scholarly journals Genetically enhanced growth causes increased mortality in hypoxic environments

2007 ◽  
Vol 3 (2) ◽  
pp. 165-168 ◽  
Author(s):  
L Sundt-Hansen ◽  
L.F Sundström ◽  
S Einum ◽  
K Hindar ◽  
I.A Fleming ◽  
...  
Keyword(s):  
Larval Stage ◽  
Rapid Growth ◽  
Coho Salmon ◽  
Survival Rates ◽  
Limiting Factor ◽  
Low Oxygen ◽  
Wide Range ◽  
Survival And Development ◽  
Survival And Growth ◽  
Low Levels

Rapid growth and development are associated with several fitness-related benefits. Yet, organisms usually grow more slowly than their physiological maximum, suggesting that rapid growth may carry costs. Here we use coho salmon ( Oncorhynchus kisutch ) eggs of wild and transgenic genotypes to test whether rapid growth causes reduced tolerance to low levels of oxygen (hypoxia). Eggs were exposed to four different durations of hypoxia, and survival and growth were recorded until the end of the larval stage. Survival rates decreased with increasing duration of hypoxia, but this decrease was most pronounced for the transgenic group. Larval mass was also negatively affected by hypoxia; however, transgenic genotypes were significantly larger than wild genotypes at the end of the larval stage. Oxygen can be a limiting factor for survival and development in a wide range of organisms, particularly during the egg stage. Thus, the reduced ability of fast-growing genotypes to cope with low oxygen levels identified in the present study may represent a general constraint on evolution of rapid growth across taxa.

Potential Usefulness of Chlorine for Controlling Pacific Salmon Leeches, Piscicola salmositica, in Hatcheries

1985 ◽  
Vol 42 (12) ◽  
pp. 1986-1993 ◽  
Author(s):  
S. M. Bower ◽  
L. Margolis ◽  
R. J. MacKay
Keyword(s):  
Logistic Regression Model ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Juvenile Fish ◽  
Gill Tissue ◽  
Residual Chlorine ◽  
Lethal Effects ◽  
Small Juvenile ◽  
Wide Range ◽  
Low Levels

Susceptibility to the lethal effects of low levels of total residual chlorine (TRC) differed between juvenile coho salmon (Oncorhynchus kisutch) and the salmon leech (Piscicola salmositica), the vector for the haemoflagellate salmonid pathogen Cryptobia salmositica. There was no salmon mortality at concentrations below approximately 50 μg TRC/L for the maximum exposure time of 24 h. Some damage to gill tissue (hypertrophy, fusion, oedema, and some necrosis), was observed at the highest concentrations of TRC that did not kill any of the fish (approximately 50 μg/L for 24 h, and approximately 100 μg/L for 8 h). This damage was repaired by the fish within 4 d of exposure, although evidence of past irritation was noted in 6 of 12 fish. All small juvenile leeches exposed to 44 μg TRC/L for 24 h died, and over half of such leeches exposed to 44 μg/L for 8 h and 21 μg/L for 24 h died. Below TRC concentrations that were lethal to the fish (approximately 50 μg/L), contours of constant leech mortality derived from a logistic regression model fitted to the data offered a wide range of concentrations and exposure times that would result in high mortality of juvenile leeches. Larger subadult and adult leeches were more resistant to chlorine than the smaller leeches but were more sensitive than the juvenile fish. Thus, chlorine may prove useful for controlling P. salmositica in salmonid hatcheries.

Oxygen Supply and Limits on Aggregation of Embryos

1995 ◽  
Vol 75 (2) ◽  
pp. 413-428 ◽  
Author(s):  
Richard R. Strathmann ◽  
Megumi F. Strathmann
Keyword(s):  
Oxygen Supply ◽  
Sea Urchins ◽  
Central Position ◽  
Limiting Factor ◽  
Low Oxygen ◽  
Egg Masses ◽  
Development Rates ◽  
Wide Range ◽  
The Masses ◽  
Oxygen Concentrations

