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Sample records for flight muscle dimorphism

  1. Variations in fuel use in the flight muscles of wing-dimorphic Gryllus firmus and implications for morph-specific dispersal.

    PubMed

    Zhang, Bao-Chang; Jiang, Cheng-Ji; An, Chun-Ju; Zhang, Qing-Wen; Zhao, Zhang-Wu

    2011-12-01

    Although a considerable amount of information is available on tradeoffs in wing-polymorphic insects, only limited data are available on the relationship between flight and biochemical variation within species. In the current study, we compared the biochemical basis in the dorsolongitudinal flight muscle of the wing-dimorphic sand cricket, Gryllus firmus Scudder, with respect to tradeoffs in energy resources related to morph-specific flight, including glycogen, trehalose, and triglycerides. Our results show that levels of glycogen and trehalose in long-winged adults (LW[f]) were significantly higher before dispersal, on days 5 and 7. Considering that this is the period during which long-winged adults are flight-capable, these results suggest that both glycogen and trehalose are important to flight. However, levels of triglycerides in short-winged crickets (SW) were higher than in long-winged crickets, suggesting that triglycerides are not directly related to initial flight. In SW adults, triglyceride content on days 5 and 7 was significantly higher just before lights off than at the same time on day 1 or at any other time after lights on all other days. This suggests that triglycerides are probably related to reproductive behaviors, such as mating and oviposition, in the SW morph. In addition, flight muscle water content was significantly lower in the LW(f) morph than in the SW morph.

  2. Physiological trade-off between cellular immunity and flight capability in the wing-dimorphic cricket, Gryllus firmus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sand cricket, Gryllus firmus, is a wing-dimorphic species with long-wing (LW) and short wing (LW) morphs. The LW forms have very well developed wings and flight muscles and their SW counterparts have reduced wings and flight muscles, coupled with greater resource allocations to reproduction. Thi...

  3. Sexual dimorphism of perineal muscles and motoneurons in spotted hyenas.

    PubMed

    Forger, N G; Frank, L G; Breedlove, S M; Glickman, S E

    1996-11-11

    Female spotted hyenas are known for their male-like genitalia, high levels of aggression, and dominance over males, characteristics which are attributed to exposure to elevated levels of testosterone in utero. Although the nervous system of spotted hyenas has not previously been examined, one might predict that neural systems which are sexually dimorphic in other mammals would be monomorphic in this species. Spinal motoneurons which innervate muscles associated with the phallus are located in Onuf's nucleus and are more numerous in males than in females in a wide array of mammals. Onuf's nucleus was examined in adult and neonatal spotted hyenas and, contrary to expectation, was found to be sexually dimorphic in the typical mammalian pattern: Males have significantly more motoneurons in Onuf's nucleus than do females. This dimorphism was correlated with a previously undescribed dimorphism in the relevant target musculature. Specifically, the morphology of the bulbocavernosus muscle is distinctly different in male and female spotted hyenas. Pregnant hyenas were treated with anti-androgen in an attempt to interfere with the actions of androgen during fetal development. Motoneuron number in Onuf's nucleus and the morphology of the bulbocavernosus muscle were feminized in males exposed to anti-androgen in utero.

  4. Sexual dimorphism of Murine Masticatory Muscle Function

    PubMed Central

    Daniels, David W.; Tian, Zuozhen; Barton, Elisabeth R.

    2008-01-01

    (1) Objective To determine if gender distinctions of force generating capacity existed in murine masticatory muscles. (2) Design In order to investigate the effect of sex on force generating capacity in this muscle group, an isolated muscle preparation was developed utilizing the murine anterior deep masseter. Age-matched male and female mice were utilized to assess function, muscle fiber type and size in this muscle. (3) Results Maximum isometric force production was not different between age-matched male and female mice. However, the rate of force generation and relaxation was slower in female masseter muscles. Assessment of fiber type distribution by immunohistochemistry revealed a threefold decrease in the proportion of myosin heavy chain 2b positive fibers in female masseters, which correlated with the differences in contraction kinetics. (4) Conclusions These results provide evidence that masticatory muscle strength in mice is not affected by sex, but there are significant distinctions in kinetics associated with force production between males and females. PMID:18028868

  5. Skeletal Muscle Gender Dimorphism from Proteomics

    PubMed Central

    Dimova, Kalina; Metskas, Lauren Ann; Kulp, Mohini; Scordilis, Stylianos P.

    2011-01-01

    Gross contraction in skeletal muscle is primarily determined by a relatively small number of contractile proteins, however this tissue is also remarkably adaptable to environmental factors1 such as hypertrophy by resistance exercise and atrophy by disuse. It thereby exhibits remodeling and adaptations to stressors (heat, ischemia, heavy metals, etc.)2,3. Damage can occur to muscle by a muscle exerting force while lengthening, the so-called eccentric contraction4. The contractile proteins can be damaged in such exertions and need to be repaired, degraded and/or resynthesized; these functions are not part of the contractile proteins, but of other much less abundant proteins in the cell. To determine what subset of proteins is involved in the amelioration of this type of damage, a global proteome must be established prior to exercise5 and then followed subsequent to the exercise to determine the differential protein expression and thereby highlight candidate proteins in the adaptations to damage and its repair. Furthermore, most studies of skeletal muscle have been conducted on the male of the species and hence may not be representative of female muscle. In this article we present a method for extracting proteins reproducibly from male and female muscles, and separating them by two-dimensional gel electrophoresis followed by high resolution digital imaging6. This provides a protocol for spots (and subsequently identified proteins) that show a statistically significant (p < 0.05) two-fold increase or decrease, appear or disappear from the control state. These are then excised, digested with trypsin and separated by high-pressure liquid chromatography coupled to a mass spectrometer (LC/MS) for protein identification (LC/MS/MS)5. This methodology (Figure 1) can be used on many tissues with little to no modification (liver, brain, heart etc.). PMID:22215112

  6. Skeletal muscle gender dimorphism from proteomics.

    PubMed

    Dimova, Kalina; Metskas, Lauren Ann; Kulp, Mohini; Scordilis, Stylianos P

    2011-01-01

    Gross contraction in skeletal muscle is primarily determined by a relatively small number of contractile proteins, however this tissue is also remarkably adaptable to environmental factors such as hypertrophy by resistance exercise and atrophy by disuse. It thereby exhibits remodeling and adaptations to stressors (heat, ischemia, heavy metals, etc.). Damage can occur to muscle by a muscle exerting force while lengthening, the so-called eccentric contraction. The contractile proteins can be damaged in such exertions and need to be repaired, degraded and/or resynthesized; these functions are not part of the contractile proteins, but of other much less abundant proteins in the cell. To determine what subset of proteins is involved in the amelioration of this type of damage, a global proteome must be established prior to exercise and then followed subsequent to the exercise to determine the differential protein expression and thereby highlight candidate proteins in the adaptations to damage and its repair. Furthermore, most studies of skeletal muscle have been conducted on the male of the species and hence may not be representative of female muscle. In this article we present a method for extracting proteins reproducibly from male and female muscles, and separating them by two-dimensional gel electrophoresis followed by high resolution digital imaging. This provides a protocol for spots (and subsequently identified proteins) that show a statistically significant (p < 0.05) two-fold increase or decrease, appear or disappear from the control state. These are then excised, digested with trypsin and separated by high-pressure liquid chromatography coupled to a mass spectrometer (LC/MS) for protein identification (LC/MS/MS). This methodology (Figure 1) can be used on many tissues with little to no modification (liver, brain, heart etc.). PMID:22215112

  7. A Beetle Flight Muscle Displays Leg Muscle Microstructure.

    PubMed

    Shimomura, Toshiki; Iwamoto, Hiroyuki; Vo Doan, Tat Thang; Ishiwata, Shin'ichi; Sato, Hirotaka; Suzuki, Madoka

    2016-09-20

    In contrast to major flight muscles in the Mecynorrhina torquata beetle, the third axillary (3Ax) muscle is a minor flight muscle that uniquely displays a powerful mechanical function despite its considerably small volume, ∼1/50 that of a major flight muscle. The 3Ax muscle contracts relatively slowly, and in flight strongly pulls the beating wing to attenuate the stroke amplitude. This attenuation leads to left-right turning in flight or wing folding to cease flying. What enables this small muscle to be so powerful? To explore this question, we examined the microstructure of the 3Ax muscle using synchrotron x-ray diffraction, optical microscopy, and immunoblotting analysis. We found that the 3Ax muscle has long (∼5 μm) myofilaments and that the ratio of thick (myosin) filaments to thin (actin) filaments is 1:5 or 1:6. These characteristics are not observed in the major flight muscles, which have shorter myofilaments (∼3.5 μm) with a smaller ratio (1:3), and instead are more typical of a leg muscle. Furthermore, the flight-muscle-specific troponin isoform, TnH, is not expressed in the 3Ax muscle. Since such a microstructure is suitable for generating large tension, the 3Ax muscle is appropriately designed to pull the wing strongly despite its small volume. PMID:27653488

  8. A Beetle Flight Muscle Displays Leg Muscle Microstructure.

    PubMed

    Shimomura, Toshiki; Iwamoto, Hiroyuki; Vo Doan, Tat Thang; Ishiwata, Shin'ichi; Sato, Hirotaka; Suzuki, Madoka

    2016-09-20

    In contrast to major flight muscles in the Mecynorrhina torquata beetle, the third axillary (3Ax) muscle is a minor flight muscle that uniquely displays a powerful mechanical function despite its considerably small volume, ∼1/50 that of a major flight muscle. The 3Ax muscle contracts relatively slowly, and in flight strongly pulls the beating wing to attenuate the stroke amplitude. This attenuation leads to left-right turning in flight or wing folding to cease flying. What enables this small muscle to be so powerful? To explore this question, we examined the microstructure of the 3Ax muscle using synchrotron x-ray diffraction, optical microscopy, and immunoblotting analysis. We found that the 3Ax muscle has long (∼5 μm) myofilaments and that the ratio of thick (myosin) filaments to thin (actin) filaments is 1:5 or 1:6. These characteristics are not observed in the major flight muscles, which have shorter myofilaments (∼3.5 μm) with a smaller ratio (1:3), and instead are more typical of a leg muscle. Furthermore, the flight-muscle-specific troponin isoform, TnH, is not expressed in the 3Ax muscle. Since such a microstructure is suitable for generating large tension, the 3Ax muscle is appropriately designed to pull the wing strongly despite its small volume.

  9. Effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (Rana catesbeiana, Shaw 1802)

    PubMed Central

    Kampe, Aaron R.; Peters, Susan E.

    2013-01-01

    Summary This study examined the effects of testosterone (T) on the contractile properties of two sexually dimorphic forelimb muscles and one non-dimorphic muscle in male bullfrogs (Rana catesbeiana, Shaw 1802). The dimorphic muscles in castrated males with testosterone replacement (T+) achieved higher forces and lower fatigability than did castrated males without replaced testosterone (T0 males), but the magnitude of the differences was low and many of the pair-wise comparisons of each muscle property were not statistically significant. However, when taken as a whole, the means of seven contractile properties varied in the directions expected of masculine values in T+ animals in the sexually dimorphic muscles. Moreover, these data, compared with previous data on male and female bullfrogs, show that values for T+ males are similar to normal males and are significantly different from females. The T0 males tended to be intermediate in character between T+ males and females, generally retaining masculine values. This suggests that the exposure of young males to T in their first breeding season produces a masculinizing effect on the sexually dimorphic muscles that is not reversed between breeding seasons when T levels are low. The relatively minor differences in contractile properties between T+ and T0 males may indicate that as circulating T levels rise during breeding season in normal males, contractile properties can be enhanced rapidly to maximal functional levels for breeding success. PMID:24143280

  10. Can Nocturnal Flight Calls of the Migrating Songbird, American Redstart, Encode Sexual Dimorphism and Individual Identity?

    PubMed Central

    Lanzone, Michael

    2016-01-01

    Bird species often use flight calls to engage in social behavior, for instance maintain group cohesion and to signal individual identity, kin or social associations, or breeding status of the caller. Additional uses also exist, in particular among migrating songbirds for communication during nocturnal migration. However, our understanding of the information that these vocalizations convey is incomplete, especially in nocturnal scenarios. To examine whether information about signaler traits could be encoded in flight calls we quantified several acoustic characteristics from calls of a nocturnally migrating songbird, the American Redstart. We recorded calls from temporarily captured wild specimens during mist-netting at the Powdermill Avian Research Center in Rector, PA. We measured call similarity among and within individuals, genders, and age groups. Calls from the same individual were significantly more similar to one another than to the calls of other individuals, and calls were significantly more similar among individuals of the same sex than between sexes. Flight calls from hatching-year and after hatching-year individuals were not significantly different. Our results suggest that American Redstart flight calls may carry identifiers of gender and individual identity. To our knowledge, this is the first evidence of individuality or sexual dimorphism in the flight calls of a migratory songbird. Furthermore, our results suggest that flight calls may have more explicit functions beyond simple group contact and cohesion. Nocturnal migration may require coordination among numerous individuals, and the use of flight calls to transmit information among intra- and conspecifics could be advantageous. Applying approaches that account for such individual and gender information may enable more advanced research using acoustic monitoring. PMID:27284697

  11. Can Nocturnal Flight Calls of the Migrating Songbird, American Redstart, Encode Sexual Dimorphism and Individual Identity?

    PubMed

    Griffiths, Emily T; Keen, Sara C; Lanzone, Michael; Farnsworth, Andrew

    2016-01-01

    Bird species often use flight calls to engage in social behavior, for instance maintain group cohesion and to signal individual identity, kin or social associations, or breeding status of the caller. Additional uses also exist, in particular among migrating songbirds for communication during nocturnal migration. However, our understanding of the information that these vocalizations convey is incomplete, especially in nocturnal scenarios. To examine whether information about signaler traits could be encoded in flight calls we quantified several acoustic characteristics from calls of a nocturnally migrating songbird, the American Redstart. We recorded calls from temporarily captured wild specimens during mist-netting at the Powdermill Avian Research Center in Rector, PA. We measured call similarity among and within individuals, genders, and age groups. Calls from the same individual were significantly more similar to one another than to the calls of other individuals, and calls were significantly more similar among individuals of the same sex than between sexes. Flight calls from hatching-year and after hatching-year individuals were not significantly different. Our results suggest that American Redstart flight calls may carry identifiers of gender and individual identity. To our knowledge, this is the first evidence of individuality or sexual dimorphism in the flight calls of a migratory songbird. Furthermore, our results suggest that flight calls may have more explicit functions beyond simple group contact and cohesion. Nocturnal migration may require coordination among numerous individuals, and the use of flight calls to transmit information among intra- and conspecifics could be advantageous. Applying approaches that account for such individual and gender information may enable more advanced research using acoustic monitoring.

  12. Nerve-muscle interactions during flight muscle development in Drosophila

    NASA Technical Reports Server (NTRS)

    Fernandes, J. J.; Keshishian, H.

    1998-01-01

    During Drosophila pupal metamorphosis, the motoneurons and muscles differentiate synchronously, providing an opportunity for extensive intercellular regulation during synapse formation. We examined the existence of such interactions by developmentally delaying or permanently eliminating synaptic partners during the formation of indirect flight muscles. When we experimentally delayed muscle development, we found that although adult-specific primary motoneuron branching still occurred, the higher order (synaptic) branching was suspended until the delayed muscle fibers reached a favourable developmental state. In reciprocal experiments we found that denervation caused a decrease in the myoblast pool. Furthermore, the formation of certain muscle fibers (dorsoventral muscles) was specifically blocked. Exceptions were the adult muscles that use larval muscle fibers as myoblast fusion targets (dorsal longitudinal muscles). However, when these muscles were experimentally compelled to develop without their larval precursors, they showed an absolute dependence on the motoneurons for their formation. These data show that the size of the myoblast pool and early events in fiber formation depend on the presence of the nerve, and that, conversely, peripheral arbor development and synaptogenesis is closely synchronized with the developmental state of the muscle.

  13. Building Muscles, Keeping Muscles: Protein Turnover During Space Flight

    NASA Technical Reports Server (NTRS)

    Ferrando, Arny; Bloomberg, Jacob; Lee, Angie (Technical Monitor)

    2002-01-01

    As we age we lose muscle mass and strength. The problem is a matter of use it or lose it and more - a fact to which any active senior can attest. An imbalance in the natural cycle of protein turnover may be a contributing factor to decreased muscle mass. But the answer is not so simple, since aging is associated with changes in hormones, activity levels, nutrition, and often, disease. The human body constantly uses amino acids to build muscle protein, which then breaks down and must be replaced. When protein turnover gets out of balance, so that more protein breaks down than the body can replace, the result is muscle loss. This is not just the bane of aging, however. Severely burned people may have difficulty building new muscle long after the burned skin has been repaired. Answers to why we lose muscle mass and strength - and how doctors can fix it - may come from space. Astronauts usually eat a well-balanced diet and maintain an exercise routine to stay in top health. During long-duration flight, they exercise regularly to reduce the muscle loss that results from being in a near-weightless environment. Despite these precautions, astronauts lose muscle mass and strength during most missions. They quickly recover after returning to Earth - this is a temporary condition in an otherwise healthy population. Members of the STS-107 crew are participating in a study of the effects of space flight, hormone levels, and stress on protein turnover. When we are under stress, the body responds with a change in hormone levels. Researchers hypothesize that this stress-induced change in hormones along with the near-weightlessness might result in the body synthesizing less muscle protein, causing muscles to lose their strength and size. Astronauts, who must perform numerous duties in a confined and unusual environment, experience some stress during their flight, making them excellent candidates for testing the researchers' hypothesis.

  14. Atypical 'fibrillar' flight muscle in strepsiptera.

    PubMed

    Smith, D S; Kathirithamby, J

    1984-01-01

    The fine structure of the principal and ancillary metathoracic flight muscle fibres in the adult male of a strepsipteran, Elenchus tenuicornis, is described. Power-producing dorsal longitudinal and dorso-ventral flight muscles show features consistent with myoneural asynchrony: myofibrils are large and discrete and are separated by large closely packed mitochondria; the sarcoplasmic reticulum is very reduced but engages with T-system membranes in dyads at the mid-sarcomere H-band level. With respect to other asynchronous insect flight muscles, the fibres of Elenchus are anomalous (i) in the small fibre diameter, (ii) in the variable contour of the myofibrils and (iii) in the absence of tracheolar invagination. The functional significance of these structural features is discussed. Ancillary metathoracic muscles are structurally comparable with other synchronous fibres in possessing an extensive SR compartment. Structural evidence for asynchrony in the flight mechanism of Strepsiptera is considered in the context of the evolution of this mechanism throughout the insect Orders. PMID:6531780

  15. Gender dimorphism in skeletal muscle leptin receptors, serum leptin and insulin sensitivity.

    PubMed

    Guerra, Borja; Fuentes, Teresa; Delgado-Guerra, Safira; Guadalupe-Grau, Amelia; Olmedillas, Hugo; Santana, Alfredo; Ponce-Gonzalez, Jesus Gustavo; Dorado, Cecilia; Calbet, José A L

    2008-01-01

    To determine if there is a gender dimorphism in the expression of leptin receptors (OB-R170, OB-R128 and OB-R98) and the protein suppressor of cytokine signaling 3 (SOCS3) in human skeletal muscle, the protein expression of OB-R, perilipin A, SOCS3 and alpha-tubulin was assessed by Western blot in muscle biopsies obtained from the m. vastus lateralis in thirty-four men (age = 27.1+/-6.8 yr) and thirty-three women (age = 26.7+/-6.7 yr). Basal serum insulin concentration and HOMA were similar in both genders. Serum leptin concentration was 3.4 times higher in women compared to men (P<0.05) and this difference remained significant after accounting for the differences in percentage of body fat or soluble leptin receptor. OB-R protein was 41% (OB-R170, P<0.05) and 163% (OB-R128, P<0.05) greater in women than men. There was no relationship between OB-R expression and the serum concentrations of leptin or 17beta-estradiol. In men, muscle OB-R128 protein was inversely related to serum free testosterone. In women, OB-R98 and OB-R128 were inversely related to total serum testosterone concentration, and OB-R128 to serum free testosterone concentration. SOCS3 protein expression was similar in men and women and was not related to OB-R. In women, there was an inverse relationship between the logarithm of free testosterone and SCOS3 protein content in skeletal muscle (r = -0.46, P<0.05). In summary, there is a gender dimorphism in skeletal muscle leptin receptors expression, which can be partly explained by the influence of testosterone. SOCS3 expression in skeletal muscle is not up-regulated in women, despite very high serum leptin concentrations compared to men. The circulating form of the leptin receptor can not be used as a surrogate measure of the amount of leptin receptors expressed in skeletal muscles.

  16. Nonmyocytic Androgen Receptor Regulates the Sexually Dimorphic Development of the Embryonic Bulbocavernosus Muscle

    PubMed Central

    Ipulan, Lerrie Ann; Suzuki, Kentaro; Sakamoto, Yuki; Murashima, Aki; Imai, Yuuki; Omori, Akiko; Nakagata, Naomi; Nishinakamura, Ryuichi; Valasek, Petr

    2014-01-01

    The bulbocavernosus (BC) is a sexually dimorphic muscle observed only in males. Androgen receptor knockout mouse studies show the loss of BC formation. This suggests that androgen signaling plays a vital role in its development. Androgen has been known to induce muscle hypertrophy through satellite cell activation and myonuclei accretion during muscle regeneration and growth. Whether the same mechanism is present during embryonic development is not yet elucidated. To identify the mechanism of sexual dimorphism during BC development, the timing of morphological differences was first established. It was revealed that the BC was morphologically different between male and female mice at embryonic day (E) 16.5. Differences in the myogenic process were detected at E15.5. The male BC possesses a higher number of proliferating undifferentiated myoblasts. To identify the role of androgen signaling in this process, muscle-specific androgen receptor (AR) mutation was introduced, which resulted in no observable phenotypes. Hence, the expression of AR in the BC was examined and found that the AR did not colocalize with any muscle markers such as Myogenic differentiation 1, Myogenin, and paired box transcription factor 7. It was revealed that the mesenchyme surrounding the BC expressed AR and the BC started to express AR at E15.5. AR mutation on the nonmyocytic cells using spalt-like transcription factor 1 (Sall1) Cre driver mouse was performed, which resulted in defective BC formation. It was revealed that the number of proliferating undifferentiated myoblasts was reduced in the Sall1 Cre:ARL−/Y mutant embryos, and the adult mutants were devoid of BC. The transition of myoblasts from proliferation to differentiation is mediated by cyclin-dependent kinase inhibitors. An increased expression of p21 was observed in the BC myoblast of the Sall1 Cre:ARL−/Y mutant and wild-type female. Altogether this study suggests that the nonmyocytic AR may paracrinely regulate the

  17. Nonmyocytic androgen receptor regulates the sexually dimorphic development of the embryonic bulbocavernosus muscle.

    PubMed

    Ipulan, Lerrie Ann; Suzuki, Kentaro; Sakamoto, Yuki; Murashima, Aki; Imai, Yuuki; Omori, Akiko; Nakagata, Naomi; Nishinakamura, Ryuichi; Valasek, Petr; Yamada, Gen

    2014-07-01

    The bulbocavernosus (BC) is a sexually dimorphic muscle observed only in males. Androgen receptor knockout mouse studies show the loss of BC formation. This suggests that androgen signaling plays a vital role in its development. Androgen has been known to induce muscle hypertrophy through satellite cell activation and myonuclei accretion during muscle regeneration and growth. Whether the same mechanism is present during embryonic development is not yet elucidated. To identify the mechanism of sexual dimorphism during BC development, the timing of morphological differences was first established. It was revealed that the BC was morphologically different between male and female mice at embryonic day (E) 16.5. Differences in the myogenic process were detected at E15.5. The male BC possesses a higher number of proliferating undifferentiated myoblasts. To identify the role of androgen signaling in this process, muscle-specific androgen receptor (AR) mutation was introduced, which resulted in no observable phenotypes. Hence, the expression of AR in the BC was examined and found that the AR did not colocalize with any muscle markers such as Myogenic differentiation 1, Myogenin, and paired box transcription factor 7. It was revealed that the mesenchyme surrounding the BC expressed AR and the BC started to express AR at E15.5. AR mutation on the nonmyocytic cells using spalt-like transcription factor 1 (Sall1) Cre driver mouse was performed, which resulted in defective BC formation. It was revealed that the number of proliferating undifferentiated myoblasts was reduced in the Sall1 Cre:AR(L-/Y) mutant embryos, and the adult mutants were devoid of BC. The transition of myoblasts from proliferation to differentiation is mediated by cyclin-dependent kinase inhibitors. An increased expression of p21 was observed in the BC myoblast of the Sall1 Cre:AR(L-/Y) mutant and wild-type female. Altogether this study suggests that the nonmyocytic AR may paracrinely regulate the

  18. THE STRUCTURE OF INSECT FIBRILLAR FLIGHT MUSCLE

    PubMed Central

    Smith, David S.

    1961-01-01

    The fine structure of fibrillar flight muscle of the mature adult beetle Tenebrio molitor is described. Although the very high frequency of contraction of fibrillar muscle has previously been in part accounted for as the result of mechanical specialization of the wing-bearing segment rather than of a correspondingly high rate of motor impulse supply, the problem of the nature of the pathway by which excitation is conducted into these large fibers remained. Therefore, particular attention has been given to the disposition and relationships of the plasma membrane and sarcoplasmic reticulum in this tissue. The invading tracheoles draw with them a sheath of plasma membrane from the surface to all depths in the fiber, and it is suggested that these sheaths, together with the extensive tubular arborisations arising from them, reduce the maximum plasma membrane-to-fibril distance from the radius of the fiber to a value of less than 2 µ. The evidence presented here confirms Veratti's contention that in fibrillar muscle the "reticulum" is associated with, though entirely distinct from the fibrils. Unlike other muscles so far examined, these flight muscle fibers contain a plasma membrane reticulum only, but it is possible that elsewhere the general "sarcoplasmic reticulum" includes a component derived from the plasma membrane, likewise acting as the pathway for inward conduction of excitation. Profiles of the internalised plasma membrane in Tenebrio showing the usual triple-layered 25-25-25 A organization are frequently seen, in sections, in close association with isolated vesicles (defined by "simple" 50 A membranes) which are here considered to represent, in vestigial form, the portion of the sarcoplasmic reticulum which in other types of muscle is complex and highly developed. Such associations, in Tenebrio, between these two dissimilar elements are here termed "dyads" and the possible morphological and functional homology between these and the "triads" of other types of

  19. De novo transcriptome assembly from fat body and flight muscles transcripts to identify morph-specific gene expression profiles in Gryllus firmus.

    PubMed

    Nanoth Vellichirammal, Neetha; Zera, Anthony J; Schilder, Rudolf J; Wehrkamp, Cody; Riethoven, Jean-Jack M; Brisson, Jennifer A

    2014-01-01

    Wing polymorphism is a powerful model for examining many aspects of adaptation. The wing dimorphic cricket species, Gryllus firmus, consists of a long-winged morph with functional flight muscles that is capable of flight, and two flightless morphs. One (obligately) flightless morph emerges as an adult with vestigial wings and vestigial flight muscles. The other (plastic) flightless morph emerges with fully-developed wings but later in adulthood histolyzes its flight muscles. Importantly both flightless morphs have substantially increased reproductive output relative to the flight-capable morph. Much is known about the physiological and biochemical differences between the morphs with respect to adaptations for flight versus reproduction. In contrast, little is known about the molecular genetic basis of these morph-specific adaptations. To address this issue, we assembled a de novo transcriptome of G. firmus using 141.5 million Illumina reads generated from flight muscles and fat body, two organs that play key roles in flight and reproduction. We used the resulting 34,411 transcripts as a reference transcriptome for differential gene expression analyses. A comparison of gene expression profiles from functional flight muscles in the flight-capable morph versus histolyzed flight muscles in the plastic flight incapable morph identified a suite of genes involved in respiration that were highly expressed in pink (functional) flight muscles and genes involved in proteolysis highly expressed in the white (histolyzed) flight muscles. A comparison of fat body transcripts from the obligately flightless versus the flight-capable morphs revealed differential expression of genes involved in triglyceride biosynthesis, lipid transport, immune function and reproduction. These data provide a valuable resource for future molecular genetics research in this and related species and provide insight on the role of gene expression in morph-specific adaptations for flight versus

  20. Diffraction Ellipsometry Studies on Insect Flight Muscle

    NASA Astrophysics Data System (ADS)

    Shen, Sui

    Characterization of the orientation and distribution of myosin cross-bridge at rigor, relax, low ionic strength (36 mM) and activation (pCa 4.3) conditions are of great interest since these states have been proposed to be transient steps in the cyclical interaction of myosin heads with actin during contraction. Measurements sensitive to the cross-bridge orientation in chemically skinned single muscle fibers of the insect, Lethocerus collossicus have been performed under various physiological conditions using laser diffraction ellipsometry. Determination of both the total birefringence, Deltan, and the differential field ratio, rm DFR (defined as {E_parallel -E_|over E_parallel-E _|}),is necessary for complete characterization of the optical polarization state. For rigor insect fiber, the birefringence value was close to the value we obtained from chemically skinned frog muscle fibers. However, the differential field ratio, DFR, was a negative value for insect fiber, while we always measured a positive value from frog muscle fibers. Polarization states of light diffracted from fibers exhibited a dependence on configurations of structural proteins at different conditions: fluid index matching using o-toluidine, alpha -chymotrypsin cleavage, KCl myosin extraction, rigor state, relaxed state, exogenous S-1 binding on rigor fiber, low ionic strength state, activation state at resting or stretched length. Results of our data analysis suggested that: (1) the negative DFR value of the insect flight muscle was contributed by alpha-actinin arranged perpendicular to the fiber axis in the Z-line, (2) in rigor fiber, 70% of myosin heads are doubly bound (45^circ and 90^ circ) while the rest of 30% are in single head binding configuration (90^circ), (3) myosin heads are randomly oriented in relaxed fiber, (4) mean axial angle is about 62^ circ for exogenous myosin heads binding on rigor fiber, (5) at low ionic strength, 25% of the total myosin heads are weakly attached to actin

  1. Skeletal muscle protein synthesis and degradation exhibit sexual dimorphism after chronic alcohol consumption but not acute intoxication.

    PubMed

    Lang, Charles H; Frost, Robert A; Vary, Thomas C

    2007-06-01

    Epidemiological evidence suggests alcoholic myopathy is more severe in females than males, but comparable animal studies are lacking that make elucidating the biochemical locus for this defect problematic. The present study determined whether skeletal muscle protein synthesis and markers of degradation exhibit a sexual dimorphic response to either chronic alcohol consumption or acute intoxication. Male and female rats were fed an alcohol-containing diet, pair-fed for 26 wk (chronic), or received an intraperitoneal injection of alcohol (acute). In males, chronic alcohol decreased gastrocnemius protein synthesis by 20%. This reduction was associated with a twofold increase in the inactive eukaryotic initiation factor (eIF) 4E.4E-binding protein 1 (4E-BP1) complex and a 60% reduction in the active eIF4E.eIF4G complex. This redistribution of eIF4E was associated with decreased phosphorylation of both 4E-BP1 and eIF4G (50-55%). The phosphorylation of ribosomal protein S6 was also reduced 60% in alcohol-consuming male rats. In contrast, neither rates of protein synthesis nor indexes of translation initiation in muscle were altered in alcohol-fed female rats despite blood alcohol levels comparable to males. Chronic alcohol ingestion did not alter atrogin-1 or muscle RING finger-1 mRNA content (biomarkers of muscle proteolysis) in males but increased their expression in females 50-100%. Acute alcohol intoxication produced a comparable decrease in muscle protein synthesis and translation initiation in both male and female rats. Our data demonstrate a sexual dimorphism for muscle protein synthesis, translation initiation, and proteolysis in response to chronic, but not acute, alcohol intoxication; however, they do not support evidence indicating females are more sensitive toward the development of alcoholic skeletal muscle myopathy.

  2. Ion currents in Drosophila flight muscles

    PubMed Central

    Salkoff, Lawrence B.; Wyman, Robert J.

    1983-01-01

    1. The dorsal longitudinal flight muscles of Drosophila melanogaster contain three voltage-activated ion currents, two distinct potassium currents and a calcium current. The currents can be isolated from each other by exploiting the developmental properties of the system and genetic tools, as well as conventional pharmacology. 2. The fast transient potassium current (IA) is the first channel to appear in the developing muscle membrane. It can be studied in isolation between 60 and 70 hr of pupal development. The channels can be observed to carry both outward and inward currents depending on the external potassium concentration. IA is blocked by both tetraethylammonium ion (TEA) and 3- or 4-aminopyridine. The inactivation and recovery properties of IA are responsible for a facilitating effect on membrane excitability. 3. The delayed outward current (IK) develops after maturation of the IA system. IK can be isolated from IA by use of a mutation that removes IA from the membrane current response and can be studied before the development of Ca2+ channels. IK shows no inactivation. The channels are more sensitive to blockage by TEA than IA channels, but are not substantially blocked by 3- or 4-aminopyridine. 4. The calcium current (ICa) is the last of the major currents to develop and must be isolated pharmacologically with potassium-blocking agents. ICa shows inactivation when Ca2+ is present but not when Ba2+ is the sole current carrier. When Ca2+ is the current carrier, the addition of Na+ or Li+ retards the inactivation of the net inward current. When the membrane voltage is not clamped, Ba2+ alone, or Ca2+ with Na+ (or Li+), produces a plateau response of extended duration. 5. The synaptic current (IJ) evoked by motoneurone stimulation is the fastest and largest of the current systems. It has a reversal potential of approximately -5 mV, indicating roughly equal permeabilities of Na+ and K+. During a nerve-driven muscle spike, IJ is the major inward current, causing

  3. Muscle function in avian flight: achieving power and control

    PubMed Central

    Biewener, Andrew A.

    2011-01-01

    Flapping flight places strenuous requirements on the physiological performance of an animal. Bird flight muscles, particularly at smaller body sizes, generally contract at high frequencies and do substantial work in order to produce the aerodynamic power needed to support the animal's weight in the air and to overcome drag. This is in contrast to terrestrial locomotion, which offers mechanisms for minimizing energy losses associated with body movement combined with elastic energy savings to reduce the skeletal muscles' work requirements. Muscles also produce substantial power during swimming, but this is mainly to overcome body drag rather than to support the animal's weight. Here, I review the function and architecture of key flight muscles related to how these muscles contribute to producing the power required for flapping flight, how the muscles are recruited to control wing motion and how they are used in manoeuvring. An emergent property of the primary flight muscles, consistent with their need to produce considerable work by moving the wings through large excursions during each wing stroke, is that the pectoralis and supracoracoideus muscles shorten over a large fraction of their resting fibre length (33–42%). Both muscles are activated while being lengthened or undergoing nearly isometric force development, enhancing the work they perform during subsequent shortening. Two smaller muscles, the triceps and biceps, operate over a smaller range of contractile strains (12–23%), reflecting their role in controlling wing shape through elbow flexion and extension. Remarkably, pigeons adjust their wing stroke plane mainly via changes in whole-body pitch during take-off and landing, relative to level flight, allowing their wing muscles to operate with little change in activation timing, strain magnitude and pattern. PMID:21502121

  4. Morphometrics of the Anterior Belly and Intermediate Tendon of the Digastric Muscle: Sexual Dimorphism and Implications for Surgery.

    PubMed

    Zdilla, Matthew J; Pancake, Alex R; Lambert, H Wayne

    2016-07-01

    The anterior belly of the digastric muscle (ABDM) is important in a variety of surgeries including submental lipectomy, rhytidectomy, alteration of the cervicomental angle via muscle resection, the "digastric corset" procedure for submental rejuvenation, the submental artery flap, and reanimation of the mouth after facial nerve palsy. Despite its clinical significance, little information exists regarding the morphometrics of the ABDM or its associated intermediate tendon. This study analyzed a total of 35 intact ABDMs and 43 intact intermediate tendons from 23 cadavers. Measurements were taken of the following parameters: muscle belly area, muscle belly length, intermediate tendon length, and intermediate tendon width at mid-tendon. Normative descriptive statistics are included within the report. Males were found to have significantly longer left-sided muscle bellies than right-sided bellies from males (U = 23.0; P = 0.044), left-sided bellies from females (U = 19.0; P = 0.020), and right-sided bellies from females (U = 12.0; P = 0.035). The morphometry, including sexual dimorphism, presented in this report can aid in the surgical planning and execution of numerous operations performed in head and neck, especially digastric muscle transfer surgery. PMID:27258716

  5. Evolution of avian flight: muscles and constraints on performance.

    PubMed

    Tobalske, Bret W

    2016-09-26

    Competing hypotheses about evolutionary origins of flight are the 'fundamental wing-stroke' and 'directed aerial descent' hypotheses. Support for the fundamental wing-stroke hypothesis is that extant birds use flapping of their wings to climb even before they are able to fly; there are no reported examples of incrementally increasing use of wing movements in gliding transitioning to flapping. An open question is whether locomotor styles must evolve initially for efficiency or if they might instead arrive due to efficacy. The proximal muscles of the avian wing output work and power for flight, and new research is exploring functions of the distal muscles in relation to dynamic changes in wing shape. It will be useful to test the relative contributions of the muscles of the forearm compared with inertial and aerodynamic loading of the wing upon dynamic morphing. Body size has dramatic effects upon flight performance. New research has revealed that mass-specific muscle power declines with increasing body mass among species. This explains the constraints associated with being large. Hummingbirds are the only species that can sustain hovering. Their ability to generate force, work and power appears to be limited by time for activation and deactivation within their wingbeats of high frequency. Most small birds use flap-bounding flight, and this flight style may offer an energetic advantage over continuous flapping during fast flight or during flight into a headwind. The use of flap-bounding during slow flight remains enigmatic. Flap-bounding birds do not appear to be constrained to use their primary flight muscles in a fixed manner. To improve understanding of the functional significance of flap-bounding, the energetic costs and the relative use of alternative styles by a given species in nature merit study.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'. PMID:27528773

  6. Evolution of avian flight: muscles and constraints on performance.

    PubMed

    Tobalske, Bret W

    2016-09-26

    Competing hypotheses about evolutionary origins of flight are the 'fundamental wing-stroke' and 'directed aerial descent' hypotheses. Support for the fundamental wing-stroke hypothesis is that extant birds use flapping of their wings to climb even before they are able to fly; there are no reported examples of incrementally increasing use of wing movements in gliding transitioning to flapping. An open question is whether locomotor styles must evolve initially for efficiency or if they might instead arrive due to efficacy. The proximal muscles of the avian wing output work and power for flight, and new research is exploring functions of the distal muscles in relation to dynamic changes in wing shape. It will be useful to test the relative contributions of the muscles of the forearm compared with inertial and aerodynamic loading of the wing upon dynamic morphing. Body size has dramatic effects upon flight performance. New research has revealed that mass-specific muscle power declines with increasing body mass among species. This explains the constraints associated with being large. Hummingbirds are the only species that can sustain hovering. Their ability to generate force, work and power appears to be limited by time for activation and deactivation within their wingbeats of high frequency. Most small birds use flap-bounding flight, and this flight style may offer an energetic advantage over continuous flapping during fast flight or during flight into a headwind. The use of flap-bounding during slow flight remains enigmatic. Flap-bounding birds do not appear to be constrained to use their primary flight muscles in a fixed manner. To improve understanding of the functional significance of flap-bounding, the energetic costs and the relative use of alternative styles by a given species in nature merit study.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

  7. Castration-induced upregulation of muscle ERα supports estrogen sensitivity of motoneuron dendrites in a sexually dimorphic neuromuscular system.

    PubMed

    Rudolph, Lauren M; Sengelaub, Dale R

    2013-12-01

    The spinal cord of rats contains the sexually dimorphic motoneurons of the spinal nucleus of the bulbocavernosus (SNB). In males, SNB dendrites fail to grow after castration, but androgen or estrogen treatment supports dendritic growth in castrated males. Estrogenic support of SNB dendrite growth is mediated by estrogen receptors (ER) in the target muscle. ERα expression in cells lacking a basal lamina (referred to as "extra-muscle fiber cells") of the SNB target musculature coincides with the period of estrogen-dependent SNB dendrite growth. In the SNB target muscle, extra-muscle fiber ERα expression declines with age and is typically absent after postnatal (P) day 21 (P21). Given that estradiol downregulates ERα in skeletal muscle, we tested the hypothesis that depleting gonadal hormones would prevent the postnatal decline in ERα expression in the SNB target musculature. We castrated male rats at P7 and assessed ERα immunolabeling at P21; ERα expression was significantly greater in castrated males compared with normal animals. Because ERα expression in SNB target muscles mediates estrogen-dependent SNB dendrogenesis, we further hypothesized that the castration-induced increase in muscle ERα would heighten the estrogen sensitivity of SNB dendrites. Male rats were castrated at P7 and treated with estradiol from P21 to P28; estradiol treatment in castrates resulted in dendritic hypertrophy in SNB motoneurons compared with normal males. We conclude that early castration results in an increase in ERα expression in the SNB target muscle, and this upregulation of ERα supports estrogen sensitivity of SNB dendrites, allowing for hypermasculinization of SNB dendritic arbors.

  8. Jaw-muscle architecture and mandibular morphology influence relative maximum jaw gapes in the sexually dimorphic Macaca fascicularis.

