scholarly journals Enhanced stability and polyadenylation of select mRNAs support rapid thermogenesis in the brown fat of a hibernator

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Katharine R Grabek ◽  
Cecilia Diniz Behn ◽  
Gregory S Barsh ◽  
Jay R Hesselberth ◽  
Sandra L Martin
Keyword(s):  
Mathematical Modeling ◽  
Low Temperatures ◽  
Temperature Sensitive ◽  
Molecular Pathways ◽  
Physiological Regulation ◽  
Brown Adipose ◽  
Activity Cycles ◽  
Intense Activity ◽  
Enhanced Stability ◽  
Periodic Arousal

During hibernation, animals cycle between torpor and arousal. These cycles involve dramatic but poorly understood mechanisms of dynamic physiological regulation at the level of gene expression. Each cycle, Brown Adipose Tissue (BAT) drives periodic arousal from torpor by generating essential heat. We applied digital transcriptome analysis to precisely timed samples to identify molecular pathways that underlie the intense activity cycles of hibernator BAT. A cohort of transcripts increased during torpor, paradoxical because transcription effectively ceases at these low temperatures. We show that this increase occurs not by elevated transcription but rather by enhanced stabilization associated with maintenance and/or extension of long poly(A) tails. Mathematical modeling further supports a temperature-sensitive mechanism to protect a subset of transcripts from ongoing bulk degradation instead of increased transcription. This subset was enriched in a C-rich motif and genes required for BAT activation, suggesting a model and mechanism to prioritize translation of key proteins for thermogenesis.

scholarly journals Metabolic regulation of the lysosomal cofactor bis(monoacylglycero)phosphate in mice

2020 ◽  
Vol 61 (7) ◽  
pp. 995-1003 ◽  
Author(s):  
Gernot F. Grabner ◽  
Nermeen Fawzy ◽  
Renate Schreiber ◽  
Lisa M. Pusch ◽  
Dominik Bulfon ◽  
...  
Keyword(s):  
Metabolic Regulation ◽  
Lipid Transfer ◽  
Tissue Samples ◽  
Physiological Regulation ◽  
Nonparenchymal Cells ◽  
Pancreatic Cells ◽  
Brown Adipose ◽  
Specific Manner ◽  
Lysobisphosphatidic Acid ◽  
Induced Changes

Bis(monoacylglycero)phosphate (BMP), also known as lysobisphosphatidic acid, is a phospholipid that promotes lipid sorting in late endosomes/lysosomes by activating lipid hydrolases and lipid transfer proteins. Changes in the cellular BMP content therefore reflect an altered metabolic activity of the endolysosomal system. Surprisingly, little is known about the physiological regulation of BMP. In this study, we investigated the effects of nutritional and metabolic factors on BMP profiles of whole tissues and parenchymal and nonparenchymal cells. Tissue samples were obtained from fed, fasted, 2 h refed, and insulin-treated mice, as well as from mice housed at 5°C, 22°C, or 30°C. These tissues exhibited distinct BMP profiles that were regulated by the nutritional state in a tissue-specific manner. Insulin treatment was not sufficient to mimic refeeding-induced changes in tissue BMP levels, indicating that BMP metabolism is regulated by other hormonal or nutritional factors. Tissue fractionation experiments revealed that fasting drastically elevates BMP levels in hepatocytes and pancreatic cells. Furthermore, we observed that the BMP content in brown adipose tissue strongly depends on housing temperatures. In conclusion, our observations suggest that BMP concentrations adapt to the metabolic state in a tissue- and cell-type-specific manner in mice. Drastic changes observed in hepatocytes, pancreatic cells, and brown adipocytes suggest that BMP plays a role in the functional adaption to nutrient starvation and ambient temperature.