Effects of oxygen supply on development rates of embryos in gelatinous masses were tested with natural masses of three species of opisthobranch gastropods and artificial masses made with embryos of a sea urchin and agarose gel. When diffusive exchange was restricted for embryos in such masses, increased oxygen alone was sufficient to maintain development rates of embryos. Diffusive supply of oxygen is therefore a limiting factor for embryos clustered in gelatinous masses. Development rates were constant over a wide range of experimentally altered oxygen concentrations but retarded with oxygen below about 10% of air saturation. Some opisthobranch embryos exposed to low oxygen concentrations hatched with shorter shells. Delayed hatching and shorter shells at hatching were both associated with a central position in the globose gelatinous mass of one of the opisthobranch species, even in air-saturated and vigorously stirred water. The pH near the centres of the masses was lower when embryos were at more advanced stages; thus the intracapsular stirring caused by cilia of embryos at later stages does not compensate for their greater metabolic rates. The pH in some egg masses was about seven or lower, and this pH affected development in separate experiments. The masses approach limits for removal of wastes, although oxygen becomes limiting for rates of development before accumulation of wastes becomes limiting. Embryos of opisthobranchs that are normally aggregated and embryos of sea urchins that are normally dispersed were similarly tolerant of low oxygen concentrations and low pH. In respect to tolerance of hypoxia and accumulating wastes, embryos in many clades are preadapted for aggregation into masses, but there are limits on the size of the aggregation. Egg masses are commonly at those limits.

Evolution of mammalian hemoglobin function

Blood ◽  
1981 ◽  
Vol 58 (2) ◽  
pp. 189-197 ◽  
Author(s):  
HF Bunn
Keyword(s):  
Oxygen Affinity ◽  
Red Cells ◽  
Red Cell ◽  
Low Oxygen ◽  
Wide Range ◽  
Blood Oxygen Affinity ◽  
Low Levels ◽  
Major Factors ◽  
2,3 Dpg ◽  
Low Oxygen Affinity

Throughout their evolution, mammalian hemoglobins have acquired a broad repertoire of functional properties well suited to the internal milieu of the red cell. Mammals display a wide range in whole blood oxygen affinity dependent on three major factors: the intrinsic oxygen affinity of the hemoglobin, the level of red cell 2,3-DPG, and the response of the hemoglobin to 2,3-DPG. The concentration of 2,3-DPG varies among groups of mammals. Those animals (cats and ruminants) that have very low levels of this intracellular mediator have hemoglobins of intrinsically low oxygen affinity that fail to respond to the addition of 2,3-DPG. Mammals that have adapted to various types of hypoxia tend to have increased oxygen affinity, primarily mediated through reduced levels of red cell 2,3-DPG. In contrast, mammals who are experimentally subjected to low oxygen tensions develop decreased oxygen affinity owing to increased red cell 2,3-DPG. Mammals employ one of three different mechanisms for the maintenance of higher oxygen affinity of fetal red cells, compared to maternal red cells. Many of these phenomena can be satisfactorily explained at the molecular level but their adaptational significance is less clear.

scholarly journals Evolution of mammalian hemoglobin function

Blood ◽  
1981 ◽  
Vol 58 (2) ◽  
pp. 189-197 ◽  
Author(s):  
HF Bunn
Keyword(s):  
Oxygen Affinity ◽  
Red Cells ◽  
Red Cell ◽  
Low Oxygen ◽  
Wide Range ◽  
Blood Oxygen Affinity ◽  
Low Levels ◽  
Major Factors ◽  
2,3 Dpg ◽  
Low Oxygen Affinity

Abstract Throughout their evolution, mammalian hemoglobins have acquired a broad repertoire of functional properties well suited to the internal milieu of the red cell. Mammals display a wide range in whole blood oxygen affinity dependent on three major factors: the intrinsic oxygen affinity of the hemoglobin, the level of red cell 2,3-DPG, and the response of the hemoglobin to 2,3-DPG. The concentration of 2,3-DPG varies among groups of mammals. Those animals (cats and ruminants) that have very low levels of this intracellular mediator have hemoglobins of intrinsically low oxygen affinity that fail to respond to the addition of 2,3-DPG. Mammals that have adapted to various types of hypoxia tend to have increased oxygen affinity, primarily mediated through reduced levels of red cell 2,3-DPG. In contrast, mammals who are experimentally subjected to low oxygen tensions develop decreased oxygen affinity owing to increased red cell 2,3-DPG. Mammals employ one of three different mechanisms for the maintenance of higher oxygen affinity of fetal red cells, compared to maternal red cells. Many of these phenomena can be satisfactorily explained at the molecular level but their adaptational significance is less clear.

A review of the composition and evolution of hydrocarbon gases during solidification of the Ilímaussaq alkaline complex, South Greenland

2001 ◽  
pp. 159-166 ◽  
Author(s):  
Jens Konnerup-Madsen
Keyword(s):  
Nepheline Syenite ◽  
Subsequent Development ◽  
High Water ◽  
Vapour Phase ◽  
Low Carbon ◽  
Low Oxygen ◽  
Alkaline Complex ◽  
Hydrocarbon Gases ◽  
Wide Range ◽  
Water Contents