    PubMed

    Terhune, Claire E; Hylander, William L; Vinyard, Christopher J; Taylor, Andrea B

    2015-05-01

    Maximum jaw gape is a performance variable related to feeding and non-feeding oral behaviors, such as canine gape displays, and is influenced by several factors including jaw-muscle fiber architecture, muscle position on the skull, and jaw morphology. Maximum gape, jaw length, and canine height are strongly correlated across catarrhine primates, but relationships between gape and other aspects of masticatory apparatus morphology are less clear. We examine the effects of jaw-adductor fiber architecture, jaw-muscle leverage, and jaw form on gape in an intraspecific sample of sexually dimorphic crab-eating macaques (Macaca fascicularis). As M. fascicularis males have relatively larger maximum gapes than females, we predict that males will have muscle and jaw morphologies that facilitate large gape, but these morphologies may come at some expense to bite force. Male crab-eating macaques have relatively longer jaw-muscle fibers, masseters with decreased leverage, and temporomandibular joint morphologies that facilitate the production of wide gapes. Because relative canine height is correlated with maximum gape in catarrhines, and males have relatively longer canines than females, these results support the hypothesis that male M. fascicularis have experienced selection to increase maximum gape. The sexes do not differ in relative masseter physiologic cross-sectional area (PCSA), but males compensate for a potential trade-off between muscle excursion versus muscle force with increased temporalis weight and PCSA. This musculoskeletal configuration is likely functionally significant for behaviors involving aggressive canine biting and displays in male M. fascicularis and provides additional evidence supporting the multifactorial nature of the catarrhine masticatory apparatus. Our results have implications for the evolution of craniofacial morphology in catarrhine primates and reinforce the importance of evaluating additional factors other than feeding behavior and diet

  9. Genetic Evidence That Captured Retroviral Envelope syncytins Contribute to Myoblast Fusion and Muscle Sexual Dimorphism in Mice.

    PubMed

    Redelsperger, François; Raddi, Najat; Bacquin, Agathe; Vernochet, Cécile; Mariot, Virginie; Gache, Vincent; Blanchard-Gutton, Nicolas; Charrin, Stéphanie; Tiret, Laurent; Dumonceaux, Julie; Dupressoir, Anne; Heidmann, Thierry

    2016-09-01

    Syncytins are envelope genes from endogenous retroviruses, "captured" for a role in placentation. They mediate cell-cell fusion, resulting in the formation of a syncytium (the syncytiotrophoblast) at the fetomaternal interface. These genes have been found in all placental mammals in which they have been searched for. Cell-cell fusion is also pivotal for muscle fiber formation and repair, where the myotubes are formed from the fusion of mononucleated myoblasts into large multinucleated structures. Here we show, taking advantage of mice knocked out for syncytins, that these captured genes contribute to myoblast fusion, with a >20% reduction in muscle mass, mean muscle fiber area and number of nuclei per fiber in knocked out mice for one of the two murine syncytin genes. Remarkably, this reduction is only observed in males, which subsequently show muscle quantitative traits more similar to those of females. In addition, we show that syncytins also contribute to muscle repair after cardiotoxin-induced injury, with again a male-specific effect on the rate and extent of regeneration. Finally, ex vivo experiments carried out on murine myoblasts demonstrate the direct involvement of syncytins in fusion, with a >40% reduction in fusion index upon addition of siRNA against both syncytins. Importantly, similar effects are observed with primary myoblasts from sheep, dog and human, with a 20-40% reduction upon addition of siRNA against the corresponding syncytins. Altogether, these results show a direct contribution of the fusogenic syncytins to myogenesis, with a demonstrated male-dependence of the effect in mice, suggesting that these captured genes could be responsible for the muscle sexual dimorphism observed in placental mammals. PMID:27589388

  10. Genetic Evidence That Captured Retroviral Envelope syncytins Contribute to Myoblast Fusion and Muscle Sexual Dimorphism in Mice

    PubMed Central

    Vernochet, Cécile; Mariot, Virginie; Gache, Vincent; Charrin, Stéphanie; Tiret, Laurent; Dumonceaux, Julie; Dupressoir, Anne; Heidmann, Thierry

    2016-01-01

    Syncytins are envelope genes from endogenous retroviruses, “captured” for a role in placentation. They mediate cell-cell fusion, resulting in the formation of a syncytium (the syncytiotrophoblast) at the fetomaternal interface. These genes have been found in all placental mammals in which they have been searched for. Cell-cell fusion is also pivotal for muscle fiber formation and repair, where the myotubes are formed from the fusion of mononucleated myoblasts into large multinucleated structures. Here we show, taking advantage of mice knocked out for syncytins, that these captured genes contribute to myoblast fusion, with a >20% reduction in muscle mass, mean muscle fiber area and number of nuclei per fiber in knocked out mice for one of the two murine syncytin genes. Remarkably, this reduction is only observed in males, which subsequently show muscle quantitative traits more similar to those of females. In addition, we show that syncytins also contribute to muscle repair after cardiotoxin-induced injury, with again a male-specific effect on the rate and extent of regeneration. Finally, ex vivo experiments carried out on murine myoblasts demonstrate the direct involvement of syncytins in fusion, with a >40% reduction in fusion index upon addition of siRNA against both syncytins. Importantly, similar effects are observed with primary myoblasts from sheep, dog and human, with a 20–40% reduction upon addition of siRNA against the corresponding syncytins. Altogether, these results show a direct contribution of the fusogenic syncytins to myogenesis, with a demonstrated male-dependence of the effect in mice, suggesting that these captured genes could be responsible for the muscle sexual dimorphism observed in placental mammals. PMID:27589388

  11. Calcium signalling indicates bilateral power balancing in the Drosophila flight muscle during manoeuvring flight.

    PubMed

    Lehmann, Fritz-Olaf; Skandalis, Dimitri A; Berthé, Ruben

    2013-05-01

    Manoeuvring flight in animals requires precise adjustments of mechanical power output produced by the flight musculature. In many insects such as fruit flies, power generation is most likely varied by altering stretch-activated tension, that is set by sarcoplasmic calcium levels. The muscles reside in a thoracic shell that simultaneously drives both wings during wing flapping. Using a genetically expressed muscle calcium indicator, we here demonstrate in vivo the ability of this animal to bilaterally adjust its calcium activation to the mechanical power output required to sustain aerodynamic costs during flight. Motoneuron-specific comparisons of calcium activation during lift modulation and yaw turning behaviour suggest slightly higher calcium activation for dorso-longitudinal than for dorsoventral muscle fibres, which corroborates the elevated need for muscle mechanical power during the wings' downstroke. During turning flight, calcium activation explains only up to 54 per cent of the required changes in mechanical power, suggesting substantial power transmission between both sides of the thoracic shell. The bilateral control of muscle calcium runs counter to the hypothesis that the thorax of flies acts as a single, equally proportional source for mechanical power production for both flapping wings. Collectively, power balancing highlights the precision with which insects adjust their flight motor to changing energetic requirements during aerial steering. This potentially enhances flight efficiency and is thus of interest for the development of technical vehicles that employ bioinspired strategies of power delivery to flapping wings.

  12. Calcium signalling indicates bilateral power balancing in the Drosophila flight muscle during manoeuvring flight.

    PubMed

    Lehmann, Fritz-Olaf; Skandalis, Dimitri A; Berthé, Ruben

    2013-05-01

    Manoeuvring flight in animals requires precise adjustments of mechanical power output produced by the flight musculature. In many insects such as fruit flies, power generation is most likely varied by altering stretch-activated tension, that is set by sarcoplasmic calcium levels. The muscles reside in a thoracic shell that simultaneously drives both wings during wing flapping. Using a genetically expressed muscle calcium indicator, we here demonstrate in vivo the ability of this animal to bilaterally adjust its calcium activation to the mechanical power output required to sustain aerodynamic costs during flight. Motoneuron-specific comparisons of calcium activation during lift modulation and yaw turning behaviour suggest slightly higher calcium activation for dorso-longitudinal than for dorsoventral muscle fibres, which corroborates the elevated need for muscle mechanical power during the wings' downstroke. During turning flight, calcium activation explains only up to 54 per cent of the required changes in mechanical power, suggesting substantial power transmission between both sides of the thoracic shell. The bilateral control of muscle calcium runs counter to the hypothesis that the thorax of flies acts as a single, equally proportional source for mechanical power production for both flapping wings. Collectively, power balancing highlights the precision with which insects adjust their flight motor to changing energetic requirements during aerial steering. This potentially enhances flight efficiency and is thus of interest for the development of technical vehicles that employ bioinspired strategies of power delivery to flapping wings. PMID:23486171

  13. Calcium signalling indicates bilateral power balancing in the Drosophila flight muscle during manoeuvring flight

    PubMed Central

    Lehmann, Fritz-Olaf; Skandalis, Dimitri A.; Berthé, Ruben

    2013-01-01

    Manoeuvring flight in animals requires precise adjustments of mechanical power output produced by the flight musculature. In many insects such as fruit flies, power generation is most likely varied by altering stretch-activated tension, that is set by sarcoplasmic calcium levels. The muscles reside in a thoracic shell that simultaneously drives both wings during wing flapping. Using a genetically expressed muscle calcium indicator, we here demonstrate in vivo the ability of this animal to bilaterally adjust its calcium activation to the mechanical power output required to sustain aerodynamic costs during flight. Motoneuron-specific comparisons of calcium activation during lift modulation and yaw turning behaviour suggest slightly higher calcium activation for dorso-longitudinal than for dorsoventral muscle fibres, which corroborates the elevated need for muscle mechanical power during the wings’ downstroke. During turning flight, calcium activation explains only up to 54 per cent of the required changes in mechanical power, suggesting substantial power transmission between both sides of the thoracic shell. The bilateral control of muscle calcium runs counter to the hypothesis that the thorax of flies acts as a single, equally proportional source for mechanical power production for both flapping wings. Collectively, power balancing highlights the precision with which insects adjust their flight motor to changing energetic requirements during aerial steering. This potentially enhances flight efficiency and is thus of interest for the development of technical vehicles that employ bioinspired strategies of power delivery to flapping wings. PMID:23486171

  14. Weight, muscle and bone loss during space flight: another perspective.

    PubMed

    Stein, T P

    2013-09-01

    Space flight is a new experience for humans. Humans adapt if not perfectly, rather well to life without gravity. There is a reductive remodeling of the musculo-skeletal system. Protein is lost from muscles and calcium from bones with anti-gravity functions. The observed biochemical and physiological changes reflect this accommodative process. The two major direct effects of the muscle loss are weakness post-flight and the increased incidence of low back ache pre- and post-flight. The muscle protein losses are compromised by the inability to maintain energy balance inflight. Voluntary dietary intake is reduced during space flight by ~20 %. These adaptations to weightlessness leave astronauts ill-equipped for life with gravity. Exercise, the obvious counter-measure has been repeatedly tried and since the muscle and bone losses persist it is not unreasonable to assume that success has been limited at best. Nevertheless, more than 500 people have now flown in space for up to 1 year and have done remarkably well. This review addresses the question of whether enough is now known about these three problems (negative energy balance, muscle loss and bone loss) for to the risks to be considered either acceptable or correctible enough to meet the requirements for a Mars mission.

  15. Weight, muscle and bone loss during space flight: another perspective.

    PubMed

    Stein, T P

    2013-09-01

    Space flight is a new experience for humans. Humans adapt if not perfectly, rather well to life without gravity. There is a reductive remodeling of the musculo-skeletal system. Protein is lost from muscles and calcium from bones with anti-gravity functions. The observed biochemical and physiological changes reflect this accommodative process. The two major direct effects of the muscle loss are weakness post-flight and the increased incidence of low back ache pre- and post-flight. The muscle protein losses are compromised by the inability to maintain energy balance inflight. Voluntary dietary intake is reduced during space flight by ~20 %. These adaptations to weightlessness leave astronauts ill-equipped for life with gravity. Exercise, the obvious counter-measure has been repeatedly tried and since the muscle and bone losses persist it is not unreasonable to assume that success has been limited at best. Nevertheless, more than 500 people have now flown in space for up to 1 year and have done remarkably well. This review addresses the question of whether enough is now known about these three problems (negative energy balance, muscle loss and bone loss) for to the risks to be considered either acceptable or correctible enough to meet the requirements for a Mars mission. PMID:23192310

  16. Electrical Stimulation of Coleopteran Muscle for Initiating Flight.

    PubMed

    Choo, Hao Yu; Li, Yao; Cao, Feng; Sato, Hirotaka

    2016-01-01

    Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera). A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs), flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%), rapid response time (< 1.0 s), and small variation (< 0.33 s; indicating little habituation). Notably, the stimulation of DLMs caused no crucial damage to the free flight ability. In contrast, stimulation of optic lobes, which was earlier demonstrated as a successful flight initiation protocol, destabilized the beetle in flight. Thus, DLM stimulation is a promising secure protocol for inducing flight in cyborg insects or biobots. PMID:27050093

  17. Electrical Stimulation of Coleopteran Muscle for Initiating Flight.

    PubMed

    Choo, Hao Yu; Li, Yao; Cao, Feng; Sato, Hirotaka

    2016-01-01

    Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera). A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs), flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%), rapid response time (< 1.0 s), and small variation (< 0.33 s; indicating little habituation). Notably, the stimulation of DLMs caused no crucial damage to the free flight ability. In contrast, stimulation of optic lobes, which was earlier demonstrated as a successful flight initiation protocol, destabilized the beetle in flight. Thus, DLM stimulation is a promising secure protocol for inducing flight in cyborg insects or biobots.

  18. Electrical Stimulation of Coleopteran Muscle for Initiating Flight

    PubMed Central

    Choo, Hao Yu; Li, Yao; Cao, Feng; Sato, Hirotaka

    2016-01-01

    Some researchers have long been interested in reconstructing natural insects into steerable robots or vehicles. However, until recently, these so-called cyborg insects, biobots, or living machines existed only in science fiction. Owing to recent advances in nano/micro manufacturing, data processing, and anatomical and physiological biology, we can now stimulate living insects to induce user-desired motor actions and behaviors. To improve the practicality and applicability of airborne cyborg insects, a reliable and controllable flight initiation protocol is required. This study demonstrates an electrical stimulation protocol that initiates flight in a beetle (Mecynorrhina torquata, Coleoptera). A reliable stimulation protocol was determined by analyzing a pair of dorsal longitudinal muscles (DLMs), flight muscles that oscillate the wings. DLM stimulation has achieved with a high success rate (> 90%), rapid response time (< 1.0 s), and small variation (< 0.33 s; indicating little habituation). Notably, the stimulation of DLMs caused no crucial damage to the free flight ability. In contrast, stimulation of optic lobes, which was earlier demonstrated as a successful flight initiation protocol, destabilized the beetle in flight. Thus, DLM stimulation is a promising secure protocol for inducing flight in cyborg insects or biobots. PMID:27050093

  19. Effects of flight speed upon muscle activity in hummingbirds.

    PubMed

    Tobalske, Bret W; Biewener, Andrew A; Warrick, Douglas R; Hedrick, Tyson L; Powers, Donald R

    2010-07-15

    Hummingbirds have the smallest body size and highest wingbeat frequencies of all flying vertebrates, so they represent one endpoint for evaluating the effects of body size on sustained muscle function and flight performance. Other bird species vary neuromuscular recruitment and contractile behavior to accomplish flight over a wide range of speeds, typically exhibiting a U-shaped curve with maxima at the slowest and fastest flight speeds. To test whether the high wingbeat frequencies and aerodynamically active upstroke of hummingbirds lead to different patterns, we flew rufous hummingbirds (Selasphorus rufus, 3 g body mass, 42 Hz wingbeat frequency) in a variable-speed wind tunnel (0-10 m s(-1)). We measured neuromuscular activity in the pectoralis (PECT) and supracoracoideus (SUPRA) muscles using electromyography (EMG, N=4 birds), and we measured changes in PECT length using sonomicrometry (N=1). Differing markedly from the pattern in other birds, PECT deactivation occurred before the start of downstroke and the SUPRA was deactivated before the start of upstroke. The relative amplitude of EMG signal in the PECT and SUPRA varied according to a U-shaped curve with flight speed; additionally, the onset of SUPRA activity became relatively later in the wingbeat at intermediate flight speeds (4 and 6 m s(-1)). Variation in the relative amplitude of EMG was comparable with that observed in other birds but the timing of muscle activity was different. These data indicate the high wingbeat frequency of hummingbirds limits the time available for flight muscle relaxation before the next half stroke of a wingbeat. Unlike in a previous study that reported single-twitch EMG signals in the PECT of hovering hummingbirds, across all flight speeds we observed 2.9+/-0.8 spikes per contraction in the PECT and 3.8+/-0.8 spikes per contraction in the SUPRA. Muscle strain in the PECT was 10.8+/-0.5%, the lowest reported for a flying bird, and average strain rate was 7.4+/-0.2 muscle

  20. Elastic proteins in the flight muscle of Manduca sexta.

    PubMed

    Yuan, Chen-Ching; Ma, Weikang; Schemmel, Peter; Cheng, Yu-Shu; Liu, Jiangmin; Tsaprailis, George; Feldman, Samuel; Ayme Southgate, Agnes; Irving, Thomas C

    2015-02-15

    The flight muscles (DLM1) of the Hawkmoth, Manduca sexta are synchronous, requiring a neural spike for each contraction. Stress/strain curves of skinned DLM1 showed hysteresis indicating the presence of titin-like elastic proteins. Projectin and kettin are titin-like proteins previously identified in Lethocerus and Drosophila flight muscles. Analysis of Manduca muscles with 1% SDS-agarose gels and western blots showed two bands near 1 MDa that cross-reacted with antibodies to Drosophila projectin. Antibodies to Drosophila kettin cross-reacted to bands at ∼500 and ∼700 kDa, but also to bands at ∼1.6 and ∼2.1 MDa, that had not been previously observed in insect flight muscles. Mass spectrometry identified the 2.1 MDa protein as a product of the Sallimus (sls) gene. Analysis of the gene sequence showed that all 4 putative Sallimus and kettin isoforms could be explained as products of alternative splicing of the single sls gene. Both projectin and sallimus isoforms were expressed to higher levels in ventrally located DLM1 subunits, primarily responsible for active work production, as compared to dorsally located subunits, which may act as damped springs. The different expression levels of the 2 projectin isoforms and 4 sallimus/kettin isoforms may be adaptations to the specific requirements of individual muscle subunits.

  1. Flight Capacity of Bactrocera dorsalis (Diptera: Tephritidae) Adult Females Based on Flight Mill Studies and Flight Muscle Ultrastructure

    PubMed Central

    Chen, Peng; Yuan, Ruiling; Wang, Xiaowei; Xu, Jin

    2015-01-01

    The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is considered a major economic threat in many regions worldwide. To better comprehend flight capacity of B. dorsalis and its physiological basis, a computer-monitored flight mill was used to study flight capacity of B. dorsalis adult females of various ages, and the changes of its flight muscle ultrastructures were studied by transmission electron microscopy. The flight capacity (both speed and distance) changed significantly with age of B. dorsalis female adults, peaking at about 15 d; the myofibril diameter of the flight muscle of test insects at 15-d old was the longest, up to 1.56 µm, the sarcomere length at 15-d old was the shortest, averaging at 1.37 µm, volume content of mitochondria of flight muscle at 15-d old reached the peak, it was 32.64%. This study provides the important scientific data for better revealing long-distance movement mechanism of B. dorsalis. PMID:26450591

  2. Flight capacity of Bactrocera dorsalis (Diptera: Tephritidae) adult females based on flight mill studies and flight muscle ultrastructure.

    PubMed

    Chen, Min; Chen, Peng; Ye, Hui; Yuan, Ruiling; Wang, Xiaowei; Xu, Jin

    2015-01-01

    The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is considered a major economic threat in many regions worldwide. To better comprehend flight capacity of B. dorsalis and its physiological basis, a computer-monitored flight mill was used to study flight capacity of B. dorsalis adult females of various ages, and the changes of its flight muscle ultrastructures were studied by transmission electron microscopy. The flight capacity (both speed and distance) changed significantly with age of B. dorsalis female adults, peaking at about 15 d; the myofibril diameter of the flight muscle of test insects at 15-d old was the longest, up to 1.56 µm, the sarcomere length at 15-d old was the shortest, averaging at 1.37 µm, volume content of mitochondria of flight muscle at 15-d old reached the peak, it was 32.64%. This study provides the important scientific data for better revealing long-distance movement mechanism of B. dorsalis.

  3. Changes in contractile properties by androgen hormones in sexually dimorphic muscles of male frogs (Xenopus laevis).

    PubMed Central

    Regnier, M; Herrera, A A

    1993-01-01

    1. Male frogs (Xenopus laevis) were castrated then given either empty or testosterone-filled implants to produce animals with low or high levels of circulating testosterone. Eight weeks later the contractile properties of an androgen-sensitive forelimb flexor, the flexor carpi radialis muscle (FCR), were measured in vitro. Another forelimb flexor muscle, the coracoradialis, and a hindlimb muscle, the iliofibularis, were analysed similarly. 2. Plasma testosterone levels were 0.9 +/- 0.3 ng/ml (+/- S.E.M.) in castrated frogs with blank implants (C) and 61.3 +/- 4.7 ng/ml in castrates with testosterone implants (CT). Unoperated males, sampled at various times of the year, ranged between 10.8 and 51.0 ng/ml. 3. With direct electrical stimulation of the FCR, contraction time of the isometric twitch was not affected by testosterone levels. Relaxation times were affected, however. Half- and 90% relaxation times were 27 and 42% longer, respectively, for CT compared to C muscles. 4. Testosterone also had no effect on the contraction time of twitches elicited by stimulation of the FCR nerve. Half- and 90% relaxation times were 51 and 76% longer, respectively, for CT compared to C muscles. 5. Tetanus tension, elicited by direct stimulation of the FCR at 50 Hz, was 86% greater in CT compared to C muscles. The average cross-sectional area of FCR muscle fibres was 84% greater in CT muscles. These results implied that testosterone treatment had no effect on specific muscle tension. 6. Stimulation of the FCR nerve at 50 Hz resulted in 53% less tension than the same stimulus applied directly to CT muscles. In C muscles the difference was only 14%. This suggested that testosterone treatment reduced synaptic efficacy. 7. In CT muscles, direct or nerve stimulation of fibres in the shoulder region of the FCR elicited twitches that contracted and relaxed more slowly than fibres in the elbow region. In C muscles there was no difference in contraction or relaxation time between fibres in

  4. Nature's strategy for optimizing power generation in insect flight muscle.

    PubMed

    Maughan, David; Vigoreaux, Jim

    2005-01-01

    Table 1 summarizes the primary mechanisms most likely responsible for modifying wing beat frequency (WBF) and muscle power in the Drosophila mutants discussed above. The different outcomes reflect different mechanisms that come into play, depending on the protein and site of the mutation. For example, the reduced muscle power and WBF of the RLC phosphorylation site mutant Mlc2(S6sA,S67A) reflect the reduced number of myosin heads available to form working cross-bridges and the concomitant reduction in muscle stiffness. The mixed results of the other mutants are more difficult to explain. For example, while the reduced muscle stiffness of the paramyosin rod mutant pm(S18A) and the projectin mutant bent(D)/+ may in part reflect mutation-related increases in compliance of the thick filaments (pm(S18A)) or connecting filaments (bent(D)/+), the elevated WBF is unexpected because one would expect reduced muscle stiffness to lower WBF rather than raise it. Other aspects of the results are equally baffling. In the case of pm(S18A), e.g., myofilament kinetics are enhanced, opposite to what one would predict from reduced myofilament stiffness (Wang et al. 1999), but consistent with a direct effect of the mutation on cross-bridge kinetics. It is tempting to speculate that the fly increases the resonance frequency of its flight system, perhaps even over-compensating, as a mechanism for bringing the optimum frequency of power output of the flight system in line with the optimum frequency of power output of the myofilaments in order to achieve flight. The fly might accomplish this by voluntarily activating flight control muscles that change the stiffness and shape of the thoracic box (Tu and Dickinson, 1996), thereby significantly changing the basal stiffness of the resonance system. This effective strategy would serve to tune flight system kinetics to that of the actomyosin motor for optimum power transmission. Notably, of the four thick filament mutations listed in Table 1

  5. The metabolic power requirements of flight and estimations of flight muscle efficiency in the cockatiel (Nymphicus hollandicus).

    PubMed

    Morris, Charlotte R; Nelson, Frank E; Askew, Graham N

    2010-08-15

    Little is known about how in vivo muscle efficiency, that is the ratio of mechanical and metabolic power, is affected by changes in locomotory tasks. One of the main problems with determining in vivo muscle efficiency is the large number of muscles generally used to produce mechanical power. Animal flight provides a unique model for determining muscle efficiency because only one muscle, the pectoralis muscle, produces nearly all of the mechanical power required for flight. In order to estimate in vivo flight muscle efficiency, we measured the metabolic cost of flight across a range of flight speeds (6-13 m s(-1)) using masked respirometry in the cockatiel (Nymphicus hollandicus) and compared it with measurements of mechanical power determined in the same wind tunnel. Similar to measurements of the mechanical power-speed relationship, the metabolic power-speed relationship had a U-shape, with a minimum at 10 m s(-1). Although the mechanical and metabolic power-speed relationships had similar minimum power speeds, the metabolic power requirements are not a simple multiple of the mechanical power requirements across a range of flight speeds. The pectoralis muscle efficiency (estimated from mechanical and metabolic power, basal metabolism and an assumed value for the 'postural costs' of flight) increased with flight speed and ranged from 6.9% to 11.2%. However, it is probable that previous estimates of the postural costs of flight have been too low and that the pectoralis muscle efficiency is higher.

  6. Crossbridges in insect flight muscles of the blowfly (Sarcophaga bullata).

    PubMed

    Heuser, J E

    1987-08-01

    Crossbridges in quick-frozen deep-etched blowfly flight muscles (from Sarcophaga bullata) were compared with those observed in the traditional waterbug preparation (Lethocerus) and found to be indistinguishable. Hence, blowfly was chosen as a fresher more accessible tissue for determining the effect of various fixatives and nucleotides on crossbridge structure. In rigor control, crossbridges were most regular in muscles that were stabilized before freezing by prefixation in glutaraldehyde followed by 'hardening' with neutralized tannic acid, so all nucleotide treatments were terminated by such fixation. MgATP (5 mM) converted the rigor pattern of crossbridges into a random array of disconnected thick filament projections. Lower levels of ATP (0.1 mM) caused a variable but generally lesser degree of crossbridge disconnection, as did 5 mM ADP (probably because it slowly converted to ATP inside the muscle fibres). Vanadate (1-2 mM) potentiated muscle relaxation in the latter two nucleotide treatments (i.e. produced a greater degree of crossbridge disconnection). Thus, differences in overall crossbridge abundance were readily apparent in chemically fixed muscles. Structural details within individual crossbridges were less well preserved, however. Chemical prefixation tended to collapse the muscle lattice, add a surface film to the filaments and thus obscure crossbridge details. Rigorous control of fixative pH largely prevented these problems and permitted recognition of the fact that in Sarcophaga flight muscle, as in Lethocerus muscle in rigor, the S1 'heads' of crossbridges attach to the thin filaments in the expected 'arrowhead' configuration.

  7. Muscle organizers in Drosophila: the role of persistent larval fibers in adult flight muscle development

    NASA Technical Reports Server (NTRS)

    Farrell, E. R.; Fernandes, J.; Keshishian, H.

    1996-01-01

    In many organisms muscle formation depends on specialized cells that prefigure the pattern of the musculature and serve as templates for myoblast organization and fusion. These include muscle pioneers in insects and muscle organizing cells in leech. In Drosophila, muscle founder cells have been proposed to play a similar role in organizing larval muscle development during embryogenesis. During metamorphosis in Drosophila, following histolysis of most of the larval musculature, there is a second round of myogenesis that gives rise to the adult muscles. It is not known whether muscle founder cells organize the development of these muscles. However, in the thorax specific larval muscle fibers do not histolyze at the onset of metamorphosis, but instead serve as templates for the formation of a subset of adult muscles, the dorsal longitudinal flight muscles (DLMs). Because these persistent larval muscle fibers appear to be functioning in many respects like muscle founder cells, we investigated whether they were necessary for DLM development by using a microbeam laser to ablate them singly and in combination. We found that, in the absence of the larval muscle fibers, DLMs nonetheless develop. Our results show that the persistent larval muscle fibers are not required to initiate myoblast fusion, to determine DLM identity, to locate the DLMs in the thorax, or to specify the total DLM fiber volume. However, they are required to regulate the number of DLM fibers generated. Thus, while the persistent larval muscle fibers are not obligatory for DLM fiber formation and differentiation, they are necessary to ensure the development of the correct number of fibers.

  8. An embryonic myosin converter domain influences Drosophila indirect flight muscle stretch activation, power generation and flight.

    PubMed

    Wang, Qian; Newhard, Christopher S; Ramanath, Seemanti; Sheppard, Debra; Swank, Douglas M

    2014-01-15

    Stretch activation (SA) is critical to the flight ability of insects powered by asynchronous, indirect flight muscles (IFMs). An essential muscle protein component for SA and power generation is myosin. Which structural domains of myosin are significant for setting SA properties and power generation levels is poorly understood. We made use of the transgenic techniques and unique single muscle myosin heavy chain gene of Drosophila to test the influence of the myosin converter domain on IFM SA and power generation. Replacing the endogenous converter with an embryonic version decreased SA tension and the rate of SA tension generation. The alterations in SA properties and myosin kinetics from the converter exchange caused power generation to drop to 10% of control fiber power when the optimal conditions for control fibers - 1% muscle length (ML) amplitude and 150 Hz oscillation frequency - were applied to fibers expressing the embryonic converter (IFI-EC). Optimizing conditions for IFI-EC fiber power production, by doubling ML amplitude and decreasing oscillation frequency by 60%, improved power output to 60% of optimized control fiber power. IFI-EC flies altered their aerodynamic flight characteristics to better match optimal fiber power generation conditions as wing beat frequency decreased and wing stroke amplitude increased. This enabled flight in spite of the drastic changes to fiber mechanical performance.

  9. An embryonic myosin converter domain influences Drosophila indirect flight muscle stretch activation, power generation and flight

    PubMed Central

    Wang, Qian; Newhard, Christopher S.; Ramanath, Seemanti; Sheppard, Debra; Swank, Douglas M.

    2014-01-01

    Stretch activation (SA) is critical to the flight ability of insects powered by asynchronous, indirect flight muscles (IFMs). An essential muscle protein component for SA and power generation is myosin. Which structural domains of myosin are significant for setting SA properties and power generation levels is poorly understood. We made use of the transgenic techniques and unique single muscle myosin heavy chain gene of Drosophila to test the influence of the myosin converter domain on IFM SA and power generation. Replacing the endogenous converter with an embryonic version decreased SA tension and the rate of SA tension generation. The alterations in SA properties and myosin kinetics from the converter exchange caused power generation to drop to 10% of control fiber power when the optimal conditions for control fibers – 1% muscle length (ML) amplitude and 150 Hz oscillation frequency – were applied to fibers expressing the embryonic converter (IFI-EC). Optimizing conditions for IFI-EC fiber power production, by doubling ML amplitude and decreasing oscillation frequency by 60%, improved power output to 60% of optimized control fiber power. IFI-EC flies altered their aerodynamic flight characteristics to better match optimal fiber power generation conditions as wing beat frequency decreased and wing stroke amplitude increased. This enabled flight in spite of the drastic changes to fiber mechanical performance. PMID:24115062

  10. Aging Enhances Indirect Flight Muscle Fiber Performance yet Decreases Flight Ability in Drosophila

    SciTech Connect

    Miller, Mark S.; Lekkas, Panagiotis; Braddock, Joan M.; Farman, Gerrie P.; Ballif, Bryan A.; Irving, Thomas C.; Maughan, David W.; Vigoreaux, Jim O.

    2008-10-02

    We investigated the effects of aging on Drosophila melanogaster indirect flight muscle from the whole organism to the actomyosin cross-bridge. Median-aged (49-day-old) flies were flight impaired, had normal myofilament number and packing, barely longer sarcomeres, and slight mitochondrial deterioration compared with young (3-day-old) flies. Old (56-day-old) flies were unable to beat their wings, had deteriorated ultrastructure with severe mitochondrial damage, and their skinned fibers failed to activate with calcium. Small-amplitude sinusoidal length perturbation analysis showed median-aged indirect flight muscle fibers developed greater than twice the isometric force and power output of young fibers, yet cross-bridge kinetics were similar. Large increases in elastic and viscous moduli amplitude under active, passive, and rigor conditions suggest that median-aged fibers become stiffer longitudinally. Small-angle x-ray diffraction indicates that myosin heads move increasingly toward the thin filament with age, accounting for the increased transverse stiffness via cross-bridge formation. We propose that the observed protein composition changes in the connecting filaments, which anchor the thick filaments to the Z-disk, produce compensatory increases in longitudinal stiffness, isometric tension, power and actomyosin interaction in aging indirect flight muscle. We also speculate that a lack of MgATP due to damaged mitochondria accounts for the decreased flight performance.

  11. Morphological and kinematic basis of the hummingbird flight stroke: scaling of flight muscle transmission ratio.

    PubMed

    Hedrick, Tyson L; Tobalske, Bret W; Ros, Ivo G; Warrick, Douglas R; Biewener, Andrew A

    2012-05-22

    Hummingbirds (Trochilidae) are widely known for their insect-like flight strokes characterized by high wing beat frequency, small muscle strains and a highly supinated wing orientation during upstroke that allows for lift production in both halves of the stroke cycle. Here, we show that hummingbirds achieve these functional traits within the limits imposed by a vertebrate endoskeleton and muscle physiology by accentuating a wing inversion mechanism found in other birds and using long-axis rotational movement of the humerus. In hummingbirds, long-axis rotation of the humerus creates additional wing translational movement, supplementing that produced by the humeral elevation and depression movements of a typical avian flight stroke. This adaptation increases the wing-to-muscle-transmission ratio, and is emblematic of a widespread scaling trend among flying animals whereby wing-to-muscle-transmission ratio varies inversely with mass, allowing animals of vastly different sizes to accommodate aerodynamic, biomechanical and physiological constraints on muscle-powered flapping flight. PMID:22171086

  12. Morphological and kinematic basis of the hummingbird flight stroke: scaling of flight muscle transmission ratio

    PubMed Central

    Hedrick, Tyson L.; Tobalske, Bret W.; Ros, Ivo G.; Warrick, Douglas R.; Biewener, Andrew A.

    2012-01-01

    Hummingbirds (Trochilidae) are widely known for their insect-like flight strokes characterized by high wing beat frequency, small muscle strains and a highly supinated wing orientation during upstroke that allows for lift production in both halves of the stroke cycle. Here, we show that hummingbirds achieve these functional traits within the limits imposed by a vertebrate endoskeleton and muscle physiology by accentuating a wing inversion mechanism found in other birds and using long-axis rotational movement of the humerus. In hummingbirds, long-axis rotation of the humerus creates additional wing translational movement, supplementing that produced by the humeral elevation and depression movements of a typical avian flight stroke. This adaptation increases the wing-to-muscle-transmission ratio, and is emblematic of a widespread scaling trend among flying animals whereby wing-to-muscle-transmission ratio varies inversely with mass, allowing animals of vastly different sizes to accommodate aerodynamic, biomechanical and physiological constraints on muscle-powered flapping flight. PMID:22171086

  13. Effects of Flight on Gene Expression and Aging in the Honey Bee Brain and Flight Muscle.

    PubMed

    Margotta, Joseph W; Mancinelli, Georgina E; Benito, Azucena A; Ammons, Andrew; Roberts, Stephen P; Elekonich, Michelle M

    2012-12-20

    Honey bees move through a series of in-hive tasks (e.g., "nursing") to outside tasks (e.g., "foraging") that are coincident with physiological changes and higher levels of metabolic activity. Social context can cause worker bees to speed up or slow down this process, and foragers may revert back to their earlier in-hive tasks accompanied by reversion to earlier physiological states. To investigate the effects of flight, behavioral state and age on gene expression, we used whole-genome microarrays and real-time PCR. Brain tissue and flight muscle exhibited different patterns of expression during behavioral transitions, with expression patterns in the brain reflecting both age and behavior, and expression patterns in flight muscle being primarily determined by age. Our data suggest that the transition from behaviors requiring little to no flight (nursing) to those requiring prolonged flight bouts (foraging), rather than the amount of previous flight per se, has a major effect on gene expression. Following behavioral reversion there was a partial reversion in gene expression but some aspects of forager expression patterns, such as those for genes involved in immune function, remained. Combined with our real-time PCR data, these data suggest an epigenetic control and energy balance role in honey bee functional senescence.

  14. Sexual dimorphism in the histologic organization of the muscle fibers in human tongue.

    PubMed

    de Campos, Deivis; Jotz, Geraldo Pereira; Heck, Layana; Xavier, Léder Leal

    2014-07-01

    Tongue movements are critical for speech, swallowing, and respiration; and tongue dysfunction could lead to dysarthria, dysphagia, and obstructive sleep apnea, respectively. Our current understanding of the contributions of specific tongue muscles (TOs) to precise movement patterns is limited. Likewise, there is still little information regarding the orientation of histologic muscle fibers of the tongue in humans, especially between men and women. Thus, the aim of this study was to compare the histologic organization in the tongue of men and women. Ten tongues were studied in human specimens obtained from necropsies (five men and five women). The muscles were analyzed using histology, and the morphometric parameters were measured using Image Pro-Plus Software (Image Pro-Plus 6.0; Media Cybernetics, Silver Spring, MD). Slices were obtained from the anterior, median, and posterior parts of the tongue. We classified and estimated the percentages of transverse (T), oblique (O), and longitudinal (L) fibers in the tongue. To quantify the percentage of fibers in each category in the tongue, the shape coefficient (Shape Z) was estimated. Statistical differences were found between the orientation of the muscle fibers of men and women only for the middle region of the tongue. The middle region of the tongue in women compared with men has a smaller difference in the variation of the percentage of fibers T (P=0.0004), O (P=0.0006), and L (P=0.0013). These morphologic findings are probably related to physiological differences.

  15. An exceptionally fast actomyosin reaction powers insect flight muscle.

    PubMed

    Swank, Douglas M; Vishnudas, Vivek K; Maughan, David W

    2006-11-14

    Insects, as a group, have been remarkably successful in adapting to a great range of physical and biological environments, in large part because of their ability to fly. The evolution of flight in small insects was accompanied by striking adaptations of the thoracic musculature that enabled very high wing beat frequencies. At the cellular and protein filament level, a stretch activation mechanism evolved that allowed high-oscillatory work to be achieved at very high frequencies as contraction and nerve stimulus became asynchronous. At the molecular level, critical adaptations occurred within the motor protein myosin II, because its elementary interactions with actin set the speed of sarcomere contraction. Here, we show that the key myosin enzymatic adaptations required for powering the very fast flight muscles in the fruit fly Drosophila melanogaster include the highest measured detachment rate of myosin from actin (forward rate constant, 3,698 s(-1)), an exceptionally weak affinity of MgATP for myosin (association constant, 0.2 mM(-1)), and a unique rate-limiting step in the cross-bridge cycle at the point of inorganic phosphate release. The latter adaptations are constraints imposed by the overriding requirement for exceptionally fast release of the hydrolytic product MgADP. Otherwise, as in Drosophila embryonic muscle and other slow muscle types, a step associated with MgADP release limits muscle contraction speed by delaying the detachment of myosin from actin.

  16. Muscle function during takeoff and landing flight in the pigeon (Columba livia).

    PubMed

    Robertson, Angela M Berg; Biewener, Andrew A

    2012-12-01

    This study explored the muscle strain and activation patterns of several key flight muscles of the pigeon (Columba livia) during takeoff and landing flight. Using electromyography (EMG) to measure muscle activation, and sonomicrometry to quantify muscle strain, we evaluated the muscle function patterns of the pectoralis, biceps, humerotriceps and scapulotriceps as pigeons flew between two perches. These recordings were analyzed in the context of three-dimensional wing kinematics. To understand the different requirements of takeoff, midflight and landing, we compared the activity and strain of these muscles among the three flight modes. The pectoralis and biceps exhibited greater fascicle strain rates during takeoff than during midflight or landing. However, the triceps muscles did not exhibit notable differences in strain among flight modes. All observed strain, activation and kinematics were consistent with hypothesized muscle functions. The biceps contracted to stabilize and flex the elbow during the downstroke. The humerotriceps contracted to extend the elbow at the upstroke-downstroke transition, followed by scapulotriceps contraction to maintain elbow extension during the downstroke. The scapulotriceps also appeared to contribute to humeral elevation. Greater muscle activation intensity was observed during takeoff, compared with mid-flight and landing, in all muscles except the scapulotriceps. The timing patterns of muscle activation and length change differed among flight modes, yet demonstrated that pigeons do not change the basic mechanical actions of key flight muscles as they shift from flight activities that demand energy production, such as takeoff and midflight, to maneuvers that require absorption of energy, such as landing. Similarly, joint kinematics were consistent among flight modes. The stereotypy of these neuromuscular and joint kinematic patterns is consistent with previously observed stereotypy of wing kinematics relative to the pigeon's body

  17. Avian pectoral muscle size rapidly tracks body mass changes during flight, fasting and fuelling.

    PubMed

    Lindström, A; Kvist, A; Piersma, T; Dekinga, A; Dietz, M W

    2000-03-01

    We used ultrasonic imaging to monitor short-term changes in the pectoral muscle size of captive red knots Calidris canutus. Pectoral muscle thickness changed rapidly and consistently in parallel with body mass changes caused by flight, fasting and fuelling. Four knots flew repeatedly for 10 h periods in a wind tunnel. Over this period, pectoral muscle thickness decreased in parallel with the decrease in body mass. The change in pectoral muscle thickness during flight was indistinguishable from that during periods of natural and experimental fasting and fuelling. The body-mass-related variation in pectoral muscle thickness between and within individuals was not related to the amount of flight, indicating that changes in avian muscle do not require power-training as in mammals. Our study suggests that it is possible for birds to consume and replace their flight muscles on a time scale short enough to allow these muscles to be used as part of the energy supply for migratory flight. The adaptive significance of the changes in pectoral muscle mass cannot be explained by reproductive needs since our knots were in the early winter phase of their annual cycle. Instead, pectoral muscle mass changes may reflect (i) the breakdown of protein during heavy exercise and its subsequent restoration, (ii) the regulation of flight capacity to maintain optimal flight performance when body mass varies, or (iii) the need for a particular protein:fat ratio in winter survival stores.