Different temperature relations of two species of toads that coexist at the border of their geographical distributions

1997 ◽  
Vol 18 (3) ◽  
pp. 259-268 ◽  
Author(s):  
U. Katz ◽  
Nira Gil
Keyword(s):  
Body Temperature ◽  
Low Temperature ◽  
Low Temperatures ◽  
Central Mechanism ◽  
Tropical Species ◽  
Temperature Sensitive ◽  
Ecological Situation ◽  
Heating Rates ◽  
Bufo Viridis

AbstractTemperature relations of two species of toads (Bufo viridis and Bufo regularis) that overlap at the border of their geographical distributions were studied in the laboratory in temperatures between 25°C and 2°C. Bufo regularis, a tropical species, could not survive at low temperatures that eventually led to its death in 1-2 days. The two species did not differ in their cooling and heating rates. At temperatures below 8-10°C, Bufo viridis maintained a body temperature that was higher than ambient by 1-2°C, while body temperature of Bufo regularis equaled that of the environment. In Bufo regularis heart beats ceased at low temperatures (< 4°C), whereas in Bufo viridis at the same temperature, a rate of 6-9 beats/min was sustained. Our experiments suggest that Bufo viridis is endowed with particular capacities that allow it to remain active at low temperatures, while in Bufo regularis, a temperature-sensitive central mechanism seems to be damaged at low temperature. The ability of Bufo viridis to endure low temperatures and to remain active in this condition is specific to the species, and is not related directly to the immediate ecological situation of the animal.

scholarly journals Conveyor-Belt Dryers with Tangential Flow for Food Drying: Mathematical Modeling and Design Guidelines for Final Moisture Content Higher Than the Critical Value

Inventions ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 22
Author(s):  
Dario Friso
Keyword(s):  
Mathematical Modeling ◽  
Moisture Content ◽  
Rational Design ◽  
Conveyor Belt ◽  
Design Guidelines ◽  
Final Moisture Content ◽  
Temperature Sensitive ◽  
Optimized Design ◽  
Tangential Flow ◽  
Product Flow

The mathematical modeling presented in this work concerns the conveyor-belt dryer with the tangential flow of air with respect to food. This dryer, if operating in co-current, has the advantage of well preserving the organoleptic and nutritional qualities of the dried product. In fact, it has a low air temperature in the final stretch where the product has low moisture content and is therefore more temperature sensitive. It is a bulkier dryer than the continuous through-circulation conveyor dryer with a perforated belt. The latter is therefore more frequently used and has received greater study attention from researchers and designers of the industry. With the aim to propose guidelines for a rational design of the conveyor-belt dryer with tangential flow, a mathematical model was developed here through the differentiation of the drying rate equation followed by its integration performed along the dryer belt. Consequently, and with the assumption that the final moisture content XF of the product is higher than the critical moisture content XC, the relationships between the intensive quantities (temperatures, humidity and enthalpies), the extensive quantities (air and product flow rates) and the dimensional ones (length and width of the belt), were obtained. Finally, on the basis of these relationships, the rules for an optimized design for XF > XC were obtained and experimentally evaluated.

Molecular pathways linking non-shivering thermogenesis and obesity: focusing on brown adipose tissue development

2014 ◽  
Vol 90 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Angelica Valente ◽  
Athanasios Z. Jamurtas ◽  
Yiannis Koutedakis ◽  
Andreas D. Flouris
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Molecular Pathways ◽  
Tissue Development ◽  
Brown Adipose ◽  
Adipose Tissue Development ◽  
Shivering Thermogenesis

Thermal effects on behavior of juvenile walleye pollock (Theragra chalcogramma): implications for energetics and food web models

2007 ◽  
Vol 64 (3) ◽  
pp. 449-457 ◽  
Author(s):  
Thomas P Hurst
Keyword(s):  
Food Web ◽  
Low Temperatures ◽  
Walleye Pollock ◽  
Activity Level ◽  
Fish Growth ◽  
Separate Experiment ◽  
Theragra Chalcogramma ◽  
Physiological Regulation ◽  
Walleye Pollock Theragra Chalcogramma ◽  
Regulation Of Activity

