Correction: An autonomous metabolic role for Spen (original) (raw)
An autonomous metabolic role for Spen
PLoS genetics, 2017
Preventing obesity requires a precise balance between deposition into and mobilization from fat stores, but regulatory mechanisms are incompletely understood. Drosophila Split ends (Spen) is the founding member of a conserved family of RNA-binding proteins involved in transcriptional regulation and frequently mutated in human cancers. We find that manipulating Spen expression alters larval fat levels in a cell-autonomous manner. Spen-depleted larvae had defects in energy liberation from stores, including starvation sensitivity and major changes in the levels of metabolic enzymes and metabolites, particularly those involved in β-oxidation. Spenito, a small Spen family member, counteracted Spen function in fat regulation. Finally, mouse Spen and Spenito transcript levels scaled directly with body fat in vivo, suggesting a conserved role in fat liberation and catabolism. This study demonstrates that Spen is a key regulator of energy balance and provides a molecular context to understan...
Spenito-dependent metabolic sexual dimorphism intrinsic to fat storage cells
Metabolism in males and females is distinct. Differences are usually linked to sexual reproduction, with circulating signals (e.g. hormones) playing major roles. By contrast, sex differences prior to sexual maturity and intrinsic to individual metabolic tissues are less understood. We analyzedDrosophila melanogasterlarvae and find that males store more fat than females, the opposite of the sexual dimorphism in adults. We show that metabolic differences are intrinsic to the major fat storage tissue, including many differences in the expression of metabolic genes. Our previous work identified fat storage roles for Spenito (Nito), a conserved RNA-binding protein and regulator of sex determination. Nito knockdown specifically in the fat storage tissue abolished fat differences between males and females. We further show that Nito is required for sex-specific expression of the master regulator of sex determination, Sex-lethal (Sxl). “Feminization” of fat storage cells via tissue-specific ...
Sanchez et al CBP 2008 spiggin
The aim of this study was to develop an enzyme-linked immunosorbent (ELISA) assay to quantify spiggin in the three-spined stickleback. Spiggin is a glue protein produced in the kidney of male three-spined stickleback under the control of androgens during the breeding period. Disturbances of spiggin production in male fish and abnormal induction of spiggin in female fish are considered as valuable biomarkers of exposure to (anti-) androgenic chemicals. Polyclonal antibodies against a peptide sequence of spiggin (HRD-16) were used and the specificity of the antibodies was verified by Western blotting and direct ELISA experiments. By using HRD-16 antibodies and spiggin standard preparation, a competitive ELISAwas set-up and validated. This assay appears sensitive, with a detection limit of 0.5 U/mL, and specific, as shown by the competition curves, obtained by serial dilution of male and female kidney homogenates, that were parallel to the spiggin standard curves. The ability of the spiggin ELISA to quantify spiggin induction was achieved by exposing male and female three-spined sticklebacks to 0.1 and 1 μg/L of methyltestosterone. The results show a significant dose-dependent induction of spiggin in methyltestosterone-exposed female fish compared to controls.
Gene-Diet Interactions: Dietary Rescue of Metabolic Defects in spen-depleted Drosophilamelanogaster
Genetics
Obesity and its co-morbidities are a growing health epidemic. Interactions between genetic background, the environment and behavior (i.e. diet) greatly influence organismal energy balance. Previously, we described obesogenic mutations in the gene Split ends (Spen) in Drosophila melanogaster, and roles for Spen in fat storage and metabolic state. Lipid catabolism is impaired in Spen-deficient fat storage cells, accompanied by a compensatory increase in glycolytic flux and protein catabolism. Here we investigate gene-diet interactions to determine if diets supplemented with specific macronutrients can rescue metabolic dysfunction in Spen-depleted animals. We show that a high-yeast diet partially rescues adiposity and developmental defects. High sugar partially improves developmental timing as well as longevity of mated females. Gene-diet interactions were heavily influenced by developmental-stage-specific organismal needs: extra yeast provides benefits early in development (larval sta...