  18. Flight and seizure motor patterns in Drosophila mutants: simultaneous acoustic and electrophysiological recordings of wing beats and flight muscle activity.

    PubMed

    Iyengar, Atulya; Wu, Chun-Fang

    2014-01-01

    Abstract Tethered flies allow studies of biomechanics and electrophysiology of flight control. We performed microelectrode recordings of spikes in an indirect flight muscle (the dorsal longitudinal muscle, DLMa) coupled with acoustic analysis of wing beat frequency (WBF) via microphone signals. Simultaneous electrophysiological recording of direct and indirect flight muscles has been technically challenging; however, the WBF is thought to reflect in a one-to-one relationship with spiking activity in a subset of direct flight muscles, including muscle m1b. Therefore, our approach enables systematic mutational analysis for changes in temporal features of electrical activity of motor neurons innervating subsets of direct and indirect flight muscles. Here, we report the consequences of specific ion channel disruptions on the spiking activity of myogenic DLMs (firing at ∼5 Hz) and the corresponding WBF (∼200 Hz). We examined mutants of the genes enconding: 1) voltage-gated Ca(2+) channels (cacophony, cac), 2) Ca(2+)-activated K(+) channels (slowpoke, slo), and 3) voltage-gated K(+) channels (Shaker, Sh) and their auxiliary subunits (Hyperkinetic, Hk and quiver, qvr). We found flight initiation in response to an air puff was severely disrupted in both cac and slo mutants. However, once initiated, slo flight was largely unaltered, whereas cac displayed disrupted DLM firing rates and WBF. Sh, Hk, and qvr mutants were able to maintain normal DLM firing rates, despite increased WBF. Notably, defects in the auxiliary subunits encoded by Hk and qvr could lead to distinct consequences, that is, disrupted DLM firing rhythmicity, not observed in Sh. Our mutant analysis of direct and indirect flight muscle activities indicates that the two motor activity patterns may be independently modified by specific ion channel mutations, and that this approach can be extended to other dipteran species and additional motor programs, such as electroconvulsive stimulation-induced seizures.

  19. Specificity and localisation of lipoprotein lipase in the flight muscles of Locusta migratoria.

    PubMed

    Wheeler, C H; Goldsworthy, G J

    1985-12-01

    Using natural lipoproteins as substrates, lipase activity has been measured in leg muscle, fat body, midgut and flight muscles of Locusta migratoria. The enzymic activity in the flight muscles is higher than in those other tissues tested, confirming the potential of the flight muscles to utilise lipids at high rates. In addition, a membrane-bound lipoprotein lipase can be extracted from flight muscle. The flight muscle enzyme activity shows a marked substrate specificity; at lipoprotein concentrations equivalent to those found normally in flown or resting locusts respectively, the enzyme hydrolyses diacylglycerols associated with lipoprotein A+ (present in the haemolymph of flown or adipokinetic hormone-injected locusts) at about 4 times the rate of those associated with lipoprotein Ayellow (which is the major lipoprotein in resting locusts). In addition, the hydrolysis of lipids carried by lipoprotein Ayellow is dramatically reduced in the presence of lipoprotein A+. These observations indicate that the enzyme plays a specific role in the uptake of lipids at the flight muscles to ensure a smooth transition from carbohydrate to lipid based metabolism during flight. PMID:4091966

  20. Differences in the Aerobic Capacity of Flight Muscles between Butterfly Populations and Species with Dissimilar Flight Abilities

    PubMed Central

    Rauhamäki, Virve; Wolfram, Joy; Jokitalo, Eija; Hanski, Ilkka; Dahlhoff, Elizabeth P.

    2014-01-01

    Habitat loss and climate change are rapidly converting natural habitats and thereby increasing the significance of dispersal capacity for vulnerable species. Flight is necessary for dispersal in many insects, and differences in dispersal capacity may reflect dissimilarities in flight muscle aerobic capacity. In a large metapopulation of the Glanville fritillary butterfly in the Åland Islands in Finland, adults disperse frequently between small local populations. Individuals found in newly established populations have higher flight metabolic rates and field-measured dispersal distances than butterflies in old populations. To assess possible differences in flight muscle aerobic capacity among Glanville fritillary populations, enzyme activities and tissue concentrations of the mitochondrial protein Cytochrome-c Oxidase (CytOx) were measured and compared with four other species of Nymphalid butterflies. Flight muscle structure and mitochondrial density were also examined in the Glanville fritillary and a long-distance migrant, the red admiral. Glanville fritillaries from new populations had significantly higher aerobic capacities than individuals from old populations. Comparing the different species, strong-flying butterfly species had higher flight muscle CytOx content and enzymatic activity than short-distance fliers, and mitochondria were larger and more numerous in the flight muscle of the red admiral than the Glanville fritillary. These results suggest that superior dispersal capacity of butterflies in new populations of the Glanville fritillary is due in part to greater aerobic capacity, though this species has a low aerobic capacity in general when compared with known strong fliers. Low aerobic capacity may limit dispersal ability of the Glanville fritillary. PMID:24416122

  1. Differences in the aerobic capacity of flight muscles between butterfly populations and species with dissimilar flight abilities.

    PubMed

    Rauhamäki, Virve; Wolfram, Joy; Jokitalo, Eija; Hanski, Ilkka; Dahlhoff, Elizabeth P

    2014-01-01

    Habitat loss and climate change are rapidly converting natural habitats and thereby increasing the significance of dispersal capacity for vulnerable species. Flight is necessary for dispersal in many insects, and differences in dispersal capacity may reflect dissimilarities in flight muscle aerobic capacity. In a large metapopulation of the Glanville fritillary butterfly in the Åland Islands in Finland, adults disperse frequently between small local populations. Individuals found in newly established populations have higher flight metabolic rates and field-measured dispersal distances than butterflies in old populations. To assess possible differences in flight muscle aerobic capacity among Glanville fritillary populations, enzyme activities and tissue concentrations of the mitochondrial protein Cytochrome-c Oxidase (CytOx) were measured and compared with four other species of Nymphalid butterflies. Flight muscle structure and mitochondrial density were also examined in the Glanville fritillary and a long-distance migrant, the red admiral. Glanville fritillaries from new populations had significantly higher aerobic capacities than individuals from old populations. Comparing the different species, strong-flying butterfly species had higher flight muscle CytOx content and enzymatic activity than short-distance fliers, and mitochondria were larger and more numerous in the flight muscle of the red admiral than the Glanville fritillary. These results suggest that superior dispersal capacity of butterflies in new populations of the Glanville fritillary is due in part to greater aerobic capacity, though this species has a low aerobic capacity in general when compared with known strong fliers. Low aerobic capacity may limit dispersal ability of the Glanville fritillary.

  2. Myosin heavy-chain isoforms in the flight and leg muscles of hummingbirds and zebra finches.

    PubMed

    Velten, Brandy P; Welch, Kenneth C

    2014-06-01

    Myosin heavy chain (MHC) isoform complement is intimately related to a muscle's contractile properties, yet relatively little is known about avian MHC isoforms or how they may vary with fiber type and/or the contractile properties of a muscle. The rapid shortening of muscles necessary to power flight at the high wingbeat frequencies of ruby-throated hummingbirds and zebra finches (25-60 Hz), along with the varied morphology and use of the hummingbird hindlimb, provides a unique opportunity to understand how contractile and morphological properties of avian muscle may be reflected in MHC expression. Isoforms of the hummingbird and zebra finch flight and hindlimb muscles were electrophoretically separated and compared with those of other avian species representing different contractile properties and fiber types. The flight muscles of the study species operate at drastically different contraction rates and are composed of different histochemically defined fiber types, yet each exhibited the same, single MHC isoform corresponding to the chicken adult fast isoform. Thus, despite quantitative differences in the contractile demands of flight muscles across species, this isoform appears necessary for meeting the performance demands of avian powered flight. Variation in flight muscle contractile performance across species may be due to differences in the structural composition of this conserved isoform and/or variation within other mechanically linked proteins. The leg muscles were more varied in their MHC isoform composition across both muscles and species. The disparity in hindlimb MHC expression between hummingbirds and the other species highlights previously observed differences in fiber type composition and thrust production during take-off.

  3. Patterning the dorsal longitudinal flight muscles (DLM) of Drosophila: insights from the ablation of larval scaffolds

    NASA Technical Reports Server (NTRS)

    Fernandes, J. J.; Keshishian, H.

    1996-01-01

    The six Dorsal Longitudinal flight Muscles (DLMs) of Drosophila develop from three larval muscles that persist into metamorphosis and serve as scaffolds for the formation of the adult fibers. We have examined the effect of muscle scaffold ablation on the development of DLMs during metamorphosis. Using markers that are specific to muscle and myoblasts we show that in response to the ablation, myoblasts which would normally fuse with the larval muscle, fuse with each other instead, to generate the adult fibers in the appropriate regions of the thorax. The development of these de novo DLMs is delayed and is reflected in the delayed expression of erect wing, a transcription factor thought to control differentiation events associated with myoblast fusion. The newly arising muscles express the appropriate adult-specific Actin isoform (88F), indicating that they have the correct muscle identity. However, there are frequent errors in the number of muscle fibers generated. Ablation of the larval scaffolds for the DLMs has revealed an underlying potential of the DLM myoblasts to initiate de novo myogenesis in a manner that resembles the mode of formation of the Dorso-Ventral Muscles, DVMs, which are the other group of indirect flight muscles. Therefore, it appears that the use of larval scaffolds is a superimposition on a commonly used mechanism of myogenesis in Drosophila. Our results show that the role of the persistent larval muscles in muscle patterning involves the partitioning of DLM myoblasts, and in doing so, they regulate formation of the correct number of DLM fibers.

  4. Effects of space flight on GLUT-4 content in rat plantaris muscle

    NASA Astrophysics Data System (ADS)

    Tabata, I.; Kawanaka, Kentaro; Sekiguchi, Chiharu; Nagaoka, Shunji; Ohira, Yoshinobu

    The effects of 14 days of space flight on the glucose transporter protein (GLUT-4) were studied in the plantaris muscle of growing 9-week-old, male Sprague Dawley rats. The rats were randomly separated into five groups: pre-flight vivarium ground controls (PF-VC) sacrificed approximately 2 h after launch; flight groups sacrificed either approximately 5 h (F-R0) or 9 days (F-R9) after the return from space; and synchronous ground controls (SC-R0 and SC-R9) sacrificed at the same time as the respective flight groups. The flight groups F-R0 and F-R9 were exposed to micro-gravity for 14 days in the Spacelab module located in the cargo bay of the shuttle transport system - 58 of the manned Space Shuttle for the NASA mission named ''Spacelab Life Sciences 2''. Body weight and plantaris weight of SC-R0 and F-R0 were significantly higher than those of PF-VC. Neither body weight nor plantaris muscle weight in either group had changed 9 days after the return from space. As a result, body weight and plantaris muscle weight did not differ between the flight and synchronous control groups at any of the time points investigated. The GLUT-4 content (cpm/µg membrane protein) in the plantaris muscle did not show any significant change in response to 14 days of space flight or 9 days after return. Similarly, citrate synthase activity did not change during the course of the space flight or the recovery period. These results suggest that 14 days of space flight does not affect muscle mass or GLUT-4 content of the fast-twitch plantaris muscle in the rat.

  5. Abdicating power for control: a precision timing strategy to modulate function of flight power muscles.

    PubMed

    Sponberg, S; Daniel, T L

    2012-10-01

    Muscles driving rhythmic locomotion typically show strong dependence of power on the timing or phase of activation. This is particularly true in insects' main flight muscles, canonical examples of muscles thought to have a dedicated power function. However, in the moth (Manduca sexta), these muscles normally activate at a phase where the instantaneous slope of the power-phase curve is steep and well below maximum power. We provide four lines of evidence demonstrating that, contrary to the current paradigm, the moth's nervous system establishes significant control authority in these muscles through precise timing modulation: (i) left-right pairs of flight muscles normally fire precisely, within 0.5-0.6 ms of each other; (ii) during a yawing optomotor response, left-right muscle timing differences shift throughout a wider 8 ms timing window, enabling at least a 50 per cent left-right power differential; (iii) timing differences correlate with turning torque; and (iv) the downstroke power muscles alone causally account for 47 per cent of turning torque. To establish (iv), we altered muscle activation during intact behaviour by stimulating individual muscle potentials to impose left-right timing differences. Because many organisms also have muscles operating with high power-phase gains (Δ(power)/Δ(phase)), this motor control strategy may be ubiquitous in locomotor systems.

  6. Deciphering the role of a coleopteran steering muscle via free flight stimulation.

    PubMed

    Sato, Hirotaka; Vo Doan, Tat Thang; Kolev, Svetoslav; Huynh, Ngoc Anh; Zhang, Chao; Massey, Travis L; van Kleef, Joshua; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M

    2015-03-16

    Testing hypotheses of neuromuscular function during locomotion ideally requires the ability to record cellular responses and to stimulate the cells being investigated to observe downstream behaviors [1]. The inability to stimulate in free flight has been a long-standing hurdle for insect flight studies. The miniaturization of computation and communication technologies has delivered ultra-small, radio-enabled neuromuscular recorders and stimulators for untethered insects [2-8]. Published stimulation targets include the areas in brain potentially responsible for pattern generation in locomotion [5], the nerve chord for abdominal flexion [9], antennal muscles [2, 10], and the flight muscles (or their excitatory junctions) [7, 11-13]. However, neither fine nor graded control of turning has been demonstrated in free flight, and responses to the stimulation vary widely [2, 5, 7, 9]. Technological limitations have precluded hypotheses of function validation requiring exogenous stimulation during flight. We investigated the role of a muscle involved in wing articulation during flight in a coleopteran. We set out to identify muscles whose stimulation produced a graded turning in free flight, a feat that would enable fine steering control not previously demonstrated. We anticipated that gradation might arise either as a function of the phase of muscle firing relative to the wing stroke (as in the classic fly b1 muscle [14, 15] or the dorsal longitudinal and ventral muscles of moth [16]), or due to regulated tonic control, in which phase-independent summation of twitch responses produces varying amounts of force delivered to the wing linkages [15, 17, 18].

  7. Characterization of the gene for mp20: a Drosophila muscle protein that is not found in asynchronous oscillatory flight muscle

    PubMed Central

    1989-01-01

    A Drosophila melanogaster gene encoding a muscle specific protein was isolated by differential screening with RNA from primary cultures of myotubes. The gene encodes a 20-kD protein, muscle protein 20 (mp20), that is not detected in the asynchronous oscillatory flight muscles, but is found in most, if not all, other muscles (the synchronous muscles). The sequence of the protein, deduced from the DNA, contains two regions of 12 amino acids with significant similarity to high- affinity calcium-binding sites of other proteins. This protein is easily extracted from the contractile apparatus and thus does not seem to be a tightly bound structural component. The gene (located in polytene region 49F 9-13) is unique in the D. melanogaster genome and yields two transcripts, 1.0 and 0.9 kb long. The levels of the two transcripts are regulated differently during development, yet the coding regions of the two transcripts are identical. PMID:2537318

  8. Female pheromones modulate flight muscle activation patterns during preflight warm-up.

    PubMed

    Crespo, José G; Vickers, Neil J; Goller, Franz

    2013-08-01

    At low ambient temperature Helicoverpa zea male moths engage in warm-up behavior prior to taking flight in response to an attractive female pheromone blend. Male H. zea warm up at a faster rate when sensing the attractive pheromone blend compared with unattractive blends or blank controls (Crespo et al. 2012), but the mechanisms involved in this olfactory modulation of the heating rate during preflight warm-up are unknown. Here, we test three possible mechanisms for increasing heat production: 1) increased rate of muscle contraction; 2) reduction in mechanical movement by increased overlap in activation of the antagonistic flight muscles; and 3) increased activation of motor units. To test which mechanisms play a role, we simultaneously recorded electrical activation patterns of the main flight muscles (dorsolongitudinal and dorsoventral muscles), wing movement, and thoracic temperature in moths exposed to both the attractive pheromone blend and a blank control. Results indicate that the main mechanism responsible for the observed increase in thoracic heating rate with pheromone stimulation is the differential activation of motor units during each muscle contraction cycle in both antagonistic flight muscles. This additional activation lengthens the contracted state within each cycle and thus accounts for the greater heat production. Interestingly, the rate of activation (frequency of contraction cycles) of motor units, which is temperature dependent, did not vary between treatments. This result suggests that the activation rate is determined by a temperature-dependent oscillator, which is not affected by the olfactory stimulus, but activation of motor units is modulated during each cycle.

  9. Mucor dimorphism.

    PubMed Central

    Orlowski, M

    1991-01-01

    Mucor dimorphism has interested microbiologists since the time of Pasteur. When deprived of oxygen, these fungi grow as spherical, multipolar budding yeasts. In the presence of oxygen, they propagate as branching coenocytic hyphae. The ease with which these morphologies can be manipulated in the laboratory, the diverse array of morphopoietic agents available, and the alternative developmental fates that can be elicited from a single cell type (the sporangiospore) make Mucor spp. a highly propitious system in which to study eukaryotic cellular morphogenesis. The composition and organization of the cell wall differ greatly in Mucor yeasts and hyphae. The deposition of new wall polymers is isodiametric in yeasts and apically polarized in hyphae. Current research has focused on the identity and control of enzymes participating in wall synthesis. An understanding of how the chitosome interacts with appropriate effectors, specific enzymes, and the plasma membrane to assemble chitin-chitosan microfibrils and to deposit them at the proper sites on the cell exterior will be critical to elucidating dimorphism. Several biochemical and physiological parameters have been reported to fluctuate in a manner that correlates with Mucor morphogenesis. The literature describing these has been reviewed critically with the intent of distinguishing between causal and casual connections. The advancement of molecular genetics has afforded powerful new tools that researchers have begun to exploit in the study of Mucor dimorphism. Several genes, some encoding products known to correlate with development in Mucor spp. or other fungi, have been cloned, sequenced, and examined for transcriptional activity during morphogenesis. Most have appeared in multiple copies displaying independent transcriptional control. Selective translation of stored mRNA molecules occurs during sporangiospore germination. Many other correlates of Mucor morphogenesis, presently described but not yet explained, should

  10. Sugar flux through the flight muscles of hovering vertebrate nectarivores: a review.

    PubMed

    Welch, Kenneth C; Chen, Chris C W

    2014-12-01

    In most vertebrates, uptake and oxidation of circulating sugars by locomotor muscles rises with increasing exercise intensity. However, uptake rate by muscle plateaus at moderate aerobic exercise intensities and intracellular fuels dominate at oxygen consumption rates of 50% of maximum or more. Further, uptake and oxidation of circulating fructose by muscle is negligible. In contrast, hummingbirds and nectar bats are capable of fueling expensive hovering flight exclusively, or nearly completely, with dietary sugar. In addition, hummingbirds and nectar bats appear capable of fueling hovering flight completely with fructose. Three crucial steps are believed to be rate limiting to muscle uptake of circulating glucose or fructose in vertebrates: (1) delivery to muscle; (2) transport into muscle through glucose transporter proteins (GLUTs); and (3) phosphorylation of glucose by hexokinase (HK) within the muscle. In this review, we summarize what is known about the functional upregulation of exogenous sugar flux at each of these steps in hummingbirds and nectar bats. High cardiac output, capillary density, and blood sugar levels in hummingbirds and bats enhance sugar delivery to muscles (step 1). Hummingbird and nectar bat flight muscle fibers have relatively small cross-sectional areas and thus relatively high surface areas across which transport can occur (step 2). Maximum HK activities in each species are enough for carbohydrate flux through glycolysis to satisfy 100 % of hovering oxidative demand (step 3). However, qualitative patterns of GLUT expression in the muscle (step 2) raise more questions than they answer regarding sugar transport in hummingbirds and suggest major differences in the regulation of sugar flux compared to nectar bats. Behavioral and physiological similarities among hummingbirds, nectar bats, and other vertebrates suggest enhanced capacities for exogenous fuel use during exercise may be more wide spread than previously appreciated. Further, how

  11. A gravity exercise system. [for muscle conditioning during manned space flight

    NASA Technical Reports Server (NTRS)

    Brandt, W. E.; Clark, A. L.

    1973-01-01

    An effective method for muscle conditioning during weightlessness flight is derived from isometric exercise. The basic principle of gravity exercise is to periodically displace the human body upon reactionless rollers so that spacial equilibrium can only be maintained by the proper tension and relaxation of the body's muscles. A rotating platform mounted upon two degrees of freedom rollers provides such a condition of gravitational reaction stress throughout each of its 360 deg rotation.

  12. A sport-physiological perspective on bird migration: evidence for flight-induced muscle damage.

    PubMed

    Guglielmo, C G; Piersma, T; Williams, T D

    2001-08-01

    Exercise-induced muscle damage is a well-described consequence of strenuous exercise, but its potential importance in the evolution of animal activity patterns is unknown. We used plasma creatine kinase (CK) activity as an indicator of muscle damage to investigate whether the high intensity, long-duration flights of two migratory shorebird species cause muscle damage that must be repaired during stopover. In two years of study, plasma CK activity was significantly higher in migrating western sandpipers (a non-synchronous, short-hop migrant), than in non-migrants. Similarly, in the bar-tailed godwit (a synchronous, long-jump migrant), plasma CK activity was highest immediately after arrival from a 4000-5000km flight from West Africa to The Netherlands, and declined before departure for the arctic breeding areas. Late-arriving godwits had higher plasma CK activity than birds that had been at the stopover site longer. Juvenile western sandpipers making their first southward migration had higher plasma CK activity than adults. These results indicate that muscle damage occurs during migration, and that it is exacerbated in young, relatively untrained birds. However, the magnitude of the increases in plasma CK activity associated with migratory flight were relatively small, suggesting that the level of muscle damage is moderate. Migrants may avoid damage behaviourally, or have efficient biochemical and physiological defences against muscle injury. PMID:11533118

  13. Temperature gradients drive mechanical energy gradients in the flight muscle of Manduca sexta.

    PubMed

    George, N T; Sponberg, S; Daniel, T L

    2012-02-01

    A temperature gradient throughout the dominant flight muscle (dorsolongitudinal muscle, DLM(1)) of the hawkmoth Manduca sexta, together with temperature-dependent muscle contractile rates, demonstrates that significant spatial variation in power production is possible within a single muscle. Using in situ work-loop analyses under varying muscle temperatures and phases of activation, we show that regional differences in muscle temperature will induce a spatial gradient in the mechanical power output throughout the DLM(1). Indeed, we note that this power gradient spans from positive to negative values across the predicted temperature range. Warm ventral subunits produce positive power at their in vivo operating temperatures, and therefore act as motors. Concurrently, as muscle temperature decreases dorsally, the subunits produce approximately zero mechanical power output, acting as an elastic energy storage source, and negative power output, behaving as a damper. Adjusting the phase of activation further influences the temperature sensitivity of power output, significantly affecting the mechanical power output gradient that is expressed. Additionally, the separate subregions of the DLM(1) did not appear to employ significant physiological compensation for the temperature-induced differences in power output. Thus, although the components of a muscle are commonly thought to operate uniformly, a significant within-muscle temperature gradient has the potential to induce a mechanical power gradient, whereby subunits within a muscle operate with separate and distinct functional roles.

  14. Energetic Metabolism and Biochemical Adaptation: A Bird Flight Muscle Model

    ERIC Educational Resources Information Center

    Rioux, Pierre; Blier, Pierre U.

    2006-01-01

    The main objective of this class experiment is to measure the activity of two metabolic enzymes in crude extract from bird pectoral muscle and to relate the differences to their mode of locomotion and ecology. The laboratory is adapted to stimulate the interest of wildlife management students to biochemistry. The enzymatic activities of cytochrome…

  15. X-ray diffraction of indirect flight muscle from Drosohila in vivo

    SciTech Connect

    Irving, T.

    2007-02-09

    The indirect flight muscle (IFM) of the fruit fly, Drosophila, represents a powerful model system for integrated structure and function studies because of the ease of genetically manipulating this organism. Recent advances in synchrotron technology have allowed collection of high quality two dimensional x-ray fiber diffraction patterns from the IFM of living fruit flies both at rest and during tethered flight. Based on many decades of x-ray and electron microscopic studies of vertebrate muscle and IFM from the waterbug, Lethocerus, there now exists a framework for interpreting changes in the x-ray diffraction patterns in terms of structural changes at the myofilament level. These developments allow testing of hypotheses concerning muscle function in a truly in vivo system.

  16. [Amino acid composition of the rat quadriceps femoris muscle after a flight on the Kosmos-936 biosatellite].

    PubMed

    Vlasova, T F; Miroshnikova, E B; Poliakov, V V; Murugova, T P

    1982-01-01

    The amino acid composition of the quadriceps muscle of rats flown onboard the biosatellite Cosmos-936 and exposed to the ground-based synchronous control experiment was studied. The weightless rats showed changes in the amino acid concentration in the quadriceps muscle. The centrifuged flight and synchronous rats displayed an accumulation of free amino acids in the above muscle.

  17. Effect of myonuclear number and mitochondrial fusion on Drosophila indirect flight muscle organization and size

    SciTech Connect

    Rai, Mamta; Nongthomba, Upendra

    2013-10-15

    Mechanisms involved in establishing the organization and numbers of fibres in a muscle are not completely understood. During Drosophila indirect flight muscle (IFM) formation, muscle growth is achieved by both incorporating hundreds of nuclei, and hypertrophy. As a result, IFMs provide a good model with which to understand the mechanisms that govern overall muscle organization and growth. We present a detailed analysis of the organization of dorsal longitudinal muscles (DLMs), a subset of the IFMs. We show that each DLM is similar to a vertebrate fascicle and consists of multiple muscle fibres. However, increased fascicle size does not necessarily change the number of constituent fibres, but does increase the number of myofibrils packed within the fibres. We also find that altering the number of myoblasts available for fusion changes DLM fascicle size and fibres are loosely packed with myofibrils. Additionally, we show that knock down of genes required for mitochondrial fusion causes a severe reduction in the size of DLM fascicles and fibres. Our results establish the organization levels of DLMs and highlight the importance of the appropriate number of nuclei and mitochondrial fusion in determining the overall organization, growth and size of DLMs. - Highlights: • Drosophila dorsal longitudinal muscles are similar to vertebrate skeletal muscles. • A threshold number of myoblasts governs the organization of a fibre and its size. • Mitochondrial fusion defect leads to abnormal fibre growth and organization.

  18. Transgenic expression and purification of myosin isoforms using the Drosophila melanogaster indirect flight muscle system.

    PubMed

    Caldwell, James T; Melkani, Girish C; Huxford, Tom; Bernstein, Sanford I

    2012-01-01

    Biophysical and structural studies on muscle myosin rely upon milligram quantities of extremely pure material. However, many biologically interesting myosin isoforms are expressed at levels that are too low for direct purification from primary tissues. Efforts aimed at recombinant expression of functional striated muscle myosin isoforms in bacterial or insect cell culture have largely met with failure, although high level expression in muscle cell culture has recently been achieved at significant expense. We report a novel method for the use of strains of the fruit fly Drosophila melanogaster genetically engineered to produce histidine-tagged recombinant muscle myosin isoforms. This method takes advantage of the single muscle myosin heavy chain gene within the Drosophila genome, the high level of expression of accessible myosin in the thoracic indirect flight muscles, the ability to knock out endogenous expression of myosin in this tissue and the relatively low cost of fruit fly colony production and maintenance. We illustrate this method by expressing and purifying a recombinant histidine-tagged variant of embryonic body wall skeletal muscle myosin II from an engineered fly strain. The recombinant protein shows the expected ATPase activity and is of sufficient purity and homogeneity for crystallization. This system may prove useful for the expression and isolation of mutant myosins associated with skeletal muscle diseases and cardiomyopathies for their biochemical and structural characterization.

  19. A direct screen identifies new flight muscle mutants on the Drosophila second chromosome.

    PubMed Central

    Nongthomba, U; Ramachandra, N B

    1999-01-01

    An ethyl methanesulfonate mutagenesis of Drosophila melanogaster was undertaken, and >3000 mutagenized second chromosomes were generated. More than 800 homozygous viable lines were established, and adults were screened directly under polarized light for muscle defects. A total of 16 mutant strains in which the indirect flight muscles were reduced in volume or disorganized or were otherwise abnormal were identified. These fell into seven recessive and one semidominant complementation groups. Five of these eight complementation groups, including the semidominant mutation, have been mapped using chromosomal deficiencies and meiotic recombination. Two complementation groups mapped close to the Myosin heavy chain gene, but they are shown to be in different loci. Developmental analysis of three mutations showed that two of these are involved in the early stages of adult myogenesis while the other showed late defects. This is the first report of results from a systematic and direct screen for recessive flight muscle defects. This mutant screen identifies genes affecting the flight muscles, which are distinct from those identified when screening for flightlessness. PMID:10471711

  20. Programmed Cell Death in Flight Muscle Histolysis of the House Cricket

    PubMed Central

    Oliver, Rush H.; Albury, Acchia N.J.; Mousseau, Timothy A.

    2007-01-01

    We have characterized the process of flight muscle histolysis in the female house cricket, Acheta domesticus, through analysis of alterations of tissue wet weight, total protein content, and percent shortening of the dorsal longitudinal flight muscles (DLMs). Our objectives were to (1) define the normal course of histolysis in the cricket, (2) analyze the effects of juvenile hormone (JH) removal and replacement, (3) determine the effects of cycloheximide treatment, and (4) examine patterns of protein expression during histolysis. Our results suggest that flight muscle histolysis in the house cricket is an example of an active, developmentally regulated cell death program induced by an endocrine signal. Initial declines of total protein in DLMs indicated the JH signal that induced histolysis occurred by Day 2 and that histolysis was essentially complete by Day 3. Significant reductions in tissue weight and percent muscle shortening were observed in DLMs from Day 3 crickets. Cervical ligation of Day 1 crickets prevented histolysis but this inhibition could be reversed by continual topical treatments with methoprene (an active JH analog) although ligation of Day 2 crickets did not prevent histolysis. A requirement for active protein expression was demonstrated by analysis of synthesis block by cycloheximide and short-term incorporation of 35S-methionine. Treatment with cycloheximide prevented histolysis. Autofluorographic imaging of DLM proteins separated by electrophoresis revealed apparent coordinated regulation of protein expression. PMID:17118399

  1. Identification of a new stem cell population that generates Drosophila flight muscles

    PubMed Central

    Gunage, Rajesh D; Reichert, Heinrich; VijayRaghavan, K

    2014-01-01

    How myoblast populations are regulated for the formation of muscles of different sizes is an essentially unanswered question. The large flight muscles of Drosophila develop from adult muscle progenitor (AMP) cells set-aside embryonically. The thoracic segments are all allotted the same small AMP number, while those associated with the wing-disc proliferate extensively to give rise to over 2500 myoblasts. An initial amplification occurs through symmetric divisions and is followed by a switch to asymmetric divisions in which the AMPs self-renew and generate post-mitotic myoblasts. Notch signaling controls the initial amplification of AMPs, while the switch to asymmetric division additionally requires Wingless, which regulates Numb expression in the AMP lineage. In both cases, the epidermal tissue of the wing imaginal disc acts as a niche expressing the ligands Serrate and Wingless. The disc-associated AMPs are a novel muscle stem cell population that orchestrates the early phases of adult flight muscle development. DOI: http://dx.doi.org/10.7554/eLife.03126.001 PMID:25135939

  2. Ecdysteroids affect in vivo protein metabolism of the flight muscle of the tobacco hornworm (Manduca sexta)

    NASA Technical Reports Server (NTRS)

    Tischler, M. E.; Wu, M.; Cook, P.; Hodsden, S.

    1990-01-01

    Ecdysteroid growth promotion of the dorsolongitudinal flight muscle of Manduca sexta was studied by measuring in vivo protein metabolism using both "flooding-dose" and "non-carrier" techniques. These procedures differ in that the former method includes injection of non-labelled phenylalanine (30 micromoles/insect) together with the [3H]amino acid. Injected radioactivity plateaued in the haemolymph within 7 min. With the flooding-dose method, haemolymph and intramuscular specific radioactivities were similar between 15 min and 2 h. Incorporation of [3H]phenylalanine into muscle protein was linear with either method between 30 and 120 min. Fractional rates (%/12 h) of synthesis with the flooding-dose technique were best measured after 1 h because of the initial delay in radioactivity equilibration. Estimation of body phenylalanine turnover with the non-carrier method showed 24-53%/h which was negligible with the flooding-dose method. Since the two methods yielded similar rates of protein synthesis, the large injection of non-labelled amino acid did not alter the rate of synthesis. Because the flooding-dose technique requires only a single time point measurement, it is the preferred method. The decline and eventual cessation of flight-muscle growth was mostly a consequence of declining protein synthesis though degradation increased between 76-86 h before eclosion and was relatively rapid. This decline in muscle growth could be prevented by treating pupae with 20-hydroxyecdysone (10 micrograms/insect). Protein accretion was promoted by a decline of up to 80% in protein breakdown, which was offset in part by a concurrent though much smaller decrease in protein synthesis. Therefore, ecdysteroids may increase flight-muscle growth by inhibiting proteolysis.

  3. Long-term effects of the trehalase inhibitor trehazolin on trehalase activity in locust flight muscle.

    PubMed

    Wegener, Gerhard; Macho, Claudia; Schlöder, Paul; Kamp, Günter; Ando, Osamu

    2010-11-15

    Trehalase (EC 3.2.1.28) hydrolyzes the main haemolymph sugar of insects, trehalose, into the essential cellular substrate glucose. Trehalase in locust flight muscle is bound to membranes that appear in the microsomal fraction upon tissue fractionation, but the exact location in vivo has remained elusive. Trehalase has been proposed to be regulated by a novel type of activity control that is based on the reversible transformation of a latent (inactive) form into an overt (active) form. Most trehalase activity from saline-injected controls was membrane-bound (95%) and comprised an overt form (∼25%) and a latent form (75%). Latent trehalase could be assayed only after the integrity of membranes had been destroyed. Trehazolin, a potent tight-binding inhibitor of trehalase, is confined to the extracellular space and has been used as a tool to gather information on the relationship between latent and overt trehalase. Trehazolin was injected into the haemolymph of locusts, and the trehalase activity of the flight muscle was determined at different times over a 30-day period. Total trehalase activity in locust flight muscle was markedly inhibited during the first half of the interval, but reappeared during the second half. Inhibition of the overt form preceded inhibition of the latent form, and the time course suggested a reversible precursor-product relation (cycling) between the two forms. The results support the working hypothesis that trehalase functions as an ectoenzyme, the activity of which is regulated by reversible transformation of latent into overt trehalase. PMID:21037064

  4. Flight muscle enzymes and metabolic flux rates during hovering flight of the nectar bat, Glossophaga soricina: further evidence of convergence with hummingbirds.

    PubMed

    Suarez, R K; Welch, K C; Hanna, S K; Herrera M, L G

    2009-06-01

    Given their high metabolic rates, nectarivorous diet, and ability to directly fuel their energetically-expensive flight using recently-ingested sugar, we tested the hypothesis that Pallas long tongued nectar bats (Glossophaga soricina) possess flight muscles similar to those of hummingbirds with respect to enzymatic flux capacities in bioenergetic pathways. In addition, we compared these biochemical capacities with flux rates achieved in vivo during hovering flight. Rates of oxygen consumption (V(O(2))) were measured during hover-feeding and used to estimate rates of ATP turnover, glucose and long-chain fatty acid oxidation per unit mass of flight muscle. Enzyme V(max) values at key steps in glucose and fatty acid oxidation obtained in vitro from pectoralis muscle samples exceed those found in the locomotory muscles of other species of small mammals and resemble data obtained from hummingbird flight muscles. The ability of nectar bats and hummingbirds to hover in fed and fasted states, fueled almost exclusively by carbohydrate or fat, respectively, allowed the estimation of fractional velocities (v/V(max)) at both the hexokinase and carnitine palmitoyltransferase-2 steps in glucose and fatty acid oxidation, respectively. The results further support the hypothesis of convergent evolution in biochemical and physiological traits in nectar bats and hummingbirds.

  5. Magnetic Resonance Imaging (MRI) of skeletal muscles in astronauts after 9 days of space flight

    NASA Technical Reports Server (NTRS)

    Jaweed, M.; Narayana, P.; Slopis, J.; Butler, I.; Schneider, V.; Leblanc, A.; Fotedar, L.; Bacon, D.

    1992-01-01

    Skylab data indicated that prolonged exposure of human subjects to microgravity environment causes significant muscle atrophy accompanied by reduced muscle strength and fatigue resistance. The objective of this study was to determine decrements in muscle size, if any, in the soleus and gastrocnemius muscles of male and female astronauts after 9 days of space flight. Methods: Eight astronauts, one female and seven male, between the ages of 31 and 59 years 59-84 kg in body weight were examined by MRI 2-3 times preflight within 16 days before launch, and 2 days, (n=6) and seven days (n=3) after landing. The right leg muscles (gastroc-soleus) were imaged with a lower extremity coil in magnets operating at 1.0 or 1.5 Tsela. The imaging protocol consisted of spin echo with a Tr of 0.70 - 1.5 sec. Thirty to forty 3-5 mm thick slices were acquired in 256 x 128 or 256 x 256 matrices. Acquisition time lasted 20-40 minutes. Multiple slices were measured by computerized planimetry. Results: Compared to the preflight, the cross-sectoral areas (CSA) of the soleus, gastrocnemius, and the leg, at 2 days after landing were reduced (at least p less than 0.05) 8.9 percent, 13.2 percent, and 9.5 percent respectively. The soleus and the leg of three astronauts evaluated at 7 days postflight did not show full recovery compared to the preflight values. Conclusions: It is concluded that l9-days of space flight may cause significant decreases in CSA of the leg muscles. The factors responsible for this loss need further determination.

  6. A dual-channel FM transmitter for acquisition of flight muscle activities from the freely flying hawkmoth, Agrius convolvuli.

    PubMed

    Ando, N; Shimoyama, I; Kanzaki, R

    2002-04-15

    Moths can perform various flight maneuvers by the contraction of some direct and indirect flight muscles. Multi-channel recording from these flight muscles and analysis of their interaction is very important for understanding insect flight motor system. In this study, we developed a dual-channel FM transmitter for acquisition of muscle potentials, with which a male hawkmoth (Agrius convolvuli) could fly freely and perform pheromone triggered zigzag flight in a wind tunnel. The transmitter weighs only 0.25 g including single battery, has a 5 m receivable range and works for more than 30 min. Doubling channels was achieved by providing two oscillators (the carrier frequencies were 82 and 85 MHz), and interference between them was overcome by buffer amplifiers and independent reference electrodes for each channel. With this transmitter, we could acquire muscle potentials from some direct and indirect muscles during free flight. Combined with simultaneous high-speed video analysis, we observed distinct changes of motor patterns during takeoff. Our radio-telemetric system allows acquisition of actual information from freely flying moths; such information will lead to further progress in the study of insect flight.

  7. Characterization and identification of a lipoprotein lipase from Manduca sexta flight muscle.

    PubMed

    Van Heusden, M C

    1993-10-01

    Lipoprotein lipase (LpL) activity in Manduca sexta flight muscle tissue was measured using in vivo radiolabeled lipophorin as a substrate. LpL hydrolyses diacylglycerol in the low density lipophorin (that occurs during flight) at a higher rate than diacylglycerol in the high density lipophorin (present in the resting insect). LpL has a pH-optimum of 7.5 and is less sensitive to NaCl than mammalian LpL. LpL is inhibited by bovine albumin and chicken ovalbumin. LpL is inhibited by the serine protease inhibitors diisopropylfluorophosphate (DFP) and phenylmethanesulfonyl fluoride (PMSF), which indicates the presence of an active site serine similar to mammalian LpL. Flight muscle LpL shows affinity for immobilized copper as well as for immobilized heparin. Using radiolabeled DFP, a protein of 37 kDa was identified (after SDS-PAGE) as the DFP-binding protein in a partially purified preparation of LpL. This 37 kDa protein is proposed to be the LpL or a subunit thereof.

  8. Subcellular trafficking of FGF controls tracheal invasion of Drosophila flight muscle

    PubMed Central

    Peterson, Soren J.; Krasnow, Mark A.

    2015-01-01

    SUMMARY To meet the extreme oxygen demand of insect flight muscle, tracheal (respiratory) tubes ramify not only on its surface, as in other tissues, but also within T-tubules and ultimately surrounding every mitochondrion. Although this remarkable physiological specialization has long been recognized, its cellular and molecular basis is unknown. Here we show that Drosophila tracheoles invade flight muscle T-tubules through transient surface openings. Like other tracheal branching events, invasion requires the Branchless FGF pathway. However, localization of the FGF chemoattractant changes from all muscle membranes to T-tubules as invasion begins. Core regulators of epithelial basolateral membrane identity localize to T-tubules, and knockdown of AP-1γ, required for basolateral trafficking, redirects FGF from T-tubules to surface, increasing tracheal surface ramification and preventing invasion. We propose that tracheal invasion is controlled by an AP-1-dependent switch in FGF trafficking. Thus, subcellular targeting of a chemoattractant can direct outgrowth to specific domains including inside the cell. PMID:25557078

  9. Functional Task Test: 3. Skeletal Muscle Performance Adaptations to Space Flight

    NASA Technical Reports Server (NTRS)

    Ryder, Jeffrey W.; Wickwire, P. J.; Buxton, R. E.; Bloomberg, J. J.; Ploutz-Snyder, L.

