Embryos of eastern rainbowfish Melanotaenia splendida splendida (Peters, 1866) tolerate fluctuating hypoxia

2018 ◽  
Vol 69 (6) ◽  
pp. 987
Author(s):  
N. Flint ◽  
R. G. Pearson ◽  
M. R. Crossland
Keyword(s):  
Plant Material ◽  
Sublethal Effects ◽  
Larval Mortality ◽  
Natural Habitat ◽  
Hypoxia Tolerance ◽  
Hypoxic Exposure ◽  
Submerged Plant ◽  
Embryo Viability ◽  
Life History Stages ◽  
Egg Incubation

Hypoxia can have profound sublethal effects on reproduction and embryonic development of some freshwater fish. In the present study, the effects of diel fluctuating hypoxia on embryo viability were investigated for the eastern rainbowfish Melanotaenia splendida splendida, a small-bodied species common in wetlands of tropical Queensland. After daily hypoxic exposure (minimum 5% saturation) from fertilisation until hatch, no effects were found on egg incubation time, egg and larval mortality, and viability and size of hatching larvae. Older life history stages of the species are vulnerable to this level of hypoxia. Embryos of phytolithophilic species are likely exposed to fluctuating dissolved oxygen saturations in their natural habitat, and hypoxia tolerance may be a requirement for fish species that spawn predominantly on submerged plant material.

The evolutionary and physiological significance of the Hif pathway in teleost fishes

2021 ◽  
Vol 224 (18) ◽  
Author(s):  
Milica Mandic ◽  
William Joyce ◽  
Steve F. Perry
Keyword(s):  
Hypoxia Inducible Factor ◽  
Duplication Event ◽  
Hypoxia Tolerance ◽  
Evolutionary Significance ◽  
Hypoxic Exposure ◽  
Cardiorespiratory System ◽  
Genome Duplication Event ◽  
Hypoxic Response ◽  
Hif Pathway ◽  
The Impact

ABSTRACT The hypoxia-inducible factor (HIF) pathway is a key regulator of cellular O2 homeostasis and an important orchestrator of the physiological responses to hypoxia (low O2) in vertebrates. Fish can be exposed to significant and frequent changes in environmental O2, and increases in Hif-α (the hypoxia-sensitive subunit of the transcription factor Hif) have been documented in a number of species as a result of a decrease in O2. Here, we discuss the impact of the Hif pathway on the hypoxic response and the contribution to hypoxia tolerance, particularly in fishes of the cyprinid lineage, which includes the zebrafish (Danio rerio). The cyprinids are of specific interest because, unlike in most other fishes, duplicated paralogs of the Hif-α isoforms arising from a teleost-specific genome duplication event have been retained. Positive selection has acted on the duplicated paralogs of the Hif-α isoforms in some cyprinid sub-families, pointing to adaptive evolutionary change in the paralogs. Thus, cyprinids are valuable models for exploring the evolutionary significance and physiological impact of the Hif pathway on the hypoxic response. Knockout in zebrafish of either paralog of Hif-1α greatly reduces hypoxia tolerance, indicating the importance of both paralogs to the hypoxic response. Here, with an emphasis on the cardiorespiratory system, we focus on the role of Hif-1α in the hypoxic ventilatory response and the regulation of cardiac function. We explore the effects of the duration of the hypoxic exposure (acute, sustained or intermittent) on the impact of Hif-1α on cardiorespiratory function and compare relevant data with those from mammalian systems.

scholarly journals Sublethal Effects of Crude Oil and Chemical Dispersants on Multiple Life History Stages of the Eastern Oyster, Crassostrea virginica

2020 ◽  
Vol 8 (10) ◽  
pp. 808
Author(s):  
Sara M. Garcia ◽  
Kevin T. Du Clos ◽  
Olivia H. Hawkins ◽  
Brad J. Gemmell
Keyword(s):  
Life History ◽  
Crude Oil ◽  
Crassostrea Virginica ◽  
Sublethal Effects ◽  
Oil Pollution ◽  
Eastern Oyster ◽  
Clearance Rates ◽  
Important Species ◽  
Life History Stages ◽  
Oil Exposure

