in nature should be capable of the same fertilization success as the parental species during sperm competition, everything else being equal. However, reduced sperm performance in the backcross generation is consistent with other evidence suggesting that genomic incompatibilities create a range of negative fitness effects in post-F1 whitefish hybrids and provides evidence for an additional postzygotic isolation mechanism involved in the incipient speciation of sympatric dwarf and normal whitefish.

Sperm quality influences male fertilization success in walleye (Sander vitreus)

2006 ◽  
Vol 63 (9) ◽  
pp. 2119-2125 ◽  
Author(s):  
Stephen J Casselman ◽  
Albrecht I Schulte-Hostedde ◽  
Robert Montgomerie
Keyword(s):  
Swimming Speed ◽  
Sperm Quality ◽  
Fertilization Success ◽  
Male Reproductive Success ◽  
Sander Vitreus ◽  
External Fertilization ◽  
Theoretical Predictions ◽  
Sperm Swimming Speed ◽  
Experimental Trials ◽  
Success Percentage

We examined how variation in sperm quality influences a male's success at fertilizing ova (male fertilization success) in a wild population of walleye (Sander vitreus). To do this, we conducted controlled fertilization trials using milt and eggs (ova) from wild-spawning fish and measured male fertilization success (percentage of ova fertilized) by examining eggs after 24 h of incubation. We found that both the number of sperm and sperm swimming speed (at 10 s after activation) were significantly related to fertilization success. There was, with respect to fertilization success, a relatively large return on male investment in the number of sperm, but this return diminished as the percentage of ova fertilized increased above 50%. This is in agreement with theoretical predictions based on external fertilization dynamics. When the number of sperm used in the experimental trials was kept constant, variation in sperm swimming speed (at 10 s after activation) explained approximately 90% of the variation in a male's fertilization success. These findings demonstrate that the variation in sperm quality found in wild spawning populations has the potential to dramatically influence male reproductive success.

scholarly journals Longer Sperm Swim More Slowly in the Canary Islands Chiffchaff

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1358
Author(s):  
Emily R. A. Cramer ◽  
Eduardo Garcia-del-Rey ◽  
Lars Erik Johannessen ◽  
Terje Laskemoen ◽  
Gunnhild Marthinsen ◽  
...  
Keyword(s):  
Canary Islands ◽  
Swimming Speed ◽  
Sperm Morphology ◽  
Swimming Performance ◽  
Fertilization Success ◽  
Sperm Length ◽  
Gran Canaria ◽  
Island Populations ◽  
Motile Cells ◽  
Sperm Swimming Speed

Sperm swimming performance affects male fertilization success, particularly in species with high sperm competition. Understanding how sperm morphology impacts swimming performance is therefore important. Sperm swimming speed is hypothesized to increase with total sperm length, relative flagellum length (with the flagellum generating forward thrust), and relative midpiece length (as the midpiece contains the mitochondria). We tested these hypotheses and tested for divergence in sperm traits in five island populations of Canary Islands chiffchaff (Phylloscopus canariensis). We confirmed incipient mitochondrial DNA differentiation between Gran Canaria and the other islands. Sperm swimming speed correlated negatively with total sperm length, did not correlate with relative flagellum length, and correlated negatively with relative midpiece length (for Gran Canaria only). The proportion of motile cells increased with relative flagellum length on Gran Canaria only. Sperm morphology was similar across islands. We thus add to a growing number of studies on passerine birds that do not support sperm morphology–swimming speed hypotheses. We suggest that the swimming mechanics of passerine sperm are sufficiently different from mammalian sperm that predictions from mammalian hydrodynamic models should no longer be applied for this taxon. While both sperm morphology and sperm swimming speed are likely under selection in passerines, the relationship between them requires further elucidation.

scholarly journals Connectivity Map Analysis Indicates PI3K/Akt/mTOR Inhibitors as Potential Anti-Hypoxia Drugs in Neuroblastoma

Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2809
Author(s):  
Paolo Uva ◽  
Maria Carla Bosco ◽  
Alessandra Eva ◽  
Massimo Conte ◽  
Alberto Garaventa ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Drug Repurposing ◽  
Enrichment Analysis ◽  
Mtor Inhibitors ◽  
Gene Set Enrichment Analysis ◽  
Low Oxygen ◽  
Connectivity Map ◽  
Hypoxic Conditions ◽  
Connectivity Score

Neuroblastoma (NB) is one of the deadliest pediatric cancers, accounting for 15% of deaths in childhood. Hypoxia is a condition of low oxygen tension occurring in solid tumors and has an unfavorable prognostic factor for NB. In the present study, we aimed to identify novel promising drugs for NB treatment. Connectivity Map (CMap), an online resource for drug repurposing, was used to identify connections between hypoxia-modulated genes in NB tumors and compounds. Two sets of 34 and 21 genes up- and down-regulated between hypoxic and normoxic primary NB tumors, respectively, were analyzed with CMap. The analysis reported a significant negative connectivity score across nine cell lines for 19 compounds mainly belonging to the class of PI3K/Akt/mTOR inhibitors. The gene expression profiles of NB cells cultured under hypoxic conditions and treated with the mTORC complex inhibitor PP242, referred to as the Mohlin dataset, was used to validate the CMap findings. A heat map representation of hypoxia-modulated genes in the Mohlin dataset and the gene set enrichment analysis (GSEA) showed an opposite regulation of these genes in the set of NB cells treated with the mTORC inhibitor PP242. In conclusion, our analysis identified inhibitors of the PI3K/Akt/mTOR signaling pathway as novel candidate compounds to treat NB patients with hypoxic tumors and a poor prognosis.

