Biology subjects

Haider, F.

Publications and source records attributed to Haider, F..

3 recordsLinked to original sources

bioRxiv2024

Perilipin 5 Phosphorylation is Dispensable for Upregulation of Hepatic Lipid Metabolism Genes upon Fasting but Required for Insulin Receptor Substrate 2 Expression in Male Mice

ObjectivePerilipin 5 (PLIN5) is a lipid droplet protein highly expressed in cells that actively oxidize fatty acids. Previous in vitro studies have revealed that PLIN5 phosphorylation (p-PLIN5) at serine 155 by PKA is critical for transcriptional regulation of PPARa target genes by which PLIN5 adapt cells for fatty acid oxidation. We aim to determine the extent of p-PLIN5 in vivo and the consequence of impaired PLIN5 phosphorylation in the liver by using a whole-body knock-in of phosphorylation resistant PLIN5 (SA/SA) in mice. MethodsWe measured PLIN5 and p-PLIN5 with mass spectrometry and Phos-tag gels. We assessed serum chemistry in WT and SA/SA mice upon fasting. RNA sequencing and qPCR compared the gene expression in the liver of SA/SA and WT mice after overnight fast. ResultsPlin5 phosphorylation at S155 was increased in the liver LD fraction of fasted mice compared with that of fed mice by mass spectrometry (p<0.05). qPCR of key lipid metabolism genes did not differ between WT and SA/SA liver upon fasting. Male SA/SA mice had a higher fasting blood glucose (p<0.05) without a difference in body weight, serum insulin, or serum lipids. IRS2 was reduced in the liver of fasted male SA/SA mice (p<0.05). ConclusionPLIN5 S155 phosphorylation is dispensable for the upregulation of lipid metabolism genes important for fasting response in vivo. Impaired phosphorylation also had little effect on serum lipids or liver TG. However, SA/SA mice showed decreased IRS2 expression in the liver, which may contribute to glucose intolerance in SA/SA male mice.

molecular biology↗

bioRxiv2024

Brewery Waste as a Sustainable Protein Source for the Banded Cricket (Gryllodes sigillatus)

Crickets, like other edible insects, can convert organic by-products of the food and agricultural industries into high-value protein. Waste products high in protein like brewers spent grain and brewers spent yeast are particularly attractive replacements for unsustainable protein sources in cricket feed like fishmeal or soy. Such replacement will only be advantageous, however, if feeding on these waste products does not impact, or only minimally impacts, cricket survival, growth, and body composition. In this study, a farmed cricket species, Gryllodes sigillatus, was reared in isolation on experimental diets in which fishmeal was wholly or partially replaced with either brewers spent grain or brewers spent yeast. Cricket survival, development and macromolecular composition were not different across diets. However, wholly replacing fishmeal with brewers spent yeast or brewers spent grain reduced cricket adult body mass by approximately 16%. To extend these findings toward a farm environment, a second cohort of crickets were reared communally on diets in which fishmeal, and fishmeal and soy (a secondary protein source), were replaced by brewers spent grain. We found that in a communal environment, crickets reared on both diets performed equally as well as the control. Therefore, brewing waste products are promising candidates for use as a primary protein source in the feed of G. sigillatus. In addition to contributing towards the goals of a circular bioeconomy through the repurposing of waste, the use of brewing waste in cricket feed may have a positive impact of the cricket farming industry as a cost-effective and sustainable alternative to traditional feed. Conflict of InterestThe authors have an ongoing research agreement with Aspire Food Group and Entomo Farms, who produce crickets as food and feed. Funding StatementThis research was funded by Discovery Grants awarded by the Natural Sciences and Engineering Research Council of Canada (NSERC) to H.A.M. (RGPIN-2018-05322) and S.M.B. (RGPIN-2017-06263). Additional support was provided by an NSERC Alliance Grant (568647-21) and a Deep Space Food Challenge grant (22IUCCAR22) from the Canadian Space Agency awarded to both H.A.M. and S.M.B. Equipment used in this study was purchased with support to H.A.M. from the Canadian Foundation for Innovation (project number 37721).

physiology↗

bioRxiv2024

The freeze-avoiding mountain pine beetle (Dendroctonus ponderosae) survives prolonged exposure to stressful cold by mitigating ionoregulatory collapse

Insect performance is intrinsically linked to environmental temperature, and surviving through winter represents a key challenge for temperate, alpine, and polar species. To overwinter, insects have adapted a wide range of strategies to become truly cold hardy. However, while the physiological mechanisms underlying the ability to avoid or tolerate freezing have been well-studied, little attention has been given to the challenge of maintaining ion homeostasis at frigid temperatures in these species, despite this being a central issue for insects susceptible to mild chilling. Here we investigate how prolonged exposure to temperatures just above the supercooling point affects ion balance in freeze-avoiding larvae of the mountain pine beetle (Dendroctonus ponderosae) in autumn, mid-winter, and spring, and relate it to organismal recovery times and survival outcomes. We found that hemolymph ion balance was gradually disrupted during the first day of exposure, characterized by hyperkalemia and hyponatremia, after which a plateau was reached and maintained for the rest of the seven day experiment. The degree of ionoregulatory collapse experienced by larvae correlated strongly with recovery times, which followed a similar asymptotical progression. Mortality increased slightly during the most severe cold exposures, where hemolymph K+ concentration was highest, and a logistic relationship was found between survival and hyperkalemia. Thus, the cold tolerance of the freeze-avoiding larvae of D. ponderosae appears limited by the ability to prevent ionoregulatory collapse in a manner similar to less tolerant chill-susceptible insects, albeit at much lower temperatures. Furthermore, we posit that a prerequisite for the evolution of insect freeze avoidance is a convergent or ancestral ability to maintain ion homeostasis during exposure to extreme cold stress.

physiology↗