The eastern oyster Crassostrea virginica is an ecologically and economically important species that is vulnerable to oil pollution. We assessed sublethal effects of soluble fractions of crude oil alone (WAF) and crude oil in combination with Corexit 9500 dispersant (CEWAF) on oysters at three life history stages. Veliger swimming, pediveliger settlement, and adult clearance rates were quantified after 24 h exposures to the contaminants. Veliger swimming speeds were not significantly impacted by 24 h exposures to WAF or CEWAF. A larger proportion of veligers were inactive following WAF and CEWAF exposure as compared to the control, but the effect was greater for pediveligers, and pediveliger settlement in the highest concentration CEWAF treatment decreased by 50% compared to controls. Thus, pediveligers may be particularly vulnerable to oil exposure. In the adults, we found significant clearance rates reductions that persisted 33 days after acute exposure to CEWAF. Knowledge of sublethal effects of oil and dispersant at multiple life history stages aids understanding of how this important species will respond to an oil spill.

scholarly journals Diet of bat-eared foxes Otocyon megalotis in the Karoo

Koedoe ◽  
1992 ◽  
Vol 35 (2) ◽  
Author(s):  
V. Kuntzsch ◽  
J.A.J. Nel
Keyword(s):  
Food Availability ◽  
Plant Material ◽  
National Park ◽  
Natural Habitat ◽  
Wild Fruit ◽  
Sheep Farm ◽  
Farming Area

The diet of bat-eared foxes Otocyon megalotis was studied from March 1988 to September 1989 at two sites near Beaufort West in the central Karoo. In a near-natural habitat (Karoo National Park), insects and wild fruit contributed almost equally to the diet, while more insects than plant material were consumed on a sheep farm (Saucyskuil). Adult and larval Coleoptera (KNP) and Orthoptera (Saucyskuil) were predominantly preyed upon in an opportunistic manner, influenced by food availability. A higher volume of Isoptera was consumed at Saucyskuil, suggesting higher availability in the farming area.

Minteriella cenotigena anam. gen. & sp. nov. from submerged plant material in Mexico

2012 ◽  
Vol 12 (2) ◽  
pp. 271-275 ◽  
Author(s):  
Gabriela Heredia ◽  
Rafael F. Castañeda Ruiz ◽  
Rosa M. Arias ◽  
Marcela Gamboa-Angulo ◽  
Susana C. De La Rosa
Keyword(s):  
Plant Material ◽  
Submerged Plant

scholarly journals Differences in Tolerance to Hypoxia: Physiological, Biochemical, and Molecular-Biological Characteristics

Biomedicines ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 428
Author(s):  
Dzhuliia Dzhalilova ◽  
Olga Makarova
Keyword(s):  
Oxygen Deficiency ◽  
Hypoxia Inducible Factor ◽  
Hypoxia Tolerance ◽  
Alternative Methods ◽  
Detection Methods ◽  
Hypoxic Exposure ◽  
Tumor Diseases ◽  
Direct Exposure ◽  
The Moment ◽  
Potential Biomarkers

Hypoxia plays an important role in the development of many infectious, inflammatory, and tumor diseases. The predisposition to such disorders is mostly provided by differences in basic tolerance to oxygen deficiency, which we discuss in this review. Except the direct exposure of different-severity hypoxia in decompression chambers or in highland conditions, there are no alternative methods for determining organism tolerance. Due to the variability of the detection methods, differences in many parameters between tolerant and susceptible organisms are still not well-characterized, but some of them can serve as biomarkers of susceptibility to hypoxia. At the moment, several potential biomarkers in conditions after hypoxic exposure have been identified both in experimental animals and humans. The main potential biomarkers are Hypoxia-Inducible Factor (HIF)-1, Heat-Shock Protein 70 (HSP70), and NO. Due to the different mechanisms of various high-altitude diseases, biomarkers may not be highly specific and universal. Therefore, it is extremely important to conduct research on hypoxia susceptibility biomarkers. Moreover, it is important to develop a method for the evaluation of organisms’ basic hypoxia tolerance without the necessity of any oxygen deficiency exposure. This can contribute to new personalized medicine approaches’ development for diagnostics and the treatment of inflammatory and tumor diseases, taking into account hypoxia tolerance differences.

New species of the aeroaquatic hyphomycete genus Clathrosporium and their relationship with Strumella Sacc.

