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Fear JM, Arbeitman MN, Salomon MP, Dalton JE, Tower J, Nuzhdin SV, McIntyre LM. The Wright stuff: reimagining path analysis reveals novel components of the sex determination hierarchy in Drosophila melanogaster. BMC SYSTEMS BIOLOGY 2015; 9:53. [PMID: 26335107 PMCID: PMC4558766 DOI: 10.1186/s12918-015-0200-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 08/20/2015] [Indexed: 11/10/2022]
Abstract
BACKGROUND The Drosophila sex determination hierarchy is a classic example of a transcriptional regulatory hierarchy, with sex-specific isoforms regulating morphology and behavior. We use a structural equation modeling approach, leveraging natural genetic variation from two studies on Drosophila female head tissues--DSPR collection (596 F1-hybrids from crosses between DSPR sub-populations) and CEGS population (75 F1-hybrids from crosses between DGRP/Winters lines to a reference strain w1118)--to expand understanding of the sex hierarchy gene regulatory network (GRN). This approach is completely generalizable to any natural population, including humans. RESULTS We expanded the sex hierarchy GRN adding novel links among genes, including a link from fruitless (fru) to Sex-lethal (Sxl) identified in both populations. This link is further supported by the presence of fru binding sites in the Sxl locus. 754 candidate genes were added to the pathway, including the splicing factors male-specific lethal 2 and Rm62 as downstream targets of Sxl which are well-supported links in males. Independent studies of doublesex and transformer mutants support many additions, including evidence for a link between the sex hierarchy and metabolism, via Insulin-like receptor. CONCLUSIONS The genes added in the CEGS population were enriched for genes with sex-biased splicing and components of the spliceosome. A common goal of molecular biologists is to expand understanding about regulatory interactions among genes. Using natural alleles we can not only identify novel relationships, but using supervised approaches can order genes into a regulatory hierarchy. Combining these results with independent large effect mutation studies, allows clear candidates for detailed molecular follow-up to emerge.
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Affiliation(s)
- Justin M Fear
- Department of Molecular Genetics and Microbiology, University of Florida, CGRC Room 116, PO Box 100266, FL 32610-0266, Gainesville, FL, USA.
| | | | - Matthew P Salomon
- Molecular and Computational Biology, University of California, Los Angeles, CA, USA.
| | - Justin E Dalton
- Biomedical Science, Florida State University, Tallahassee, FL, USA.
| | - John Tower
- Molecular and Computational Biology, University of California, Los Angeles, CA, USA.
| | - Sergey V Nuzhdin
- Molecular and Computational Biology, University of California, Los Angeles, CA, USA.
| | - Lauren M McIntyre
- Department of Molecular Genetics and Microbiology, University of Florida, CGRC Room 116, PO Box 100266, FL 32610-0266, Gainesville, FL, USA.
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52
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Aversion for bitter taste reveals sexual differences in alimentation strategies in a praying mantis. Anim Behav 2015. [DOI: 10.1016/j.anbehav.2015.05.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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53
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Takahashi KH, Blanckenhorn WU. Effect of genomic deficiencies on sexual size dimorphism through modification of developmental time in Drosophila melanogaster. Heredity (Edinb) 2015; 115:140-5. [PMID: 25899012 DOI: 10.1038/hdy.2015.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Revised: 09/03/2014] [Accepted: 12/23/2014] [Indexed: 11/09/2022] Open
Abstract
Sexual size dimorphism (SSD), a difference in body size between sexes, is common in many taxa. In insects, females are larger than males in >70% of all taxa in most orders. The fruit fly, Drosophila melanogaster is one prominent model organism to investigate SSD since its clear and representative female-biased SSD and its growth regulation are well studied. Elucidating the number and nature of genetic elements that can potentially influence SSD would be helpful in understanding the evolutionary potential of SSD. Here, we investigated the SSD pattern caused by artificially introduced genetic variation in D. melanogaster, and examined whether variation in SSD was mediated by the sex-specific modification of developmental time. To map the genomic regions that had effects on sexual wing size and/or developmental time differences (SDtD), we reanalyzed previously published genome-wide deficiency mapping data to evaluate the effects of 376 isogenic deficiencies covering a total of ~67% of the genomic regions of the second and third chromosomes of D. melanogaster. We found genetic variation in SSD and SDtD generated by genomic deficiencies, and a negative genetic correlation between size and development time. We also found SSD and SDtD allometries that are not qualitatively congruent, which however overall at best only partly help in explaining the patterns found. We identified several genomic deficiencies with the tendency to either exaggerate or suppress SSD, in agreement with quantitative genetic null expectations of many loci with small effects. These novel findings contribute to a better understanding of the evolutionary potential of sexual dimorphism.