The behavioral responses of fishes to temperature variation have received little attention despite their direct implications to bioenergetics-based models of production and encounter-based models of food web dynamics. Behavioral characteristics of juvenile walleye pollock (Theragra chalcogramma), a pelagic marine zooplanktivore, were examined between 2 and 9 °C in large arenas. Routine swim speed, path sinuosity, and schooling cohesiveness of fish in small groups were described from overhead video observations. In a separate experiment, maximum swimming speeds were measured in a recirculating flume. Routine and maximum swimming speeds had contrasting responses to temperature demonstrating a behavioral rather than physiological regulation of activity level. Routine swim speed was 48% faster at 2 °C than at 9 °C. This result is inconsistent with the assumption of a constant activity multiplier for metabolism incorporated into most bioenergetics models of fish growth. Increased swim speed, along with the reduced path sinuosity observed at low temperatures, may reflect kinetic aspects of habitat selection. Group cohesion increased at low temperatures, with nearest neighbors averaging 32% closer at 2 °C than at 9 °C. These results demonstrate that representative models of energy flow through marine food webs depend on an improved understanding of the behavioral as well as physiological responses of fishes to thermal variation.

Physiological regulation and metabolic role of browning in white adipose tissue

2017 ◽  
Vol 31 (1) ◽  
Author(s):  
Aleksandra Jankovic ◽  
Vesna Otasevic ◽  
Ana Stancic ◽  
Biljana Buzadzic ◽  
Aleksandra Korac ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Diabetes Type 2 ◽  
Cellular Mechanisms ◽  
Physiological Regulation ◽  
Metabolic Role ◽  
Brown Adipose ◽  
Beige Adipose Tissue

AbstractGreat progress has been made in our understanding of the browning process in white adipose tissue (WAT) in rodents. The recognition that i) adult humans have physiologically inducible brown adipose tissue (BAT) that may facilitate resistance to obesity and ii) that adult human BAT molecularly and functionally resembles beige adipose tissue in rodents, reignited optimism that obesity and obesity-related diabetes type 2 can be battled by controlling the browning of WAT. In this review the main cellular mechanisms and molecular mediators of browning of WAT in different physiological states are summarized. The relevance of browning of WAT in metabolic health is considered primarily through a modulation of biological role of fat tissue in overall metabolic homeostasis.

scholarly journals Molecular Lesions Associated With Alleles of decapentuplegic Identify Residues Necessary for TGF-β/BMP Cell Signaling in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 493-505 ◽  
Author(s):  
Kristi Wharton ◽  
Robert P Ray ◽  
Seth D Findley ◽  
Holly E Duncan ◽  
William M Gelbart
Keyword(s):  
Cell Signaling ◽  
Low Temperatures ◽  
Point Mutations ◽  
Molecular Probes ◽  
Genetic Interactions ◽  
Temperature Sensitive ◽  
In Vitro Mutagenesis ◽  
Mutant Phenotypes

Abstract We have identified the molecular lesions associated with six point mutations in the Drosophila TGF-β homologue decapentaplegic (dpp). The sites of these mutations define residues within both the pro and ligand regions that are essential for dpp function in vivo. While all of these mutations affect residues that are highly conserved among TGF-β superfamily members, the phenotypic consequences of the different alleles are quite distinct. Through an analysis of these mutant phenotypes, both in cuticle preparations and with molecular probes, we have assessed the functional significance of specific residues that are conserved among the different members of the superfamily. In addition, we have tested for conditional genetic interactions between the different alleles. We show that two of the alleles are temperature sensitive for the embyronic functions of dpp, such that these alleles are not only embryonic viable as homozygotes but also partially complement other dpp hypomorphs at low temperatures. Our results are discussed with regard to in vitro mutagenesis data on other TGF-β-like molecules, as well as with regard to the regulation of dpp cell signaling in Drosophila.

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