    2011-01-01

    The functional task test is a multi-disciplinary study investigating how space-flight induced changes to physiological systems impacts functional task performance. Impairment of neuromuscular function would be expected to negatively affect functional performance of crewmembers following exposure to microgravity. This presentation reports the results for muscle performance testing in crewmembers. Functional task performance will be presented in the abstract "Functional Task Test 1: sensory motor adaptations associated with postflight alternations in astronaut functional task performance." METHODS: Muscle performance measures were obtained in crewmembers before and after short-duration space flight aboard the Space Shuttle and long-duration International Space Station (ISS) missions. The battery of muscle performance tests included leg press and bench press measures of isometric force, isotonic power and total work. Knee extension was used for the measurement of central activation and maximal isometric force. Upper and lower body force steadiness control were measured on the bench press and knee extension machine, respectively. Tests were implemented 60 and 30 days before launch, on landing day (Shuttle crew only), and 6, 10 and 30 days after landing. Seven Space Shuttle crew and four ISS crew have completed the muscle performance testing to date. RESULTS: Preliminary results for Space Shuttle crew reveal significant reductions in the leg press performance metrics of maximal isometric force, power and total work on R+0 (p<0.05). Bench press total work was also significantly impaired, although maximal isometric force and power were not significantly affected. No changes were noted for measurements of central activation or force steadiness. Results for ISS crew were not analyzed due to the current small sample size. DISCUSSION: Significant reductions in lower body muscle performance metrics were observed in returning Shuttle crew and these adaptations are likely

  10. Myofilament proteins in the synchronous flight muscles of Manduca sexta show both similarities and differences to Drosophila melanogaster.

    PubMed

    Ayme-Southgate, Agnes; Feldman, Samuel; Fulmer, Diana

    2015-07-01

    Insect flight muscles have been classified as either synchronous or asynchronous based on the coupling between excitation and contraction. In the moth Manduca sexta, the flight muscles are synchronous and do not display stretch activation, which is a property of asynchronous muscles. We annotated the M. sexta genes encoding the major myofibrillar proteins and analyzed their isoform pattern and expression. Comparison with the homologous genes in Drosophila melanogaster indicates both difference and similarities. For proteins such as myosin heavy chain, tropomyosin, and troponin I the availability and number of potential variants generated by alternative spicing is mostly conserved between the two insects. The exon usage associated with flight muscles indicates that some exon sets are similarly used in the two insects, whereas others diverge. For actin the number of individual genes is different and there is no evidence for a flight muscle specific isoform. In contrast for troponin C, the number of genes is similar, as well as the isoform composition in flight muscles despite the different calcium regulation. Both troponin I and tropomyosin can include COOH-terminal hydrophobic extensions similar to tropomyosinH and troponinH found in D. melanogaster and the honeybee respectively. PMID:25797474

  11. Myofilament proteins in the synchronous flight muscles of Manduca sexta show both similarities and differences to Drosophila melanogaster.

    PubMed

    Ayme-Southgate, Agnes; Feldman, Samuel; Fulmer, Diana

    2015-07-01

    Insect flight muscles have been classified as either synchronous or asynchronous based on the coupling between excitation and contraction. In the moth Manduca sexta, the flight muscles are synchronous and do not display stretch activation, which is a property of asynchronous muscles. We annotated the M. sexta genes encoding the major myofibrillar proteins and analyzed their isoform pattern and expression. Comparison with the homologous genes in Drosophila melanogaster indicates both difference and similarities. For proteins such as myosin heavy chain, tropomyosin, and troponin I the availability and number of potential variants generated by alternative spicing is mostly conserved between the two insects. The exon usage associated with flight muscles indicates that some exon sets are similarly used in the two insects, whereas others diverge. For actin the number of individual genes is different and there is no evidence for a flight muscle specific isoform. In contrast for troponin C, the number of genes is similar, as well as the isoform composition in flight muscles despite the different calcium regulation. Both troponin I and tropomyosin can include COOH-terminal hydrophobic extensions similar to tropomyosinH and troponinH found in D. melanogaster and the honeybee respectively.

  12. Changes in isoform composition, structure, and functional properties of titin from Mongolian gerbil (Meriones unguiculatus) cardiac muscle after space flight.

    PubMed

    Vikhlyantsev, I M; Okuneva, A D; Shpagina, M D; Shumilina, Yu V; Molochkov, N V; Salmov, N N; Podlubnaya, Z A

    2011-12-01

    Changes in isoform composition, secondary structure, and titin phosphorylation in Mongolian gerbil (Meriones unguiculatus) cardiac muscle were studied after 12-day-long space flight onboard the Russian spacecraft Foton-M3. The effect of titin on the actin-activated myosin ATPase activity at pCa 7.5 and 4.6 was also studied. Almost twofold increase in titin long N2BA isoform content relative to that of short N2B isoform was found on electrophoregrams of cardiac muscle left ventricle of the flight group gerbils. Differences in secondary structure of titin isolated from cardiac muscle of control and flight groups of gerbils were found. An increase in phosphorylation (1.30-1.35-fold) of titin of cardiac muscle of the flight group gerbils was found. A decrease in activating effect of titin of cardiac muscle of the flight group gerbils on actomyosin ATPase activity in vitro was also found. The observed changes are discussed in the context of M. unguiculatus cardiac muscle adaptation to conditions of weightlessness.

  13. Accumulation of Tumor Suppressor P53 in Rat Muscle After a Space Flight

    NASA Astrophysics Data System (ADS)

    Ohnishi, T.; Wang, X.; Fukuda, S.; Takahashi, A.; Ohnishi, K.; Nagaoka, S.

    Tumor suppressor p53 functions as a cell cycle checkpoint under stressful conditions. Early studies have shown that genotoxic stress activates p53 pathway. Recently, many kinds of non-genotoxic stress such as heat shock, cold shock, and low pH also have been found to activate p53 pathway. The effects on living organism remains to be explored. Here, we show that an 18-day space flight induced a 3.6 fold accumulation of p53 in rat skeletal muscle. This results suggests that the p53 pathway plays a role in safeguarding genomic stability against the stressful space environments and supports our previous observation of p53 accumulation in rat skin after a space flight

  14. Spring or string: does tendon elastic action influence wing muscle mechanics in bat flight?

    PubMed

    Konow, Nicolai; Cheney, Jorn A; Roberts, Thomas J; Waldman, J Rhea S; Swartz, Sharon M

    2015-10-01

    Tendon springs influence locomotor movements in many terrestrial animals, but their roles in locomotion through fluids as well as in small-bodied mammals are less clear. We measured muscle, tendon and joint mechanics in an elbow extensor of a small fruit bat during ascending flight. At the end of downstroke, the tendon was stretched by elbow flexion as the wing was folded. At the end of upstroke, elastic energy was recovered via tendon recoil and extended the elbow, contributing to unfurling the wing for downstroke. Compared with a hypothetical 'string-like' system lacking series elastic compliance, the tendon spring conferred a 22.5% decrease in muscle fascicle strain magnitude. Our findings demonstrate tendon elastic action in a small flying mammal and expand our understanding of the occurrence and action of series elastic actuator mechanisms in fluid-based locomotion.

  15. Spring or string: does tendon elastic action influence wing muscle mechanics in bat flight?

    PubMed Central

    Konow, Nicolai; Cheney, Jorn A.; Roberts, Thomas J.; Waldman, J. Rhea S.; Swartz, Sharon M.

    2015-01-01

    Tendon springs influence locomotor movements in many terrestrial animals, but their roles in locomotion through fluids as well as in small-bodied mammals are less clear. We measured muscle, tendon and joint mechanics in an elbow extensor of a small fruit bat during ascending flight. At the end of downstroke, the tendon was stretched by elbow flexion as the wing was folded. At the end of upstroke, elastic energy was recovered via tendon recoil and extended the elbow, contributing to unfurling the wing for downstroke. Compared with a hypothetical ‘string-like’ system lacking series elastic compliance, the tendon spring conferred a 22.5% decrease in muscle fascicle strain magnitude. Our findings demonstrate tendon elastic action in a small flying mammal and expand our understanding of the occurrence and action of series elastic actuator mechanisms in fluid-based locomotion. PMID:26423848

  16. Isoform composition, gene expression and sarcomeric protein phosphorylation in striated muscle of mice after space flight

    NASA Astrophysics Data System (ADS)

    Vikhlyantsev, Ivan; Ulanova, Anna; Salmov, Nikolay; Gritsyna, Yulia; Bobylev, Alexandr; Rogachevsky, Vadim; Shenkman, Boris; Podlubnaya, Zoya

    Using RT-PCR and SDS-PAGE, changes in isoform composition, gene expression, titin and nebulin phosphorylation, as well as changes in isoform composition of myosin heavy chains in striated muscles of mice were studied after 30-day-long space flight onboard the Russian spacecraft “BION-M” No. 1. The muscle fibre-type shift from slow-to-fast was observed in m. gastrocnemius and m. tibialis anterior of animals from “Flight” group. A decrease in the content of the NT and N2A titin isoforms and nebulin in the skeletal muscles of animals from “Flight” group was found. Meanwhile, significant differences in gene expression of these proteins in skeletal muscles of mice from “Flight” and “Control” groups were not observed. Using Pro-Q Diamond stain, an increase in titin phosphorylation in m. gastrocnemius of mice from “Flight” group was detected. The content of the NT, N2BA and N2B titin isoforms in cardiac muscle of mice from “Flight” and “Control” groups did not differ, nevertheless an increase in titin gene expression in the myocardium of the “Flight” group animals was found. The observed changes will be discussed in the context of theirs role in contractile activity of striated muscles of mice in conditions of weightlessness. This work was supported by the Russian Foundation for Basic Research (grants No. 14-04-32240, 14-04-00112). Acknowledgement. We express our gratitude to the teams of Institute of Biomedical Problems RAS and “PROGRESS” Corporation involved in the preparation of the “BION-M” mission.

  17. Effects of prolonged space flight on human skeletal muscle enzyme and substrate profiles.

    PubMed

    Fitts, R H; Colloton, P A; Trappe, S W; Costill, D L; Bain, J L W; Riley, D A

    2013-09-01

    Our primary goal was to determine the effects of 6-mo flight on the International Space Station (ISS) on selected anaerobic and aerobic enzymes, and the content of glycogen and lipids in slow and fast fibers of the soleus and gastrocnemius. Following local anesthesia, biopsies were obtained from nine ISS crew members ∼45 days preflight and on landing day (R+0) postflight. We subdivided the crew into those who ran 200 min/wk or more (high treadmill, HT) in-flight from those who ran <100 min/wk (low treadmill, LT). In the LT group, there was a loss of lipid in soleus type I fibers, and muscle glycogen significantly increased in soleus fiber types postflight. Soleus cytochrome oxidase (CO) activity was significantly depressed postflight in the type I fiber. This was attributed to the LT group where CO activity was reduced 59%. Otherwise, there was no change in the crew mean for type I or IIa fiber glycolytic or mitochondrial enzyme activities pre- vs. postflight in either muscle. However, two of the three HT subjects (Subjects E and H) showed significant increases in both β-hydroxyacyl-CoA dehydrogenase and citrate synthase in the soleus type I fibers, and Subject E, exhibiting the largest increase in soleus oxidative enzymes, was the only subject to show a significant decrease in glycolytic enzyme activity. It is apparent that crew members performing adequate treadmill running can maintain calf muscle enzymes, which suggests that increased fatigue with weightlessness cannot be directly caused by a decline in muscle enzyme capacity.

  18. Anatomy and histochemistry of flight muscles in a wing-propelled diving bird, the Atlantic puffin, Fratercula arctica.

    PubMed

    Kovacs, C E; Meyers, R A

    2000-05-01

    Twenty-three species within the avian family Alcidae are capable of wing-propelled flight in the air and underwater. Alcids have been viewed as Northern Hemisphere parallels to penguins, and have often been studied to see if their underwater flight comes at a cost, compromising their aerial flying ability. We examined the anatomy and histochemistry of select wing muscles (Mm. pectoralis, supracoracoideus, latissimus dorsi caudalis, coracobrachialis caudalis, triceps scapularis, and scapulohumeralis caudalis) from Atlantic puffins (Fratercula arctica) to assess if the muscle fiber types reveal the existence of a compromise associated with "dual-medium" flight. Pectoralis was found to be proportional in size with that of nondiving species, although the supracoracoideus was proportionally larger in puffins. Muscle fiber types were largely aerobic in both muscles, with two distinct fast-twitch types demonstrable: a smaller, aerobic, moderately glycolytic population (FOg), and a larger, moderately aerobic, glycolytic population (FoG). The presence of these two fiber types in the primary flight muscles of puffins suggests that aerial and underwater flight necessitate a largely aerobic fiber complement. We suggest that alcids do not represent an adaptive compromise, but a stable adaptation for wing-propelled locomotion both in the air and underwater. PMID:10761049

  19. Kettin, a major source of myofibrillar stiffness in Drosophila indirect flight muscle

    PubMed Central

    Kulke, Michael; Neagoe, Ciprian; Kolmerer, Bernhard; Minajeva, Ave; Hinssen, Horst; Bullard, Belinda; Linke, Wolfgang A.

    2001-01-01

    Kettin is a high molecular mass protein of insect muscle that in the sarcomeres binds to actin and α-actinin. To investigate kettin's functional role, we combined immunolabeling experiments with mechanical and biochemical studies on indirect flight muscle (IFM) myofibrils of Drosophila melanogaster. Micrographs of stretched IFM sarcomeres labeled with kettin antibodies revealed staining of the Z-disc periphery. After extraction of the kettin-associated actin, the A-band edges were also stained. In contrast, the staining pattern of projectin, another IFM–I-band protein, was not altered by actin removal. Force measurements were performed on single IFM myofibrils to establish the passive length-tension relationship and record passive stiffness. Stiffness decreased within seconds during gelsolin incubation and to a similar degree upon kettin digestion with μ-calpain. Immunoblotting demonstrated the presence of kettin isoforms in normal Drosophila IFM myofibrils and in myofibrils from an actin-null mutant. Dotblot analysis revealed binding of COOH-terminal kettin domains to myosin. We conclude that kettin is attached not only to actin but also to the end of the thick filament. Kettin along with projectin may constitute the elastic filament system of insect IFM and determine the muscle's high stiffness necessary for stretch activation. Possibly, the two proteins modulate myofibrillar stiffness by expressing different size isoforms. PMID:11535621

  20. Sallimus and the dynamics of sarcomere assembly in Drosophila flight muscles.

    PubMed

    Orfanos, Zacharias; Leonard, Kevin; Elliott, Chris; Katzemich, Anja; Bullard, Belinda; Sparrow, John

    2015-06-19

    The Drosophila indirect flight muscles (IFM) can be used as a model for the study of sarcomere assembly. Here we use a transgenic line with a green fluorescent protein (GFP) exon inserted into the Z-disc-proximal portion of sallimus (Sls), also known as Drosophila titin, to observe sarcomere assembly during IFM development. Firstly, we confirm that Sls-GFP can be used in the heterozygote state without an obvious phenotype in IFM and other muscles. We then use Sls-GFP in the IFM to show that sarcomeres grow individually and uniformly throughout the fibre, growing linearly in length and in diameter. Finally, we show that limiting the amounts of Sls in the IFM using RNAi leads to sarcomeres with smaller Z-discs in their core, whilst the thick/thin filament lattice can form peripherally without a Z-disc. Thick filament preparations from those muscles show that although the Z-disc-containing core has thick filaments of a regular length, filaments from the peripheral lattice are longer and asymmetrical around the bare zone. Therefore, the Z-disc and Sls are required for thick filament length specification but not for the assembly of the thin/thick filament lattice.

  1. Thick-to-Thin Filament Surface Distance Modulates Cross-Bridge Kinetics in Drosophila Flight Muscle

    SciTech Connect

    Tanner, Bertrand C.W.; Farman, Gerrie P.; Irving, Thomas C.; Maughan, David W.; Palmer, Bradley M.; Miller, Mark S.

    2012-09-19

    The demembranated (skinned) muscle fiber preparation is widely used to investigate muscle contraction because the intracellular ionic conditions can be precisely controlled. However, plasma membrane removal results in a loss of osmotic regulation, causing abnormal hydration of the myofilament lattice and its proteins. We investigated the structural and functional consequences of varied myofilament lattice spacing and protein hydration on cross-bridge rates of force development and detachment in Drosophila melanogaster indirect flight muscle, using x-ray diffraction to compare the lattice spacing of dissected, osmotically compressed skinned fibers to native muscle fibers in living flies. Osmolytes of different sizes and exclusion properties (Dextran T-500 and T-10) were used to differentially alter lattice spacing and protein hydration. At in vivo lattice spacing, cross-bridge attachment time (t{sub on}) increased with higher osmotic pressures, consistent with a reduced cross-bridge detachment rate as myofilament protein hydration decreased. In contrast, in the swollen lattice, t{sub on} decreased with higher osmotic pressures. These divergent responses were reconciled using a structural model that predicts t{sub on} varies inversely with thick-to-thin filament surface distance, suggesting that cross-bridge rates of force development and detachment are modulated more by myofilament lattice geometry than protein hydration. Generalizing these findings, our results suggest that cross-bridge cycling rates slow as thick-to-thin filament surface distance decreases with sarcomere lengthening, and likewise, cross-bridge cycling rates increase during sarcomere shortening. Together, these structural changes may provide a mechanism for altering cross-bridge performance throughout a contraction-relaxation cycle.

  2. Thick-to-thin filament surface distance modulates cross-bridge kinetics in Drosophila flight muscle.

    PubMed

    Tanner, Bertrand C W; Farman, Gerrie P; Irving, Thomas C; Maughan, David W; Palmer, Bradley M; Miller, Mark S

    2012-09-19

    The demembranated (skinned) muscle fiber preparation is widely used to investigate muscle contraction because the intracellular ionic conditions can be precisely controlled. However, plasma membrane removal results in a loss of osmotic regulation, causing abnormal hydration of the myofilament lattice and its proteins. We investigated the structural and functional consequences of varied myofilament lattice spacing and protein hydration on cross-bridge rates of force development and detachment in Drosophila melanogaster indirect flight muscle, using x-ray diffraction to compare the lattice spacing of dissected, osmotically compressed skinned fibers to native muscle fibers in living flies. Osmolytes of different sizes and exclusion properties (Dextran T-500 and T-10) were used to differentially alter lattice spacing and protein hydration. At in vivo lattice spacing, cross-bridge attachment time (t(on)) increased with higher osmotic pressures, consistent with a reduced cross-bridge detachment rate as myofilament protein hydration decreased. In contrast, in the swollen lattice, t(on) decreased with higher osmotic pressures. These divergent responses were reconciled using a structural model that predicts t(on) varies inversely with thick-to-thin filament surface distance, suggesting that cross-bridge rates of force development and detachment are modulated more by myofilament lattice geometry than protein hydration. Generalizing these findings, our results suggest that cross-bridge cycling rates slow as thick-to-thin filament surface distance decreases with sarcomere lengthening, and likewise, cross-bridge cycling rates increase during sarcomere shortening. Together, these structural changes may provide a mechanism for altering cross-bridge performance throughout a contraction-relaxation cycle.

  3. The invertebrate myosin filament: subfilament arrangement of the solid filaments of insect flight muscles.

    PubMed Central

    Beinbrech, G; Ashton, F T; Pepe, F A

    1992-01-01

    Transverse sections (approximately 140 nm thick) of solid myosin filaments of the flight muscles of the fleshfly, Phormia terrae-novae, the honey bee, Apis mellifica, and the waterbug, Lethocerus uhleri, were photographed in a JEM model 200A electron microscope at 200 kV. The images were digitized and computer processed by rotational filtering. In each of these filaments it was found that the symmetry of the core and the wall was not the same. The power spectra of the images showed sixfold symmetry for the wall and threefold symmetry for the core of the filaments. The images of the filaments in each muscle were superimposed according to the sixfold center of the wall. These averaged images for all three muscles showed six pairs of subunits in the wall similar to those found in the wall of tubular filaments. From serial sections of the fleshfly filaments, we conclude that the subunits in the wall of the filaments represent subfilaments essentially parallel to the long axis of the filament. In each muscle there are additional subunits in the core, closely related to the subunits in the wall. Evaluation of serial sections through fleshfly filaments suggests that the relationship of the three subunits observed in the core to those in the wall varies along the length of the filaments. In waterbug filaments there are three dense and three less dense subunits for a total of six all closely related to the wall. Bee filaments have three subunits related to the wall and three subunits located eccentrically in the core of the filaments. The presence of core subunits can be related to the paramyosin content of the filaments. Images FIGURE 1 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 7 FIGURE 9 FIGURE 12 PMID:1617135

  4. Age-related changes in the flight muscle mitochondria from the blowfly Sarcophaga bullata.

    PubMed

    Wohlrab, H

    1976-05-01

    Flight muscle mitochondria have been isolated from female blowflies (Sarcophaga bullata) of different ages, alpha-Glycerophosphate and pyruvate-proline respiration rates increase during development. Only pyruvate-proline respiration declines toward senescence (30%). This decline can be overcome by ATP-NaHCO3. Cytochrome concentrations and hydrogen peroxide generation rates per protein increase during development but remain constant thereafter. Total NAD+ of metabolically completely oxidized mitochondria decreases during development; a small decline occurs between mature and senescent mitochondria. Respiring young mitochondria do not swell in potassium isethionate, very little in potassium chloride, and relatively slowly in potassium acetate. Mature and senescent mitochondria do swell in these three salts but cannot be differentiated from each other on this basis. None of the preparations swells in sodium chloride, sodium- or potassium Mops. While many differences exist between young and mature mitochondria, only the decline in pyruvate-proline respiration distinguishes mature from senescent mitochondria.

  5. The Apparent Rates of Crossbridge Attachment and Detachment Estimated from Atpase Activity in Insect Flight Muscle

    PubMed Central

    Güth, K.; Poole, K. J. V.; Maughan, D.; Kuhn, H. J.

    1987-01-01

    The ATPase activity of single fibers of small fiber bundles (one to three fibers) of insect flight muscle was measured when fibers were repetitively released and restretched by 1.5% of their initial length. The ATPase activity increased with increasing duration of release-restretch pulses applied at a constant repetition frequency, reaching a maximum at a duration of ∼20 ms. For a given duration, the average ATPase activity also increased with increasing frequency of applied length changes and reached a maximum (200% of the isometric ATPase) at a frequency of ∼50 Hz. The data could be fitted to a two-state model in which the apparent rate of crossbridge detachment is enhanced when the crossbridges are mechanically released. Estimates of the apparent rates of attachment and detachment in the isometrically contracting state and of the enhanced detachment rate of unloaded crossbridges were derived from fits to the two-state model. After short pulses of releasing and restretching the fiber the force was low and increased after the restretch in a roughly exponential manner to the initial level. The rate at which force increased after a release-restretch pulse was similar to the sum of the apparent attachment and detachment rates for the isometrically contracting muscle derived from the ATPase activity measurements. PMID:19431712

  6. Electron Tomography of Cryofixed, Isometrically Contracting Insect Flight Muscle Reveals Novel Actin-Myosin Interactions

    SciTech Connect

    Wu, Shenping; Liu, Jun; Reedy, Mary C.; Tregear, Richard T.; Winkler, Hanspeter; Franzini-Armstrong, Clara; Sasaki, Hiroyuki; Lucaveche, Carmen; Goldman, Yale E.; Reedy, Michael K.; Taylor, Kenneth A.

    2010-10-22

    Isometric muscle contraction, where force is generated without muscle shortening, is a molecular traffic jam in which the number of actin-attached motors is maximized and all states of motor action are trapped with consequently high heterogeneity. This heterogeneity is a major limitation to deciphering myosin conformational changes in situ. We used multivariate data analysis to group repeat segments in electron tomograms of isometrically contracting insect flight muscle, mechanically monitored, rapidly frozen, freeze substituted, and thin sectioned. Improved resolution reveals the helical arrangement of F-actin subunits in the thin filament enabling an atomic model to be built into the thin filament density independent of the myosin. Actin-myosin attachments can now be assigned as weak or strong by their motor domain orientation relative to actin. Myosin attachments were quantified everywhere along the thin filament including troponin. Strong binding myosin attachments are found on only four F-actin subunits, the 'target zone', situated exactly midway between successive troponin complexes. They show an axial lever arm range of 77{sup o}/12.9 nm. The lever arm azimuthal range of strong binding attachments has a highly skewed, 127{sup o} range compared with X-ray crystallographic structures. Two types of weak actin attachments are described. One type, found exclusively in the target zone, appears to represent pre-working-stroke intermediates. The other, which contacts tropomyosin rather than actin, is positioned M-ward of the target zone, i.e. the position toward which thin filaments slide during shortening. We present a model for the weak to strong transition in the myosin ATPase cycle that incorporates azimuthal movements of the motor domain on actin. Stress/strain in the S2 domain may explain azimuthal lever arm changes in the strong binding attachments. The results support previous conclusions that the weak attachments preceding force generation are very

  7. Individual variation in thermogenic capacity is correlated with flight muscle size but not cellular metabolic capacity in American goldfinches (Spinus tristis).

    PubMed

    Swanson, David L; Zhang, Yufeng; King, Marisa O

    2013-01-01

    Abstract Cold tolerance and overwinter survival are positively correlated with organismal thermogenic capacity (=summit metabolic rate [Msum]) in endotherms. Msum varies seasonally in small-bird populations and may be mechanistically associated with variation in flight muscle size or cellular metabolic capacity, but the relative roles of these traits as drivers of individual variation in thermogenic performance are poorly known. We measured flight muscle size by ultrasonography, pectoralis and supracoracoideus muscle masses, and muscular activities of key aerobic enzymes (citrate synthase, carnitine palmitoyl transferase, and β-hydroxyacyl-CoA dehydrogenase) and correlated these measurements with Msum for individual American goldfinches (Spinus tristis) to test the hypotheses that muscle size and/or cellular metabolic capacity serve as prominent drivers of individual variation in organismal metabolic capacity. Ultrasonographic flight muscle size was weakly positively correlated with Msum ([Formula: see text]). Both log10-transformed Msum and flight muscle mass were significantly correlated with log10 body mass, so we calculated allometric residuals for log Msum and for log flight muscle mass to test their correlation independent of body mass. Flight muscle mass residuals were significantly positively correlated with Msum residuals, and this correlation was primarily driven by variation in pectoralis muscle mass. In contrast, none of the mass-specific activities of any enzyme in any muscle were significantly correlated with Msum. These data suggest that flight muscle size, not cellular metabolic capacity, is the primary driver of individual variation in thermogenic performance in goldfinches. This is consistent with the idea that phenotypic flexibility of flight muscle mass is a general mechanism mediating variation in metabolic performance in response to changing energy demands in birds.

  8. Setting the pace of life: membrane composition of flight muscle varies with metabolic rate of hovering orchid bees

    PubMed Central

    Rodríguez, Enrique; Weber, Jean-Michel; Pagé, Benoît; Roubik, David W.; Suarez, Raul K.; Darveau, Charles-A.

    2015-01-01

    Patterns of metabolic rate variation have been documented extensively in animals, but their functional basis remains elusive. The membrane pacemaker hypothesis proposes that the relative abundance of polyunsaturated fatty acids in membrane phospholipids sets the metabolic rate of organisms. Using species of tropical orchid bees spanning a 16-fold range in body size, we show that the flight muscles of smaller bees have more linoleate (%18 : 3) and stearate (%18 : 0), but less oleate (%18 : 1). More importantly, flight metabolic rate (FlightMR) varies with the relative abundance of 18 : 3 according to the predictions of the membrane pacemaker hypothesis. Although this relationship was found across large differences in metabolic rate, a direct association could not be detected when taking phylogeny and body mass into account. Higher FlightMR, however, was related to lower %16 : 0, independent of phylogeny and body mass. Therefore, this study shows that flight muscle membrane composition plays a significant role in explaining diversity in FlightMR, but that body mass and phylogeny are other factors contributing to their variation. Multiple factors are at play to modulate metabolic capacity, and changing membrane composition can have gradual and stepwise effects to achieve a new range of metabolic rates. Orchid bees illustrate the correlated evolution between membrane composition and metabolic rate, supporting the functional link proposed in the membrane pacemaker hypothesis. PMID:25652831

  9. Setting the pace of life: membrane composition of flight muscle varies with metabolic rate of hovering orchid bees.

    PubMed

    Rodríguez, Enrique; Weber, Jean-Michel; Pagé, Benoît; Roubik, David W; Suarez, Raul K; Darveau, Charles-A

    2015-03-01

    Patterns of metabolic rate variation have been documented extensively in animals, but their functional basis remains elusive. The membrane pacemaker hypothesis proposes that the relative abundance of polyunsaturated fatty acids in membrane phospholipids sets the metabolic rate of organisms. Using species of tropical orchid bees spanning a 16-fold range in body size, we show that the flight muscles of smaller bees have more linoleate (%18 : 3) and stearate (%18 : 0), but less oleate (%18 : 1). More importantly, flight metabolic rate (FlightMR) varies with the relative abundance of 18 : 3 according to the predictions of the membrane pacemaker hypothesis. Although this relationship was found across large differences in metabolic rate, a direct association could not be detected when taking phylogeny and body mass into account. Higher FlightMR, however, was related to lower %16 : 0, independent of phylogeny and body mass. Therefore, this study shows that flight muscle membrane composition plays a significant role in explaining diversity in FlightMR, but that body mass and phylogeny are other factors contributing to their variation. Multiple factors are at play to modulate metabolic capacity, and changing membrane composition can have gradual and stepwise effects to achieve a new range of metabolic rates. Orchid bees illustrate the correlated evolution between membrane composition and metabolic rate, supporting the functional link proposed in the membrane pacemaker hypothesis.

  10. Dual dimensionality reduction reveals independent encoding of motor features in a muscle synergy for insect flight control.

    PubMed

    Sponberg, Simon; Daniel, Thomas L; Fairhall, Adrienne L

    2015-04-01

    What are the features of movement encoded by changing motor commands? Do motor commands encode movement independently or can they be represented in a reduced set of signals (i.e. synergies)? Motor encoding poses a computational and practical challenge because many muscles typically drive movement, and simultaneous electrophysiology recordings of all motor commands are typically not available. Moreover, during a single locomotor period (a stride or wingstroke) the variation in movement may have high dimensionality, even if only a few discrete signals activate the muscles. Here, we apply the method of partial least squares (PLS) to extract the encoded features of movement based on the cross-covariance of motor signals and movement. PLS simultaneously decomposes both datasets and identifies only the variation in movement that relates to the specific muscles of interest. We use this approach to explore how the main downstroke flight muscles of an insect, the hawkmoth Manduca sexta, encode torque during yaw turns. We simultaneously record muscle activity and turning torque in tethered flying moths experiencing wide-field visual stimuli. We ask whether this pair of muscles acts as a muscle synergy (a single linear combination of activity) consistent with their hypothesized function of producing a left-right power differential. Alternatively, each muscle might individually encode variation in movement. We show that PLS feature analysis produces an efficient reduction of dimensionality in torque variation within a wingstroke. At first, the two muscles appear to behave as a synergy when we consider only their wingstroke-averaged torque. However, when we consider the PLS features, the muscles reveal independent encoding of torque. Using these features we can predictably reconstruct the variation in torque corresponding to changes in muscle activation. PLS-based feature analysis provides a general two-sided dimensionality reduction that reveals encoding in high dimensional

  11. Dual Dimensionality Reduction Reveals Independent Encoding of Motor Features in a Muscle Synergy for Insect Flight Control

    PubMed Central

    Sponberg, Simon; Daniel, Thomas L.; Fairhall, Adrienne L.

    2015-01-01

    What are the features of movement encoded by changing motor commands? Do motor commands encode movement independently or can they be represented in a reduced set of signals (i.e. synergies)? Motor encoding poses a computational and practical challenge because many muscles typically drive movement, and simultaneous electrophysiology recordings of all motor commands are typically not available. Moreover, during a single locomotor period (a stride or wingstroke) the variation in movement may have high dimensionality, even if only a few discrete signals activate the muscles. Here, we apply the method of partial least squares (PLS) to extract the encoded features of movement based on the cross-covariance of motor signals and movement. PLS simultaneously decomposes both datasets and identifies only the variation in movement that relates to the specific muscles of interest. We use this approach to explore how the main downstroke flight muscles of an insect, the hawkmoth Manduca sexta, encode torque during yaw turns. We simultaneously record muscle activity and turning torque in tethered flying moths experiencing wide-field visual stimuli. We ask whether this pair of muscles acts as a muscle synergy (a single linear combination of activity) consistent with their hypothesized function of producing a left-right power differential. Alternatively, each muscle might individually encode variation in movement. We show that PLS feature analysis produces an efficient reduction of dimensionality in torque variation within a wingstroke. At first, the two muscles appear to behave as a synergy when we consider only their wingstroke-averaged torque. However, when we consider the PLS features, the muscles reveal independent encoding of torque. Using these features we can predictably reconstruct the variation in torque corresponding to changes in muscle activation. PLS-based feature analysis provides a general two-sided dimensionality reduction that reveals encoding in high dimensional

  12. Fourier analysis of wing beat signals: assessing the effects of genetic alterations of flight muscle structure in Diptera.

    PubMed Central

    Hyatt, C J; Maughan, D W

    1994-01-01

    A method for determining and analyzing the wing beat frequency in Diptera is presented. This method uses an optical tachometer to measure Diptera wing movement during flight. The resulting signal from the optical measurement is analyzed using a Fast Fourier Transform (FFT) technique, and the dominant frequency peak in the Fourier spectrum is selected as the wing beat frequency. Also described is a method for determining quantitatively the degree of variability of the wing beat frequency about the dominant frequency. This method is based on determination of a quantity called the Hindex, which is derived using data from the FFT analysis. Calculation of the H index allows computer-based selection of the most suitable segment of recorded data for determination of the representative wing beat frequency. Experimental data suggest that the H index can also prove useful in examining wing beat frequency variability in Diptera whose flight muscle structure has been genetically altered. Examples from Drosophila indirect flight muscle studies as well as examples of artificial data are presented to illustrate the method. This method fulfills a need for a standardized method for determining wing beat frequencies and examining wing beat frequency variability in insects whose flight muscles have been altered by protein engineering methods. PMID:7811927

  13. Drosophila indirect flight muscle specific Act88F actin mutants as a model system for studying congenital myopathies of the human ACTA1 skeletal muscle actin gene.

    PubMed

    Haigh, Sarah E; Salvi, Sheetal S; Sevdali, Maria; Stark, Meg; Goulding, David; Clayton, Jonathan D; Bullard, Belinda; Sparrow, John C; Nongthomba, Upendra

    2010-06-01

    Most human ACTA1 skeletal actin gene mutations cause dominant, congenital myopathies often with severely reduced muscle function and neonatal mortality. High sequence conservation of actin means many mutated ACTA1 residues are identical to those in the DrosophilaAct88F, an indirect flight muscle specific sarcomeric actin. Four known Act88F mutations occur at the same actin residues mutated in ten ACTA1 nemaline mutations, A138D/P, R256H/L, G268C/D/R/S and R372C/S. These Act88F mutants were examined for similar muscle phenotypes. Mutant homozygotes show phenotypes ranging from a lack of myofibrils to almost normal sarcomeres at eclosion. Aberrant Z-disc-like structures and serial Z-disc arrays, 'zebra bodies', are observed in homozygotes and heterozygotes of all four Act88F mutants. These electron-dense structures show homologies to human nemaline bodies/rods, but are much smaller than those typically found in the human myopathy. We conclude that the Drosophila indirect flight muscles provide a good model system for studying ACTA1 mutations. PMID:20452215

  14. Control of respiration in flight muscle from the high-altitude bar-headed goose and low-altitude birds.

    PubMed

    Scott, Graham R; Richards, Jeffrey G; Milsom, William K

    2009-10-01

    Bar-headed geese fly at altitudes of up to 9,000 m on their biannual migration over the Himalayas. To determine whether the flight muscle of this species has evolved to facilitate exercise at high altitude, we compared the respiratory properties of permeabilized muscle fibers from bar-headed geese and several low-altitude waterfowl species. Respiratory capacities were assessed for maximal ADP stimulation (with single or multiple inputs to the electron transport system) and cytochrome oxidase excess capacity (with an exogenous electron donor) and were generally 20-40% higher in bar-headed geese when creatine was present. When respiration rates were extrapolated to the entire pectoral muscle mass, bar-headed geese had a higher mass-specific aerobic capacity. This may represent a surplus capacity that counteracts the depressive effects of hypoxia on mitochondrial respiration. However, there were no differences in activity for mitochondrial or glycolytic enzymes measured in homogenized muscle. The [ADP] leading to half-maximal stimulation (K(m)) was approximately twofold higher in bar-headed geese (10 vs. 4-6 microM), and, while creatine reduced K(m) by 30% in this species, it had no effect on K(m) in low-altitude birds. Mitochondrial creatine kinase may therefore contribute to the regulation of oxidative phosphorylation in flight muscle of bar-headed geese, which could promote efficient coupling of ATP supply and demand. However, this was not based on differences in creatine kinase activity in isolated mitochondria or homogenized muscle. The unique differences in bar-headed geese existed without prior exercise or hypoxia exposure and were not a result of phylogenetic history, and may, therefore, be important evolutionary specializations for high-altitude flight.

  15. Site directed mutagenesis of Drosophila flightin disrupts phosphorylation and impairs flight muscle structure and mechanics.

    PubMed

    Barton, Byron; Ayer, Gretchen; Maughan, David W; Vigoreaux, Jim O

    2007-01-01

    Flightin is a myosin rod binding protein that in Drosophila melanogaster is expressed exclusively in the asynchronous indirect flight muscles (IFM). Hyperphosphorylation of flightin coincides with the completion of myofibril assembly and precedes the emergence of flight competency in young adults. To investigate the role of flightin phosphorylation in vivo we generated three flightin null (fln(0)) Drosophila strains that express a mutant flightin transgene with two (Thr158, Ser 162), three (Ser139, Ser141, Ser145) or all five potential phosphorylation sites mutated to alanines. These amino acid substitutions result in lower than normal levels of flightin accumulation and transgenic strains that are unable to beat their wings. On two dimensional gels of IFM proteins, the transgenic strain with five mutant sites (fln(5STA)) is devoid of all phosphovariants, the transgenic strain with two mutant sites (fln(2TSA)) expresses only the two least acidic of the nine phosphovariants, and the transgenic strain with three mutant sites (fln(3SA)) expresses all nine phosphovariants, as the wild-type strain. These results suggest that phosphorylation of Thr158 and/or Ser162 is necessary for subsequent phosphorylation of other sites. All three transgenic strains show normal, albeit long, IFM sarcomeres in newly eclosed adults. In contrast, sarcomeres in fully mature fln(5STA) and fln(2TSA) adults show extensive breakdown while those in fln(3SA) are not as disordered. The fiber hypercontraction phenotype that characterizes fln(0) is fully evident in fln(5STA) and fln(2TSA) but partially rescued in fln(3SA). Mechanics on skinned fibers from newly eclosed flies show alterations in viscous modulus for fln(5STA) and fln(2TSA) that result in a significant reduction in oscillatory power output. Expression of fln(5STA) and fln(2TSA), but not fln(3SA), in a wild-type (fln(+)/fln(+)) background resulted in a dominant negative effect manifested as flight impairments and hypercontracted IFM

  16. The effects of space flight on the contractile apparatus of antigravity muscles: implications for aging and deconditioning.

    PubMed

    Baldwin, K M; Caiozzo, V J; Haddad, F; Baker, M J; Herrick, R E

    1994-05-01

    Previous studies have shown that the unloading of skeletal muscle, as occurring during exposure to space flight, exerts a profound effect on both the mass (cross sectional area) of skeletal muscle fibers and the relative expression of protein isoforms comprising the contractile system. Available information suggests that slow (type I) fibers, comprising chiefly the antigravity muscles of experimental animals, in addition to atrophying, undergo alterations in the type of myosin heavy chain (MHC) expressed such that faster isoforms become concomitantly expressed in a sub-population of slow fibers when insufficient force-bearing activity is maintained on the muscle. Consequently, these transformations in both mass and myosin heavy chain phenotype could exert a significant impact on the functional properties of skeletal muscle as manifest in the strength, contractile speed, and endurance scope of the muscle. To further explore these issues, a study was performed in which young adult male rats were exposed to zero gravity for six days, following which, the antigravity soleus muscle was examined for a) contractile properties, determined in situ and b) isomyosin expression, as studied using biochemical, molecular biology, and histochemical/immunohistochemical techniques.

  17. The effects of space flight on the contractile apparatus of antigravity muscles: implications for aging and deconditioning

    NASA Technical Reports Server (NTRS)

    Baldwin, K. M.; Caiozzo, V. J.; Haddad, F.; Baker, M. J.; Herrick, R. E.

