title: Eating behaviour regulation in Zebrafish (Danio rerio): a comparative analysis

authors: Ahmadi, Ramtin

subjects: Zebrafish

abstract: The structure, function, and tissue specific expression profiles of neuropeptides involved in regulating eating behaviour are well researched in mammals, the corresponding literature on fish homologs however is scarce. The work presented here endeavoured to characterise the full coding sequences of peptide homologs in zebrafish as well as the expression profiles of said peptides under different energy states to elucidate their function in fish. Zebrafish were chosen as a model to represent fish species as they are amenable to molecular study. Conducting a literature and TBLASTn search, genes were identified in zebrafish that are known to be involved in affecting appetite and satiety in other vertebrates. Comparison of the translated sequences of these genes against fish and other vertebrates provided confidence in the identity of AGRP, GHRL, POMCb, CART1, CART3, and CART4 and all genes showed homology against mammalian transcripts through structural and syntenic comparison. RACE synthesis of the full coding sequence of these genes was attempted from isolated brain mRNA but only resulted in the production of a partial 3’ sequence for CART1 and CART4 which showed high identity against the predicted nucleotide but not the translated sequence. To observe the functional properties of a suite of genes, a qPCR analysis of the expression profiles of AGRP, GHRL, POMCa, POMCb, CART1, CART2, CART3, CART4, OXT, NPY, and AVPwas undertaken  in 24 hour fasted zebrafish. The results were comparable to both other fish and mammals as AGRP was orexigenically upregulated in fasted zebrafish, while POMCb and OXT were anorexigenically downregulated. This is the first time that an expression study has been conducted across all of these genes together in a single species and, while the results are preliminary, they outline that the simultaneous analysis of the many genes thought to be involved in eating behaviour is a viable approach to discovering the functional roles of the range of genes, their interaction with each other, and how that relates to eating behaviour and provides some confidence in use of zebrafish as a model to highlight this.

text: Eating behaviour regulation in Zebrafish (Danio rerio): a comparative analysis The structure, function, and tissue specific expression profiles of neuropeptides involved in regulating eating behaviour are well researched in mammals, the corresponding literature on fish homologs however is scarce. The work presented here endeavoured to characterise the full coding sequences of peptide homologs in zebrafish as well as the expression profiles of said peptides under different energy states to elucidate their function in fish. Zebrafish were chosen as a model to represent fish species as they are amenable to molecular study. Conducting a literature and TBLASTn search, genes were identified in zebrafish that are known to be involved in affecting appetite and satiety in other vertebrates. Comparison of the translated sequences of these genes against fish and other vertebrates provided confidence in the identity of AGRP, GHRL, POMCb, CART1, CART3, and CART4 and all genes showed homology against mammalian transcripts through structural and syntenic comparison. RACE synthesis of the full coding sequence of these genes was attempted from isolated brain mRNA but only resulted in the production of a partial 3’ sequence for CART1 and CART4 which showed high identity against the predicted nucleotide but not the translated sequence. To observe the functional properties of a suite of genes, a qPCR analysis of the expression profiles of AGRP, GHRL, POMCa, POMCb, CART1, CART2, CART3, CART4, OXT, NPY, and AVPwas undertaken  in 24 hour fasted zebrafish. The results were comparable to both other fish and mammals as AGRP was orexigenically upregulated in fasted zebrafish, while POMCb and OXT were anorexigenically downregulated. This is the first time that an expression study has been conducted across all of these genes together in a single species and, while the results are preliminary, they outline that the simultaneous analysis of the many genes thought to be involved in eating behaviour is a viable approach to discovering the functional roles of the range of genes, their interaction with each other, and how that relates to eating behaviour and provides some confidence in use of zebrafish as a model to highlight this.

year: 2014

title: Microbially induced calcium carbonate precipitation: a widespread phenomenon in the biological world

authors: Seifan, Mostafa

subjects: Science & Technology

abstract: Biodeposition of minerals is a widespread phenomenon in the biological world and is mediated by bacteria, fungi, protists, and plants. Calcium carbonate is one of those minerals that naturally precipitate as a by-product of microbial metabolic activities. Over recent years, microbially induced calcium carbonate precipitation (MICP) has been proposed as a potent solution to address many environmental and engineering issues. However, for being a viable alternative to conventional techniques as well as being financially and industrially competitive, various challenges need to be overcome. In this review, the detailed metabolic pathways, including ammonification of amino acids, dissimilatory reduction of nitrate, and urea degradation (ureolysis), along with the potent bacteria and the favorable conditions for precipitation of calcium carbonate, are explained. Moreover, this review highlights the potential environmental and engineering applications of MICP, including restoration of stones and concrete, improvement of soil properties, sand consolidation, bioremediation of contaminants, and carbon dioxide sequestration. The key research and development questions necessary for near future large-scale applications of this innovative technology are also discussed.

text: Microbially induced calcium carbonate precipitation: a widespread phenomenon in the biological world Biodeposition of minerals is a widespread phenomenon in the biological world and is mediated by bacteria, fungi, protists, and plants. Calcium carbonate is one of those minerals that naturally precipitate as a by-product of microbial metabolic activities. Over recent years, microbially induced calcium carbonate precipitation (MICP) has been proposed as a potent solution to address many environmental and engineering issues. However, for being a viable alternative to conventional techniques as well as being financially and industrially competitive, various challenges need to be overcome. In this review, the detailed metabolic pathways, including ammonification of amino acids, dissimilatory reduction of nitrate, and urea degradation (ureolysis), along with the potent bacteria and the favorable conditions for precipitation of calcium carbonate, are explained. Moreover, this review highlights the potential environmental and engineering applications of MICP, including restoration of stones and concrete, improvement of soil properties, sand consolidation, bioremediation of contaminants, and carbon dioxide sequestration. The key research and development questions necessary for near future large-scale applications of this innovative technology are also discussed.

year: 2019

title: The state of the Rotorua Lakes in 2017

authors: Hamilton, David P.

abstract: I have been asked to give an overview of the Rotorua Te Arawa Lakes and then focus on just four of the lakes. Chris McBride will pick up other lakes.  I would like to acknowledge Warwick Silvester who set up the Lakes Chair, Simon Stuart who is working outside the rohe, on Lake Taupō, but has a great body of knowledge on the food chain in that lake, with potential applications to the Te Arawa lakes. Also to Kohji Muraoka who helped me over the last 24 hours, putting data together which enabled me to synthesise my thoughts on these lakes.

text: The state of the Rotorua Lakes in 2017 I have been asked to give an overview of the Rotorua Te Arawa Lakes and then focus on just four of the lakes. Chris McBride will pick up other lakes.  I would like to acknowledge Warwick Silvester who set up the Lakes Chair, Simon Stuart who is working outside the rohe, on Lake Taupō, but has a great body of knowledge on the food chain in that lake, with potential applications to the Te Arawa lakes. Also to Kohji Muraoka who helped me over the last 24 hours, putting data together which enabled me to synthesise my thoughts on these lakes.

year: 2017