Quantitative and molecular genetic determination of protein and fat deposition
HOMO, 2003
After 30 years of selection, breeding of the pig breed sus scrofa Piétrain has resulted in reduced backfat thickness (from 3.2 to 1.9 mm) and increased loin muscle area (40 to 60 cm 2) which indicates high genetic determination of these body composition traits. The use of sophisticated quantitative genetic methods that include all genetic relationships of large populations has led to a high response to selection of these traits. Selection on feed intake, lean and fat tissue growth using nonlinear functions to optimise these traits during the entire growth period in a biological model offers the opportunity to further improve total genetic potential. Protein and lipid deposition rates during the entire growth period have to be known for this biological model to be applied; thus knowledge of the genetic background of these traits is of high economic value. With the use of molecular genetic methods, such as candidate gene and genome scan approaches, the identification of genes for obesity and growth can be obtained. In sus scrofa, candidate genes associated with obesity and growth include Leptin Receptor, Melanocortin-4 Receptor, Agouti related protein, Heart fatty acid binding protein 3, and Insulin-like growth factor 2. Some of these candidate genes also explain variation in obesity levels in humans. Initial genome-wide scans have identified quantitative trait loci (QTL) on chromosomes 1, 4, 5, 7 and X for obesity and on chromosomes 1, 4, 7, 8, 13 and 18 for growth. Physiological candidate genes and predispositional QTL for obesity are not always located on the same chromosome; this is known the «polygenic paradox». Use of a nonlinear growth function is recommended in order to give more insight into the physiological regulation of obesity traits. Sus scrofa is an excellent model organism to examine the genetic regulation of obesity. The conservation of DNA sequence and chromosomal segments between sus scrofa and homo sapiens will permit easy transfer of results to human studies. Zusammenfassung Aufgrund der vermehrt erhaltenen Chromosomenregionen von Homo sapiens und Sus scrofa im Vergleich zu Nagetieren und der großen Übereinstimmung der Ernährungsphysiologie und des Metabolismus sowie der Morphologie von zahlreichen Organen, ist Sus scrofa ein sehr geeignetes Modell für die Erforschung der Genetik der humanen Adipositas. Die Züchtung der Sus scrofa Rasse Piétrain führte zu einer Verminderung der Rückenspeckdicke von 3,2 auf 1,9 mm und erhöhte die Rückenmuskelfläche von 40 auf 60 cm 2 nach 30 Jahren der Selektion, wodurch die hohe genetische Determination von Adipositas und Muskelfleischmerkmalen aufgezeigt wird. Die Verwendung von hochentwickelten quantitativ genetischen Methoden, die u.a. eine Einbeziehung aller genetischen Verwandtschaftsbeziehungen von großen Populationen ermöglichen, haben zu dem hohen Selektionserfolg dieser Merkmale geführt. Die Heritabilität des Lipidansatzes ist sehr hoch (h 2 = 0,5) und genetisch positiv korreliert mit Wachstumsrate und täglicher Futteraufnahme (r g = 0,47 und 0,56). Um diese Merkmale mittels genetischer Selektion zu optimieren, muss die genetische Regulation des Protein-und Lipidansatzes während der gesamten Wachstumsperiode bekannt sein, deren Erkenntnisse neue Einblicke in die komplexe genetische Natur der Adipositas auch beim Menschen ergeben wird. Durch die Anwendung von moleku
2012
Phenotypic change in response to variation in environmental cues has been widely documented in fish. Transitions in social dominance, in particular, have been shown to induce a rapid switch in reproductive phenotypes in many species. However, this effect has been mainly studied in adults and focused on behavioural transitions. The way social cues constraint the phenotypic development of juveniles remains poorly studied in fish. We tested the importance of social dominance and density in the phenotypic development of juveniles of the peacock blenny Salaria pavo. This species shows sequential male alternative reproductive tactics. In the first breeding season males can reproduce as nest-holders or as parasitic males (female-mimicking), or postpone reproduction; from the following season afterwards all males reproduce as nest-holders. Parasitic males have relatively larger testes that lack a testicular gland, present in the testes of nest-holders. The testicular gland is the main source of androgens in the testes and accordingly nest-holders have higher circulating androgen levels. In addition, exogenous androgen administration to parasitic males promotes the development of secondary sexual characters (SSC) only present in nest-holders such as a head crest and an anal gland. We raised juveniles under a high or low-density treatment and monitored social interactions for 1 month. No significant effect of density on the development of juvenile males was detected. However, within each replicate, the relative body size of juvenile males at the beginning of the experiment determined their dominance status, with dominant males developing towards the nest-holder morphotype. Dominant males engaged in more nest defence behaviour, showed larger testicular glands, had higher levels of 11-ketotestosterone (11-KT) and testosterone (T) and developed more SSC, as compared to subordinate males. However, these effects of social dominance were moderated by body condition as only dominant males in good body condition developed SSC. The effect of social dominance and of the area of the testicular gland on the development of SSC was mediated by 11-KT and on the expression of nest defence behaviour by T. Interestingly, in spite of the higher androgen levels and more pronounced morphologic development of SSC in dominant individuals, gonadal development was independent of social dominance and most fish still had underdeveloped testis at the end of the experiment. In conclusion, social dominance promoted the development of the testicular gland, an increase in circulating androgen levels and the development of SSC, but did not promote testicular development. This suggests a dissociation of mechanisms underlying sexual maturation and the expression of male reproductive traits. This dissociation seems to be the key for the occurrence of female-mimicking males in this species, which are sexually mature despite lacking the SSC typical of nest-holders.