Oxygen consumption and blood gases ofOctopus vulgaris in hypoxic conditions

1982 ◽  
Vol 148 (1) ◽  
pp. 35-40 ◽  
Author(s):  
D. F. Houlihan ◽  
A. J. Innes ◽  
M. J. Wells ◽  
J. Wells
Keyword(s):  
Oxygen Consumption ◽  
Blood Gases ◽  
Hypoxic Conditions

Impact of Diet on Metabolism and Swimming Performance in Juvenile Lake Trout, Salvelinus namaycush

1989 ◽  
Vol 46 (3) ◽  
pp. 384-388 ◽  
Author(s):  
F. W. H. Beamish ◽  
J. C. Howlett ◽  
T. E. Medland
Keyword(s):  
Oxygen Consumption ◽  
Swimming Speed ◽  
Lake Trout ◽  
Swimming Performance ◽  
Salvelinus Namaycush ◽  
Feeding Trial ◽  
Direct Association ◽  
Feeding Trials ◽  
Velocity Increments ◽  
Isocaloric Diets

Juvenile lake trout, Salvelinus namaycush, of similar size were fed one of three isocaloric diets, each differing in protein and lipid content. Oxygen consumption and swimming performance were measured in a recirculating water flume at intervals throughout the 70-d feeding trials (10 °C). Swimming speed was increased by stepwise velocity increments (5 cm∙s−1) and oxygen consumption was measured at each velocity between 20 and 45 cm∙s−1. Oxygen consumption for a given speed did not differ significantly throughout the feeding trial nor among the diets implying a similarity in the quality and quantity of substrate catabolized for energy. Basal metabolism (0 cm∙s−1) was also independent of diet and feeding interval. Critical swimming speed increased with dietary and carcass protein content to suggest a direct association with muscle mass and number of myofilaments.

scholarly journals The Function of the Gills of Mayfly Nymphs from Different Habitats

1939 ◽  
Vol 16 (3) ◽  
pp. 363-373 ◽  
Author(s):  
C. A. WINGFIELD
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Content ◽  
The Body ◽  
Gaseous Exchange ◽  
Low Oxygen ◽  
Respiratory Mechanism ◽  
Tracheal Gills ◽  
Cloeon Dipterum ◽  
Gill Function ◽  
Oxygen Concentrations

1. The oxygen consumption of normal and gill-less nymphs of the mayflies Baetis sp., Cloeon dipterum and Ephemera vulgata has been measured at various oxygen concentrations. 2. It has been found that over the complete range of oxygen concentrations studied, the tracheal gills do not aid oxygen consumption in Baetis sp. In Cloeon dipterum, at all oxygen concentrations tested, no gaseous exchange takes place through the gills; at low oxygen concentrations, however, the gills function as an accessory respiratory mechanism in ventilating the respiratory surface of the body and so aid oxygen consumption. In Ephemera Vulgata the gills aid oxygen consumption even at high oxygen concentrations. In this species the gills may function both as true respiratory organs and as a ventilating mechanism. 3. It is shown that the differences in gill function can be related to the oxygen content of the habitat of each species.

scholarly journals Hypoxia-Induced Gene Expression Occurs Solely through the Action of Hypoxia-Inducible Factor 1α (HIF-1α): Role of Cytoplasmic Trapping of HIF-2α

2003 ◽  
Vol 23 (14) ◽  
pp. 4959-4971 ◽  
Author(s):  
Sang-ki Park ◽  
Agnes M. Dadak ◽  
Volker H. Haase ◽  
Lucrezia Fontana ◽  
Amato J. Giaccia ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Activity ◽  
Hypoxia Inducible Factor ◽  
Low Oxygen ◽  
Hypoxic Conditions ◽  
Show Evidence ◽  
Dependent Protein ◽  
A Cell ◽  
Cell Type Specific ◽  
Inducible Genes

ABSTRACT The hypoxia-inducible factors 1α (HIF-1α) and 2α (HIF-2α) have extensive structural homology and have been identified as key transcription factors responsible for gene expression in response to hypoxia. They play critical roles not only in normal development, but also in tumor progression. Here we report on the differential regulation of protein expression and transcriptional activity of HIF-1α and -2α by hypoxia in immortalized mouse embryo fibroblasts (MEFs). We show that oxygen-dependent protein degradation is restricted to HIF-1α, as HIF-2α protein is detected in MEFs regardless of oxygenation and is localized primarily to the cytoplasm. Endogenous HIF-2α remained transcriptionally inactive under hypoxic conditions; however, ectopically overexpressed HIF-2α translocated into the nucleus and could stimulate expression of hypoxia-inducible genes. We show that the factor inhibiting HIF-1 can selectively inhibit the transcriptional activity of HIF-1α but has no effect on HIF-2α-mediated transcription in MEFs. We propose that HIF-2α is not a redundant transcription factor of HIF-1α for hypoxia-induced gene expression and show evidence that there is a cell type-specific modulator(s) that enables selective activation of HIF-1α but not HIF-2α in response to low-oxygen stress.

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