    1994-01-01

    Previous studies have shown that the unloading of skeletal muscle, as occurring during exposure to space flight, exerts a profound effect on both the mass (cross sectional area) of skeletal muscle fibers and the relative expression of protein isoforms comprising the contractile system. Available information suggests that slow (type I) fibers, comprising chiefly the antigravity muscles of experimental animals, in addition to atrophying, undergo alterations in the type of myosin heavy chain (MHC) expressed such that faster isoforms become concomitantly expressed in a sub-population of slow fibers when insufficient force-bearing activity is maintained on the muscle. Consequently, these transformations in both mass and myosin heavy chain phenotype could exert a significant impact on the functional properties of skeletal muscle as manifest in the strength, contractile speed, and endurance scope of the muscle. To further explore these issues, a study was performed in which young adult male rats were exposed to zero gravity for six days, following which, the antigravity soleus muscle was examined for a) contractile properties, determined in situ and b) isomyosin expression, as studied using biochemical, molecular biology, and histochemical/immunohistochemical techniques.

  18. [Lactate dehydrogenase isoenzymatic makeup of the skeletal muscles of rats after a flight on the Kosmos-690 biosatellite].

    PubMed

    Petrova, N V

    1978-01-01

    The isoenzyme composition of lactate dehydrogenase in the soleus and plantaris muscles of rats which had flown for 20.5 days onboard the biosatellite Cosmos-690 equipped with a radiation source was studied. Difference in the isoenzyme composition of lactate dehydrogenase in flight and synchronous rats disappeared 27 days after the experiments; however, some changes persisted as compared with vivarium controls. The data obtained give evidence that irradiation-induced effects in skeletal muscles manifested themselves at a far later stage than weightlessness-induced changes.

  19. Electron tomography of insect flight muscle in rigor and AMPPNP at 23 degrees C.

    PubMed

    Schmitz, H; Reedy, M C; Reedy, M K; Tregear, R T; Winkler, H; Taylor, K A

    1996-11-29

    Treatment of rigor fibers of insect flight muscle (IFM) with AMPPNP at 23 degrees C causes a 70% drop in tension with little change in stiffness. In order to visualize the changes in crossbridge conformation and distribution that give rise to the mechanical response, we have produced three-dimensional reconstructions by tomography of both rigor and AMPPNP-treated muscle that do not average the repeating motifs of crossbridges, and thereby retain information on variability of crossbridge structure and distribution. Tomograms can be averaged when display of only the regular features is wanted. Tomograms of rigor IFM show double-headed lead and single-headed rear crossbridges. Tomograms of IFM treated with AMPPNP at 23 degrees C reveal many double-headed and some single-headed "lead" bridges but few crossbridges corresponding to the rear bridges of rigor. Instead, new non-rigor forms of variably angled crossbridges are found bound to actin sites not labeled with myosin heads in rigor. This indicates that the rear bridges of rigor have redistributed during the transition from rigor to the AMPPNP state, which could explain the maintenance of rigor stiffness despite the loss of tension. Comparison of in situ crossbridges in tomograms of rigor with atomic model of acto-S1, the complex formed by myosin subfragment 1 and actin, reveals that the regulatory domain of S1 would require significant bending and realignment to fit into both types of rigor crossbridges. The modifications are particularly significant for the rear bridges and suggest that differential strain in the regulatory domain of rear bridges may be the basis for their detachment and redistribution upon binding AMPPNP. Similar comparison using lead-type crossbridges in AMPPNP reveals departures from the rigor acto-S1 atomic model that include azimuthal straightening and a slight M-ward bending in the regulatory domain. Both the motor and regulatory domains of the new non-rigor crossbridges differ from those in

  20. Blood-Feeding Induces Reversible Functional Changes in Flight Muscle Mitochondria of Aedes aegypti Mosquito

    PubMed Central

    Gonçalves, Renata L. S.; Machado, Ana Carolina L.; Paiva-Silva, Gabriela O.; Sorgine, Marcos H. F.; Momoli, Marisa M.; Oliveira, Jose Henrique M.; Vannier-Santos, Marcos A.; Galina, Antonio; Oliveira, Pedro L.; Oliveira, Marcus F.

    2009-01-01

    Background Hematophagy poses a challenge to blood-feeding organisms since products of blood digestion can exert cellular deleterious effects. Mitochondria perform multiple roles in cell biology acting as the site of aerobic energy-transducing pathways, and also an important source of reactive oxygen species (ROS), modulating redox metabolism. Therefore, regulation of mitochondrial function should be relevant for hematophagous arthropods. Here, we investigated the effects of blood-feeding on flight muscle (FM) mitochondria from the mosquito Aedes aegypti, a vector of dengue and yellow fever. Methodology/Principal Findings Blood-feeding caused a reversible reduction in mitochondrial oxygen consumption, an event that was parallel to blood digestion. These changes were most intense at 24 h after blood meal (ABM), the peak of blood digestion, when oxygen consumption was inhibited by 68%. Cytochromes c and a+a3 levels and cytochrome c oxidase activity of the electron transport chain were all reduced at 24 h ABM. Ultrastructural and molecular analyses of FM revealed that mitochondria fuse upon blood meal, a condition related to reduced ROS generation. Consistently, BF induced a reversible decrease in mitochondrial H2O2 formation during blood digestion, reaching their lowest values at 24 h ABM where a reduction of 51% was observed. Conclusion Blood-feeding triggers functional and structural changes in hematophagous insect mitochondria, which may represent an important adaptation to blood feeding. PMID:19924237

  1. Surface apposition and multiple cell contacts promote myoblast fusion in Drosophila flight muscles

    PubMed Central

    Dhanyasi, Nagaraju; Segal, Dagan; Shimoni, Eyal; Shinder, Vera

    2015-01-01

    Fusion of individual myoblasts to form multinucleated myofibers constitutes a widely conserved program for growth of the somatic musculature. We have used electron microscopy methods to study this key form of cell–cell fusion during development of the indirect flight muscles (IFMs) of Drosophila melanogaster. We find that IFM myoblast–myotube fusion proceeds in a stepwise fashion and is governed by apparent cross talk between transmembrane and cytoskeletal elements. Our analysis suggests that cell adhesion is necessary for bringing myoblasts to within a minimal distance from the myotubes. The branched actin polymerization machinery acts subsequently to promote tight apposition between the surfaces of the two cell types and formation of multiple sites of cell–cell contact, giving rise to nascent fusion pores whose expansion establishes full cytoplasmic continuity. Given the conserved features of IFM myogenesis, this sequence of cell interactions and membrane events and the mechanistic significance of cell adhesion elements and the actin-based cytoskeleton are likely to represent general principles of the myoblast fusion process. PMID:26459604

  2. Surface apposition and multiple cell contacts promote myoblast fusion in Drosophila flight muscles.

    PubMed

    Dhanyasi, Nagaraju; Segal, Dagan; Shimoni, Eyal; Shinder, Vera; Shilo, Ben-Zion; VijayRaghavan, K; Schejter, Eyal D

    2015-10-12

    Fusion of individual myoblasts to form multinucleated myofibers constitutes a widely conserved program for growth of the somatic musculature. We have used electron microscopy methods to study this key form of cell-cell fusion during development of the indirect flight muscles (IFMs) of Drosophila melanogaster. We find that IFM myoblast-myotube fusion proceeds in a stepwise fashion and is governed by apparent cross talk between transmembrane and cytoskeletal elements. Our analysis suggests that cell adhesion is necessary for bringing myoblasts to within a minimal distance from the myotubes. The branched actin polymerization machinery acts subsequently to promote tight apposition between the surfaces of the two cell types and formation of multiple sites of cell-cell contact, giving rise to nascent fusion pores whose expansion establishes full cytoplasmic continuity. Given the conserved features of IFM myogenesis, this sequence of cell interactions and membrane events and the mechanistic significance of cell adhesion elements and the actin-based cytoskeleton are likely to represent general principles of the myoblast fusion process.

  3. ELECTRON MICROSCOPIC STUDIES ON THE INDIRECT FLIGHT MUSCLES OF DROSOPHILA MELANOGASTER

    PubMed Central

    Shafiq, S. Ahmad

    1963-01-01

    The myofibrils in Drosophila have thick and thin types of myofilaments arranged in the hexagonal pattern described for Calliphora by Huxley and Hanson (15). The thick filaments, along most of their length in the A band, seem to be binary in structure, consisting of a dense cortex and a lighter medulla. In the H zone, however, they show more uniform density; lateral projections (bridges) also appear to be absent in this region. The M band has a varying number of granules (probably of glycogen) distributed between the myofilaments. The myofilaments on reaching the Z region appear to change their hexagonal arrangement and become connected to one another by Z filaments. The regular arrangement of the filaments found in most regions of the fibrils is not seen in the terminal sarcomeres of some flight muscles; the two types of filaments appear to be intermingled in an irregular pattern in these parts of the fibrils. The attachment of myofibrils to the cuticle through the epidermal cells is described. PMID:13988339

  4. Neurons associated with the dorsal longtitudinal flight muscles of Drosophilla melanogaster.

    PubMed

    Coggshall, J C

    1978-02-15

    The anatomy of the neurons associated with the six fibers forming the dorsal longitudinal flight muscle (DLM) of Drosophila melanogaster has been investigated using a horseradis peroxidase lable. The two dorsal-most fibers are innervated by the same neuron whose cell body is in the dorsal, contralateral, mesothoracic region of the thoracic ganglion. The ventral-most four fibers are innervated by four neurons whose cell bodies are clustered in the ventral, ipsilateral, prothoracic region. The processes of all five of these cells ramify extensively in the dorsal part of the ipsilateral and contralateral mesothoracic neuromeres. A large interneuron has been discovered which is associated with the DLM and whose cell body is located contralaterally. Several neurons with small cell bodies on the ventral midline of the mesothoracic neuromere are also consistently labeled. A single fiber projects dorsally from a midline cell body, forms a Y-branch near the top of the ganglion and apparently sends an axon into each posterior dorsal mesothoracic nerve (PDMN) subsequently innervating the DLM. PMID:415072

  5. Effects of calcium ions and adenosine diphosphate on the activities of NAD+-linked isocitrate dehydrogenase from the radular muscles of the whelk and flight muscles of insects.

    PubMed Central

    Zammit, V A; Newsholme, E A

    1976-01-01

    1. The activity of NAD+-linked isocitrate dehydrogenase from the radular muscle of the whelk is higher than those in many vertebrate muscles and only slightly lower than in the flight muscles of insects. The enzyme activity from the whelk (Buccinum undatum) is stable for several hours after homogenization of the radular muscle, whereas that from insect flight muscle is very unstable. Consequently, the enzyme from the whelk muscle is suitable for a systematic investigation of the effects of Ca2+ and ADP. 2. The sigmoid response of the enzyme activity to isocitrate concentration is markedly increased by raising the Ca2+ concentration from 0.001 to 10 muM, but it is decreased by ADP. The inhibitory effect of Ca2+ is most pronounced at pH7.1; it is not observed at pH 6.5. Similar effects are observed for the enzyme from the flight muscle of the locust (Schistocerca gregaria) and the water bug (Lethocerus cordofanus). The percentage activation by ADP of the enzyme from either the whelk or the insects is greater at 10 muM-Ca2+, and 50% of the maximum activation is obtained at 0.10 and 0.16 mM-ADP for the enzyme from whelk and locust respectively at this Ca2+ concentration. At 10 muM-Ca2+ in the absence of added ADP, the apparent Km for isocitrate is markedly higher than in other conditions. Ca2+ concentrations of 0.01, 0.1 and 0.2 muM cause 50% inhibition of maximum activity of the enzyme from the muscles of the whelk, locust and water bug respectively. 3. Recent work has indicated that mitochondria may play a complementary role to the sarcoplasmic reticulum in the control of the distribution of Ca2+ in muscle. The opposite effects of Ca2+ on the activities of isocitrate dehydrogenase and mitochondrial glycerol phosphate dehydrogenase from muscle tissue are consistent with the hypothesis that changes in the intracellular distribution of Ca2+ control the activities of these two enzymes in order to stimulate energy production for the contraction process in the muscle

  6. Effects of calcium ions and adenosine diphosphate on the activities of NAD+-linked isocitrate dehydrogenase from the radular muscles of the whelk and flight muscles of insects.

    PubMed

    Zammit, V A; Newsholme, E A

    1976-03-15

    1. The activity of NAD+-linked isocitrate dehydrogenase from the radular muscle of the whelk is higher than those in many vertebrate muscles and only slightly lower than in the flight muscles of insects. The enzyme activity from the whelk (Buccinum undatum) is stable for several hours after homogenization of the radular muscle, whereas that from insect flight muscle is very unstable. Consequently, the enzyme from the whelk muscle is suitable for a systematic investigation of the effects of Ca2+ and ADP. 2. The sigmoid response of the enzyme activity to isocitrate concentration is markedly increased by raising the Ca2+ concentration from 0.001 to 10 muM, but it is decreased by ADP. The inhibitory effect of Ca2+ is most pronounced at pH7.1; it is not observed at pH 6.5. Similar effects are observed for the enzyme from the flight muscle of the locust (Schistocerca gregaria) and the water bug (Lethocerus cordofanus). The percentage activation by ADP of the enzyme from either the whelk or the insects is greater at 10 muM-Ca2+, and 50% of the maximum activation is obtained at 0.10 and 0.16 mM-ADP for the enzyme from whelk and locust respectively at this Ca2+ concentration. At 10 muM-Ca2+ in the absence of added ADP, the apparent Km for isocitrate is markedly higher than in other conditions. Ca2+ concentrations of 0.01, 0.1 and 0.2 muM cause 50% inhibition of maximum activity of the enzyme from the muscles of the whelk, locust and water bug respectively. 3. Recent work has indicated that mitochondria may play a complementary role to the sarcoplasmic reticulum in the control of the distribution of Ca2+ in muscle. The opposite effects of Ca2+ on the activities of isocitrate dehydrogenase and mitochondrial glycerol phosphate dehydrogenase from muscle tissue are consistent with the hypothesis that changes in the intracellular distribution of Ca2+ control the activities of these two enzymes in order to stimulate energy production for the contraction process in the muscle

  7. Histochemical localization of trehalase activity in dorsal flight muscle of the flesh fly Sarcophaga bullata with light and electron microscopy.

    PubMed

    Chang, P L; Morrison, P E

    1975-11-01

    Trehalase activity in flight muscle of the flesh fly Sacrophaga bullata is detected histochemically at light- and electron-microscopic levels by using diaminobenzidine, glucose oxidase and peroxidase in the incubation medium. The association of trehalase activity with the inner mitochondrial membrane is confirmed. Biochemical assay shows that about 50% of the initial total trehalase activity is lost from the tissue during the histochemical processing and about 50% remains for histochemical detection.

  8. The impact of beef cattle temperament assessed using flight speed on muscle glycogen, muscle lactate and plasma lactate concentrations at slaughter.

    PubMed

    Coombes, S V; Gardner, G E; Pethick, D W; McGilchrist, P

    2014-12-01

    This study evaluated the effect of animal temperament measured using flight speed (FS) on plasma lactate, muscle glycogen and lactate concentrations at slaughter plus ultimate pH in 648 lot finished cattle of mixed breed and sex. Muscle samples were collected at slaughter from the m. semimembranosus, m. semitendinosus and m. longissimus thoracis (LT) for analysis of glycogen and lactate concentration. Blood was collected after exsanguination and analysed for plasma lactate concentration and ultimate pH of the LT was measured. FS had no effect on muscle glycogen concentration in any muscle or ultimate pH of the LT (P>0.05). As FS increased from 1 to 5m/s, plasma and muscle lactate concentration increased by 54% and 11.4% (P<0.01). The mechanisms through which temperament contributes to variation in glycogen metabolism remain unclear. The risk of dark cutting was not impacted by temperament, indicating that other production and genetic factors have a greater impact on the incidence of dark cutting.

  9. The structure of insect flight muscle in the presence of AMPPNP.

    PubMed

    Reedy, M C; Reedy, M K; Goody, R S

    1987-12-01

    Glycerinated insect (Lethocerus) flight muscle in the presence of the non-hydrolysable ATP-analogue AMPPNP (1 mM at 4 degrees C) has been prepared for electron microscopy using X-ray diffraction monitoring during fixation and embedding. Superior preservation of the original structure has been achieved through use of a fixative which included tannic acid and excess Mg2+. New features have been recognized in single filament layers (myac and actin) and 15 nm cross sections. As previously shown, some aspects of relaxed structure (14.5 nm shelves along thick filaments) and of rigor (38.7 nm angled bridges along thin filaments) are retained in a modified form. New observations include: (1) In 15 nm cross sections that show single 14.5 nm levels: (a) The flared X structure characteristic of rigor is replaced by a straight-X figure in which the crossbridge density is aligned along the myosin-actin plane, rather than skewed across it as in rigor. (b) In AMPPNP, each crossbridge appears to have a separate origin from the thick filament, rather than bifurcating two from one stem as in the flared X of rigor. The separation of crossbridge origins is also evidenced by the loss of 'ladder rungs' in actin layers. (2) A halving (19.3 nm) of the 38.7 nm axial repeat along actin, rather than a thirding (12.9 nm) as in rigor, indicates redistribution of bridge attachments in cold AMPPNP. (3) In AMPPNP, the 14.5 nm shelves of density around the thick filament shaft are thicker but extend to smaller radius than similar shelves in ATP-relaxed muscle. This is shown by a lack of 14.5 nm periodicity and diffraction in actin layers of AMPPNP, in contrast to ATP-relaxed actin layers, in which the 14.5 nm period is present. Our results suggest that attached crossbridges are modified by AMPPNP and that ordered features of the analogue state are not accounted for solely by detached myosin heads or by a mixture of relaxed and rigor crossbridges. A two-domain model for the crossbridge is proposed

  10. Differential allocation of protein resources to flight muscles and reproductive organs in the flightless wing-polymorphic bug, Pyrrhocoris apterus (L.) (Heteroptera).

    PubMed

    Socha, R; Sula, J

    2008-02-01

    Differences in the growth of dorsolongitudinal flight muscles and gonads in 1-28 days old long-winged (macropterous) and short-winged (brachypterous) adults of the firebug (Pyrrhocoris apterus L.) and the resource allocation to these organs were studied by means of total protein analysis. We found predominant allocation of food resources to flight muscles compared to reproductive organs in both macropterous males and females during the first 5 days of adult life. Subsequent histolysis of developed flight muscles coincided with increased total protein content in some reproductive organs. Initiation of intensive food intake after starvation or application of higher dose of methoprene on macropterous adults changed the resource allocation in favour of growth of reproductive organs and induced precocious histolysis of flight muscles. It indicates an involvement of juvenile hormone in wing morph-related differential allocation of resources in the bug. Increased total protein contents in the ovaries and accessory glands of starved macropterous females and males treated with methoprene, respectively, indicate that proteins derived from the methoprene-induced histolysis of the flight muscles are re-utilized for the growth of the reproductive organs. It is the first report of persistence of differential resource allocation to flight muscles and reproductive organs in the wing-polymorphic insects with non-functional macropterism.

  11. Three-dimensional image reconstruction of insect flight muscle. I. The rigor myac layer

    PubMed Central

    1989-01-01

    We have obtained detailed three-dimensional images of in situ cross- bridge structure in insect flight muscle by electron microscopy of multiple tilt views of single filament layers in ultrathin sections, supplemented with data from thick sections. In this report, we describe the images obtained of the myac layer, a 25-nm longitudinal section containing a single layer of alternating myosin and actin filaments. The reconstruction reveals averaged rigor cross-bridges that clearly separate into two classes constituting lead and rear chevrons within each 38.7-nm axial repeat. These two classes differ in tilt angle, size and shape, density, and slew. This new reconstruction confirms our earlier interpretation of the lead bridge as a two-headed cross-bridge and the rear bridge as a single-headed cross-bridge. The importance of complementing tilt series with additional projections outside the goniometer tilt range is demonstrated by comparison with our earlier myac layer reconstruction. Incorporation of this additional data reveals new details of rigor cross-bridge structure in situ which include clear delineation of (a) a triangular shape for the lead bridge, (b) a smaller size for the rear bridge, and (c) density continuity across the thin filament in the lead bridge. Within actin's regular 38.7-nm helical repeat, local twist variations in the thin filament that correlate with the two cross-bridge classes persist in this new reconstruction. These observations show that in situ rigor cross-bridges are not uniform, and suggest three different myosin head conformations in rigor. PMID:2768334

  12. Sexual Dimorphism in the Regulation of Estrogen, Progesterone, and Androgen Receptors by Sex Steroids in the Rat Airway Smooth Muscle Cells.

    PubMed

    Zarazúa, Abraham; González-Arenas, Aliesha; Ramírez-Vélez, Gabriela; Bazán-Perkins, Blanca; Guerra-Araiza, Christian; Campos-Lara, María G

    2016-01-01

    The role of sex hormones in lung is known. The three main sex steroid receptors, estrogen, progesterone, and androgen, have not been sufficiently studied in airway smooth muscle cells (ASMC), and the sex hormone regulation on these receptors is unknown. We examined the presence and regulation of sex hormone receptors in female and male rat ASMC by Western blotting and flow cytometry. Gonadectomized rats were treated with 17β-estradiol, progesterone, 17β-estradiol + progesterone, or testosterone. ASMC were enzymatically isolated from tracheas and bronchi. The experiments were performed with double staining flow cytometry (anti-α-actin smooth muscle and antibodies to each hormone receptor). ERα, ERβ, tPR, and AR were detected in females or males. ERα was upregulated by E2 and T and downregulated by P4 in females; in males, ERα was downregulated by P4, E + P, and T. ERβ was downregulated by each treatment in females, and only by E + P and T in males. tPR was downregulated by P4, E + P, and T in females. No hormonal regulation was observed in male receptors. AR was downregulated in males treated with E + P and T. We have shown the occurrence of sex hormone receptors in ASMC and their regulation by the sex hormones in female and male rats. PMID:27110242

  13. Sexual Dimorphism in the Regulation of Estrogen, Progesterone, and Androgen Receptors by Sex Steroids in the Rat Airway Smooth Muscle Cells

    PubMed Central

    Zarazúa, Abraham; González-Arenas, Aliesha; Ramírez-Vélez, Gabriela; Bazán-Perkins, Blanca; Guerra-Araiza, Christian; Campos-Lara, María G.

    2016-01-01

    The role of sex hormones in lung is known. The three main sex steroid receptors, estrogen, progesterone, and androgen, have not been sufficiently studied in airway smooth muscle cells (ASMC), and the sex hormone regulation on these receptors is unknown. We examined the presence and regulation of sex hormone receptors in female and male rat ASMC by Western blotting and flow cytometry. Gonadectomized rats were treated with 17β-estradiol, progesterone, 17β-estradiol + progesterone, or testosterone. ASMC were enzymatically isolated from tracheas and bronchi. The experiments were performed with double staining flow cytometry (anti-α-actin smooth muscle and antibodies to each hormone receptor). ERα, ERβ, tPR, and AR were detected in females or males. ERα was upregulated by E2 and T and downregulated by P4 in females; in males, ERα was downregulated by P4, E + P, and T. ERβ was downregulated by each treatment in females, and only by E + P and T in males. tPR was downregulated by P4, E + P, and T in females. No hormonal regulation was observed in male receptors. AR was downregulated in males treated with E + P and T. We have shown the occurrence of sex hormone receptors in ASMC and their regulation by the sex hormones in female and male rats. PMID:27110242

  14. CF2 represses Actin 88F gene expression and maintains filament balance during indirect flight muscle development in Drosophila.

    PubMed

    Gajewski, Kathleen M; Schulz, Robert A

    2010-01-01

    The zinc finger protein CF2 is a characterized activator of muscle structural genes in the body wall muscles of the Drosophila larva. To investigate the function of CF2 in the indirect flight muscle (IFM), we examined the phenotypes of flies bearing five homozygous viable mutations. The gross structure of the IFM was not affected, but the stronger hypomorphic alleles caused an increase of up to 1.5X in the diameter of the myofibrils. This size increase did not cause any disruption of the hexameric arrangement of thick and thin filaments. RT-PCR analysis revealed an increase in the transcription of several structural genes. Ectopic overexpression of CF2 in the developing IFM disrupts muscle formation. While our results indicate a role for CF2 as a direct negative regulator of the thin filament protein gene Actin 88F (Act88F), effects on levels of transcripts of myosin heavy chain (mhc) appear to be indirect. This role is in direct contrast to that described in the larval muscles, where CF2 activates structural gene expression. The variation in myofibril phenotypes of CF2 mutants suggest the CF2 may have separate functions in fine-tuning expression of structural genes to insure proper filament stoichiometry, and monitoring and/or controlling the final myofibril size. PMID:20520827

  15. Pseudo-acetylation of K326 and K328 of actin disrupts Drosophila melanogaster indirect flight muscle structure and performance.

    PubMed

    Viswanathan, Meera C; Blice-Baum, Anna C; Schmidt, William; Foster, D Brian; Cammarato, Anthony

    2015-01-01

    In striated muscle tropomyosin (Tm) extends along the length of F-actin-containing thin filaments. Its location governs access of myosin binding sites on actin and, hence, force production. Intermolecular electrostatic associations are believed to mediate critical interactions between the proteins. For example, actin residues K326, K328, and R147 were predicted to establish contacts with E181 of Tm. Moreover, K328 also potentially forms direct interactions with E286 of myosin when the motor is strongly bound. Recently, LC-MS/MS analysis of the cardiac acetyl-lysine proteome revealed K326 and K328 of actin were acetylated, a post-translational modification (PTM) that masks the residues' inherent positive charges. Here, we tested the hypothesis that by removing the vital actin charges at residues 326 and 328, the PTM would perturb Tm positioning and/or strong myosin binding as manifested by altered skeletal muscle function and structure in the Drosophila melanogaster model system. Transgenic flies were created that permit tissue-specific expression of K326Q, K328Q, or K326Q/K328Q acetyl-mimetic actin and of wild-type actin via the UAS-GAL4 bipartite expression system. Compared to wild-type actin, muscle-restricted expression of mutant actin had a dose-dependent effect on flight ability. Moreover, excessive K328Q and K326Q/K328Q actin overexpression induced indirect flight muscle degeneration, a phenotype consistent with hypercontraction observed in other Drosophila myofibrillar mutants. Based on F-actin-Tm and F-actin-Tm-myosin models and on our physiological data, we conclude that acetylating K326 and K328 of actin alters electrostatic associations with Tm and/or myosin and thereby augments contractile properties. Our findings highlight the utility of Drosophila as a model that permits efficient targeted design and assessment of molecular and tissue-specific responses to muscle protein modifications, in vivo. PMID:25972811

  16. Pseudo-acetylation of K326 and K328 of actin disrupts Drosophila melanogaster indirect flight muscle structure and performance

    PubMed Central

    Viswanathan, Meera C.; Blice-Baum, Anna C.; Schmidt, William; Foster, D. Brian; Cammarato, Anthony

    2015-01-01

    In striated muscle tropomyosin (Tm) extends along the length of F-actin-containing thin filaments. Its location governs access of myosin binding sites on actin and, hence, force production. Intermolecular electrostatic associations are believed to mediate critical interactions between the proteins. For example, actin residues K326, K328, and R147 were predicted to establish contacts with E181 of Tm. Moreover, K328 also potentially forms direct interactions with E286 of myosin when the motor is strongly bound. Recently, LC-MS/MS analysis of the cardiac acetyl-lysine proteome revealed K326 and K328 of actin were acetylated, a post-translational modification (PTM) that masks the residues' inherent positive charges. Here, we tested the hypothesis that by removing the vital actin charges at residues 326 and 328, the PTM would perturb Tm positioning and/or strong myosin binding as manifested by altered skeletal muscle function and structure in the Drosophila melanogaster model system. Transgenic flies were created that permit tissue-specific expression of K326Q, K328Q, or K326Q/K328Q acetyl-mimetic actin and of wild-type actin via the UAS-GAL4 bipartite expression system. Compared to wild-type actin, muscle-restricted expression of mutant actin had a dose-dependent effect on flight ability. Moreover, excessive K328Q and K326Q/K328Q actin overexpression induced indirect flight muscle degeneration, a phenotype consistent with hypercontraction observed in other Drosophila myofibrillar mutants. Based on F-actin-Tm and F-actin-Tm-myosin models and on our physiological data, we conclude that acetylating K326 and K328 of actin alters electrostatic associations with Tm and/or myosin and thereby augments contractile properties. Our findings highlight the utility of Drosophila as a model that permits efficient targeted design and assessment of molecular and tissue-specific responses to muscle protein modifications, in vivo. PMID:25972811

  17. Rapid evolution of larval life history, adult immune function and flight muscles in a poleward-moving damselfly.

    PubMed

    Therry, L; Nilsson-Örtman, V; Bonte, D; Stoks, R

    2014-01-01

    Although a growing number of studies have documented the evolution of adult dispersal-related traits at the range edge of poleward-expanding species, we know little about evolutionary changes in immune function or traits expressed by nondispersing larvae. We investigated differentiation in larval (growth and development) and adult traits (immune function and flight-related traits) between replicated core and edge populations of the poleward-moving damselfly Coenagrion scitulum. These traits were measured on individuals reared in a common garden experiment at two different food levels, as allocation trade-offs may be easier to detect under energy shortage. Edge individuals had a faster larval life history (growth and development rates), a higher adult immune function and a nearly significant higher relative flight muscle mass. Most of the differentiation between core and edge populations remained and edge populations had a higher relative flight muscle mass when corrected for latitude-specific thermal regimes, and hence could likely be attributed to the range expansion process per se. We here for the first time document a higher immune function in individuals at the expansion front of a poleward-expanding species and documented the rarely investigated evolution of faster life histories during range expansion. The rapid multivariate evolution in these ecological relevant traits between edge and core populations is expected to translate into changed ecological interactions and therefore has the potential to generate novel eco-evolutionary dynamics at the expansion front. PMID:24313892

  18. X-ray diffraction from flight muscle with a headless myosin mutation: implications for interpreting reflection patterns

    PubMed Central

    Iwamoto, Hiroyuki; Trombitás, Károly; Yagi, Naoto; Suggs, Jennifer A.; Bernstein, Sanford I.

    2014-01-01

    Fruit fly (Drosophila melanogaster) is one of the most useful animal models to study the causes and effects of hereditary diseases because of its rich genetic resources. It is especially suitable for studying myopathies caused by myosin mutations, because specific mutations can be induced to the flight muscle-specific myosin isoform, while leaving other isoforms intact. Here we describe an X-ray-diffraction-based method to evaluate the structural effects of mutations in contractile proteins in Drosophila indirect flight muscle. Specifically, we describe the effect of the headless myosin mutation, Mhc10-Y97, in which the motor domain of the myosin head is deleted, on the X-ray diffraction pattern. The loss of general integrity of the filament lattice is evident from the pattern. A striking observation, however, is the prominent meridional reflection at d = 14.5 nm, a hallmark for the regularity of the myosin-containing thick filament. This reflection has long been considered to arise mainly from the myosin head, but taking the 6th actin layer line reflection as an internal control, the 14.5-nm reflection is even stronger than that of wild-type muscle. We confirmed these results via electron microscopy, wherein image analysis revealed structures with a similar periodicity. These observations have major implications on the interpretation of myosin-based reflections. PMID:25400584

  19. Human congenital myopathy actin mutants cause myopathy and alter Z-disc structure in Drosophila flight muscle.

    PubMed

    Sevdali, Maria; Kumar, Vikash; Peckham, Michelle; Sparrow, John

    2013-03-01

    Over 190 mutations in the human skeletal muscle α-actin gene, ACTA1 cause congenital actin myopathies. We transgenically expressed six different mutant actins, G15R, I136M, D154N, V163L, V163M and D292V in Drosophila indirect flight muscles and investigated their effects in flies that express one wild type and one mutant actin copy. All the flies were flightless, and the IFMs showed incomplete Z-discs, disorganised actin filaments and 'zebra bodies'. No differences in levels of sarcomeric protein expression were observed, but tropomodulin staining was somewhat disrupted in D164N, V163L, G15R and V163M heterozygotes. A single copy of D292V mutant actin rescued the hypercontractile phenotypes caused by TnI and TnT mutants, suggesting that the D292V mutation interferes with thin filament regulation. Our results show that expression of actin mutations homologous to those in humans in the indirect flight muscles of Drosophila disrupt sarcomere organisation, with somewhat similar phenotypes to those observed in humans. Using Drosophila to study actin mutations may help aid our understanding of congential myopathies caused by actin mutations.

  20. Binding partners of the kinase domains in Drosophila obscurin and their effect on the structure of the flight muscle.

    PubMed

    Katzemich, Anja; West, Ryan J H; Fukuzawa, Atsushi; Sweeney, Sean T; Gautel, Mathias; Sparrow, John; Bullard, Belinda

    2015-09-15

    Drosophila obscurin (Unc-89) is a titin-like protein in the M-line of the muscle sarcomere. Obscurin has two kinase domains near the C-terminus, both of which are predicted to be inactive. We have identified proteins binding to the kinase domains. Kinase domain 1 bound Bällchen (Ball, an active kinase), and both kinase domains 1 and 2 bound MASK (a 400-kDa protein with ankyrin repeats). Ball was present in the Z-disc and M-line of the indirect flight muscle (IFM) and was diffusely distributed in the sarcomere. MASK was present in both the M-line and the Z-disc. Reducing expression of Ball or MASK by siRNA resulted in abnormalities in the IFM, including missing M-lines and multiple Z-discs. Obscurin was still present, suggesting that the kinase domains act as a scaffold binding Ball and MASK. Unlike obscurin in vertebrate skeletal muscle, Drosophila obscurin is necessary for the correct assembly of the IFM sarcomere. We show that Ball and MASK act downstream of obscurin, and both are needed for development of a well defined M-line and Z-disc. The proteins have not previously been identified in Drosophila muscle.

  1. Comparison of a space shuttle flight (STS-78) and bed rest on human muscle function

    NASA Technical Reports Server (NTRS)

    Trappe, S. W.; Trappe, T. A.; Lee, G. A.; Widrick, J. J.; Costill, D. L.; Fitts, R. H.

    2001-01-01

    The purpose of this investigation was to assess muscle fiber size, composition, and in vivo contractile characteristics of the calf muscle of four male crew members during a 17-day spaceflight (SF; Life and Microgravity Sciences Spacelab Shuttle Transport System-78 mission) and eight men during a 17-day bed rest (BR). The protocols and timelines of these two investigations were identical, therefore allowing for direct comparisons between SF and the BR. The subjects' age, height, and weight were 43 +/- 2 yr, 183 +/- 4 cm, and 86 +/- 3 kg for SF and 43 +/- 2 yr, 182 +/- 3 cm, and 82 +/- 4 kg for BR, respectively. Calf muscle strength was examined before SF and BR; on days 2, 8, and 12 during SF and BR; and on days 2 and 8 of recovery. Muscle biopsies were obtained before and within 3 h after SF (gastrocnemius and soleus) and BR (soleus) before reloading. Maximal isometric calf strength and the force-velocity characteristics were unchanged with SF or BR. Additionally, neither SF nor BR had any effect on fiber composition or fiber size of the calf muscles studied. In summary, no changes in calf muscle strength and morphology were observed after the 17-day SF and BR. Because muscle strength is lost during unloading, both during spaceflight and on the ground, these data suggest that the testing sequence employed during the SF and BR may have served as a resistance training countermeasure to attenuate whole muscle strength loss.

  2. Isoform composition and gene expression of thick and thin filament proteins in striated muscles of mice after 30-day space flight.

    PubMed

    Ulanova, Anna; Gritsyna, Yulia; Vikhlyantsev, Ivan; Salmov, Nikolay; Bobylev, Alexander; Abdusalamova, Zarema; Rogachevsky, Vadim; Shenkman, Boris; Podlubnaya, Zoya

    2015-01-01

    Changes in isoform composition, gene expression of titin and nebulin, and isoform composition of myosin heavy chains as well as changes in titin phosphorylation level in skeletal (m. gastrocnemius, m. tibialis anterior, and m. psoas) and cardiac muscles of mice were studied after a 30-day-long space flight onboard the Russian spacecraft "BION-M" number 1. A muscle fibre-type shift from slow-to-fast and a decrease in the content of titin and nebulin in the skeletal muscles of animals from "Flight" group was found. Using Pro-Q Diamond staining, an ~3-fold increase in the phosphorylation level of titin in m. gastrocnemius of mice from the "Flight" group was detected. The content of titin and its phosphorylation level in the cardiac muscle of mice from "Flight" and "Control" groups did not differ; nevertheless an increase (2.2 times) in titin gene expression in the myocardium of flight animals was found. The observed changes are discussed in the context of their role in the contractile activity of striated muscles of mice under conditions of weightlessness.

  3. Isoform composition and gene expression of thick and thin filament proteins in striated muscles of mice after 30-day space flight.

    PubMed

    Ulanova, Anna; Gritsyna, Yulia; Vikhlyantsev, Ivan; Salmov, Nikolay; Bobylev, Alexander; Abdusalamova, Zarema; Rogachevsky, Vadim; Shenkman, Boris; Podlubnaya, Zoya

    2015-01-01

    Changes in isoform composition, gene expression of titin and nebulin, and isoform composition of myosin heavy chains as well as changes in titin phosphorylation level in skeletal (m. gastrocnemius, m. tibialis anterior, and m. psoas) and cardiac muscles of mice were studied after a 30-day-long space flight onboard the Russian spacecraft "BION-M" number 1. A muscle fibre-type shift from slow-to-fast and a decrease in the content of titin and nebulin in the skeletal muscles of animals from "Flight" group was found. Using Pro-Q Diamond staining, an ~3-fold increase in the phosphorylation level of titin in m. gastrocnemius of mice from the "Flight" group was detected. The content of titin and its phosphorylation level in the cardiac muscle of mice from "Flight" and "Control" groups did not differ; nevertheless an increase (2.2 times) in titin gene expression in the myocardium of flight animals was found. The observed changes are discussed in the context of their role in the contractile activity of striated muscles of mice under conditions of weightlessness. PMID:25664316

  4. Bilateral flight muscle activity predicts wing kinematics and 3-dimensional body orientation of locusts responding to looming objects.

    PubMed

    McMillan, Glyn A; Loessin, Vicky; Gray, John R

    2013-09-01

    We placed locusts in a wind tunnel using a loose tether design that allowed for motion in all three rotational degrees of freedom during presentation of a computer-generated looming disc. High-speed video allowed us to extract wing kinematics, abdomen position and 3-dimensional body orientation. Concurrent electromyographic (EMG) recordings monitored bilateral activity from the first basalar depressor muscles (m97) of the forewings, which are implicated in flight steering. Behavioural responses to a looming disc included cessation of flight (wings folded over the body), glides and active steering during sustained flight in addition to a decrease and increase in wingbeat frequency prior to and during, respectively, an evasive turn. Active steering involved shifts in bilateral m97 timing, wing asymmetries and whole-body rotations in the yaw (ψ), pitch (χ) and roll (η) planes. Changes in abdomen position and hindwing asymmetries occurred after turns were initiated. Forewing asymmetry and changes in η were most highly correlated with m97 spike latency. Correlations also increased as the disc approached, peaking prior to collision. On the inside of a turn, m97 spikes occurred earlier relative to forewing stroke reversal and bilateral timing corresponded to forewing asymmetry as well as changes in whole-body rotation. Double spikes in each m97 occurred most frequently at or immediately prior to the time the locusts turned, suggesting a behavioural significance. These data provide information on mechanisms underlying 3-dimensional flight manoeuvres and will be used to drive a closed loop flight simulator to study responses of motion-sensitive visual neurons during production of realistic behaviours.

  5. Bilateral flight muscle activity predicts wing kinematics and 3-dimensional body orientation of locusts responding to looming objects.

    PubMed

    McMillan, Glyn A; Loessin, Vicky; Gray, John R

    2013-09-01

    We placed locusts in a wind tunnel using a loose tether design that allowed for motion in all three rotational degrees of freedom during presentation of a computer-generated looming disc. High-speed video allowed us to extract wing kinematics, abdomen position and 3-dimensional body orientation. Concurrent electromyographic (EMG) recordings monitored bilateral activity from the first basalar depressor muscles (m97) of the forewings, which are implicated in flight steering. Behavioural responses to a looming disc included cessation of flight (wings folded over the body), glides and active steering during sustained flight in addition to a decrease and increase in wingbeat frequency prior to and during, respectively, an evasive turn. Active steering involved shifts in bilateral m97 timing, wing asymmetries and whole-body rotations in the yaw (ψ), pitch (χ) and roll (η) planes. Changes in abdomen position and hindwing asymmetries occurred after turns were initiated. Forewing asymmetry and changes in η were most highly correlated with m97 spike latency. Correlations also increased as the disc approached, peaking prior to collision. On the inside of a turn, m97 spikes occurred earlier relative to forewing stroke reversal and bilateral timing corresponded to forewing asymmetry as well as changes in whole-body rotation. Double spikes in each m97 occurred most frequently at or immediately prior to the time the locusts turned, suggesting a behavioural significance. These data provide information on mechanisms underlying 3-dimensional flight manoeuvres and will be used to drive a closed loop flight simulator to study responses of motion-sensitive visual neurons during production of realistic behaviours. PMID:23737560

  6. Allosteric regulation of 6-phosphofructo-1-kinase activity of fat body and flight muscle from the bloodsucking bug Rhodnius prolixus.

    PubMed

    Alves, Gutemberg G; Marinho-Carvalho, Monica M; Atella, Georgia C; Silva-Neto, Mario A C; Sola-Penna, Mauro

    2007-03-01

    6-Phosphofructo-1-kinase (phosphofructokinase; PFK) activity from Rhodnius prolixus, a haematophagous insect which is usually a poor flyer, was measured and compared in two metabolically active tissues - flight muscle and fat body. The activity of this important regulatory glycolytic enzyme was much more pronounced in muscle (15.1 +/- 1.4 U/mg) than in fat body extracts (3.6+/-0.4 U/mg), although the latter presented higher levels of enzyme per protein content, as measured by western-blotting. Muscle extracts are more responsible than fat body to ATP and fructose 6-phosphate, both substrates of PFK. Allosteric regulation exerted by different effectors such as ADP, AMP and fructose 2,6-phosphate presented a singular pattern for each tissue. Optimal pH (8.0-8.5) and sensitivity to pH variation was very similar, and citrate was unable to inhibit PFK activity in both extracts. Our results suggest the existence of a particular PFK activity for each tissue, with regulatory patterns that are consistent with their physiological roles.