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Affiliation(s)
- K H Takahashi
- Graduate School of Environmental Science, Okayama University, Kita-ku, Okayama, Japan
| | - W U Blanckenhorn
- Institute of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
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54
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Soares JBRC, Gaviraghi A, Oliveira MF. Mitochondrial physiology in the major arbovirus vector Aedes aegypti: substrate preferences and sexual differences define respiratory capacity and superoxide production. PLoS One 2015; 10:e0120600. [PMID: 25803027 PMCID: PMC4372595 DOI: 10.1371/journal.pone.0120600] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 01/24/2015] [Indexed: 12/03/2022] Open
Abstract
Adult females of Aedes aegypti are facultative blood sucking insects and vectors of Dengue and yellow fever viruses. Insect dispersal plays a central role in disease transmission and the extremely high energy demand posed by flight is accomplished by a very efficient oxidative phosphorylation process, which take place within flight muscle mitochondria. These organelles play a central role in energy metabolism, interconnecting nutrient oxidation to ATP synthesis, but also represent an important site of cellular superoxide production. Given the importance of mitochondria to cell physiology, and the potential contributions of this organelle for A. aegypti biology and vectorial capacity, here, we conducted a systematic assessment of mitochondrial physiology in flight muscle of young adult A. aegypti fed exclusively with sugar. This was carried out by determining the activities of mitochondrial enzymes, the substrate preferences to sustain respiration, the mitochondrial bioenergetic efficiency and capacity, in both mitochondria-enriched preparations and mechanically permeabilized flight muscle in both sexes. We also determined the substrates preferences to promote mitochondrial superoxide generation and the main sites where it is produced within this organelle. We observed that respiration in A. aegypti mitochondria was essentially driven by complex I and glycerol 3 phosphate dehydrogenase substrates, which promoted distinct mitochondrial bioenergetic capacities, but with preserved efficiencies. Respiration mediated by proline oxidation in female mitochondria was strikingly higher than in males. Mitochondrial superoxide production was essentially mediated through proline and glycerol 3 phosphate oxidation, which took place at sites other than complex I. Finally, differences in mitochondrial superoxide production among sexes were only observed in male oxidizing glycerol 3 phosphate, exhibiting higher rates than in female. Together, these data represent a significant step towards the understanding of fundamental mitochondrial processes in A. aegypti, with potential implications for its physiology and vectorial capacity.