1998 ◽  
Vol 76 (9) ◽  
pp. 1596-1607 ◽  
Author(s):  
Grégoire Laurent Hennebert
Keyword(s):  
New Species ◽  
Plant Material ◽  
Type Species ◽  
Submerged Plant ◽  
Rotten Wood ◽  
Two New Species

Clathrosporium Nawawi & Kuthubutheen is found to be synonymous with Strumella Sacc. (lectotypified by Strumella olivatra (Sacc.) Sacc.), a later illegitimate homonym of Strumella Fr. Consequently, Strumella olivatra is redisposed in Clathrosporium, alongside the type species Clathrosporium intricatum Nawawi & Kuthubutheen. Two new species, Clathrosporium delicatum Hennebert sp.nov. and Clathrosporium compactum Hennebert n.sp., are described and illustrated. These hyphomycetes are aeroaquatic, growing on periodically submerged plant material, leaves, and rotten wood. They produce pigmented, multicellular propagules comprising coiled, branching hyphae that disarticulate into arthroconidia when mature.Key words: aeroaquatic, hyphomycete, Clathrosporium olivatra, Clathrosporium vinosa, Clathrosporium delicatula, Clathrosporium compacta, Strumella, Spirosphaera, taxonomy.

scholarly journals Behavioural responses of naked mole rats to acute hypoxia and anoxia

2017 ◽  
Vol 13 (12) ◽  
pp. 20170545 ◽  
Author(s):  
Aaron N. Ilacqua ◽  
Alexia M. Kirby ◽  
Matthew E. Pamenter
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Acute Hypoxia ◽  
Natural Habitat ◽  
Hypoxia Tolerance ◽  
Moderate Hypoxia ◽  
Behavioural Responses ◽  
Behavioural Activity ◽  
Acute Anoxia ◽  
Hypoxic Environment

Naked mole rats (NMRs) are among the most hypoxia-tolerant mammals. Other species respond to hypoxia by either escaping the hypoxic environment or drastically decreasing behavioural activity and body temperature ( T b ) to conserve energy. However, NMRs rarely leave their underground burrows, which are putatively hypoxic and thermally stable near the NMRs' preferred T b . Therefore, we asked whether NMRs are able to employ behavioural and thermoregulatory strategies in response to hypoxia despite their need to remain active and the minimal thermal scope in their burrows. We exposed NMRs to progressively deeper levels of hypoxia (from 21 to 0% O 2 ) while measuring their behaviour and T b . Behavioural activity decreased 40–60% in hypoxia and T b decreased slightly in moderate hypoxia (5–9%) and then further with deeper hypoxia (3% O 2 ). However, even at 3% O 2 NMRs remained somewhat active and warm, and continued to explore their environment. Remarkably, NMRs were active for greater than 90 s in acute anoxia and T b and metabolic rate decreased rapidly. We conclude that NMRs are adapted to remain awake and functional even at the extremes of their hypoxia-tolerance. This adaptation likely reflects variable and challenging levels of environmental hypoxia in the natural habitat of this species.

Reproduction and embryo viability of a range-limited tropical freshwater fish exposed to fluctuating hypoxia

2018 ◽  
Vol 69 (2) ◽  
pp. 267 ◽  
Author(s):  
Nicole Flint ◽  
Richard G. Pearson ◽  
Michael R. Crossland
Keyword(s):  
Freshwater Fish ◽  
Larval Mortality ◽  
Oxygen Depletion ◽  
Embryo Viability ◽  
Lowland Streams ◽  
Parental Exposure ◽  
Lethal Level ◽  
Tropical Australia ◽  
Increasing Temperature ◽  
Tropical Freshwater

Hypoxia can profoundly affect fish reproduction and larval development, but its effects on fish from tropical Australia are not well understood. In the present study, the effects of diel fluctuating hypoxia on reproduction and embryo viability were investigated for a range-limited tropical freshwater fish, namely the Utchee Creek rainbowfish (Melanotaenia utcheensis). The lethal level for adult rainbowfish after gradual oxygen depletion was ~7% dissolved oxygen (DO) saturation. After 28 days, the reproductive success of adult fish exposed to fluctuating hypoxia treatments was measured by fecundity, gonad health, egg incubation time, egg and larval mortality, viability and size of hatching larvae. Reproduction was impaired in the lowest sublethal treatment (minimum 10% DO saturation each day). No ill effects of parental exposure to diel fluctuating hypoxia on embryos were identified, and minor differences in temperature between aquaria had a greater effect on embryos than parental hypoxia treatments. Similarly, no effects of embryonic exposure to diel fluctuating hypoxia were identified. Utchee Creek rainbowfish appear to be more hypoxia tolerant than temperate species, in keeping with their habitat in warm lowland streams, but they are still susceptible to the increasing frequency and intensity of hypoxia possible with increasing temperature and reduced flow as a result of climate change.

scholarly journals Impact of Environmental Conditions on Growth and the Phenolic Profile of Achillea atrata L.