  7. Neck and shoulder muscle activity and posture among helicopter pilots and crew-members during military helicopter flight.

    PubMed

    Murray, Mike; Lange, Britt; Chreiteh, Shadi Samir; Olsen, Henrik Baare; Nørnberg, Bo Riebeling; Boyle, Eleanor; Søgaard, Karen; Sjøgaard, Gisela

    2016-04-01

    Neck pain among helicopter pilots and crew-members is common. This study quantified the physical workload on neck and shoulder muscles using electromyography (EMG) measures during helicopter flight. Nine standardized sorties were performed, encompassing: cruising from location A to location B (AB) and performing search and rescue (SAR). SAR was performed with Night Vision Goggles (NVG), while AB was performed with (AB+NVG) and without NVG (AB-NVG). EMG was recorded for: trapezius (TRA), upper neck extensors (UNE), and sternocleido-mastoid (SCM). Maximal voluntary contractions (MVC) were performed for normalization of EMG (MVE). Neck posture of pilots and crew-members was monitored and pain intensity of neck, shoulder, and back was recorded. Mean muscle activity for UNE was ∼10% MVE and significantly higher than TRA and SCM, and SCM was significantly lower than TRA. There was no significant difference between AB-NVG and AB+NVG. Muscle activity in the UNE was significantly higher during SAR+NVG than AB-NVG. Sortie time (%) with non-neutral neck posture for SAR+NVG and AB-NVG was: 80.4%, 74.5% (flexed), 55.5%, 47.9% (rotated), 4.5%, 3.7% (lateral flexed). Neck pain intensity increased significantly from pre- (0.7±1.3) to post-sortie (1.6±1.9) for pilots (p=0.028). If sustained, UNE activity of ∼10% MVE is high, and implies a risk for neck disorders.

  8. Dimorphism and patellofemoral disorders.

    PubMed

    Arendt, Elizabeth A

    2006-10-01

    Sex is defined as the classification of living things according to their chromosomal compliment. Gender is defined as a person's self-representation as a male or female or how social institutions respond to that person on the basis of his or her gender presentation. One frequently divides the topic or dimorphism into the biologic response inherent in their sex and the environmental response that might be better termed "gender differences." Clinicians have anecdotally agreed for years that patellofemoral disorders are more common in women. Given the difficulty in classifying patellofemoral disorders, literature support for this assumption is meager. For the purposes of this article we divide patellofemoral disorders into three categories: patellofemoral pain, patellofemoral instability, and patellofemoral arthritis. possible sex difference in these disorders are reviewed. PMID:17141017

  9. A muscle-specific intron enhancer required for rescue of indirect flight muscle and jump muscle function regulates Drosophila tropomyosin I gene expression

    SciTech Connect

    Schultz, J.A.; Gremke, L.; Storti, R.V. ); Tansey, T. )

    1991-04-01

    The control of expression of the Drosophila melanogaster tropomyosin I (TmI) gene has been investigated by P-element transformation and rescue of the flightless TmI mutant strain, Ifm(3)3. To localize cis-acting DNA sequences that control TmI gene expression, Ifm(3)3 flies were transformed with P-element plasmids containing various deletions and rearrangements of the TmI gene. The effects of these mutations on TmI gene expression were studied by analyzing both the extent of rescue of the Ifm(3)3 mutant phenotypes and determining TmI RNA levels in the transformed flies by primer extension analysis. The results of this analysis indicate that a region located within intron 1 of the gene is necessary and sufficient for directing muscle-specific TmI expression in the adult fly. This intron region has characteristics of a muscle regulatory enhancer element that can function in conjunction with the heterologous nonmuscle hsp70 promoter to promote rescue of the mutant phenotypes and to direct expression of an hsp70-Escherichia coli lacZ reporter gene in adult muscle. The enhancer can be subdivided further into two domains of activity based on primer extension analysis of TmI mRNA levels and on the rescue of mutant phenotypes.

  10. Structure of myosin filaments from relaxed Lethocerus flight muscle by cryo-EM at 6 Å resolution

    PubMed Central

    Hu, Zhongjun; Taylor, Dianne W.; Reedy, Michael K.; Edwards, Robert J.; Taylor, Kenneth A.

    2016-01-01

    We describe a cryo–electron microscopy three-dimensional image reconstruction of relaxed myosin II–containing thick filaments from the flight muscle of the giant water bug Lethocerus indicus. The relaxed thick filament structure is a key element of muscle physiology because it facilitates the reextension process following contraction. Conversely, the myosin heads must disrupt their relaxed arrangement to drive contraction. Previous models predicted that Lethocerus myosin was unique in having an intermolecular head-head interaction, as opposed to the intramolecular head-head interaction observed in all other species. In contrast to the predicted model, we find an intramolecular head-head interaction, which is similar to that of other thick filaments but oriented in a distinctly different way. The arrangement of myosin’s long α-helical coiled-coil rod domain has been hypothesized as either curved layers or helical subfilaments. Our reconstruction is the first report having sufficient resolution to track the rod α helices in their native environment at resolutions ~5.5 Å, and it shows that the layer arrangement is correct for Lethocerus. Threading separate paths through the forest of myosin coiled coils are four nonmyosin peptides. We suggest that the unusual position of the heads and the rod arrangement separated by nonmyosin peptides are adaptations for mechanical signal transduction whereby applied tension disrupts the myosin heads as a component of stretch activation. PMID:27704041

  11. Detection of G-Induced Loss of Consciousness (G-LOC) prognosis through EMG monitoring on gastrocnemius muscle in flight.

    PubMed

    Booyong Choi; Yongkyun Lee; Taehwan Cho; Hyojin Koo; Dongsoo Kim

    2015-08-01

    G-Induced Loss of Consciousness (G-LOC) is mainly caused by the sudden acceleration in the direction of +Gz axis from the fighter pilots, and is considered as an emergent situation of which fighter pilots are constantly aware. In order to resist against G-LOC, fighter pilots are subject to run Anti-G straining maneuver (AGSM), which includes L-1 respiration maneuvering and muscular contraction of the whole body. The purpose of this study is to create a G-LOC warning alarm prior to G-LOC by monitoring the Electromyogram (EMG) of the gastrocnemius muscle on the calf, which goes under constant muscular contraction during the AGSM process. EMG data was retrieved from pilots and pilot trainees of the Korean Air Force, during when subjects were under high G-trainings on a human centrifugal simulator. Out of the EMG features, integrated absolute value (IAV), reflecting muscle contraction, and waveform length (WL), reflecting muscle contraction and fatigue, have shown a rapid decay during the alarm phase, 3 seconds before G-LOC, compared to that of a normal phase withstanding G-force. Such results showed consistency amongst pilots and pilot trainees who were under G-LOC. Based on these findings, this study developed an algorithm which can detect G-LOC prognosis during flight, and at the same time, generate warning signals. The probability of G-LOC occurrence is detected through monitoring the decay trend and degree of the IVA and WL value of when the pilot initiates AGSM during sudden acceleration above 6G. Conclusively, this G-LOC prognosis detecting and warning system is a customized, real-time countermeasure which enhanced the accuracy of detecting G-LOC. PMID:26737905

  12. Neck and shoulder muscle activity and posture among helicopter pilots and crew-members during military helicopter flight.

    PubMed

    Murray, Mike; Lange, Britt; Chreiteh, Shadi Samir; Olsen, Henrik Baare; Nørnberg, Bo Riebeling; Boyle, Eleanor; Søgaard, Karen; Sjøgaard, Gisela

    2016-04-01

    Neck pain among helicopter pilots and crew-members is common. This study quantified the physical workload on neck and shoulder muscles using electromyography (EMG) measures during helicopter flight. Nine standardized sorties were performed, encompassing: cruising from location A to location B (AB) and performing search and rescue (SAR). SAR was performed with Night Vision Goggles (NVG), while AB was performed with (AB+NVG) and without NVG (AB-NVG). EMG was recorded for: trapezius (TRA), upper neck extensors (UNE), and sternocleido-mastoid (SCM). Maximal voluntary contractions (MVC) were performed for normalization of EMG (MVE). Neck posture of pilots and crew-members was monitored and pain intensity of neck, shoulder, and back was recorded. Mean muscle activity for UNE was ∼10% MVE and significantly higher than TRA and SCM, and SCM was significantly lower than TRA. There was no significant difference between AB-NVG and AB+NVG. Muscle activity in the UNE was significantly higher during SAR+NVG than AB-NVG. Sortie time (%) with non-neutral neck posture for SAR+NVG and AB-NVG was: 80.4%, 74.5% (flexed), 55.5%, 47.9% (rotated), 4.5%, 3.7% (lateral flexed). Neck pain intensity increased significantly from pre- (0.7±1.3) to post-sortie (1.6±1.9) for pilots (p=0.028). If sustained, UNE activity of ∼10% MVE is high, and implies a risk for neck disorders. PMID:26852114

  13. Detection of G-Induced Loss of Consciousness (G-LOC) prognosis through EMG monitoring on gastrocnemius muscle in flight.

    PubMed

    Booyong Choi; Yongkyun Lee; Taehwan Cho; Hyojin Koo; Dongsoo Kim

    2015-08-01

    G-Induced Loss of Consciousness (G-LOC) is mainly caused by the sudden acceleration in the direction of +Gz axis from the fighter pilots, and is considered as an emergent situation of which fighter pilots are constantly aware. In order to resist against G-LOC, fighter pilots are subject to run Anti-G straining maneuver (AGSM), which includes L-1 respiration maneuvering and muscular contraction of the whole body. The purpose of this study is to create a G-LOC warning alarm prior to G-LOC by monitoring the Electromyogram (EMG) of the gastrocnemius muscle on the calf, which goes under constant muscular contraction during the AGSM process. EMG data was retrieved from pilots and pilot trainees of the Korean Air Force, during when subjects were under high G-trainings on a human centrifugal simulator. Out of the EMG features, integrated absolute value (IAV), reflecting muscle contraction, and waveform length (WL), reflecting muscle contraction and fatigue, have shown a rapid decay during the alarm phase, 3 seconds before G-LOC, compared to that of a normal phase withstanding G-force. Such results showed consistency amongst pilots and pilot trainees who were under G-LOC. Based on these findings, this study developed an algorithm which can detect G-LOC prognosis during flight, and at the same time, generate warning signals. The probability of G-LOC occurrence is detected through monitoring the decay trend and degree of the IVA and WL value of when the pilot initiates AGSM during sudden acceleration above 6G. Conclusively, this G-LOC prognosis detecting and warning system is a customized, real-time countermeasure which enhanced the accuracy of detecting G-LOC.

  14. Giant fiber activation of flight muscles in Drosophila: asynchrony in latency of wing depressor fibers.

    PubMed

    Hummon, M R; Costello, W J

    1989-09-01

    In Drosophila, brain stimulation of the giant fiber pathway brings about highly stereotyped electrical responses in target muscles involved in the escape response. Both the order of muscle response and the latency of that response are predictable in wild-type flies. The neuronal circuit to the targets is well defined and has been used in the analysis of a number of mutant phenotypes, including induced anomalies in temperature-sensitive (ts) mutations such as shibire (shi). It has been assumed that the stereotyped response includes simultaneous activation of all six fibers of the wing depressor muscle, DLM, resulting in equal latencies for all fibers. We report here a small, but distinct, inherent difference in latency between two sets of DLM fibers in a proportion of two wild-type strains as well as in a strain carrying the ts mutation shi. This difference may occur on one or both sides of an individual, is stable over time, and persists when the motor axon is stimulated peripherally. These results, due to the circuit leading to the target, suggest that the difference in latency arises peripherally. In flies reared at the shi permissive temperature (22 degrees C), the difference is more common in shi than in wild-type flies; however, in shi flies reared at 18 degrees C, the prevalence resembles that of wild-type flies. This indicates a subtle expression of the shi defect even at the presumed permissive temperature of 22 degrees C. The difference in latency is similar to that induced in shi flies whose development is affected by pupal heat pulse. Thus, correct interpretation of differences in latency, e.g., in shi/wild-type mosaic flies or in flies with mutations affecting the GF pathway, requires recognition of the inherent asynchrony that can occur between DLM fibers.

  15. Sexual dimorphism in early anthropoids.

    PubMed

    Fleagle, J G; Kay, R F; Simons, E L

    1980-09-25

    Sexual dimorphism in canine/premolar tooth size and in body size is found among many species of living primates and has been shown to be correlated with social organization. Among extant higher primate species that normally live in the nuclear families consisting of a mated pair with their offspring, adult males and females are similar in body size and in the size of canine and anterior premolar teeth. In contrast, higher primate species living in more 'complex' polygynous groups (either single-male harems or multi-male groups) are characterized by sexual dimorphism in the size of canine/premolar teeth and frequently by body size dimorphism as well. We provide here the first evidence for sexual dimorphism in three species of primates from the Oligocene of Egypt--Aegyptopithecus zeuxis, Propliopithecus chirobates, and Apidium phiomense. This is the earliest record of sexual dimorphism among higher primates and suggests, by analogy with living species, that the earliest known fossil Old World anthropoids lived in polygynous (either single-male harems or multi-male groups) rather than monogamous social groups.

  16. Sexual size dimorphism in anurans.

    PubMed

    Monnet, Jean-Matthieu; Cherry, Michael I

    2002-11-22

    Several hypotheses have been proposed to explain the direction and extent of sexual size dimorphism in anurans (in which males are usually smaller than females) as a result of sexual selection. Here, we present an analysis to test the hypothesis that sexual dimorphism in anurans is largely a function of differences between the sexes in life-history strategies. Morphological and demographic data for anurans were collected from the literature, and the mean size and age in each sex were calculated for 51 populations, across 30 species and eight genera. Comparisons across 14 Rana species, eight Bufo species and across the genera showed a highly significant relationship between size dimorphism, measured using the female-male size ratio, and mean female-male age difference. A comparison of a subset of 17 of these species for which phylogenetic information was available, using the method of independent contrasts, yielded a similar result. These results indicate that most of the variation in size dimorphism in the anura can be explained in terms of differences in the age structure between the sexes in breeding populations. If sexual selection has an effect on size dimorphism in anurans, it is likely to be only a secondary one.

  17. Countermeasures for Maintenance of Cardiovascular and Muscle Function in Space Flight

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In this session, Session FA2, the discussion focuses on the following topics: Effects of Repeated Long Duration +2Gz Load on Man's Cardiovascular Function; Certain Approaches to the Development of On-Board Automated Training System; Cardiac, Arterial, and Venous Adaptation to Og during 6 Month MIR-Spaceflights with and without "Thigh Cuffs" (93-95); Space Cycle(TM) Induced Physiologic Responses; Muscular Deconditioning During Long-term Spaceflight Exercise Recommendations to Optimize Crew Performance; Structure And Function of Knee Extensors After Long-Duration Spaceflight in Man, Effects of Countermeasure Exercise Training; Force and power characteristics of an exercise ergometer designed for use in space; and The simulating of overgravity conditions for astronauts' motor apparatus at the conditions of the training for orbital flights.

  18. Passive tension and stiffness of vertebrate skeletal and insect flight muscles: the contribution of weak cross-bridges and elastic filaments.

    PubMed Central

    Granzier, H L; Wang, K

    1993-01-01

    Tension and dynamic stiffness of passive rabbit psoas, rabbit semitendinosus, and waterbug indirect flight muscles were investigated to study the contribution of weak-binding cross-bridges and elastic filaments (titin and minititin) to the passive mechanical behavior of these muscles. Experimentally, a functional dissection of the relative contribution of actomyosin cross-bridges and titin and minititin was achieved by 1) comparing mechanically skinned muscle fibers before and after selective removal of actin filaments with a noncalcium-requiring gelsolin fragment (FX-45), and 2) studying passive tension and stiffness as a function of sarcomere length, ionic strength, temperature, and the inhibitory effect of a carboxyl-terminal fragment of smooth muscle caldesmon. Our data show that weak bridges exist in both rabbit skeletal muscle and insect flight muscle at physiological ionic strength and room temperature. In rabbit psoas fibers, weak bridge stiffness appears to vary with both thin-thick filament overlap and with the magnitude of passive tension. Plots of passive tension versus passive stiffness are multiphasic and strikingly similar for these three muscles of distinct sarcomere proportions and elastic proteins. The tension-stiffness plot appears to be a powerful tool in discerning changes in the mechanical behavior of the elastic filaments. The stress-strain and stiffness-strain curves of all three muscles can be merged into one, by normalizing strain rate and strain amplitude of the extensible segment of titin and minititin, further supporting the segmental extension model of resting tension development. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 PMID:8298040

  19. Research opportunities in muscle atrophy

    NASA Technical Reports Server (NTRS)

    Herbison, G. J.; Talbot, J. M.

    1984-01-01

    A trophy of skeletal muscle; muscle a trophy associated with manned space flight; the nature, causes, and mechanisms of muscle atrophy associated with space flight, selected physiological factors, biochemical aspects, and countermeasures are addressed.

  20. Isoform Composition and Gene Expression of Thick and Thin Filament Proteins in Striated Muscles of Mice after 30-Day Space Flight

    PubMed Central

    Ulanova, Anna; Gritsyna, Yulia; Vikhlyantsev, Ivan; Salmov, Nikolay; Bobylev, Alexander; Abdusalamova, Zarema; Rogachevsky, Vadim; Shenkman, Boris; Podlubnaya, Zoya

    2015-01-01

    Changes in isoform composition, gene expression of titin and nebulin, and isoform composition of myosin heavy chains as well as changes in titin phosphorylation level in skeletal (m. gastrocnemius, m. tibialis anterior, and m. psoas) and cardiac muscles of mice were studied after a 30-day-long space flight onboard the Russian spacecraft “BION-M” number 1. A muscle fibre-type shift from slow-to-fast and a decrease in the content of titin and nebulin in the skeletal muscles of animals from “Flight” group was found. Using Pro-Q Diamond staining, an ~3-fold increase in the phosphorylation level of titin in m. gastrocnemius of mice from the “Flight” group was detected. The content of titin and its phosphorylation level in the cardiac muscle of mice from “Flight” and “Control” groups did not differ; nevertheless an increase (2.2 times) in titin gene expression in the myocardium of flight animals was found. The observed changes are discussed in the context of their role in the contractile activity of striated muscles of mice under conditions of weightlessness. PMID:25664316

  1. Structure of cortical cytoskeleton in fibers of mouse muscle cells after being exposed to a 30-day space flight on board the BION-M1 biosatellite.

    PubMed

    Ogneva, I V; Maximova, M V; Larina, I M

    2014-05-15

    The aim of the work was to analyze changes in the organization of the cortical cytoskeleton in fibers of the mouse soleus muscle, tibialis anterior muscle and left ventricular cardiomyocytes after completion of a 30-day space flight on board the BION-M1 biosatellite (Russia, 2013). The transversal stiffness of the cortical cytoskeleton of the cardiomyocytes and fibers of the skeletal muscles did not differ significantly within the study groups compared with the vivarium control group. The content of beta- and gamma-actin in the membranous fraction of proteins in the left ventricular cardiomyocytes did not differ significantly within all study groups and correlated with the transversal stiffness. A similar situation was revealed in fibers of the soleus muscle and tibialis anterior muscle. At the same time, the content of beta-actin in the cytoplasmic fraction of proteins was found to be decreased in all types of studied tissues compared with the control levels in the postflight group, with lowered beta-actin gene expression rates in the postflight group. After completion of the space flight, the content of alpha-actinin-4 was found to be reduced in the membranous fraction of proteins from the mouse cardiomyocytes, while its content in the cytoplasmic fraction of proteins did not change significantly. Furthermore, gene expression rates of this protein were decreased at the time of dissection (it was started after 13 h after landing). At the same time, the content of alpha-actinin-1 decreased in the membranous fraction and increased in the cytoplasmic fraction of proteins from the soleus muscle fibers.

  2. Genome-wide methylation analysis identified sexually dimorphic methylated regions in hybrid tilapia

    PubMed Central

    Wan, Zi Yi; Xia, Jun Hong; Lin, Grace; Wang, Le; Lin, Valerie C. L.; Yue, Gen Hua

    2016-01-01

    Sexual dimorphism is an interesting biological phenomenon. Previous studies showed that DNA methylation might play a role in sexual dimorphism. However, the overall picture of the genome-wide methylation landscape in sexually dimorphic species remains unclear. We analyzed the DNA methylation landscape and transcriptome in hybrid tilapia (Oreochromis spp.) using whole genome bisulfite sequencing (WGBS) and RNA-sequencing (RNA-seq). We found 4,757 sexually dimorphic differentially methylated regions (DMRs), with significant clusters of DMRs located on chromosomal regions associated with sex determination. CpG methylation in promoter regions was negatively correlated with the gene expression level. MAPK/ERK pathway was upregulated in male tilapia. We also inferred active cis-regulatory regions (ACRs) in skeletal muscle tissues from WGBS datasets, revealing sexually dimorphic cis-regulatory regions. These results suggest that DNA methylation contribute to sex-specific phenotypes and serve as resources for further investigation to analyze the functions of these regions and their contributions towards sexual dimorphisms. PMID:27782217

  3. A method for determining the periodicity of a troponin component in isolated insect flight muscle thin filaments by gold/Fab labelling.

    PubMed

    Newman, R; Butcher, G W; Bullard, B; Leonard, K R

    1992-03-01

    Insect flight muscle has a large component (Tn-H) in the tropomyosin-troponin complex that is not present in vertebrate striated muscle thin filaments. Tn-H is shown by gold/Fab labelling to be present at regular intervals in insect flight muscle thin filaments. The Fab fragment of a monoclonal antibody to Tn-H was conjugated directly with colloidal gold and this probe used to label isolated thin filaments from the flight muscle of Lethocerus indicus (water bug). The distribution of gold particles seen in electron microscope images of negatively stained thin filaments was analysed to show that the probe bound to sites having a periodicity of approximately 40 nm, which is the expected value for the tropomyosin-troponin repeat. Conjugates of Fab with colloidal gold particles of 3 nm diameter labelled almost all sites. Conjugates with gold particles of 5 nm and 10 nm diameter labelled less efficiently (70% and 30%, respectively) but analysis of the distribution of inter-particle intervals among a number of filaments again gave the same fundamental spacing of 40 nm. The error in the measurements (standard deviation approximately +/- 4.2 for 5 nm gold/Fab) is less than earlier estimates for the size of the gold/Fab complex. Measurements on gold/Fab in negative stain suggest that the bound Fab contributes a shell about 2 nm in thickness around the gold particle. The radius of the probe (about 4.5 nm for 5 nm gold/Fab) would then be consistent with the value of error found. The size of the probe suggests that the gold particle binds to the side of the Fab molecule, rather close to the antibody combining site. The potential resolution of the technique may thus be better than originally expected.

  4. Migration- and exercise-induced changes to flight muscle size in migratory birds and association with IGF1 and myostatin mRNA expression.

    PubMed

    Price, Edwin R; Bauchinger, Ulf; Zajac, Daria M; Cerasale, David J; McFarlan, Jay T; Gerson, Alexander R; McWilliams, Scott R; Guglielmo, Christopher G

    2011-09-01

    Seasonal adjustments to muscle size in migratory birds may result from preparatory physiological changes or responses to changed workloads. The mechanisms controlling these changes in size are poorly understood. We investigated some potential mediators of flight muscle size (myostatin and insulin-like growth factor, IGF1) in pectoralis muscles of wild wintering or migrating white-throated sparrows (Zonotrichia albicollis), captive white-throated sparrows that were photoperiod manipulated to be in a `wintering' or `migratory' (Zugunruhe) state, and captive European starlings (Sturnus vulgaris) that were either exercised for 2 weeks in a wind tunnel or untrained. Flight muscle size increased in photo-stimulated `migrants' and in exercised starlings. Acute exercise but not long-term training caused increased expression of IGF1, but neither caused a change in expression of myostatin or its metalloprotease activator TLL1. Photo-stimulated `migrant' sparrows demonstrated increased expression of both myostatin and IGF1, but wild sparrows exhibited no significant seasonal changes in expression of either myostatin or IGF1. Additionally, in both study species we describe several splice variants of myostatin that are shared with distantly related bird species. We demonstrate that their expression patterns are not different from those of the typical myostatin, suggesting that they have no functional importance and may be mistakes of the splicing machinery. We conclude that IGF1 is likely to be an important mediator of muscle phenotypic flexibility during acute exercise and during endogenous, seasonal preparation for migration. The role of myostatin is less clear, but its paradoxical increase in photo-stimulated `migrants' may indicate a role in seasonal adjustments of protein turnover. PMID:21832125

  5. [Desmin content and transversal stiffness of the left ventricle mouse cardiomyocytes and skeletal muscle fibers after a 30-day space flight on board "BION-M1" biosatellite].

    PubMed

    Ogneva, I V; Maximova, M V; Larina, I M

    2014-01-01

    The aim of this study was to determine the transversal stiffness of the cortical cytoskeleton and the cytoskeletal protein desmin content in the left ventricle cardiomyocytes, fibers of the mouse soleus and tibialis anterior muscle after a 30-day space flight on board the "BION-M1" biosatellite (Russia, 2013). The dissection was made after 13-16.5 h after landing. The transversal stiffness was measured in relaxed and calcium activated state by, atomic force microscopy. The desmin content was estimated by western blotting, and the expression level of desmin-coding gene was detected using real-time PCR. The results indicate that, the transversal stiffness of the left ventricle cardiomyocytes and fibers of the soleus muscle in relaxed and activated states did not differ from the control. The transversal stiffness of the tibialis muscle fibers in relaxed and activated state was increased in the mice group after space flight. At the same time, in all types of studied tissues the desmin content and the expression level of desmin-coding gene did not differ from the control level.

  6. Myosin Head Configuration in Relaxed Insect Flight Muscle: X-Ray Modeled Resting Cross-Bridges in a Pre-Powerstroke State Are Poised for Actin Binding

    PubMed Central

    AL-Khayat, Hind A.; Hudson, Liam; Reedy, Michael K.; Irving, Thomas C.; Squire, John M.

    2003-01-01

    Low-angle x-ray diffraction patterns from relaxed insect flight muscle recorded on the BioCAT beamline at the Argonne APS have been modeled to 6.5 nm resolution (R-factor 9.7%, 65 reflections) using the known myosin head atomic coordinates, a hinge between the motor (catalytic) domain and the light chain-binding (neck) region (lever arm), together with a simulated annealing procedure. The best head conformation angles around the hinge gave a head shape that was close to that typical of relaxed M•ADP•Pi heads, a head shape never before demonstrated in intact muscle. The best packing constrained the eight heads per crown within a compact crown shelf projecting at ∼90° to the filament axis. The two heads of each myosin molecule assume nonequivalent positions, one head projecting outward while the other curves round the thick filament surface to nose against the proximal neck of the projecting head of the neighboring molecule. The projecting heads immediately suggest a possible cross-bridge cycle. The relaxed projecting head, oriented almost as needed for actin attachment, will attach, then release Pi followed by ADP, as the lever arm with a purely axial change in tilt drives ∼10 nm of actin filament sliding on the way to the nucleotide-free limit of its working stroke. The overall arrangement appears well designed to support precision cycling for the myogenic oscillatory mode of contraction with its enhanced stretch-activation response used in flight by insects equipped with asynchronous fibrillar flight muscles. PMID:12885653

  7. Incorporation of 3-deoxy-3-fluoro-D-glucose into glycogen and trehalose in fat body and flight muscle in Locusta migratoria.

    PubMed

    Agbanyo, M; Taylor, N F

    1986-03-01

    Flight muscle and fat body extracts from Locusta migratoria were incubated with D-[U-14C]-glucose or D-[3-3H]-3-deoxy-3-fluoroglucose and the products were analyzed. In the case of the latter compound, radio-chromatographic analysis yielded glycogen and trehalose fractions that were shown by 19F nuclear magnetic resonance to contain fluorine. Acid hydrolysis of these fractions liberated tritium labelled 3-deoxy-3-fluoro-D-glucose. In addition to the formation of "fluoroglycogen" and "fluorotrehalose" in these tissue extracts, there was an accumulation of tritium labelled fructose. PMID:3524699

  8. β-Adrenergic–regulated phosphorylation of the skeletal muscle CaV1.1 channel in the fight-or-flight response

    PubMed Central

    Emrick, Michelle A.; Sadilek, Martin; Konoki, Keiichi; Catterall, William A.

    2010-01-01

    CaV1 channels initiate excitation–contraction coupling in skeletal and cardiac muscle. During the fight-or-flight response, epinephrine released by the adrenal medulla and norepinephrine released from sympathetic nerves increase muscle contractility by activation of the β-adrenergic receptor/cAMP-dependent protein kinase pathway and up-regulation of CaV1 channels in skeletal and cardiac muscle. Although the physiological mechanism of this pathway is well defined, the molecular mechanism and the sites of protein phosphorylation required for CaV1 channel regulation are unknown. To identify the regulatory sites of phosphorylation under physiologically relevant conditions, CaV1.1 channels were purified from skeletal muscle and sites of phosphorylation on the α1 subunit were identified by mass spectrometry. Two phosphorylation sites were identified in the proximal C-terminal domain, serine 1575 (S1575) and threonine 1579 (T1579), which are conserved in cardiac CaV1.2 channels (S1700 and T1704, respectively). In vitro phosphorylation revealed that CaV1.1-S1575 is a substrate for both cAMP-dependent protein kinase and calcium/calmodulin-dependent protein kinase II, whereas CaV1.1-T1579 is a substrate for casein kinase 2. Treatment of rabbits with isoproterenol to activate β-adrenergic receptors increased phosphorylation of S1575 in skeletal muscle CaV1.1 channels in vivo, and treatment with propranolol to inhibit β-adrenergic receptors reduced phosphorylation. As S1575 and T1579 in CaV1.1 channels and their homologs in CaV1.2 channels are located at a key regulatory interface between the distal and proximal C-terminal domains, it is likely that phosphorylation of these sites in skeletal and cardiac muscle is directly involved in calcium channel regulation in response to the sympathetic nervous system in the fight-or-flight response. PMID:20937870

  9. Beta-adrenergic-regulated phosphorylation of the skeletal muscle Ca(V)1.1 channel in the fight-or-flight response.

    PubMed

    Emrick, Michelle A; Sadilek, Martin; Konoki, Keiichi; Catterall, William A

    2010-10-26

    Ca(V)1 channels initiate excitation-contraction coupling in skeletal and cardiac muscle. During the fight-or-flight response, epinephrine released by the adrenal medulla and norepinephrine released from sympathetic nerves increase muscle contractility by activation of the β-adrenergic receptor/cAMP-dependent protein kinase pathway and up-regulation of Ca(V)1 channels in skeletal and cardiac muscle. Although the physiological mechanism of this pathway is well defined, the molecular mechanism and the sites of protein phosphorylation required for Ca(V)1 channel regulation are unknown. To identify the regulatory sites of phosphorylation under physiologically relevant conditions, Ca(V)1.1 channels were purified from skeletal muscle and sites of phosphorylation on the α1 subunit were identified by mass spectrometry. Two phosphorylation sites were identified in the proximal C-terminal domain, serine 1575 (S1575) and threonine 1579 (T1579), which are conserved in cardiac Ca(V)1.2 channels (S1700 and T1704, respectively). In vitro phosphorylation revealed that Ca(V)1.1-S1575 is a substrate for both cAMP-dependent protein kinase and calcium/calmodulin-dependent protein kinase II, whereas Ca(V)1.1-T1579 is a substrate for casein kinase 2. Treatment of rabbits with isoproterenol to activate β-adrenergic receptors increased phosphorylation of S1575 in skeletal muscle Ca(V)1.1 channels in vivo, and treatment with propranolol to inhibit β-adrenergic receptors reduced phosphorylation. As S1575 and T1579 in Ca(V)1.1 channels and their homologs in Ca(V)1.2 channels are located at a key regulatory interface between the distal and proximal C-terminal domains, it is likely that phosphorylation of these sites in skeletal and cardiac muscle is directly involved in calcium channel regulation in response to the sympathetic nervous system in the fight-or-flight response.

  10. Scaling relationships between craniofacial sexual dimorphism and body mass dimorphism in primates: implications for the fossil record.

    PubMed

    Plavcan, J Michael

    2003-01-01

    Craniofacial remains (the most abundant identifiable remains in the fossil record) potentially offer important information about body size dimorphism in extinct species. This study evaluates the scaling relationships between body mass dimorphism and different measures of craniofacial dimorphism, evaluating taxonomic differences in the magnitude and scaling of craniofacial dimorphism across higher taxonomic groups. Data on 40 dimensions from 129 primate species and subspecies demonstrate that few dimensions change proportionally with body mass dimorphism. Primates show general patterns of greater facial vs. neurocranial and orbital dimorphism, and greater dimorphism in lengths as opposed to breadths. Within any species, though, different craniofacial dimensions can yield very different reconstructions of size dimorphism. There are significant taxonomic differences in the relationships between size and craniofacial dimorphism among primate groups that can have a significant impact on reconstructions of body mass dimorphism. Hominoids tend to show lower degrees of facial dimorphism proportional to size dimorphism than other primates. This in turn implies that strong craniofacial dimorphism in Australopithecus africanus could imply very strong body size dimorphism, conflicting with the relatively modest size dimorphism inferred from postcrania. Different methods of estimating the magnitude of size dimorphism from craniofacial measurements yield similar results, and yield comparatively low percent prediction errors for a number of dimensions. However, confidence intervals for most estimates are so large as to render most estimates highly tentative.

  11. The 2013 German-Russian BION-M1 Joint Flight Project: Skeletal Muscle and Neuromuscular Changes in Mice Housed for 30 Days in a Biosatellite on Orbit

    NASA Astrophysics Data System (ADS)

    Blottner, Dieter; Shenkman, Boris; Salanova, Michele

    Exposure to microgravity results in various structural, biochemical and molecular changes of the skeletal neuromuscular system. The BION Joint Flight Proposal between the Charité Berlin Center of Space Medicine (www.zwmb.de) in Berlin, and the Institute of Biomedical Problem (IMBP) in Moscow, provided an exciting opportunity for a more detailed analysis of neuromuscular changes in mice (C57/bl6) exposed to real microgravity housed for 30 days in a BION M1 biosatellite on orbit. The mice from the BION flight group (n=5) were compared to three different on-ground control groups (Flight control, BION-ground and Vivarium, each n=5 mice). We started to analyse various skeletal muscles from the hind limbs or trunk. Apart from routine structural and biochemical analysis (fiber size and type distribution, slow/fastMyHC) we test the hypothesis for the presence of a microgravity-induced sarcolemma-cytosolic protein shift of nitric oxide synthase (NOS) and partial loss in neuromuscular synapse scaffold protein (Homer) immunoexpression known to be prone to disuse in mice or humans (hind limb unloading, bed rest) as previously shown (Sandonà D et al., PLoS One, 2012, Salanova M et al., FASEB J, 2011). National Sponsors: Federal Ministry of Economics and Technology (BMWi) via the German AeroSpace Board, DLR e.V., Bonn-Oberkassel, Germany (#50WB1121); Contract RAS-IMBP/Charité Berlin # Bion-M1/2013

  12. Evolutionary relationships among food habit, loss of flight, and reproductive traits: life-history evolution in the Silphinae (Coleoptera: Silphidae).

    PubMed

    Ikeda, Hiroshi; Kagaya, Takashi; Kubota, Kohei; Abe, Toshio

    2008-08-01

    Flightlessness in insects is generally thought to have evolved due to changes in habitat environment or habitat isolation. Loss of flight may have changed reproductive traits in insects, but very few attempts have been made to assess evolutionary relationships between flight and reproductive traits in a group of related species. We elucidated the evolutionary history of flight loss and its relationship to evolution in food habit, relative reproductive investment, and egg size in the Silphinae (Coleoptera: Silphidae). Most flight-capable species in this group feed primarily on vertebrate carcasses, whereas flightless or flight-dimorphic species feed primarily on soil invertebrates. Ancestral state reconstruction based on our newly constructed molecular phylogenetic tree implied that flight muscle degeneration occurred twice in association with food habit changes from necrophagy to predatory, suggesting that flight loss could evolve independently from changes in the environmental circumstances per se. We found that total egg production increased with flight loss. We also found that egg size increased with decreased egg number following food habit changes in the lineage leading to predaceous species, suggesting that selection for larger larvae intensified with the food habit change. This correlated evolution has shaped diverse life-history patterns among extant species of Silphinae.

  13. Sexual dimorphism and human enhancement.

    PubMed

    Casal, Paula

    2013-12-01

    Robert Sparrow argues that because of women's longer life expectancy philosophers who advocate the genetic modification of human beings to enhance welfare rather than merely supply therapy are committed to favouring the selection of only female embryos, an implication he deems sufficiently implausible to discredit their position. If Sparrow's argument succeeds, then philosophers who advocate biomedical moral enhancement also seem vulnerable to a similar charge because of men's greater propensity for various forms of harmful wrongdoing. This paper argues there are various flaws in Sparrow's argument that render it unsuccessful. The paper also examines whether dimorphism reduction is a more desirable outcome than male elimination, thereby further illustrating the difficulties besetting the distinction between therapy and enhancement.

  14. Sex Hormones and Immune Dimorphism

    PubMed Central

    Bhatia, Aruna; Sekhon, Harmandeep Kaur; Kaur, Gurpreet

    2014-01-01

    The functioning of the immune system of the body is regulated by many factors. The abnormal regulation of the immune system may result in some pathological conditions. Sex hormones of reproductive system are one of the major factors that regulate immune system due to the presence of hormone receptors on immune cells. The interaction of sex hormones and immune cells through the receptors on these cells effect the release of cytokines which determines the proliferation, differentiation, and maturation of different types of immunocytes and as a result the outcome of inflammatory or autoimmune diseases. The different regulations of sex hormones in both sexes result in immune dimorphism. In this review article the mechanism of regulation of immune system in different sexes and its impact are discussed. PMID:25478584

  15. Investigate methods for measuring muscle and bone mass changes in astronauts and animals which occur during space flight

    NASA Technical Reports Server (NTRS)

    Palmer, H. E.

    1977-01-01

    Sodium-22 is being used as a tracer for bone mineral metabolism studies. Dogs are being grown from puppies to adulthood on a diet containing a constant level of sodium-22 in order to uniformly tag the entire skeleton with a long lived radionuclide. This study is still in progress and the dogs are still growing. Potassium-40 measurements were made on people, who are replacing muscle mass lost due to leg injuries, in a second study. It appears that potassium-40 measurements provide an accurate and convenient method for determining relative changes in the muscle content of the leg.

  16. Dimorphic Olfactory Lobes in the Arthropoda

    PubMed Central

    Strausfeld, Nicholas; Reisenman, Carolina E.

    2009-01-01

    Specialized olfactory lobe glomeruli relating to sexual or caste differences have been observed in at least five orders of insects, suggesting an early appearance of this trait in insect evolution. Dimorphism is not limited to nocturnal species, but occurs even in insects that are known to use vision for courtship. Other than a single description there is no evidence for similar structures occuring in the Crustacea, suggesting that the evolution of dimorphic olfactory systems may typify terrestrial arthropods. PMID:19686183

  17. Dimorphic olfactory lobes in the arthropoda.

    PubMed

    Strausfeld, Nicholas; Reisenman, Carolina E

    2009-07-01

    Specialized olfactory lobe glomeruli relating to sexual or caste differences have been observed in at least five orders of insects, suggesting an early appearance of this trait in insect evolution. Dimorphism is not limited to nocturnal species, but occurs even in insects that are known to use vision for courtship. Other than a single description, there is no evidence for similar structures occurring in the Crustacea, suggesting that the evolution of dimorphic olfactory systems may typify terrestrial arthropods.

  18. An analysis of cercopithecoid odontometrics. II. Relations between dental dimorphism, body size dimorphism and diet.

    PubMed

    Post, D; Goldstein, S; Melnick, D

    1978-11-01

    Odontometric, dietary, and body weight data were collected for a sample of 29 cercopithecoid species. Each species was assigned to one of three diet classes (frugivore, folivore, and omnivore) , and indices were constructed to estimate the extent of sexual dimorphism in body weight, postcanine area and incisor width in each of the species. Analysis proceeded by means of the analysis of covariance with the dental dimorphism indices as the dependent variables. Body weight dimorphism was not significantly related to either measure of dental dimorphism across the sample, and an analysis by diet alone revealed that omnivores show significantly higher dental dimorphism than do either of the other two diet classes. The relationship between this result and theories of sexual subniche differentiation is discussed.

  19. COOH-terminal truncation of flightin decreases myofilament lattice organization, cross-bridge binding, and power output in Drosophila indirect flight muscle.