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Affiliation(s)
- Juliana B. R. Correa Soares
- Laboratório de Bioquímica de Resposta ao Estresse, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil
- Laboratório de Inflamação e Metabolismo, Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem (INBEB), Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Alessandro Gaviraghi
- Laboratório de Bioquímica de Resposta ao Estresse, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil
- Laboratório de Inflamação e Metabolismo, Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem (INBEB), Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Marcus F. Oliveira
- Laboratório de Bioquímica de Resposta ao Estresse, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil
- Laboratório de Inflamação e Metabolismo, Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem (INBEB), Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- * E-mail:
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55
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An automated system for quantitative analysis of Drosophila larval locomotion. BMC DEVELOPMENTAL BIOLOGY 2015; 15:11. [PMID: 25881248 PMCID: PMC4345013 DOI: 10.1186/s12861-015-0062-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 02/16/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND Drosophila larvae have been used as a model to study to genetic and cellular circuitries modulating behaviors. One of the challenges in behavioral study is the quantification of complex phenotypes such as locomotive behaviors. Experimental capability can be greatly enhanced by an automatic single-animal tracker that records an animal at a high resolution for an extended period, and analyzes multiple behavioral parameters. RESULTS Here we present MaggotTracker, a single-animal tracking system for Drosophila larval locomotion analysis. This system controls the motorized microscope stage while taking a video, so that the animal remains in the viewing center. It then reduces the animal to 13 evenly distributed points along the midline, and computes over 20 parameters evaluating the shape, peristalsis movement, stamina, and track of the animal. To demonstrate its utility, we applied MaggotTracker to analyze both wild-type and mutant animals to identify factors affecting locomotive behaviors. Each animal was tracked for four minutes. Our analysis on Canton-S third-instar larvae revealed that the distance an animal travelled was correlated to its striding speed rather than the percentage of time the animal spent striding, and that the striding speed was correlated to both the distance and the duration of one stride. Sexual dimorphism was observed in body length but not in locomotive parameters such as speed. Locomotive parameters were affected by animal developmental stage and the crawling surface. No significant changes in movement speed were detected in mutants of circadian genes such as period (per), timeout, and timeless (tim). The MaggotTracker analysis showed that ether a go-go (eag), Shaker (Sh), slowpoke (slo), and dunce (dnc) mutant larvae had severe phenotypes in multiple locomotive parameters such as stride distance and speed, consistent with their function in neuromuscular junctions. Further, the phenotypic patterns of the K(+) channel genes eag, Sh and slo are highly similar. CONCLUSIONS These results showed that MaggotTracker is an efficient tool for automatic phenotyping. The MaggotTracker software as well as the data presented here can be downloaded from our open-access site www.WormLoco.org/Mag.
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Koyama T, Rodrigues MA, Athanasiadis A, Shingleton AW, Mirth CK. Nutritional control of body size through FoxO-Ultraspiracle mediated ecdysone biosynthesis. eLife 2014; 3:e03091. [PMID: 25421296 PMCID: PMC4337420 DOI: 10.7554/elife.03091] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 10/18/2014] [Indexed: 01/21/2023] Open
Abstract
Despite their fundamental importance for body size regulation, the mechanisms that stop growth are poorly understood. In Drosophila melanogaster, growth ceases in response to a peak of the molting hormone ecdysone that coincides with a nutrition-dependent checkpoint, critical weight. Previous studies indicate that insulin/insulin-like growth factor signaling (IIS)/Target of Rapamycin (TOR) signaling in the prothoracic glands (PGs) regulates ecdysone biosynthesis and critical weight. Here we elucidate a mechanism through which this occurs. We show that Forkhead Box class O (FoxO), a negative regulator of IIS/TOR, directly interacts with Ultraspiracle (Usp), part of the ecdysone receptor. While overexpressing FoxO in the PGs delays ecdysone biosynthesis and critical weight, disrupting FoxO-Usp binding reduces these delays. Further, feeding ecdysone to larvae eliminates the effects of critical weight. Thus, nutrition controls ecdysone biosynthesis partially via FoxO-Usp prior to critical weight, ensuring that growth only stops once larvae have achieved a target nutritional status.
