The occurrence and distribution of hexabromocyclododecanes in freshwater systems, focusing on tissue-specific bioaccumulation in crucian carp

Mechanisms of anoxia tolerance were investigated in crucian carp. Rates of protein synthesis were calculated in selected tissues of normoxic and anoxic animals. Exposure to 48 h of anoxia resulted in a significant reduction in protein synthesis in the liver (> 95%), heart (53%), and red and white muscle (52 and 56%, respectively), whereas brain protein synthesis rates were unaffected. Seven days of anoxia produced similar results. After 24 h of recovery from a 48-h anoxic period, protein synthesis rates had virtually returned to normoxic values. The effect of anoxia on the amount of RNA (relative to protein) varied depending on the tissue and also the length of exposure (except in the brain, where it was consistently reduced). However, the effect on RNA translational efficiency was purely tissue specific (i.e., independent of exposure time) and was unaffected in the heart, reduced in the liver and red and white muscle, and increased in the brain. Downregulation of protein synthesis on a tissue-specific basis appears to be a significant mechanism for energy conservation as well as maintaining neural function, thus promoting survival during anoxia.

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Microplastic pollution characteristic in surface water and freshwater fish of Gehu Lake, China

10.21203/rs.3.rs-220128/v1 ◽

2021 ◽

Author(s):

Xia Xu ◽

Ling Zhang ◽

Yingang Xue ◽

Yu Gao ◽

Liping Wang ◽

...

Keyword(s):

Surface Water ◽

Freshwater Fish ◽

Crucian Carp ◽

Taihu Lake ◽

Factors Affecting ◽

Freshwater Systems ◽

Fish Samples ◽

Average Abundance ◽

Topographical Factors ◽

Abundance And Distribution

Abstract Much more attention has been poured into microplastic pollution in freshwater systems recently. In the present study, the pollution of microplastics (MPs) in surface water and freshwater fish (crucian carp, etc.) were investigated from Gehu Lake, which is the second largest lake in southern Jiangsu after Taihu Lake. The result manifested that the average abundance of MPs was respectively 6.33 ± 2.67 n/L for surface water and 10.7 items per individual for freshwater fish. The distribution of MPs in Gehu Lake varied from place to place, with the highest abundance of MPs was observed in the two estuaries of the eastern part of the lake. It was speculated that topographical factors and human factors were the main factors affecting the abundance and distribution of MPs. Transparent fibers were the main type of MPs in water samples, accounting for 69.70% of all detected particles. Meanwhile, most of the MPs ingested by freshwater fish were fibers, and the main colors were transparent and blue. In addition, the dominant size of the MPs was between 0.1 mm to 0.5 mm in water and fish samples. Moreover, PES, Man-made fiber, and PP were the dominant polymer types in the surface water and fish samples. The results of this investigation can provide basic data for the research and management of MPs in freshwater systems.

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Tissue-specific changes in RNA synthesis in vivo during anoxia in crucian carp

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1999.277.3.r690 ◽

1999 ◽

Vol 277 (3) ◽

pp. R690-R697 ◽

Cited By ~ 5

Author(s):

Richard W. Smith ◽

Dominic F. Houlihan ◽

Göran E. Nilsson ◽

Julie Alexandre

Keyword(s):

Protein Synthesis ◽

Rna Synthesis ◽

Crucian Carp ◽

Synthesis Process ◽

Synthesis Rate ◽

Variable Component ◽

Tissue Specific ◽

Species Survival ◽

Energetic Demand

The overall energy budget for protein synthesis (i.e., transcription plus translation) is thought to consist of fixed and variable components, with RNA synthesis accounting for the former and protein synthesis the latter. During anoxia, the downregulation of protein synthesis (i.e., the variable component), to reduce energetic demand, is an important aspect of survival in crucian carp. The present study examines RNA synthesis during anoxia by labeling with [3H]uridine. A novel synthesis rate calculation is presented, which allows for the tissue-specific salvage of uridine, with synthesis rates finally expressed relative to DNA. After 48 h anoxia, the decline (29%) in brain RNA synthesis and increases in the heart and liver (132 and 871%, respectively) support known RNA functions during hypoxic/anoxic survival. This study provides evidence that, in an anoxia-tolerant species, survival mechanisms involving RNA are able to operate because tissue-specific restructuring of the RNA synthesis process enables fixed synthesis costs to be maintained; this may be as vital to survival as exploiting the variable energetic demand of protein synthesis.

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