    PubMed

    Tanner, Bertrand C W; Miller, Mark S; Miller, Becky M; Lekkas, Panagiotis; Irving, Thomas C; Maughan, David W; Vigoreaux, Jim O

    2011-08-01

    The indirect flight muscle (IFM) of insects is characterized by a near crystalline myofilament lattice structure that likely evolved to achieve high power output. In Drosophila IFM, the myosin rod binding protein flightin plays a crucial role in thick filament organization and sarcomere integrity. Here we investigate the extent to which the COOH terminus of flightin contributes to IFM structure and mechanical performance using transgenic Drosophila expressing a truncated flightin lacking the 44 COOH-terminal amino acids (fln(ΔC44)). Electron microscopy and X-ray diffraction measurements show decreased myofilament lattice order in the fln(ΔC44) line compared with control, a transgenic flightin-null rescued line (fln(+)). fln(ΔC44) fibers produced roughly 1/3 the oscillatory work and power of fln(+), with reduced frequencies of maximum work (123 Hz vs. 154 Hz) and power (139 Hz vs. 187 Hz) output, indicating slower myosin cycling kinetics. These reductions in work and power stem from a slower rate of cross-bridge recruitment and decreased cross-bridge binding in fln(ΔC44) fibers, although the mean duration of cross-bridge attachment was not different between both lines. The decreases in lattice order and myosin kinetics resulted in fln(ΔC44) flies being unable to beat their wings. These results indicate that the COOH terminus of flightin is necessary for normal myofilament lattice organization, thereby facilitating the cross-bridge binding required to achieve high power output for flight.

  20. Sexual dimorphism in newborns and adults.

    PubMed

    Antoszewska, A; Wolański, N

    1992-01-01

    A total of 1034 newborns were used to analyze sexual dimorphism with respect to 37 somatic traits and ratios between them, describing body shape. Arithmetic means and standard deviations were calculated for both sexes. Similarly, sexual dimorphism of adults was analyzed. Sexual differences in newborns were statistically significant for most measurements but only for some body proportions (relative chest size, foot shape, relative lower extremity length, and the ratio of head to chest circumference). The highest degree of sexual dimorphism in newborns was shown by the index standardized on the mean (dsex/mean) of such traits as the thickness of subcutaneous fat tissue on the thigh, subscapular fat tissue and fat tissue on the 10th rib, body weight, hand breadth, and relative chest size (Marty index). A moderate dimorphism was found for the length of upper extremities, forearm with the hand, head with the neck, hand and trunk, the size of the nose and foot, the breadth of hips and mandible, and the upper-face height. A low dimorphism was found for body length, circumference and breadth of head, face diameter, chest circumference, foot shape, relative length of lower extremities, and proportion between head and chest circumferences. Sexual differences (dsex/mean) for all the somatic traits examined in adults were statistically significant. The dimorphism of all the traits (except hip breadth) was higher in adults than in newborns. The highest increase in sexual dimorphism was noted for chest breadth (ca 55 times), then for chest depth (ca 17 times), thickness of subcutaneous fat tissue on arm (ca. 17 times), and the length of lower extremities (ca 15 times). Sexual differences in proportions (shape) of the body were also better pronounced in adults than in newborns. Sexual dimorphism standardized for dispersion (dsex/SD) in newborns differed from that in adults with respect to the degree of its expression and the sequence of the traits showing the highest and the

  1. Sexual Dimorphism and Allometric Effects Associated With the Wing Shape of Seven Moth Species of Sphingidae (Lepidoptera: Bombycoidea)

    PubMed Central

    de Camargo, Nícholas Ferreira; Corrêa, Danilo do Carmo Vieira; de Camargo, Amabílio J. Aires; Diniz, Ivone Rezende

    2015-01-01

    Sexual dimorphism is a pronounced pattern of intraspecific variation in Lepidoptera. However, moths of the family Sphingidae (Lepidoptera: Bombycoidea) are considered exceptions to this rule. We used geometric morphometric techniques to detect shape and size sexual dimorphism in the fore and hindwings of seven hawkmoth species. The shape variables produced were then subjected to a discriminant analysis. The allometric effects were measured with a simple regression between the canonical variables and the centroid size. We also used the normalized residuals to assess the nonallometric component of shape variation with a t-test. The deformations in wing shape between sexes per species were assessed with a regression between the nonreduced shape variables and the residuals. We found sexual dimorphism in both wings in all analyzed species, and that the allometric effects were responsible for much of the wing shape variation between the sexes. However, when we removed the size effects, we observed shape sexual dimorphism. It is very common for females to be larger than males in Lepidoptera, so it is expected that the shape of structures such as wings suffers deformations in order to preserve their function. However, sources of variation other than allometry could be a reflection of different reproductive flight behavior (long flights in search for sexual mates in males, and flight in search for host plants in females). PMID:26206895

  2. Sexual Dimorphism and Allometric Effects Associated With the Wing Shape of Seven Moth Species of Sphingidae (Lepidoptera: Bombycoidea).

    PubMed

    de Camargo, Willian Rogers Ferreira; de Camargo, Nícholas Ferreira; Corrêa, Danilo do Carmo Vieira; de Camargo, Amabílio J Aires; Diniz, Ivone Rezende

    2015-01-01

    Sexual dimorphism is a pronounced pattern of intraspecific variation in Lepidoptera. However, moths of the family Sphingidae (Lepidoptera: Bombycoidea) are considered exceptions to this rule. We used geometric morphometric techniques to detect shape and size sexual dimorphism in the fore and hindwings of seven hawkmoth species. The shape variables produced were then subjected to a discriminant analysis. The allometric effects were measured with a simple regression between the canonical variables and the centroid size. We also used the normalized residuals to assess the nonallometric component of shape variation with a t-test. The deformations in wing shape between sexes per species were assessed with a regression between the nonreduced shape variables and the residuals. We found sexual dimorphism in both wings in all analyzed species, and that the allometric effects were responsible for much of the wing shape variation between the sexes. However, when we removed the size effects, we observed shape sexual dimorphism. It is very common for females to be larger than males in Lepidoptera, so it is expected that the shape of structures such as wings suffers deformations in order to preserve their function. However, sources of variation other than allometry could be a reflection of different reproductive flight behavior (long flights in search for sexual mates in males, and flight in search for host plants in females). PMID:26206895

  3. Modular genetic control of sexually dimorphic behaviors

    PubMed Central

    Xu, Xiaohong; Coats, Jennifer K.; Yang, Cindy F.; Wang, Amy; Ahmed, Osama M.; Alvarado, Maricruz; Izumi, Tetsuro; Shah, Nirao M.

    2012-01-01

    SUMMARY Sex hormones such as estrogen and testosterone are essential for sexually dimorphic behaviors in vertebrates. However, the hormone-activated molecular mechanisms that control the development and function of the underlying neural circuits remain poorly defined. We have identified numerous sexually dimorphic gene expression patterns in the adult mouse hypothalamus and amygdala. We find that adult sex hormones regulate these expression patterns in a sex-specific, regionally-restricted manner, suggesting that these genes regulate sex typical behaviors. Indeed, we find that mice with targeted disruptions of each of four of these genes (Brs3, Cckar, Irs4, Sytl4) exhibit extremely specific deficits in sex specific behaviors, with single genes controlling the pattern or extent of male sexual behavior, male aggression, maternal behavior, or female sexual behavior. Taken together, our findings demonstrate that various components of sexually dimorphic behaviors are governed by separable genetic programs. PMID:22304924

  4. [Sexual dimorphism of marbled polecat Vormela peregusna (Carnivora: Mustelidae)].

    PubMed

    Rozhnov, V V; Abramov, A V

    2006-01-01

    Analysis of morphometric variation in 26 cranial characters were studied in 85 individuals of marbled polecat Vormela peregusna from Turkmenistan demonstrated a low level of sexual dimorphism in the species. The properties of sexual dimorphism in marbled polecat are discussed in terms of available hypotheses of sexual dimorphism in carnivores.

  5. Fine-Tuning of PI3K/AKT Signalling by the Tumour Suppressor PTEN Is Required for Maintenance of Flight Muscle Function and Mitochondrial Integrity in Ageing Adult Drosophila melanogaster

    PubMed Central

    Mensah, Lawrence B.; Davison, Claire; Fan, Shih-Jung; Morris, John F.; Goberdhan, Deborah C. I.; Wilson, Clive

    2015-01-01

    Insulin/insulin-like growth factor signalling (IIS), acting primarily through the PI3-kinase (PI3K)/AKT kinase signalling cassette, plays key evolutionarily conserved regulatory roles in nutrient homeostasis, growth, ageing and longevity. The dysfunction of this pathway has been linked to several age-related human diseases including cancer, Type 2 diabetes and neurodegenerative disorders. However, it remains unclear whether minor defects in IIS can independently induce the age-dependent functional decline in cells that accompany some of these diseases or whether IIS alters the sensitivity to other aberrant signalling. We identified a novel hypomorphic allele of PI3K’s direct antagonist, Phosphatase and tensin homologue on chromosome 10 (Pten), in the fruit fly, Drosophila melanogaster. Adults carrying combinations of this allele, Pten5, combined with strong loss-of-function Pten mutations exhibit subtle or no increase in mass, but are highly susceptible to a wide range of stresses. They also exhibit dramatic upregulation of the oxidative stress response gene, GstD1, and a progressive loss of motor function that ultimately leads to defects in climbing and flight ability. The latter phenotype is associated with mitochondrial disruption in indirect flight muscles, although overall muscle structure appears to be maintained. We show that the phenotype is partially rescued by muscle-specific expression of the Bcl-2 homologue Buffy, which in flies, maintains mitochondrial integrity, modulates energy homeostasis and suppresses cell death. The flightless phenotype is also suppressed by mutations in downstream IIS signalling components, including those in the mechanistic Target of Rapamycin Complex 1 (mTORC1) pathway, suggesting that elevated IIS is responsible for functional decline in flight muscle. Our data demonstrate that IIS levels must be precisely regulated by Pten in adults to maintain the function of the highly metabolically active indirect flight muscles

  6. Interpreting hominid behavior on the basis of sexual dimorphism.

    PubMed

    Plavcan, J M; van Schaik, C P

    1997-04-01

    Numerous studies use estimates of sexual dimorphism in canine tooth size and body weight to support speculation about the behavior of australopithecines. However, the range of mating systems inferred for australopithecines encompasses virtually the entire spectrum of mating systems seen among extant anthropoid primates, from monogamy to polygyny characterized by intense male male competition. This variety of opinion can be attributed partly to the unusual combination of high body size dimorphism and reduced canine dimorphism in australopithecines. Here we provide a joint comparison of recent models for the behavioral correlates of both canine dimorphism and body size dimorphism, and apply this to published estimates of dimorphism in body size and canine tooth size in hominids. Among extant species, body weight dimorphism and canine dimorphism are strongly correlated with estimates of intrasexual competition. Canine crown height dimorphism provides the best discrimination between taxa that show high degrees of male-male competition, and those that do not. Relative male maxillary canine tooth size offers additional evidence about male-male competition. On the other hand, canine occlusal dimorphism offers little discrimination among species of different male-male competition levels. Estimates of canine dimorphism, relative canine size, and body weight dimorphism in australopithecines provide little definitive information about male-male competition or mating systems. Dimorphism of Australopithecus africanus and Australopithecus robustus can be reconciled with a mating system characterized by low-intensity male-male competition. The pattern of dimorphism and relative canine size in Australopithecus afarensis and A. robustus provides contradictory evidence about mating systems and male-male competition. We review a number of hypotheses that may explain the unusual pattern of dimorphism of A. afarensis and Australopithecus boisei, but non-satisfactorily resolves the

  7. Interpreting hominid behavior on the basis of sexual dimorphism.

    PubMed

    Plavcan, J M; van Schaik, C P

    1997-04-01

    Numerous studies use estimates of sexual dimorphism in canine tooth size and body weight to support speculation about the behavior of australopithecines. However, the range of mating systems inferred for australopithecines encompasses virtually the entire spectrum of mating systems seen among extant anthropoid primates, from monogamy to polygyny characterized by intense male male competition. This variety of opinion can be attributed partly to the unusual combination of high body size dimorphism and reduced canine dimorphism in australopithecines. Here we provide a joint comparison of recent models for the behavioral correlates of both canine dimorphism and body size dimorphism, and apply this to published estimates of dimorphism in body size and canine tooth size in hominids. Among extant species, body weight dimorphism and canine dimorphism are strongly correlated with estimates of intrasexual competition. Canine crown height dimorphism provides the best discrimination between taxa that show high degrees of male-male competition, and those that do not. Relative male maxillary canine tooth size offers additional evidence about male-male competition. On the other hand, canine occlusal dimorphism offers little discrimination among species of different male-male competition levels. Estimates of canine dimorphism, relative canine size, and body weight dimorphism in australopithecines provide little definitive information about male-male competition or mating systems. Dimorphism of Australopithecus africanus and Australopithecus robustus can be reconciled with a mating system characterized by low-intensity male-male competition. The pattern of dimorphism and relative canine size in Australopithecus afarensis and A. robustus provides contradictory evidence about mating systems and male-male competition. We review a number of hypotheses that may explain the unusual pattern of dimorphism of A. afarensis and Australopithecus boisei, but non-satisfactorily resolves the

  8. COOH-terminal truncation of flightin decreases myofilament lattice organization, cross-bridge binding, and power output in Drosophila indirect flight muscle

    SciTech Connect

    Tanner, Bertrand C.W.; Miller, Mark S.; Miller, Becky M.; Lekkas, Panagiotis; Irving, Thomas C.; Maughan, David W.; Vigoreaux, Jim O.

    2011-08-26

    The indirect flight muscle (IFM) of insects is characterized by a near crystalline myofilament lattice structure that likely evolved to achieve high power output. In Drosophila IFM, the myosin rod binding protein flightin plays a crucial role in thick filament organization and sarcomere integrity. Here we investigate the extent to which the COOH terminus of flightin contributes to IFM structure and mechanical performance using transgenic Drosophila expressing a truncated flightin lacking the 44 COOH-terminal amino acids (fln{sup {Delta}C44}). Electron microscopy and X-ray diffraction measurements show decreased myofilament lattice order in the fln{sup {Delta}C44} line compared with control, a transgenic flightin-null rescued line (fln{sup +}). fln{sup {Delta}C44} fibers produced roughly 1/3 the oscillatory work and power of fln{sup +}, with reduced frequencies of maximum work (123 Hz vs. 154 Hz) and power (139 Hz vs. 187 Hz) output, indicating slower myosin cycling kinetics. These reductions in work and power stem from a slower rate of cross-bridge recruitment and decreased cross-bridge binding in fln{sup {Delta}C44} fibers, although the mean duration of cross-bridge attachment was not different between both lines. The decreases in lattice order and myosin kinetics resulted in fln{sup {Delta}C44} flies being unable to beat their wings. These results indicate that the COOH terminus of flightin is necessary for normal myofilament lattice organization, thereby facilitating the cross-bridge binding required to achieve high power output for flight.

  9. The Contributions of the Amino and Carboxy Terminal Domains of Flightin to the Biomechanical Properties of Drosophila Flight Muscle Thick Filaments.

    PubMed

    Gasek, Nathan S; Nyland, Lori R; Vigoreaux, Jim O

    2016-01-01

    Flightin is a myosin binding protein present in Pancrustacea. In Drosophila, flightin is expressed in the indirect flight muscles (IFM), where it is required for the flexural rigidity, structural integrity, and length determination of thick filaments. Comparison of flightin sequences from multiple Drosophila species revealed a tripartite organization indicative of three functional domains subject to different evolutionary constraints. We use atomic force microscopy to investigate the functional roles of the N-terminal domain and the C-terminal domain that show different patterns of sequence conservation. Thick filaments containing a C-terminal domain truncated flightin (fln(ΔC44)) are significantly shorter (2.68 ± 0.06 μm; p < 0.005) than thick filaments containing a full length flightin (fln⁺; 3.21 ± 0.05 μm) and thick filaments containing an N-terminal domain truncated flightin (fln(ΔN62); 3.21 ± 0.06 μm). Persistence length was significantly reduced in fln(ΔN62) (418 ± 72 μm; p < 0.005) compared to fln⁺ (1386 ± 196μm) and fln(ΔC44)(1128 ± 193 μm). Statistical polymer chain analysis revealed that the C-terminal domain fulfills a secondary role in thick filament bending propensity. Our results indicate that the flightin amino and carboxy terminal domains make distinct contributions to thick filament biomechanics. We propose these distinct roles arise from the interplay between natural selection and sexual selection given IFM's dual role in flight and courtship behaviors.

  10. The Contributions of the Amino and Carboxy Terminal Domains of Flightin to the Biomechanical Properties of Drosophila Flight Muscle Thick Filaments

    PubMed Central

    Gasek, Nathan S.; Nyland, Lori R.; Vigoreaux, Jim O.

    2016-01-01

    Flightin is a myosin binding protein present in Pancrustacea. In Drosophila, flightin is expressed in the indirect flight muscles (IFM), where it is required for the flexural rigidity, structural integrity, and length determination of thick filaments. Comparison of flightin sequences from multiple Drosophila species revealed a tripartite organization indicative of three functional domains subject to different evolutionary constraints. We use atomic force microscopy to investigate the functional roles of the N-terminal domain and the C-terminal domain that show different patterns of sequence conservation. Thick filaments containing a C-terminal domain truncated flightin (flnΔC44) are significantly shorter (2.68 ± 0.06 μm; p < 0.005) than thick filaments containing a full length flightin (fln+; 3.21 ± 0.05 μm) and thick filaments containing an N-terminal domain truncated flightin (flnΔN62; 3.21 ± 0.06 μm). Persistence length was significantly reduced in flnΔN62 (418 ± 72 μm; p < 0.005) compared to fln+ (1386 ± 196μm) and flnΔC44(1128 ± 193 μm). Statistical polymer chain analysis revealed that the C-terminal domain fulfills a secondary role in thick filament bending propensity. Our results indicate that the flightin amino and carboxy terminal domains make distinct contributions to thick filament biomechanics. We propose these distinct roles arise from the interplay between natural selection and sexual selection given IFM’s dual role in flight and courtship behaviors. PMID:27128952

  11. Odontometric Sexual Dimorphism: A Sibling Correlation

    PubMed Central

    Sharma, Sonali; Dinkar, Ajit D.; Bedi, Sumit

    2014-01-01

    Aims and Background: Teeth form an excellent material for anthropological, genetic, odontologic and forensic investigations. The aim of this study was to establish the genetic control of sexual dimorphism in tooth size amongst siblings of Goan children in age range of 14-22 years. Materials and Methods: Twenty-two sibling pairs were selected (22 males and 22 females) to assess genetic control of sexual dimorphism in tooth size. Alginate impressions were obtained for maxillary and mandibular arches and study models were prepared. Measurements were done using Zoom Digimatic Vernier Calipers with a resolution of 0.01 mm. Statistical Analysis: Correlation between mesiodistal and buccolingual tooth sizes amongst siblings was calculated using Pearson’s correlation coefficient. Results: A statistically significant association was found between Mesiodistal Widths of Permanent Maxillary Right and Left Second Molars and between Maxillary Right and Left First Premolars amongst sibling pairs. A statistically significant association was also found between Buccolingual Widths of Mandibular Right and Left First Premolars amongst sibling pairs. This statistically significant correlation found amongst siblings establishes a genetic control over sexual dimorphism in these teeth. Conclusion: The genetic basis of sexual dimorphism in human dentition was ascertained as a significant correlation was found between mesio-distal and bucco-lingual widths of premolars between sibling pairs. PMID:24783145

  12. Nuclear dimorphism: two peas in a pod.

    PubMed

    Goldfarb, David S; Gorovsky, Martin A

    2009-06-01

    The macro- and micronuclei of Tetrahymena reside in the same cytoplasm but are about as different as night and day. This extreme case of nuclear dimorphism can now be partially attributed to differences in the subunit compositions of their nuclear pore complexes.

  13. Phosphorylation and the N-terminal extension of the regulatory light chain help orient and align the myosin heads in Drosophila flight muscle

    SciTech Connect

    Farman, Gerrie P.; Miller, Mark S.; Reedy, Mary C.; Soto-Adames, Felipe N.; Vigoreaux, Jim O.; Maughan, David W.; Irving, Thomas C.

    2010-02-02

    X-ray diffraction of the indirect flight muscle (IFM) in living Drosophila at rest and electron microscopy of intact and glycerinated IFM was used to compare the effects of mutations in the regulatory light chain (RLC) on sarcomeric structure. Truncation of the RLC N-terminal extension (Dmlc2{sup {Delta}2-46}) or disruption of the phosphorylation sites by substituting alanines (Dmlc2{sup S66A, S67A}) decreased the equatorial intensity ratio (I{sub 20}/I{sub 10}), indicating decreased myosin mass associated with the thin filaments. Phosphorylation site disruption (Dmlc2{sup S66A, S67A}), but not N-terminal extension truncation (Dmlc2{sup {Delta}2-46}), decreased the 14.5 nm reflection intensity, indicating a spread of the axial distribution of the myosin heads. The arrangement of thick filaments and myosin heads in electron micrographs of the phosphorylation mutant (Dmlc2{sup S66A, S67A}) appeared normal in the relaxed and rigor states, but when calcium activated, fewer myosin heads formed cross-bridges. In transgenic flies with both alterations to the RLC (Dmlc2{sup {Delta}2-46; S66A, S67A}), the effects of the dual mutation were additive. The results suggest that the RLC N-terminal extension serves as a 'tether' to help pre-position the myosin heads for attachment to actin, while phosphorylation of the RLC promotes head orientations that allow optimal interactions with the thin filament.

  14. The effect of the coupled oxidation of substrate on the permeability of blowfly flight-muscle mitochondria to potassium and other cations.

    PubMed

    Hansford, R G; Lehninger, A L

    1972-02-01

    1. Blowfly flight-muscle mitochondria respiring in the absence of phosphate acceptor (i.e. in state 4) take up greater amounts of K(+), Na(+), choline, phosphate and Cl(-) (but less NH(4) (+)) than non-respiring control mitochondria. 2. Uptake of cations is accompanied by an increase in the volume of the mitochondrial matrix, determined with the use of [(14)C]-sucrose and (3)H(2)O. The osmolarity of the salt solution taken up was approximately that of the suspending medium. 3. The [(14)C]sucrose-inaccessible space decreased with increasing osmolarity of potassium chloride in the suspending medium, confirming that the blowfly mitochondrion behaves as an osmometer. 4. Light-scattering studies showed that both respiratory substrate and a permeant anion such as phosphate or acetate are required for rapid and massive entry of K(+), which occurs in an electrophoretic process rather than in exchange for H(+). The increase in permeability to K(+) and other cations is probably the result of a large increase in the exposed area of inner membrane surface in these mitochondria, with no intrinsic increase in the permeability per unit area. 5. No increase in permeability to K(+) and other cations occurs during phosphorylation of ADP in state 3 respiration.

  15. Muscle Session Summary

    NASA Technical Reports Server (NTRS)

    Baldwin, Kenneth; Feeback, Daniel

    1999-01-01

    Presentations from the assembled group of investigators involved in specific research projeects related to skeletal muscle in space flight can categorized in thematic subtopics: regulation of contractile protein phenotypes, muscle growth and atrophy, muscle structure: injury, recovery,and regeneration, metabolism and fatigue, and motor control and loading factors.

  16. Research opportunities in muscle atrophy

    NASA Technical Reports Server (NTRS)

    Herbison, G. J. (Editor); Talbot, J. M. (Editor)

    1984-01-01

    Muscle atrophy in a weightless environment is studied. Topics of investigation include physiological factors of muscle atrophy in space flight, biochemistry, countermeasures, modelling of atrophied muscle tissue, and various methods of measurement of muscle strength and endurance. A review of the current literature and suggestions for future research are included.

  17. Protandry, sexual size dimorphism, and adaptive growth.

    PubMed

    Morbey, Yolanda E

    2013-12-21

    Adaptive growth refers to the strategic adjustment of growth rate by individuals to maximize some component of fitness. The concept of adaptive growth proliferated in the 1990s, in part due to an influential theoretical paper by Peter Abrams and colleagues. In their 1996 paper, Abrams et al. explored the effects of time stress on optimal growth rate, development time, and adult size in seasonal organisms. In this review, I explore how the concept of adaptive growth informs our understanding of protandry (the earlier arrival of males to sites of reproduction than females) and sexual size dimorphism in seasonal organisms. I conclude that growth rate variation is an important mechanism that helps to conserve optimal levels of protandry and sexual size dimorphism in changing environments.

  18. Evidence of a calcium-ion-transport system in mitochondria isolated from flight muscle of the developing sheep blowfly Lucilia cuprina.

    PubMed Central

    Bygrave, F L; Daday, A A; Doy, F A

    1975-01-01

    The EGTA (ethanedioxybis(ethylamine)tetra-acetic acid)-Ruthenium Red-quench technique (Reed & Bygrave, 1974a) was used to measure initial rates of Ca-2+ transport in mitochondria from flight muscle of the blowfly Lucilia cuprina. Evidence is provided for the existence in these mitochondria of a Ca-2+-transport system that has many features in common with that known to exist in rat liver mitochondria. These include requirement for energy, saturation at high concentrations of Ca-2+, a sigmoidal relation between initial rates of Ca-2+ transport and Ca-2+ concentration, a high affinity for free Ca-2+ (Km approx. 5 muM) and high affinity for the Ca-2+-transport inhibitoy, Ruthenium Red (approx. 0.03 nmol of carrier-specific binding-sites/mg of protein; Ki approx. 1.6 x 10- minus 8 M). Controlled respiration can be stimulated by Ca-2+ after a short lag-period provided the incubation medium contains KCl and not sucrose. The ability of Lucilia mitochondria to transport Ca-2+ critically depends on the stage of mitochondrial development; Ca-2+ transport is minimal in mitochondria from pharate adults, is maximal between 0 and 2h post-emergence and thereafter rapidly declines to reach less than 20% of the maximum value by about 2-3 days post-emergence. Respiration in mitochondria from newly emerged flies does not respond to added Ca-2+; that from 3-5-day-old flies is stimulated approx. 50%. Whereas very low concentrations of Ca-2+ inhibit ADP-stimulated respiration and oxidative phosphorylation in mitochondria from newly emerged flies (Ki approx. 60 ng-ions of Ca-2+/mg of protein); much higher concentrations (approx. 200 ng-ion/mg of protein) are needed to inhibit these processes in those from older flies. The potential of this system for studying the function and development of metabolite transport systems in mitochondria is discussed. PMID:807204

  19. Miracle Flights

    MedlinePlus

    ... the perfect solution for your needs. Book A Flight Request a flight now Click on the link ... Now Make your donation today Saving Lives One Flight At A Time Miracle Flights provides free flights ...

  20. The 2013 German-Russian Bion-M1 Joint Flight Project: Altered cAMP/PKA Signaling Pathway in Skeletal Muscle during Exposure to Real Microgravity in Mice Housed for 30 Days in a Biosatellite on Orbit

    NASA Astrophysics Data System (ADS)

    Salanova, Michele; Blottner, Dieter; Shenkman, Boris S.; Lomonosova, Yulia

    Exposure to real microgravity (muG) results in an impaired skeletal muscle structure and function. We here hypothesized that the cAMP/PKA cell signaling pathway, which triggers a multitude of intracellular effects in response to a variety of extracellular stimuli and which further promote muscle growth, play an important role during Spaceflight- induced disuse atrophy. Particularly, we hypothesized that different effectors of the cAMP-PKA signaling machinery, which are highly compartmentalized into subcellular functional microdomains in order to guarantee signal specificity, are altered after long term exposure to real µG. Taking advantage of the Bion-M1 Spaceflight program which provided us an excellent opportunity to explore mice skeletal muscle exposed for 30 days to real µG, by investigating at the cAMP-dependent protein kinase A (PKA) subcellular localization we compared muscle soleus (SOL) and extensor digitorum longus (EDL) of C57/black mice of a Bion-flight (n=5) group with a Bion-ground control (n=5) group and a ground control (n=5) group which was housed in a standard cage considered as vivarium control. Preliminary results of our experiments showed that different cAMP-PKA micro pools were normally detectable using high-resolution images of immunofluorescence experiments in different subcellular compartments of both SOL and EDL of Bion-ground and ground control groups which were not any longer detectable in Bion-flight group. In summary, our data indicate that an efficient organization in microdomains of the cAMP/PKA pathway may exist in skeletal muscle on ground and that such compartmentalization may be altered in response to prolonged exposure to real muG. National Sponsors: Federal Ministry of Economics and Technology (BMWi) via the German AeroSpace Board, DLR e.V., Bonn-Oberkassel, Germany (#50WB1121 to DB); Contract RAS-IMPB/Charité Berlin # Bion-M1/2013

  1. Developmental basis of sexually dimorphic digit ratios

    PubMed Central

    Zheng, Zhengui; Cohn, Martin J.

    2011-01-01

    Males and females generally have different finger proportions. In males, digit 2 is shorter than digit 4, but in females digit 2 is the same length or longer than digit 4. The second- to fourth-digit (2D:4D) ratio correlates with numerous sexually dimorphic behavioral and physiological conditions. Although correlational studies suggest that digit ratios reflect prenatal exposure to androgen, the developmental mechanism underlying sexually dimorphic digit development remains unknown. Here we report that the 2D:4D ratio in mice is controlled by the balance of androgen to estrogen signaling during a narrow window of digit development. Androgen receptor (AR) and estrogen receptor α (ER-α) activity is higher in digit 4 than in digit 2. Inactivation of AR decreases growth of digit 4, which causes a higher 2D:4D ratio, whereas inactivation of ER-α increases growth of digit 4, which leads to a lower 2D:4D ratio. We also show that addition of androgen has the same effect as inactivation of ER and that addition of estrogen mimics the reduction of AR. Androgen and estrogen differentially regulate the network of genes that controls chondrocyte proliferation, leading to differential growth of digit 4 in males and females. These studies identify previously undescribed molecular dimorphisms between male and female limb buds and provide experimental evidence that the digit ratio is a lifelong signature of prenatal hormonal exposure. Our results also suggest that the 2D:4D ratio can serve as an indicator of disrupted endocrine signaling during early development, which may aid in the identification of fetal origins of adult diseases. PMID:21896736

  2. Sexual Dimorphism: How Female Cells Win the Race.

    PubMed

    Deng, Hansong; Jasper, Heinrich

    2016-03-01

    Sexual dimorphisms are established by sex determination pathways and are maintained during regeneration of adult tissues. Two recent studies in Drosophila elucidate the contribution of cell-autonomous and endocrine mechanisms to the establishment and maintenance of growth dimorphism in larvae and the adult intestine.

  3. Cost-effective method for identification of dimorphic fungi.

    PubMed

    Hughes, Alice D; Lorusso, Giovanni D; Greer, Donald L

    2004-09-01

    Traditional methods to identify dimorphic fungi dictate that the mold be converted to the yeast phase at 35 to 37 degrees C. We present a time- and cost-saving method of confirming the identification of a dimorph by using special stains to demonstrate the yeast phase directly growing in the original clinical specimens. PMID:15365058

  4. Sexual Dimorphism: How Female Cells Win the Race.

    PubMed

    Deng, Hansong; Jasper, Heinrich

    2016-03-01

    Sexual dimorphisms are established by sex determination pathways and are maintained during regeneration of adult tissues. Two recent studies in Drosophila elucidate the contribution of cell-autonomous and endocrine mechanisms to the establishment and maintenance of growth dimorphism in larvae and the adult intestine. PMID:26954444

  5. Evidence for ecological causation of sexual dimorphism in a hummingbird.

    PubMed

    Temeles, E J; Pan, I L; Brennan, J L; Horwitt, J N

    2000-07-21

    Unambiguous examples of ecological causes of animal sexual dimorphism are rare. Here we present evidence for ecological causation of sexual dimorphism in the bill morphology of a hummingbird, the purple-throated carib. This hummingbird is the sole pollinator of two Heliconia species whose flowers correspond to the bills of either males or females. Each sex feeds most quickly at the flower species approximating its bill dimensions, which supports the hypothesis that floral specialization has driven the evolution of bill dimorphism. Further evidence for ecological causation of sexual dimorphism was provided by a geographic replacement of one Heliconia species by the other and the subsequent development of a floral dimorphism, with one floral morph matching the bills of males and the other of females.

  6. Sexually dimorphic myofilament function in a mouse model of nemaline myopathy.

    PubMed

    Lindqvist, Johan; Hardeman, Edna C; Ochala, Julien

    2014-12-15

    Nemaline myopathy, the most common congenital myopathy, is characterized by mutations in genes encoding myofilament proteins such as skeletal α-actin. These mutations are thought to ultimately lead to skeletal muscle weakness. Interestingly, some of the mutations appear to be more potent in males than in females. The underlying mechanisms remain obscure but may be related to sex-specific differences in the myofilament function of both limb and respiratory muscles. To verify this, in the present study, we used skeletal muscles (tibialis anterior and diaphragm) from a transgenic mouse model harbouring the His40Tyr amino acid substitution in skeletal α-actin. In this animal model, 60% of males die by 13weeks of age (the underlying causes of death are obscure but probably due to respiratory insufficiency) whereas females have a normal lifespan. By recording and analysing the mechanics of membrane-permeabilized myofibres, we only observed sex-related differences in the tibialis anterior muscles. Indeed, the concomitant deficits in maximal steady-state isometric force and stiffness of myofibres were less exacerbated in transgenic females than in males, potentially explaining the lower potency in limb muscles. However, the absence of sex-difference in the diaphragm muscles was rather unexpected and suggests that myofilament dysfunction does not solely underlie the sexually dimorphic phenotypes. PMID:25261348

  7. On the origins of sexual dimorphism in butterflies.

    PubMed

    Oliver, Jeffrey C; Monteiro, Antónia

    2011-07-01

    The processes governing the evolution of sexual dimorphism provided a foundation for sexual selection theory. Two alternative processes, originally proposed by Darwin and Wallace, differ primarily in the timing of events creating the dimorphism. In the process advocated by Darwin, a novel ornament arises in a single sex, with no temporal separation in the origin and sex-limitation of the novel trait. By contrast, Wallace proposed a process where novel ornaments appear simultaneously in both sexes, but are then converted into sex-limited expression by natural selection acting against showy coloration in one sex. Here, we investigate these alternative modes of sexual dimorphism evolution in a phylogenetic framework and demonstrate that both processes contribute to dimorphic wing patterns in the butterfly genera Bicyclus and Junonia. In some lineages, eyespots and bands arise in a single sex, whereas in other lineages they appear in both sexes but are then lost in one of the sexes. In addition, lineages displaying sexual dimorphism were more likely to become sexually monomorphic than they were to remain dimorphic. This derived monomorphism was either owing to a loss of the ornament ('drab monomorphism') or owing to a gain of the same ornament by the opposite sex ('mutual ornamentation'). Our results demonstrate the necessity of a plurality in theories explaining the evolution of sexual dimorphism within and across taxa. The origins and evolutionary fate of sexual dimorphism are probably influenced by underlying genetic architecture responsible for sex-limited expression and the degree of intralocus sexual conflict. Future comparative and developmental work on sexual dimorphism within and among taxa will provide a better understanding of the biases and constraints governing the evolution of animal sexual dimorphism. PMID:21123259

  8. On the origins of sexual dimorphism in butterflies.

    PubMed

    Oliver, Jeffrey C; Monteiro, Antónia

    2011-07-01

    The processes governing the evolution of sexual dimorphism provided a foundation for sexual selection theory. Two alternative processes, originally proposed by Darwin and Wallace, differ primarily in the timing of events creating the dimorphism. In the process advocated by Darwin, a novel ornament arises in a single sex, with no temporal separation in the origin and sex-limitation of the novel trait. By contrast, Wallace proposed a process where novel ornaments appear simultaneously in both sexes, but are then converted into sex-limited expression by natural selection acting against showy coloration in one sex. Here, we investigate these alternative modes of sexual dimorphism evolution in a phylogenetic framework and demonstrate that both processes contribute to dimorphic wing patterns in the butterfly genera Bicyclus and Junonia. In some lineages, eyespots and bands arise in a single sex, whereas in other lineages they appear in both sexes but are then lost in one of the sexes. In addition, lineages displaying sexual dimorphism were more likely to become sexually monomorphic than they were to remain dimorphic. This derived monomorphism was either owing to a loss of the ornament ('drab monomorphism') or owing to a gain of the same ornament by the opposite sex ('mutual ornamentation'). Our results demonstrate the necessity of a plurality in theories explaining the evolution of sexual dimorphism within and across taxa. The origins and evolutionary fate of sexual dimorphism are probably influenced by underlying genetic architecture responsible for sex-limited expression and the degree of intralocus sexual conflict. Future comparative and developmental work on sexual dimorphism within and among taxa will provide a better understanding of the biases and constraints governing the evolution of animal sexual dimorphism.

  9. The dilemma of choosing a reference character for measuring sexual size dimorphism, sexual body component dimorphism, and character scaling: cryptic dimorphism and allometry in the scorpion Hadrurus arizonensis.

    PubMed

    Fox, Gerad A; Cooper, Allen M; Hayes, William K

    2015-01-01

    Sexual differences in morphology, ranging from subtle to extravagant, occur commonly in many animal species. These differences can encompass overall body size (sexual size dimorphism, SSD) or the size and/or shape of specific body parts (sexual body component dimorphism, SBCD). Interacting forces of natural and sexual selection shape much of the expression of dimorphism we see, though non-adaptive processes may be involved. Differential scaling of individual features can result when selection favors either exaggerated (positive allometry) or reduced (negative allometry) size during growth. Studies of sexual dimorphism and character scaling rely on multivariate models that ideally use an unbiased reference character as an overall measure of body size. We explored several candidate reference characters in a cryptically dimorphic taxon, Hadrurus arizonensis. In this scorpion, essentially every body component among the 16 we examined could be interpreted as dimorphic, but identification of SSD and SBCD depended on which character was used as the reference (prosoma length, prosoma area, total length, principal component 1, or metasoma segment 1 width). Of these characters, discriminant function analysis suggested that metasoma segment 1 width was the most appropriate. The pattern of dimorphism in H. arizonensis mirrored that seen in other more obviously dimorphic scorpions, with static allometry trending towards isometry in most characters. Our findings are consistent with the conclusions of others that fecundity selection likely favors a larger prosoma in female scorpions, whereas sexual selection may favor other body parts being larger in males, especially the metasoma, pectines, and possibly the chela. For this scorpion and probably most other organisms, the choice of reference character profoundly affects interpretations of SSD, SBCD, and allometry. Thus, researchers need to broaden their consideration of an appropriate reference and exercise caution in interpreting

  10. The Dilemma of Choosing a Reference Character for Measuring Sexual Size Dimorphism, Sexual Body Component Dimorphism, and Character Scaling: Cryptic Dimorphism and Allometry in the Scorpion Hadrurus arizonensis

    PubMed Central

    Fox, Gerad A.; Cooper, Allen M.; Hayes, William K.

    2015-01-01

    Sexual differences in morphology, ranging from subtle to extravagant, occur commonly in many animal species. These differences can encompass overall body size (sexual size dimorphism, SSD) or the size and/or shape of specific body parts (sexual body component dimorphism, SBCD). Interacting forces of natural and sexual selection shape much of the expression of dimorphism we see, though non-adaptive processes may be involved. Differential scaling of individual features can result when selection favors either exaggerated (positive allometry) or reduced (negative allometry) size during growth. Studies of sexual dimorphism and character scaling rely on multivariate models that ideally use an unbiased reference character as an overall measure of body size. We explored several candidate reference characters in a cryptically dimorphic taxon, Hadrurus arizonensis. In this scorpion, essentially every body component among the 16 we examined could be interpreted as dimorphic, but identification of SSD and SBCD depended on which character was used as the reference (prosoma length, prosoma area, total length, principal component 1, or metasoma segment 1 width). Of these characters, discriminant function analysis suggested that metasoma segment 1 width was the most appropriate. The pattern of dimorphism in H. arizonensis mirrored that seen in other more obviously dimorphic scorpions, with static allometry trending towards isometry in most characters. Our findings are consistent with the conclusions of others that fecundity selection likely favors a larger prosoma in female scorpions, whereas sexual selection may favor other body parts being larger in males, especially the metasoma, pectines, and possibly the chela. For this scorpion and probably most other organisms, the choice of reference character profoundly affects interpretations of SSD, SBCD, and allometry. Thus, researchers need to broaden their consideration of an appropriate reference and exercise caution in interpreting

  11. Sexual dimorphism in teeth? Clinical relevance.

    PubMed

    Radlanski, Ralf J; Renz, Herbert; Hopfenmüller, Werner

    2012-04-01

    Many morphometric studies show a sexual dimorphism in human teeth. We wanted to know whether it is possible to determine the sex of an individual if only the anterior teeth are visible. Fifty intraoral photographs showing the front tooth region of female and male individuals (age: from 7 to 75 years) were randomly arranged in actual size on a questionnaire. The lip region was covered in each case. Besides "female" and "male", one was also able to check "?" if undecided. The questionnaires were distributed to 50 expert test persons (dentists, dental technicians, dental assistants, and students of dental medicine) and to 50 laymen and were all returned for evaluation. Although the correct sex was recognized on single photographs to a maximum of 76%, it was incorrect in 69% on other photographs. Altogether, the statistical evaluation showed that in most cases, the sex was only recognized correctly by one half, and incorrect by the other half. It can be concluded that a sexual dimorphism of human teeth-although measurable morphometrically-could not be recognized visually on the basis of photographs of the front tooth region. Neither experts in the field of dentistry nor laymen were able to properly distinguish between male and female teeth.