A new method for the study of essential fatty acid requirements in fish larvae
British Journal of Nutrition, 2009
Larvae were collected at 2 hatcheries, one using marine zooplankton (Lofilab AS, Norway) until 27 days after hatch (DAH), the other using rotifers (Marine Harvest Cod, Norway) until 23DAH where formulated diet (Gemma Micro) and rotifers were co-fed for a period of 7 days followed by the use of only formulated diet. Collected larvae were fixed on PBS buffered 4% paraformaldehyde for 24h and then kept on 70% ethanol at 4°C until processed. Larvae from different developmental stages were bleached and stained with either Alizarin Red S or Alcian Blue according to (Alex M. Schreiber, personal comm.). Calcein was used to observe calcification processes in vivo. Calcein (1% w/v) was dissolved in fresh salt water and filtered through a 45-µm filter. Larvae was then immersed in this water and allowed to drink for about 30 minutes. To eliminate unspecific staining, the larvae was then transferred into a larger amount of fresh salt water and left for a minimum of 40 minutes prior to documentation, using a digital camera (Olympus DP 50) connected to a stereoscope (Olympus SZX12) with a fluorescent filter (set for G excitation of SZX-RFA, exciter filter BP460-560, dichroic mirror DM580, barrier filter OG590). Pictures from all staining techniques will be shown on the poster.
Article no.ARRB.42123 (2) George Perry, Dean and Professor of Biology
Concepts of polyculture of Vietnamese koi (Anabas testudineus) with others short cycle fish species especially in the semi-arid zone of Bangladesh helps to increase the production and utilization of water bodies. Optimization of stocking density with and economics of the culture system was evaluated to mini seasonals pond in Rangpur region, Bangladesh for a period 120 days (30 April to 30 August) ponds were randomly divided into three treatments with different stocking density, explicitly Vietnamese koi were stocked 74,000 ha-1 , 98,000ha-1 and 1,23,000 ha-1 with other fish species in T 1 , T 2 and T 3 with triplicate. Fishes were given to commercially available pelleted feed (30% protein). Recorded water quality parameters were within the acceptable limit for fish culture. Sampling was done every fortnightly interval. After 120 days of culture period average harvesting Original Research Article Ahamed et al.; ARRB, 27(6): 1-7, 2018; Article no.ARRB.42123 2 weight was found 198.67±3.28 g, 179.67±9.06 g and 174.33±4.25 g in T 1 , T 2 and T 3 respectively. Specific growth rate (SGR) in T 1 (4.19) was significantly higher (P<0.05) than T 3 (4.07) but less significant with T 2 (4.10). Survival rate in T 1 (85.3%) varied significantly among the treatment, however total production (kgha-1) in T 3 was (17859.96±230.21) significantly higher (P<0.05) rather than T 2 (15237.46±669.31) and T 1 (13278.91± 78.0) but benefit cost ratio in T 1 (1.64±0.03) varied with T 2 (1.52±0.0) and T 3 (1.40±0.02). It can be calculated that there is a huge potentiality for utilization of seasonals ponds with proper culture technique of short cycle fishes in the semi-arid zone of Bangladesh.