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Konnerup-Madsen, J. (2001). A review of the composition and evolution of hydrocarbon gases during solidification of the Ilímaussaq alkaline complex, South Greenland. Geology of Greenland Survey Bulletin, 190, 159-166. https://doi.org/10.34194/ggub.v190.5187 _______________ Fluid inclusions in minerals from agpaitic nepheline syenites and hydrothermal veins in the Ilímaussaq complex and in similar agpaitic complexes on the Kola Peninsula, Russia, are dominated by hydrocarbon gases (predominantly methane) and hydrogen. Such volatile compositions differ considerably from those of most other igneous rocks and their formation and entrapment in minerals reflects low oxygen fugacities and a wide range of crystallisation temperatures extending to a low-temperature solidus. Their composition reflects initial low carbon contents and high water contents of the magma resulting in the exsolution of a waterrich CO2–H2O dominated vapour phase. Fractionation of chlorides into the vapour phase results in high salinities and the subsequent development of a heterogeneous vapour phase with a highly saline aqueous-rich fraction and a methane-dominated fraction, with preferential entrapment of the latter, possibly due to different wetting characteristics. The light stable isotope compositions support an abiogenic origin for the hydrocarbons in agpaitic nepheline syenite complexes.

scholarly journals Ways into Understanding HIF Inhibition

Cancers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 159
Author(s):  
Tina Schönberger ◽  
Joachim Fandrey ◽  
Katrin Prost-Fingerle
Keyword(s):  
Protein Interactions ◽  
Target Genes ◽  
Protein Protein Interactions ◽  
Low Oxygen ◽  
Drug Candidates ◽  
Open Questions ◽  
Wide Range ◽  
Hif Pathway

Hypoxia is a key characteristic of tumor tissue. Cancer cells adapt to low oxygen by activating hypoxia-inducible factors (HIFs), ensuring their survival and continued growth despite this hostile environment. Therefore, the inhibition of HIFs and their target genes is a promising and emerging field of cancer research. Several drug candidates target protein–protein interactions or transcription mechanisms of the HIF pathway in order to interfere with activation of this pathway, which is deregulated in a wide range of solid and liquid cancers. Although some inhibitors are already in clinical trials, open questions remain with respect to their modes of action. New imaging technologies using luminescent and fluorescent methods or nanobodies to complement widely used approaches such as chromatin immunoprecipitation may help to answer some of these questions. In this review, we aim to summarize current inhibitor classes targeting the HIF pathway and to provide an overview of in vitro and in vivo techniques that could improve the understanding of inhibitor mechanisms. Unravelling the distinct principles regarding how inhibitors work is an indispensable step for efficient clinical applications and safety of anticancer compounds.

Effects of Air Temperature on Combustion Characteristics of LPG Diffusion Flame

2020 ◽  
Vol 1008 ◽  
pp. 128-138
Author(s):  
Ahmed M. Salman ◽  
Ibrahim A. Ibrahim ◽  
Hamada M. Gad ◽  
Tharwat M. Farag
Keyword(s):  
Air Temperature ◽  
Diffusion Flame ◽  
Nitrogen Addition ◽  
Flame Length ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Low Oxygen ◽  
Air Temperatures ◽  
Air Stream ◽  
Wide Range

In the present study, the combustion characteristics of LPG gaseous fuel diffusion flame at elevated air temperatures were experimentally investigated. An experimental test rig was manufactured to examine a wide range of operating conditions. The investigated parameters are the air temperatures of 300, 350, 400, 450, and 500 K with constant percentage of nitrogen addition in combustion air stream of 5 % to give low oxygen concentration of 18.3 % by mass at constant air swirl number, air to fuel mass ratio, and thermal load of 1.5, 30, and 23 kW, respectively. The gaseous combustion characteristics were represented as axial and radial temperatures distributions, temperatures gradient, visible flame length and species concentrations. The results indicated that as the air temperature increased, the chemical reaction rate increased and flame volume decreased, the combustion time reduced leading to a reduction in flame length. The NO concentration reaches its maximum values near the location of the maximum centerline axial temperature. Increasing the combustion air temperature by 200 K, the NO consequently O2 concentrations are increased by about % 355 and 20 % respectively, while CO2 and CO concentrations are decreased by about % 21 and 99 % respectively, at the combustor end.

scholarly journals Acceptance threshold theory can explain occurrence of homosexual behaviour

2015 ◽  
Vol 11 (1) ◽  
pp. 20140603 ◽  
Author(s):  
Katharina C. Engel ◽  
Lisa Männer ◽  
Manfred Ayasse ◽  
Sandra Steiger
Keyword(s):  
Animal Species ◽  
Reproductive Potential ◽  
Search Time ◽  
Same Sex ◽  
Burying Beetles ◽  
Acceptance Threshold ◽  
Threshold Theory ◽  
Wide Range ◽  
Low Levels ◽  
Perceived Costs

