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Author

Samwel Mchele Limbu

Other affiliations: East China Normal University
Bio: Samwel Mchele Limbu is an academic researcher from University of Dar es Salaam. The author has contributed to research in topics: Nile tilapia & Oreochromis. The author has an hindex of 19, co-authored 70 publications receiving 1067 citations. Previous affiliations of Samwel Mchele Limbu include East China Normal University.

Papers published on a yearly basis

Papers
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Journal ArticleDOI
TL;DR: Both LECAs and LADAs impair general physiological functions, nutritional metabolism, and compromise fish immune system, resulting in retarded growth performance and DNA damage in treated fish.

208 citations

Journal ArticleDOI
TL;DR: It is indicated that environmental antibiotic concentrations can impair the gut health of zebrafish and the potential health risk of antibiotic residues in water should be evaluated in the future.

179 citations

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TL;DR: The results show that fiddler crabs presented moderate mortality levels in these artificial mangrove wetlands, but mainly in sewage impacted cells, however, they still function as ecosystem engineers through bioturbation activities and burrow construction.

82 citations

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TL;DR: This study demonstrates that fasting may be a protective strategy for fish to survive under cold stress andression of mechanistic target of rapamycin (mTOR) signalling pathway by Rapamycin largely mimicked the beneficial effects of fasting in promoting cold resistance.
Abstract: Key points In a cold environment, mammals increase their food intake while fish decrease or stop feeding. However, the physiological value of fasting during cold resistance in fish is currently unknown. Fasting for more than 48 h enhanced acute cold resistance in zebrafish, which correlated with lipid catabolism and cell damage attenuation. Lipid catabolism and autophagy were necessary for cold resistance in fish and the inhibition of mitochondrial fatty acid β-oxidation or autophagy weakened the fasting-induced cold resistance. Repression of mechanistic target of rapamycin (mTOR) signalling pathway by rapamycin largely mimicked the beneficial effects of fasting in promoting cold resistance, suggesting mTOR signalling may be involved in the fasting-induced cold resistance in fish. Our study demonstrates that fasting may be a protective strategy for fish to survive under cold stress. Abstract In cold environments, most homeothermic animals increase their food intake to supply more energy to maintain body temperature, whereas most poikilothermic animals such as fishes decrease or even stop feeding under cold stress. However, the physiological value of fasting during cold resistance in poikilotherms has not been explained. Here, we show that moderate fasting largely enhanced cold resistance in fish. By using pharmacological (fenofibrate, mildronate, chloroquine and rapamycin) and nutritional approaches (fatty acids diets and amino acids diets) in wild-type or specific gene knock-out zebrafish models (carnitine palmitoyltransferase-1b-deficient strain, CPT1b-/- , or autophagy-related protein 12-deficient strain, ATG12-/- ), we verified that fasting-stimulated lipid catabolism and autophagy played essential roles in the improved cold resistance. Moreover, suppression of the mechanistic target of rapamycin (mTOR) pathway by using rapamycin mostly mimicked the beneficial effects of fasting in promoting cold resistance as either the physiological phenotype or transcriptomic pattern. However, these beneficial effects were largely reduced when the mTOR pathway was activated through high dietary leucine supplementation. We conclude that fasting helps fish to resist cold stress by modulating lipid catabolism and autophagy, which correlates with the mTOR signalling pathway. Therefore, fasting can act as a protective strategy of fish in resisting coldness.

77 citations

Journal ArticleDOI
TL;DR: The National Key Research and Development Program of China (2018YFD0900400) and the scholarship given by The Chinese government through Chinese Scholarship Council (CSC) as mentioned in this paper.
Abstract: The National Key Research and Development Program of China (2018YFD0900400) and the scholarship given by The Chinese government through Chinese Scholarship Council (CSC)

75 citations


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Journal ArticleDOI
TL;DR: The term "bioturbation" is frequently used to describe how living organisms affect the substratum in which they live as discussed by the authors, and it has been used in aquatic scientific disciplines to describe all transport processes carried out by animals that directly or indirectly affect sediment matrices.
Abstract: The term 'bioturbation' is frequently used to describe how living organisms affect the substratum in which they live. A closer look at the aquatic science literature reveals, however, an inconsistent usage of the term with increasing perplexity in recent years. Faunal disturbance has often been referred to as particle reworking, while water movement (if considered) is re ferred to as bioirrigation in many cases. For consistency, we therefore propose that, for contemporary aquatic scientific disciplines, faunal bioturbation in aquatic environments includes all transport processes carried out by animals that directly or indirectly affect sediment matrices. These pro- cesses include both particle reworking and burrow ventilation. With this definition, bioturbation acts as an 'umbrella' term that covers all transport processes and their physical effects on the sub- stratum. Particle reworking occurs through burrow construction and maintenance, as well as ingestion and defecation, and causes biomixing of the substratum. Organic matter and microor- ganisms are thus displaced vertically and laterally within the sediment matrix. Particle reworking animals can be categorized as biodiffusors, upward conveyors, downward conveyors and regen- erators depending on their behaviour, life style and feeding type. Burrow ventilation occurs when animals flush their open- or blind-ended burrows with overlying water for respiratory and feeding purposes, and it causes advective or diffusive bioirrigation ex change of solutes between the sedi- ment pore water and the overlying water body. Many bioturbating species perform reworking and ventilation simultaneously. We also propose that the effects of bioturbation on other organisms and associated processes (e.g. microbial driven biogeochemical transformations) are considered within the conceptual framework of ecosystem engineering.

604 citations

Journal ArticleDOI
TL;DR: The present paper reviews the current knowledge on the occurrence, bioavailability and toxic effects of trace contaminants in mangrove ecosystems and highlights the major data and methodological gaps which should be addressed to refine the risk assessment of trace pollutants in manGrove ecosystems.

328 citations

Journal ArticleDOI
TL;DR: In this paper , the authors present a global-scale study of API pollution in 258 of the world's rivers, representing the environmental influence of 471.4 million people across 137 geographic regions.
Abstract: Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans. While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective. Furthermore, comparison of the existing data, generated for different studies/regions/continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world's rivers, representing the environmental influence of 471.4 million people across 137 geographic regions. Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in sub-Saharan Africa, south Asia, and South America. The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored. Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals.

272 citations