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Affiliation(s)
- Takashi Koyama
- Development, Evolution and the Environment
Laboratory, Instituto Gulbenkian de
Ciência, Oeiras, Portugal
| | - Marisa A Rodrigues
- Development, Evolution and the Environment
Laboratory, Instituto Gulbenkian de
Ciência, Oeiras, Portugal
| | - Alekos Athanasiadis
- Protein-Nucleic Acids Interactions Laboratory,
Instituto Gulbenkian de Ciência,
Oeiras, Portugal
| | - Alexander W Shingleton
- Department of Biology, Lake Forest
College, Lake
Forest, United States
- Department of Zoology, Michigan State
University, East
Lansing, United States
| | - Christen K Mirth
- Development, Evolution and the Environment
Laboratory, Instituto Gulbenkian de
Ciência, Oeiras, Portugal
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57
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Stillwell RC, Daws A, Davidowitz G. The ontogeny of sexual size dimorphism of a moth: when do males and females grow apart? PLoS One 2014; 9:e106548. [PMID: 25184664 PMCID: PMC4153660 DOI: 10.1371/journal.pone.0106548] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/09/2014] [Indexed: 11/24/2022] Open
Abstract
Sexual dimorphism in body size (sexual size dimorphism) is common in many species. The sources of selection that generate the independent evolution of adult male and female size have been investigated extensively by evolutionary biologists, but how and when females and males grow apart during ontogeny is poorly understood. Here we use the hawkmoth, Manduca sexta, to examine when sexual size dimorphism arises by measuring body mass every day during development. We further investigated whether environmental variables influence the ontogeny of sexual size dimorphism by raising moths on three different diet qualities (poor, medium and high). We found that size dimorphism arose during early larval development on the highest quality food treatment but it arose late in larval development when raised on the medium quality food. This female-biased dimorphism (females larger) increased substantially from the pupal-to-adult stage in both treatments, a pattern that appears to be common in Lepidopterans. Although dimorphism appeared in a few stages when individuals were raised on the poorest quality diet, it did not persist such that male and female adults were the same size. This demonstrates that the environmental conditions that insects are raised in can affect the growth trajectories of males and females differently and thus when dimorphism arises or disappears during development. We conclude that the development of sexual size dimorphism in M. sexta occurs during larval development and continues to accumulate during the pupal/adult stages, and that environmental variables such as diet quality can influence patterns of dimorphism in adults.
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Affiliation(s)
- R Craig Stillwell
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Andrew Daws
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Goggy Davidowitz
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
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58
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Juvenile hormone regulates body size and perturbs insulin signaling in Drosophila. Proc Natl Acad Sci U S A 2014; 111:7018-23. [PMID: 24778227 DOI: 10.1073/pnas.1313058111] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The role of juvenile hormone (JH) in regulating the timing and nature of insect molts is well-established. Increasing evidence suggests that JH is also involved in regulating final insect size. Here we elucidate the developmental mechanism through which JH regulates body size in developing Drosophila larvae by genetically ablating the JH-producing organ, the corpora allata (CA). We found that larvae that lack CA pupariated at smaller sizes than control larvae due to a reduced larval growth rate. Neither the timing of the metamorphic molt nor the duration of larval growth was affected by the loss of JH. Further, we show that the effects of JH on growth rate are dependent on the forkhead box O transcription factor (FOXO), which is negatively regulated by the insulin-signaling pathway. Larvae that lacked the CA had elevated levels of FOXO activity, whereas a loss-of-function mutation of FOXO rescued the effects of CA ablation on final body size. Finally, the effect of JH on growth appears to be mediated, at least in part, via ecdysone synthesis in the prothoracic gland. These results indicate a role of JH in regulating growth rate via the ecdysone- and insulin-signaling pathways.