Same-sex sexual behaviour (SSB) has been documented in a wide range of animals, but its evolutionary causes are not well understood. Here, we investigated SSB in the light of Reeve's acceptance threshold theory. When recognition is not error-proof, the acceptance threshold used by males to recognize potential mating partners should be flexibly adjusted to maximize the fitness pay-off between the costs of erroneously accepting males and the benefits of accepting females. By manipulating male burying beetles' search time for females and their reproductive potential, we influenced their perceived costs of making an acceptance or rejection error. As predicted, when the costs of rejecting females increased, males exhibited more permissive discrimination decisions and showed high levels of SSB; when the costs of accepting males increased, males were more restrictive and showed low levels of SSB. Our results support the idea that in animal species, in which the recognition cues of females and males overlap to a certain degree, SSB is a consequence of an adaptive discrimination strategy to avoid the costs of making rejection errors.

STATE AND PROSPECTS OF PROCESSING OF SECONDARY RAW MATERIALS OF WINE-MAKING IN UKRAINE

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
L. Osipova ◽  
O. Radionova ◽  
L. Tkachenko ◽  
T. Abramova
Keyword(s):  
Agricultural Land ◽  
Animal Feed ◽  
Raw Materials ◽  
Acid Soil ◽  
Biologically Active ◽  
Limiting Factor ◽  
Wine Making ◽  
Secondary Raw Materials ◽  
Use Of Resources ◽  
Wide Range

The analysis of the current state of processing of secondary raw materials of wine-making in Ukraine is given. It is proved that the latter is a rich source of biologically active compounds, including phenolic ones, which makes it possible to use it for the production of a wide range of products (raccoon, polyphenol extracts, tartaric acid, beverages, fertilizers, grape oil, cake, vitamin D, animal feed, food powder, abrasives) with high consumer value for various industries: food, pharmaceutical, perfume and cosmetics, chemical, feed, etc. In the light of modern research, the role of phenolic compounds as essential nutrition factors that cannot remain out of the field of view of physiologists, pharmacologists, and food hygiene specialists is shown. However, currently in Ukraine there are no specialized enterprises for complex processing of secondary raw materials of winemaking; traditional technologies are not effective from a technological, economic and environmental point of view, which indicates not rational use of resources and loss of material resources; there are no systematic studies on physical and chemical, microbiological, Toxicological composition in order to determine the optimal direction of its use. A limiting factor is also the lack of comparative analysis of innovative domestic and foreign technologies for processing secondary raw materials of winemaking. In the vast majority of cases, in particular, combs and pomace are taken out of control to agricultural land without special treatment, which leads to acid soil erosion and pollution of the environment with metabolites of micromycetes, increasing one of the global problems of mankind-environmental. At the present stage of technological development, there are a number of innovative developments in the field of processing secondary raw materials, in particular grape pomace, in order to obtain biologically active additives, the limiting factor for the introduction of which is the lack of domestic and expensive imported equipment. A promising way to solve the existing problems is to create a mechanism that will unite the interests of wineries (producers of secondary raw materials of winemaking), processing enterprises (producers of products from secondary raw materials of winemaking), scientists and potential consumers of innovative products. Consolidation of the above-mentioned institutions and enterprises is possible by creating clusters for the development and implementation of innovative technologies and equipment

Evaporite Palynology: a case study on the Permian (Lopgingian) Zechstein Sea

2021 ◽  
pp. jgs2020-174
Author(s):  
Martha E. Gibson ◽  
David J. Bodman
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Rapid Growth ◽  
Western Europe ◽  
Thermal Maturity ◽  
Near Surface ◽  
Wide Range ◽  
Terrestrial Environments ◽  
Insight Into

Evaporites characterize the Lopingian of Europe but present obstacles for biostratigraphic analysis. Here we present a case study for processing the Lopingian Zechstein Group evaporites of central-western Europe for the recovery of palynomorph assemblages. We demonstrate that full recovery is easily achieved with two main modes of palynomorph preservation observed; palynomorphs are either exceptionally well-preserved and orange-brown in colour, or poorly-preserved, brown-black, opaque and fragmented. The latter are reminiscent of palynomorphs of high thermal maturity. However, we propose that the intact nature of preservation is a result of the rapid growth of near-surface halite crystals, with their darkening a consequence of locally-enhanced heat flux due to the relatively high thermal conductivity of salt. This case study has enabled novel insight into an otherwise undescribed environment, and demonstrates the utility and possibility of extracting palynomorphs from a variety of rock salt types. This method should be applicable to a wide range of ancient evaporite and could also be applied to other Permian evaporite systems, which are used as analogues for extra-terrestrial environments.

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