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 853
Author(s):  
Lysanne Salomon ◽  
Peter Lorenz ◽  
Bernhard Ehrmann ◽  
Otmar Spring ◽  
Florian C. Stintzing ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Environmental Conditions ◽  
Plant Material ◽  
Acne Vulgaris ◽  
Natural Habitat ◽  
Wild Plants ◽  
Phenolic Profile ◽  
Phenolic Constituents ◽  
A Minor ◽  
Pharmaceutical Production

Achillea atrata L. is a traditionally used medicinal plant. With its pronounced antimicrobial potential, this alpine Achillea species may also be used in modern phytotherapy to treat MRSA infections and prevent dermal infections, such as acne vulgaris. For the present study, A. atrata was cultivated in its natural habitat in Switzerland as well as in Germany to elucidate the potential of standardizing plant material derived from this species for pharmaceutical production. Phytochemical characterization of phenolic constituents by HPLC-DAD-MSn revealed that environmental conditions have only a minor impact on the phenolic profile. Metabolic differences between cultivated and wild plants grown in the same environment suggested the possible existence of genetically derived chemotypes. In total, 28 substances were identified, with marked differences in the occurrence of phenolic compounds observed between flowers and leaves. Moreover, to the best of our knowledge, 7 phenolic compounds have been reported for the first time in A. atrata in the present study. The quantitation of individual constituents revealed their contents to depend on environmental factors and to reach their maximum at increasing altitudes. The results here presented may help to select and cultivate A. atrata plant material with defined and constant compound profiles, which is of particular importance for potential pharmaceutical use.

scholarly journals Different patterns of chronic hypoxia lead to hierarchical adaptative mechanisms in goldfish metabolism

2021 ◽  
Author(s):  
Elisa Thoral ◽  
Elie Farhat ◽  
Damien Roussel ◽  
Hang Cheng ◽  
Ludovic Guillard ◽  
...  
Keyword(s):  
Intermittent Hypoxia ◽  
Citrate Synthase ◽  
Swimming Performance ◽  
Natural Habitat ◽  
Anaerobic Capacity ◽  
Hypoxic Exposure ◽  
Muscle Fibres ◽  
Cost Of Transport ◽  
Physiological Adaptations ◽  
Metabolic Suppression

Some hypoxia-tolerant species, such as goldfish, experience intermittent and severe hypoxia in their natural habitat causing them to develop multiple physiological adaptations. However, in fish, the metabolic impact of regular hypoxic exposure on swimming performance in normoxia is less well understood. Therefore, we experimentally tested whether chronic exposure to constant (30 days at 10% air saturation) or intermittent hypoxia (3hrs in normoxia and 21hrs in hypoxia, 5 days a week) would result in similar metabolic and swimming performance benefits after reoxygenation. Moreover, half of the normoxic and intermittent hypoxic fish were put on a 20-day normoxic training regime. After these treatments, metabolic rate (standard and maximum metabolic rates: SMR and MMR) and swimming performance (critical swimming speed [Ucrit] and cost of transport [COT]) were assessed. In addition, enzyme activities (citrate synthase CS, cytochrome c oxidase COX and lactate dehydrogenase LDH) and mitochondrial respiration were examined in red muscle fibres. We found that acclimation to constant hypoxia resulted in (1) metabolic suppression (-45% SMR, and -27% MMR), (2) increased anaerobic capacity (+117% LDH), (3) improved swimming performance (+80% Ucrit, -71% COT) and (4) no changes at the mitochondrial level. Conversely, the enhancement of swimming performance was reduced following acclimation to intermittent hypoxia (+45% Ucrit, -41% COT), with a 55% decrease in aerobic scope, despite a significant increase in oxidative metabolism (+201% COX, +49% CS). This study demonstrates that constant hypoxia leads to the greatest benefit in swimming performance and that mitochondrial metabolic adjustments only provide minor help in coping with hypoxia.

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