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59
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Nikitovic D, Bogin B. Ontogeny of sexual size dimorphism and environmental quality in Guatemalan children. Am J Hum Biol 2013; 26:117-23. [DOI: 10.1002/ajhb.22492] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 11/06/2013] [Accepted: 11/14/2013] [Indexed: 11/09/2022] Open
Affiliation(s)
- Dejana Nikitovic
- Department of Anthropology; University of Toronto; Toronto Ontario Canada M5S 2S2
- Department of Anthropology; University of Toronto Scarborough; Toronto Ontario Canada M1C 1A4
| | - Barry Bogin
- Centre for Global Health & Human Development; SSEHS, Loughborough University, Loughborough, Leicestershire LE11 3TU; United Kingdom
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Ragan TJ, Bailey AP, Gould AP, Driscoll PC. Volume determination with two standards allows absolute quantification and improved chemometric analysis of metabolites by NMR from submicroliter samples. Anal Chem 2013; 85:12046-54. [PMID: 24251761 PMCID: PMC3871890 DOI: 10.1021/ac403111s] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
![]()
The accurate measurement of metabolite
concentrations in miniscule
biological sample volumes is often desirable, yet it remains challenging.
In many cases, the starting analyte volumes are imprecisely known,
or not directly measurable, and hence absolute metabolite concentrations
are difficult to calculate. Here, we introduce volume determination
using two standards (VDTS) as a general quantitative method for the
analysis of polar metabolites in submicrolitre samples using 1H NMR spectroscopy. This approach permits the back calculation
of absolute metabolite concentrations from small biological samples
of unknown volume. Where small sample volumes are also variable, VDTS
can improve multivariate chemometric analysis. In this context, principal
component analysis (PCA) yielded more logically consistent and biologically
insightful outputs when we used volume-corrected spectra, calculated
using VDTS, rather than probabilistic quotient normalization (PQN)
of raw spectra. As proof-of-principle, the VDTS-based method and PCA
were used to analyze polar metabolites in the hemolymph (blood) extracted
from larvae of the very small but widely used genetic model organism Drosophila. This analysis showed that the hemolymph metabolomes
of males and females are markedly different when larvae are well fed.
However, gender-specific metabolomes tend to converge when larval
dietary nutrients are restricted. We discuss the biological implications
of these surprising results and compare and contrast them to previous
analyses of Drosophila hemolymph and mammalian blood
plasma. Together, these findings reveal an interesting and hitherto
unknown sexual dimorphism in systemic Drosophila metabolites,
clearly warranting further biological investigation. Importantly,
the VDTS approach should be adaptable to many different analytical
platforms, including mass spectrometry.
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Affiliation(s)
- Timothy J Ragan
- Division of Molecular Structure, Medical Research Council National Institute for Medical Research , The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom
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61
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Ghosh SM, Testa ND, Shingleton AW. Temperature-size rule is mediated by thermal plasticity of critical size in Drosophila melanogaster. Proc Biol Sci 2013; 280:20130174. [PMID: 23595269 PMCID: PMC3652456 DOI: 10.1098/rspb.2013.0174] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 03/28/2013] [Indexed: 11/12/2022] Open
Abstract
Most ectotherms show an inverse relationship between developmental temperature and body size, a phenomenon known as the temperature-size rule (TSR). Several competing hypotheses have been proposed to explain its occurrence. According to one set of views, the TSR results from inevitable biophysical effects of temperature on the rates of growth and differentiation, whereas other views suggest the TSR is an adaptation that can be achieved by a diversity of mechanisms in different taxa. Our data reveal that the fruitfly, Drosophila melanogaster, obeys the TSR using a novel mechanism: reduction in critical size at higher temperatures. In holometabolous insects, attainment of critical size initiates the hormonal cascade that terminates growth, and hence, Drosophila larvae appear to instigate the signal to stop growth at a smaller size at higher temperatures. This is in contrast to findings from another holometabolous insect, Manduca sexta, in which the TSR results from the effect of temperature on the rate and duration of growth. This contrast suggests that there is no single mechanism that accounts for the TSR. Instead, the TSR appears to be an adaptation that is achieved at a proximate level through different mechanisms in different taxa.
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Affiliation(s)
- Shampa M Ghosh
- Department of Zoology: Ecology, Evolutionary Biology and Behavior Program, Michigan State University, East Lansing, MI 48824, USA.
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