  12. Stomatal Dimorphism of Neodiplogaster acaloleptae (Diplogastromorpha: Diplogastridae)

    PubMed Central

    Kanzaki, Natsumi

    2016-01-01

    Several genera belonging to the nematode family Diplogastridae show characteristic dimorphism in their feeding structures; specifically, they have microbial feeding stenostomatous and predatory eurystomatous morphs. A diplogastrid satellite model species, Pristionchus pacificus, and its close relatives have become a model system for studying this phenotypic plasticity, with intensive physiological and structural studies having been undertaken. However, the many other species that are morphologically and phylogenetically divergent from P. pacificus have not been examined to date. In the present study, the detailed stomatal structure and induction of dimorphism in Neodiplogaster acaloleptae were examined. N. acaloleptae has a fungal feeding stenostomatous morph and a predatory eurystomatous morph. The predatory morph was induced by starvation, high population density, and co-culturing with its potential prey, Caenorhabditis elegans. The feeding behavior of the stenostomatous and eurystomatous morphs of N. acaloleptae was confirmed, demonstrating that 1) the stomatal and pharyngeal movements of the two morphs were basically identical, and 2) the stomatal elements were protracted to cut open the hyphae and/or prey to feed when a N. acaloleptae flips its dorsal movable tooth dorsally and tilts its subventral stegostomatal cylinder ventrally, forming a pair of scissors to cut the food source. The stoma morphology of N. acaloleptae with a single movable tooth and a long stoma is markedly different from that of Pristionchus, which has two movable teeth and a short stoma. It is, however, similar to that of Mononchoides, tentatively a sister to Neodiplogaster. PMID:27196730

  13. Effects of sexual dimorphism on facial attractiveness.

    PubMed

    Perrett, D I; Lee, K J; Penton-Voak, I; Rowland, D; Yoshikawa, S; Burt, D M; Henzi, S P; Castles, D L; Akamatsu, S

    1998-08-27

    Testosterone-dependent secondary sexual characteristics in males may signal immunological competence and are sexually selected for in several species. In humans, oestrogen-dependent characteristics of the female body correlate with health and reproductive fitness and are found attractive. Enhancing the sexual dimorphism of human faces should raise attractiveness by enhancing sex-hormone-related cues to youth and fertility in females, and to dominance and immunocompetence in males. Here we report the results of asking subjects to choose the most attractive faces from continua that enhanced or diminished differences between the average shape of female and male faces. As predicted, subjects preferred feminized to average shapes of a female face. This preference applied across UK and Japanese populations but was stronger for within-population judgements, which indicates that attractiveness cues are learned. Subjects preferred feminized to average or masculinized shapes of a male face. Enhancing masculine facial characteristics increased both perceived dominance and negative attributions (for example, coldness or dishonesty) relevant to relationships and paternal investment. These results indicate a selection pressure that limits sexual dimorphism and encourages neoteny in humans. PMID:9732869

  14. Magnesium and Space Flight

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Zwart, Sara R.

    2016-01-01

    Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in astronauts before, during, and after space missions, in 43 astronauts (34 male, 9 female) on 4-6 month space flight missions. We also studied individuals participating in a ground analog of space flight, (head-down tilt bed rest, n=27, 35 +/- 7 y). We evaluated serum concentration and 24-hour urinary excretion of magnesium along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-d space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4- to 6-month space missions.

  15. Biomechanics of bird flight.

    PubMed

    Tobalske, Bret W

    2007-09-01

    Power output is a unifying theme for bird flight and considerable progress has been accomplished recently in measuring muscular, metabolic and aerodynamic power in birds. The primary flight muscles of birds, the pectoralis and supracoracoideus, are designed for work and power output, with large stress (force per unit cross-sectional area) and strain (relative length change) per contraction. U-shaped curves describe how mechanical power output varies with flight speed, but the specific shapes and characteristic speeds of these curves differ according to morphology and flight style. New measures of induced, profile and parasite power should help to update existing mathematical models of flight. In turn, these improved models may serve to test behavioral and ecological processes. Unlike terrestrial locomotion that is generally characterized by discrete gaits, changes in wing kinematics and aerodynamics across flight speeds are gradual. Take-off flight performance scales with body size, but fully revealing the mechanisms responsible for this pattern awaits new study. Intermittent flight appears to reduce the power cost for flight, as some species flap-glide at slow speeds and flap-bound at fast speeds. It is vital to test the metabolic costs of intermittent flight to understand why some birds use intermittent bounds during slow flight. Maneuvering and stability are critical for flying birds, and design for maneuvering may impinge upon other aspects of flight performance. The tail contributes to lift and drag; it is also integral to maneuvering and stability. Recent studies have revealed that maneuvers are typically initiated during downstroke and involve bilateral asymmetry of force production in the pectoralis. Future study of maneuvering and stability should measure inertial and aerodynamic forces. It is critical for continued progress into the biomechanics of bird flight that experimental designs are developed in an ecological and evolutionary context.

  16. Sexual dimorphism in the human pelvis: testing a new hypothesis.

    PubMed

    Correia, H; Balseiro, S; De Areia, M

    2005-01-01

    Sexual dimorphism in the human pelvis is inferentially related to parturition. Investigators disagree about the identification and obstetric significance of pelvic dimorphism. Benefiting from a large sample of complete skeletons from the Coimbra Identified Skeletal Collection, we show that the dimensions of the true pelvis (birth canal) that are most sexually dimorphic (that is, the dimensions of females are greater than males) are those which are related to biparietal deformation, which often leads to the death of the human neonate. These dimensions are: the anteroposterior diameter of the inlet (index of dimorphism = 108.41), the transverse diameter of the bispinous midplane (index of dimorphism = 117.13) and the transverse diameter of the outlet (index of dimorphism = 112.3). Therefore, sexual dimorphism in the human pelvis is a reflection of differential selection on the two sexes. These results may stimulate further studies with a fresh approach regarding the fossil and comparative evidence for when and how the modern pattern of birth has evolved.

  17. Sexual dimorphism in permanent teeth of modern Greeks.

    PubMed

    Zorba, Eleni; Moraitis, Konstantinos; Manolis, Sotiris K

    2011-07-15

    Sex determination is considered an important step in reconstructing the biological profile of unknown individuals from a forensic context. Forensic anthropologists have long used teeth as an additional tool for sex determination as they resist postmortem destruction. In this case the use of population-specific data is necessary since sexual dimorphism varies between different populations. Currently there are no odontometric standards for determining sex in Greek populations. The purpose of this study is to examine the degree of sexual dimorphism in permanent teeth of modern Greeks. A total of 839 permanent teeth in 133 individuals (70 males and 63 females) from the Athens Collection were examined. Mesiodistal and buccolingual crown and cervical diameters of both maxillary and mandibular teeth were measured. It was found that males have bigger teeth than females and in 65 out of 88 dimensions measured, male teeth exceeded female teeth significantly (P<0.05). Canines were the most dimorphic teeth followed by first premolars, maxillary second premolar and mandibular second molar. Although other teeth were also sexually dimorphic they did not have a statistically significant difference in all dimensions. The most dimorphic dimension was buccolingual cervical diameter followed by buccolingual crown diameter. A comparison of sexual dimorphism in teeth between different populations showed that it differs among different groups. European population groups presented the highest degree of sexual dimorphism in teeth whereas Native South Americans the lowest.

  18. Mimetic butterflies support Wallace's model of sexual dimorphism.

    PubMed

    Kunte, Krushnamegh

    2008-07-22

    Theoretical and empirical observations generally support Darwin's view that sexual dimorphism evolves due to sexual selection on, and deviation in, exaggerated male traits. Wallace presented a radical alternative, which is largely untested, that sexual dimorphism results from naturally selected deviation in protective female coloration. This leads to the prediction that deviation in female rather than male phenotype causes sexual dimorphism. Here I test Wallace's model of sexual dimorphism by tracing the evolutionary history of Batesian mimicry-an example of naturally selected protective coloration-on a molecular phylogeny of Papilio butterflies. I show that sexual dimorphism in Papilio is significantly correlated with both female-limited Batesian mimicry, where females are mimetic and males are non-mimetic, and with the deviation of female wing colour patterns from the ancestral patterns conserved in males. Thus, Wallace's model largely explains sexual dimorphism in Papilio. This finding, along with indirect support from recent studies on birds and lizards, suggests that Wallace's model may be more widely useful in explaining sexual dimorphism. These results also highlight the contribution of naturally selected female traits in driving phenotypic divergence between species, instead of merely facilitating the divergence in male sexual traits as described by Darwin's model. PMID:18426753

  19. Mimetic butterflies support Wallace's model of sexual dimorphism.

    PubMed

    Kunte, Krushnamegh

    2008-07-22

    Theoretical and empirical observations generally support Darwin's view that sexual dimorphism evolves due to sexual selection on, and deviation in, exaggerated male traits. Wallace presented a radical alternative, which is largely untested, that sexual dimorphism results from naturally selected deviation in protective female coloration. This leads to the prediction that deviation in female rather than male phenotype causes sexual dimorphism. Here I test Wallace's model of sexual dimorphism by tracing the evolutionary history of Batesian mimicry-an example of naturally selected protective coloration-on a molecular phylogeny of Papilio butterflies. I show that sexual dimorphism in Papilio is significantly correlated with both female-limited Batesian mimicry, where females are mimetic and males are non-mimetic, and with the deviation of female wing colour patterns from the ancestral patterns conserved in males. Thus, Wallace's model largely explains sexual dimorphism in Papilio. This finding, along with indirect support from recent studies on birds and lizards, suggests that Wallace's model may be more widely useful in explaining sexual dimorphism. These results also highlight the contribution of naturally selected female traits in driving phenotypic divergence between species, instead of merely facilitating the divergence in male sexual traits as described by Darwin's model.

  20. A conserved dimorphism-regulating histidine kinase controls the dimorphic switching in Paracoccidioides brasiliensis.

    PubMed

    Chaves, Alison F A; Navarro, Marina V; Castilho, Daniele G; Calado, Juliana C P; Conceição, Palloma M; Batista, Wagner L

    2016-08-01

    Paracoccidioides brasiliensis and P. lutzii, thermally dimorphic fungi, are the causative agents of paracoccidioidomycosis (PCM). Paracoccidioides infection occurs when conidia or mycelium fragments are inhaled by the host, which causes the Paracoccidioides cells to transition to the yeast form. The development of disease requires conidia inside the host alveoli to differentiate into yeast cells in a temperature-dependent manner. We describe the presence of a two-component signal transduction system in P. brasiliensis, which we investigated by expression analysis of a hypothetical protein gene (PADG_07579) that showed high similarity with the dimorphism-regulating histidine kinase (DRK1) gene of Blastomyces dermatitidis and Histoplasma capsulatum This gene was sensitive to environmental redox changes, which was demonstrated by a dose-dependent decrease in transcript levels after peroxide stimulation and a subtler decrease in transcript levels after NO stimulation. Furthermore, the higher PbDRK1 levels after treatment with increasing NaCl concentrations suggest that this histidine kinase can play a role as osmosensing. In the mycelium-yeast (M→Y) transition, PbDRK1 mRNA expression increased 14-fold after 24 h incubation at 37°C, consistent with similar observations in other virulent fungi. These results demonstrate that the PbDRK1 gene is differentially expressed during the dimorphic M→Y transition. Finally, when P. brasiliensis mycelium cells were exposed to a histidine kinase inhibitor and incubated at 37°C, there was a delay in the dimorphic M→Y transition, suggesting that histidine kinases could be targets of interest for PCM therapy. PMID:27268997

  1. Isavuconazole Treatment of Cryptococcosis and Dimorphic Mycoses

    PubMed Central

    Thompson, George R.; Rendon, Adrian; Ribeiro dos Santos, Rodrigo; Queiroz-Telles, Flavio; Ostrosky-Zeichner, Luis; Azie, Nkechi; Maher, Rochelle; Lee, Misun; Kovanda, Laura; Engelhardt, Marc; Vazquez, Jose A.; Cornely, Oliver A.; Perfect, John R.

    2016-01-01

    Background. Invasive fungal diseases (IFD) caused by Cryptococcus and dimorphic fungi are associated with significant morbidity and mortality. Isavuconazole (ISAV) is a novel, broad-spectrum, triazole antifungal agent (IV and by mouth [PO]) developed for the treatment of IFD. It displays potent activity in vitro against these pathogens and in this report we examine outcomes of patients with cryptococcosis or dimorphic fungal infections treated with ISAV. Methods. The VITAL study was an open-label nonrandomized phase 3 trial conducted to evaluate the efficacy and safety of ISAV treatment in management of rare IFD. Patients received ISAV 200 mg 3 times daily for 2 days followed by 200 mg once-daily (IV or PO). Proven IFD and overall response at end of treatment (EOT) were determined by an independent, data-review committee. Mortality and safety were also assessed. Results. Thirty-eight patients received ISAV for IFD caused by Cryptococcus spp. (n = 9), Paracoccidioides spp. (n = 10), Coccidioides spp. (n = 9), Histoplasma spp. (n = 7) and Blastomyces spp. (n = 3). The median length of therapy was 180 days (range 2–331 days). At EOT 24/38 (63%) patients exhibited a successful overall response. Furthermore, 8 of 38 (21%) had stable IFD at the end of therapy without progression of disease, and 6 (16%) patients had progressive IFD despite this antifungal therapy. Thirty-three (87%) patients experienced adverse events. Conclusions. ISAV was well tolerated and demonstrated clinical activity against these endemic fungi with a safety profile similar to that observed in larger studies, validating its broad-spectrum in vitro activity and suggesting it may be a valuable alternative to currently available agents. Clinical Trials Registration. NCT00634049. PMID:27169478

  2. Adaptations for rapid and forceful contraction in wing muscles of the male golden-collared manakin: sex and species comparisons.

    PubMed

    Schultz, J D; Hertel, F; Bauch, M; Schlinger, B A

    2001-11-01

    The courtship display of the male golden-collared manakin (Manacus vitellinus) of Panamanian rainforests is noteworthy for several types of whip-crack-like sounds created by a rapid overhead flip of the wings. We have hypothesized that this courtship behavior. which is not performed by females, is associated with steroid-sensitive and sexually dimorphic neuromuscular systems. Presumably, muscles creating the motion of the wingsnap in males are specialized for greater force generation and speed of contraction. We tested this hypothesis by examining mass, fiber diameter, metabolic enzyme activity, and myosin isoform expression in several muscles of male and female manakins and in both sexes of a non-wingsnapping bird, the zebra finch (Taenopygia guttata). We have identified three wing muscles, the scapulohumeralis caudalis, the supracoracoideus, and the pectoralis major, that differ in one or more of these characteristics across sex and species, suggesting they are specialized for faster contraction and greater force production in male manakins. These muscles normally function to raise and lower the wings during flight. As this movement is the principal motion of the wingsnap, these adaptations presumably underlie the performance of the wingsnap display. PMID:11778830

  3. Sexually dimorphic actions of glucocorticoids: beyond chromosomes and sex hormones.

    PubMed

    Quinn, Matthew; Ramamoorthy, Sivapriya; Cidlowski, John A

    2014-05-01

    Sexual dimorphism is a well-documented phenomenon that is observed at all levels of the animal kingdom. Historically, sex hormones (testosterone and estrogen) have been implicated as key players in a wide array of pathologies displaying sexual dimorphism in their etiology and progression. While these hormones clearly contribute to sexually dimorphic diseases, other factors may be involved in this phenomenon as well. In particular, the stress hormone cortisol exerts differential effects in both males and females. The underlying molecular basis for the sexually dimorphic actions of glucocorticoids is unknown but clearly important to understand, since synthetic glucocorticoids are the most widely prescribed medication for the treatment of chronic inflammatory diseases and hematological cancers in humans. PMID:24739020

  4. Magnesium and Space Flight

    PubMed Central

    Smith, Scott M.; Zwart, Sara R.

    2015-01-01

    Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in 43 astronauts (34 male, 9 female; 47 ± 5 years old, mean ± SD) before, during, and after 4–6-month space missions. We also studied individuals participating in a ground analog of space flight (head-down-tilt bed rest; n = 27 (17 male, 10 female), 35 ± 7 years old). We evaluated serum concentration and 24-h urinary excretion of magnesium, along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-day space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4–6-month space missions. PMID:26670248

  5. Magnesium and Space Flight.

    PubMed

    Smith, Scott M; Zwart, Sara R

    2015-12-08

    Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in 43 astronauts (34 male, 9 female; 47 ± 5 years old, mean ± SD) before, during, and after 4-6-month space missions. We also studied individuals participating in a ground analog of space flight (head-down-tilt bed rest; n = 27 (17 male, 10 female), 35 ± 7 years old). We evaluated serum concentration and 24-h urinary excretion of magnesium, along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-day space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4-6-month space missions.

  6. Magnesium and Space Flight.

    PubMed

    Smith, Scott M; Zwart, Sara R

    2015-12-01

    Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in 43 astronauts (34 male, 9 female; 47 ± 5 years old, mean ± SD) before, during, and after 4-6-month space missions. We also studied individuals participating in a ground analog of space flight (head-down-tilt bed rest; n = 27 (17 male, 10 female), 35 ± 7 years old). We evaluated serum concentration and 24-h urinary excretion of magnesium, along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-day space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4-6-month space missions. PMID:26670248

  7. Sex Dimorphism in Late Gestational Sleep Fragmentation and Metabolic Dysfunction in Offspring Mice

    PubMed Central

    Khalyfa, Abdelnaby; Carreras, Alba; Almendros, Isaac; Hakim, Fahed; Gozal, David

    2015-01-01

    Background: Excessive sleep fragmentation (SF) is common in pregnant women. Adult-onset metabolic disorders may begin during early development and exhibit substantial sex dimorphism. We hypothesized that metabolic dysfunction induced by gestational SF in male mice would not be apparent in female littermates. Methods: Body weight and food consumption were measured weekly in male and female offspring after late gestational SF or control sleep (SC). At 20 weeks, plasma leptin, adiponectin, lipid profiles, and insulin and glucose tolerance tests were assessed. Leptin and adiponectin, M1, and M2 macrophage messenger RNA expression and polarity were examined. Adiponectin gene promoter methylation levels in several tissues were assessed. Results: Food intake, body weight, visceral fat mass, and insulin resistance were higher, and adiponectin levels lower in male but not female offspring exposed to gestational SF. However, dyslipidemia was apparent in both male and female offspring exposed to SF, albeit of lesser magnitude. In visceral fat, leptin messenger RNA expression was selectively increased and adiponectin expression was decreased in male offspring exposed to gestational SF, but adiponectin was increased in exposed female offspring. Differences in adipokine expression also emerged in liver, subcutaneous fat, and muscle. Increased M1 macrophage markers were present in male offspring exposed to SF (SFOM) while increased M2 markers emerged in SF in female offspring (SFOF). Similarly, significant differences emerged in the methylation patterns of adiponectin promoter in SFOM and SFOF. Conclusion: Gestational sleep fragmentation increases the susceptibility to obesity and metabolic syndrome in male but not in female offspring, most likely via epigenetic changes. Thus, sleep perturbations impose long-term detrimental effects to the fetus manifesting as sex dimorphic metabolic dysfunction in adulthood. Citation: Khalyfa A, Carreras A, Almendros I, Hakim F, Gozal D. Sex

  8. The postnatal ontogeny of the sexually dimorphic vocal apparatus in goitred gazelles (Gazella subgutturosa).

    PubMed

    Efremova, Kseniya O; Frey, Roland; Volodin, Ilya A; Fritsch, Guido; Soldatova, Natalia V; Volodina, Elena V

    2016-06-01

    This study quantitatively documents the progressive development of sexual dimorphism of the vocal organs along the ontogeny of the goitred gazelle (Gazella subgutturosa). The major, male-specific secondary sexual features, of vocal anatomy in goitred gazelle are an enlarged larynx and a marked laryngeal descent. These features appear to have evolved by sexual selection and may serve as a model for similar events in male humans. Sexual dimorphism of larynx size and larynx position in adult goitred gazelles is more pronounced than in humans, whereas the vocal anatomy of neonate goitred gazelles does not differ between sexes. This study examines the vocal anatomy of 19 (11 male, 8 female) goitred gazelle specimens across three age-classes, that is, neonates, subadults and mature adults. The postnatal ontogenetic development of the vocal organs up to their respective end states takes considerably longer in males than in females. Both sexes share the same features of vocal morphology but differences emerge in the course of ontogeny, ultimately resulting in the pronounced sexual dimorphism of the vocal apparatus in adults. The main differences comprise larynx size, vocal fold length, vocal tract length, and mobility of the larynx. The resilience of the thyrohyoid ligament and the pharynx, including the soft palate, and the length changes during contraction and relaxation of the extrinsic laryngeal muscles play a decisive role in the mobility of the larynx in both sexes but to substantially different degrees in adult females and males. Goitred gazelles are born with an undescended larynx and, therefore, larynx descent has to develop in the course of ontogeny. This might result from a trade-off between natural selection and sexual selection requiring a temporal separation of different laryngeal functions at birth and shortly after from those later in life. J. Morphol. 277:826-844, 2016. © 2016 Wiley Periodicals, Inc. PMID:26997608

  9. Sexual Dimorphism and Bilateral Asymmetry of Syrinx and Vocal Tract in the European Starling (Sturnus vulgaris)

    PubMed Central

    Prince, Ben; Riede, Tobias; Goller, Franz

    2014-01-01

    Sexually dimorphic vocal behavior in zebra finches (Taeniopygia guttata) is associated with a 100% larger syrinx in males and other morphological adaptations of the sound source. The songbird syrinx consists of two independent sound sources, whose specialization for different spectral ranges may be reflected in morphological properties, but the morphology of labia and syringeal skeleton have not been investigated for lateralized specializations. Similarly, little is known whether the morphology of the songbird vocal tract reflects differences in vocal behavior. Here, we tested the hypothesis that different vocal behavior and specialization is reflected in the morphology. We investigated syringeal and upper vocal tract morphology of male and female European starlings (Sturnus υulgaris). Female starlings exhibit smaller vocal repertoires and sing at lower rates than males. In males, the left syrinx produces mostly low frequencies, while the right one is used for higher notes. Macroscopic and histological techniques were used to record nineteen measurements from the syrinx and the vocal tract which were tested for sexual differences in syrinx and vocal tract and for lateral asymmetry within the syrinx. Sexually dimorphic vocal behavior is reflected in the morphology of the starling syrinx. Males have a larger syrinx with the size difference attributable to increased muscle mass and three enlarged elements of the syringeal skeleton. The upper vocal tract, however, does not differ between males and females. Distinct lateralization was found in two elements of the syringeal skeleton of females, and the labia in the left syrinx are larger than those on the right in both sexes. The sexual dimorphism of the syringeal size is smaller in starlings (35%) than in zebra finches (100%), which is consistent with the different vocal behavior of females in both species. The morphological differences between the two sound sources are discussed in relation to their vocal performance

  10. Sexual dimorphism and bilateral asymmetry of syrinx and vocal tract in the European starling (Sturnus vulgaris).

    PubMed

    Prince, Ben; Riede, Tobias; Goller, Franz

    2011-12-01

    Sexually dimorphic vocal behavior in zebra finches (Taeniopygia guttata) is associated with a 100% larger syrinx in males and other morphological adaptations of the sound source. The songbird syrinx consists of two independent sound sources, whose specialization for different spectral ranges may be reflected in morphological properties, but the morphology of labia and syringeal skeleton have not been investigated for lateralized specializations. Similarly, little is known whether the morphology of the songbird vocal tract reflects differences in vocal behavior. Here, we tested the hypothesis that different vocal behavior and specialization is reflected in the morphology. We investigated syringeal and upper vocal tract morphology of male and female European starlings (Sturnus vulgaris). Female starlings exhibit smaller vocal repertoires and sing at lower rates than males. In males, the left syrinx produces mostly low frequencies, while the right one is used for higher notes. Macroscopic and histological techniques were used to record nineteen measurements from the syrinx and the vocal tract which were tested for sexual differences in syrinx and vocal tract and for lateral asymmetry within the syrinx. Sexually dimorphic vocal behavior is reflected in the morphology of the starling syrinx. Males have a larger syrinx with the size difference attributable to increased muscle mass and three enlarged elements of the syringeal skeleton. The upper vocal tract, however, does not differ between males and females. Distinct lateralization was found in two elements of the syringeal skeleton of females, and the labia in the left syrinx are larger than those on the right in both sexes. The sexual dimorphism of the syringeal size is smaller in starlings (35%) than in zebra finches (100%), which is consistent with the different vocal behavior of females in both species. The morphological differences between the two sound sources are discussed in relation to their vocal performance

  11. Surface facial modelling and allometry in relation to sexual dimorphism.

    PubMed

    Velemínská, J; Bigoni, L; Krajíček, V; Borský, J; Šmahelová, D; Cagáňová, V; Peterka, M

    2012-04-01

    Sexual dimorphism is responsible for a substantial part of human facial variability, the study of which is essential for many scientific fields ranging from evolution to special biomedical topics. Our aim was to analyse the relationship between size variability and shape facial variability of sexual traits in the young adult Central European population and to construct average surface models of adult males and females. The method of geometric morphometrics allowed not only the identification of dimorphic traits, but also the evaluation of static allometry and the visualisation of sexual facial differences. Facial variability in the studied sample was characterised by a strong relationship between facial size and shape of sexual dimorphic traits. Large size of face was associated with facial elongation and vice versa. Regarding shape sexual dimorphic traits, a wide, vaulted and high forehead in combination with a narrow and gracile lower face were typical for females. Variability in shape dimorphic traits was smaller in females compared to males. For female classification, shape sexual dimorphic traits are more important, while for males the stronger association is with face size. Males generally had a closer inter-orbital distance and a deeper position of the eyes in relation to the facial plane, a larger and wider straight nose and nostrils, and more massive lower face. Using pseudo-colour maps to provide a detailed schematic representation of the geometrical differences between the sexes, we attempted to clarify the reasons underlying the development of such differences. PMID:22425585

  12. Evolution of sexual dimorphism in phenotypic covariance structure in Phymata.

    PubMed

    Punzalan, David; Rowe, Locke

    2015-06-01

    Sexual dimorphism is a consequence of both sex-specific selection and potential constraints imposed by a shared genetic architecture underlying sexually homologous traits. However, genetic architecture is expected to evolve to mitigate these constraints, allowing the sexes to approach their respective optimal mean phenotype. In addition, sex-specific selection is expected to generate sexual dimorphism of trait covariance structure (e.g., the phenotypic covariance matrix, P), but previous empirical work has not fully addressed this prediction. We compared patterns of phenotypic divergence, for three traits in seven taxa in the insect genus Phymata (Reduviidae), to ask whether sexual dimorphism in P is common and whether its magnitude relates to the extent of sexual dimorphism in trait means. We found that sexual dimorphism in both mean and covariance structure was pervasive but also that the multivariate distance between sex-specific means was correlated with sex differences in the leading eigenvector of P, while accounting for uncertainty in phylogenetic relationships. Collectively, our findings suggest that sexual dimorphism in covariance structure may be a common but underappreciated feature of dioecious populations.

  13. Your Muscles

    MedlinePlus

    ... Homework? Here's Help White House Lunch Recipes Your Muscles KidsHealth > For Kids > Your Muscles Print A A ... and skeletal (say: SKEL-uh-tul) muscle. Smooth Muscles Smooth muscles — sometimes also called involuntary muscles — are ...

  14. A possible instance of sexual dimorphism in the tails of two oviraptorosaur dinosaurs.

    PubMed

    Persons, W Scott; Funston, Gregory F; Currie, Philip J; Norell, Mark A

    2015-03-31

    The hypothesis that oviraptorosaurs used tail-feather displays in courtship behavior previously predicted that oviraptorosaurs would be found to display sexually dimorphic caudal osteology. MPC-D 100/1002 and MPC-D 100/1127 are two specimens of the oviraptorosaur Khaan mckennai. Although similar in absolute size and in virtually all other anatomical details, the anterior haemal spines of MPC-D 100/1002 exceed those of MPC-D 100/1127 in ventral depth and develop a hitherto unreported "spearhead" shape. This dissimilarity cannot be readily explained as pathologic and is too extreme to be reasonably attributed to the amount of individual variation expected among con-specifics. Instead, this discrepancy in haemal spine morphology may be attributable to sexual dimorphism. The haemal spine form of MPC-D 100/1002 offers greater surface area for caudal muscle insertions. On this basis, MPC-D 100/1002 is regarded as most probably male, and MPC-D 100/1127 is regarded as most probably female.

  15. Sexual dimorphism and feeding ecology of Diamond-backed Terrapins (Malaclemys terrapin)

    USGS Publications Warehouse

    Underwood, Elizabeth B.; Bowers, Sarah; Guzy, Jacquelyn C.; Lovich, Jeffrey E.; Taylor, Carole A.; Gibbons, J. Whitfield; Dorcas, Michael E.

    2013-01-01

    Natural and sexual selection are frequently invoked as causes of sexual size dimorphism in animals. Many species of turtles, including the Diamond-backed Terrapin (Malaclemys terrapin), exhibit sexual dimorphism in body size, possibly enabling the sexes to exploit different resources and reduce intraspecific competition. Female terrapins not only have larger body sizes but also disproportionately larger skulls and jaws relative to males. To better understand the relationship between skull morphology and terrapin feeding ecology, we measured the in-lever to out-lever ratios of 27 male and 33 female terrapin jaws to evaluate biomechanics of the trophic apparatus. In addition, we measured prey handling times by feeding Fiddler Crabs (Uca pugnax), a natural prey item, to 24 terrapins in the laboratory. Our results indicate that although females have disproportionately larger heads, they have similar in:out lever ratios to males, suggesting that differences in adductor muscle mass are more important in determining bite force than jaw in:out lever ratios. Females also had considerably reduced prey handling times. Understanding the factors affecting terrapin feeding ecology can illuminate the potential roles male and female terrapins play as top-down predators that regulate grazing of Periwinkle Snails (Littorina irrorata) on Cord Grass (Spartina alterniflora).

  16. A possible instance of sexual dimorphism in the tails of two oviraptorosaur dinosaurs

    PubMed Central

    IV, W. Scott Persons; Funston, Gregory F.; Currie, Philip J.; Norell, Mark A.

    2015-01-01

    The hypothesis that oviraptorosaurs used tail-feather displays in courtship behavior previously predicted that oviraptorosaurs would be found to display sexually dimorphic caudal osteology. MPC-D 100/1002 and MPC-D 100/1127 are two specimens of the oviraptorosaur Khaan mckennai. Although similar in absolute size and in virtually all other anatomical details, the anterior haemal spines of MPC-D 100/1002 exceed those of MPC-D 100/1127 in ventral depth and develop a hitherto unreported “spearhead” shape. This dissimilarity cannot be readily explained as pathologic and is too extreme to be reasonably attributed to the amount of individual variation expected among con-specifics. Instead, this discrepancy in haemal spine morphology may be attributable to sexual dimorphism. The haemal spine form of MPC-D 100/1002 offers greater surface area for caudal muscle insertions. On this basis, MPC-D 100/1002 is regarded as most probably male, and MPC-D 100/1127 is regarded as most probably female. PMID:25824625

  17. Sexually dimorphic neuronal responses to social isolation

    PubMed Central

    Senst, Laura; Baimoukhametova, Dinara; Sterley, Toni-Lee; Bains, Jaideep Singh

    2016-01-01

    Many species use social networks to buffer the effects of stress. The mere absence of a social network, however, may also be stressful. We examined neuroendocrine, PVN CRH neurons and report that social isolation alters the intrinsic properties of these cells in sexually dimorphic fashion. Specifically, isolating preadolescent female mice from littermates for <24 hr increased first spike latency (FSL) and decreased excitability of CRH neurons. These changes were not evident in age-matched males. By contrast, subjecting either males (isolated or grouped) or group housed females to acute physical stress (swim), increased FSL. The increase in FSL following either social isolation or acute physical stress was blocked by the glucocorticoid synthesis inhibitor, metyrapone and mimicked by exogenous corticosterone. The increase in FSL results in a decrease in the excitability of CRH neurons. Our observations demonstrate that social isolation, but not acute physical stress has sex-specific effects on PVN CRH neurons. DOI: http://dx.doi.org/10.7554/eLife.18726.001 PMID:27725087

  18. Craniofacial sexual dimorphism patterns and allometry among extant hominids.

    PubMed

    Schaefer, Katrin; Mitteroecker, Philipp; Gunz, Philipp; Bernhard, Markus; Bookstein, Fred L

    2004-12-01

    Craniofacial sexual dimorphism in primates varies in both magnitude and pattern among species. In the past two decades, there has been an increasing emphasis in exploring the correlations of these patterns with taxonomy and the variation in patterns within and among the craniofacial regions. Scrutinising these relationships for hominids, we decompose the craniofacial morphology in five taxa: Homo sapiens, Pan paniscus, Pan troglodytes, Gorilla gorilla and Pongo pygmaeus. 3D coordinates of 35 traditional landmarks and 61 semilandmarks, covering five ridge curves, are measured for each of 268 adult and sub-adult specimens and analysed using geometric morphometric methods. A multivariate analysis in size-shape space shows that ontogenetic scaling contributes to the development of sexual dimorphism in all five taxa, but to a varying extent. In absolute as well as in relative terms P. pygmaeus shows the greatest allometric component, followed by G. gorilla. Homo is intermediate, while in Pan the non-allometric constituent part contributes a large fraction to the actual sexual dimorphism, most markedly in the pygmy chimpanzee. An eigendecomposition of the five vectors of sexual dimorphism reveals two dimensions independent of allometry. One separates orang-utan sexual dimorphism from the African apes and Homo, and the other differentiates between the great apes and Homo with Pan mediating. We discuss these patterns and speculate on their use as characters for taxonomic analysis in the fossil record.

  19. ALTERATIONS IN SEXUALLY DIMORPHIC BIOTRANSFORMATION OF TESTOSTERONE IN JUVENILE AMERICAN ALLIGATORS (ALLIGATOR MISSISSIPPIENSIS) FROM CONTAMINATED LAKES

    EPA Science Inventory

    The goal of this study was to determine whether hepatic biotransformation of testosterone is normally sexually dimorphic in juvenile alligators and whether living in a contaminated environment affects hepatic dimorphism. Lake Woodruff served as our reference site. Moonshine Bay, ...

  20. The use of dimorphic Alu insertions in human DNA fingerprinting

    SciTech Connect

    Novick, G.E.; Gonzalez, T.; Garrison, J.; Novick, C.C.; Herrera, R.J.; Batzer, M.A.; Deininger, P.L.

    1992-12-04

    We have characterized certain Human Specific Alu Insertions as either dimorphic (TPA25, PV92, APO), sightly dimorphic (C2N4 and C4N4) or monomorphic (C3N1, C4N6, C4N2, C4N5, C4N8), based on studies of Caucasian, Asian, American Black and African Black populations. Our approach is based upon: (1) PCR amplification using primers directed to the sequences that flank the site of insertion of the different Alu elements studied; (2) gel electrophoresis and scoring according to the presence or absence of an Alu insertion in one or both homologous chromosomes; (3) allelic frequencies calculated and compared according to Hardy-Weinberg equilibrium. Our DNA fingerprinting procedure using PCR amplification of dimorphic Human Specific Alu insertions, is stable enough to be used not only as a tool for genetic mapping but also to characterize populations, study migrational patterns and track the inheritance of human genetic disorders.

  1. The earliest fossil evidence for sexual dimorphism in primates

    NASA Technical Reports Server (NTRS)

    Krishtalka, Leonard; Stucky, Richard K.; Beard, K. C.

    1990-01-01

    Recently obtained material of the early Eocene primate Notharctus venticolus, including two partial skulls from a single stratigraphic horizon, provides the geologically earliest evidence of sexual dimorphism in canine size and shape in primates and the only unequivocal evidence for such dimorphism in strepsirhines. By analogy with living platyrrhines, these data suggest that Notharctus venticolus may have lived in polygynous social groups characterized by a relatively high level of intermale competition for mates and other limited resources. The anatomy of the upper incisors and related evidence imply that Notharctus is not as closely related to extant lemuriform primates as has been recently proposed. The early Eocene evidence for canine sexual dimorphism reported here, and its occurrence in a nonanthropoid, indicates that in the order Primates such a condition is either primitive or evolved independently more than once.

  2. Seasonal dimorphism in the horny bills of sparrows

    PubMed Central

    Greenberg, Russell; Etterson, Matthew; Danner, Raymond M

    2013-01-01

    Bill size is often viewed as a species-specific adaptation for feeding, but it sometimes varies between sexes, suggesting that sexual selection or intersexual competition may also be important. Hypotheses to explain sexual dimorphism in avian bill size include divergence in feeding niche or thermoregulatory demands, intrasexual selection based on increased competition among males, or female preference. Birds also show seasonal changes in bill size due to shifts in the balance between growth rate and wear, which may be due to diet or endogenous rhythms in growth. Insight into the function of dimorphism can be gained using the novel approach of digital x-ray imaging of museum skins to examine the degree to which the skeletal core or the rhamphotheca contribute to overall dimorphism. The rhamphotheca is ever-growing and ever-wearing, varying in size throughout life; whereas the skeletal core shows determinant growth. Because tidal marsh sparrows are more dimorphic in bill size than related taxa, we selected two marsh taxa to investigate dimorphism and seasonality in the size of the overall bill, the skeletal core, and the rhamphotheca. Bill size varied by sex and season, with males having larger bills than females, and bill size increasing from nonbreeding to breeding season more in males. Skeletal bill size varied with season, but not sex. The rhamphotheca varied primarily with sex; males had a larger rhamphotheca (corrected for skeletal bill size), which showed a greater seasonal increase than females. The rhamphotheca, rather than the skeletal bill, was responsible for sexual dimorphism in overall bill size, which was particularly well developed in the breeding season. The size of the rhamphotheca may be a condition-based character that is shaped by sexual selection. These results are consistent with the evidence that bill size is influenced by sexual selection as well as trophic ecology. PMID:23467758

  3. Singularity theory of fitness functions under dimorphism equivalence.

    PubMed

    Wang, Xiaohui; Golubitsky, Martin

    2016-09-01

    We apply singularity theory to classify monomorphic singular points as they occur in adaptive dynamics. Our approach is based on a new equivalence relation called dimorphism equivalence, which is the largest equivalence relation on strategy functions that preserves ESS singularities, CvSS singularities, and dimorphisms. Specifically, we classify singularities up to topological codimension two and compute their normal forms and universal unfoldings. These calculations lead to the classification of local mutual invasibility plots that can be seen generically in systems with two parameters.

  4. Effect of ajoene on dimorphism of Paracoccidioides brasiliensis.

    PubMed

    San-Blas, G; Mariño, L; San-Blas, F; Apitz-Castro, R

    1993-01-01

    Ajoene, a compound derived from ethanolic garlic extracts, inhibits the growth of the dimorphic pathogenic fungus Paracoccidioides brasiliensis, yeast cells being more sensitive to its action than mycelial cultures. Sulphydryl protector groups were able to cancel the inhibitory effect on the yeast cells but not on the mycelial cultures. The dimorphic process was also blocked when mycelia were placed to transform to yeast. Synthesis in vitro of cell wall glucan was not affected by ajoene. We discuss the possible involvement of ajoene on sulphydryl metabolism of P. brasiliensis.

  5. Determination of aminoglycoside residues in milk and muscle based on a simple and fast extraction procedure followed by liquid chromatography coupled to tandem mass spectrometry and time of flight mass spectrometry.

    PubMed

    Arsand, Juliana Bazzan; Jank, Louíse; Martins, Magda Targa; Hoff, Rodrigo Barcellos; Barreto, Fabiano; Pizzolato, Tânia Mara; Sirtori, Carla

    2016-07-01

    Antibiotics are widely used in veterinary medicine mainly for treatment and prevention of diseases. The aminoglycosides are one of the antibiotics classes that have been extensively employed in animal husbandry for the treatment of bacterial infections, but also as growth promotion. The European Union has issued strict Maximum Residue Levels (MRLs) for aminoglycosides in several animal origin products including bovine milk, bovine, swine and poultry muscle. This paper describes a fast and simple analytical method for the determination of ten aminoglycosides (spectinomycin, tobramycin, gentamicin, kanamycin, hygromycin, apramycin, streptomycin, dihydrostreptomycin, amikacin and neomycin) in bovine milk and bovine, swine and poultry muscle. For sample preparation, an extraction method was developed using trichloroacetic acid and clean up with low temperature precipitation and C18 bulk. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to carry out quantitative analysis and liquid chromatography-quadrupole-time of flight-mass spectrometry (LC-QTOF-MS) was used to screening purposes. Both methods were validated according to the European Union Commission Directive 2002/657/EC. Good performance characteristics were obtained for recovery, precision, calibration curve, specificity, decision limits (CCα) and detection capabilities (CCβ) in all matrices evaluated. The detection limit (LOD) and quantification limit (LOQ) were ranging from 5 to 100ngg(-1) and 12.5 to 250ngg(-1), respectively. Good linearity (r)-above 0.99-was achieved in concentrations ranging from 0.0 to 2.0×MRL. Recoveries ranged from 36.8% to 98.0% and the coefficient of variation from 0.9 to 20.2%, noting that all curves have been made into their own matrices in order to minimize the matrix effects. The CCβ values obtained in qualitative method were between 25 and 250ngg(-1). The proposed method showed to be simple, easy, and adequate for high-throughput analysis of a large

  6. A novel approach to the quantitative detection of anabolic steroids in bovine muscle tissue by means of a hybrid quadrupole time-of-flight-mass spectrometry instrument.

    PubMed

    Bussche, Julie Vanden; Decloedt, Anneleen; Van Meulebroek, Lieven; De Clercq, Nathalie; Lock, Stephen; Stahl-Zeng, Jianru; Vanhaecke, Lynn

    2014-09-19

    In recent years, the analysis of veterinary drugs and growth-promoting agents has shifted from target-oriented procedures, mainly based on liquid chromatography coupled to triple-quadrupole mass spectrometry (LC-QqQ-MS), towards accurate mass full scan MS (such as Time-of-Flight (ToF) and Fourier Transform (FT)-MS). In this study, the performance of a hybrid analysis instrument (i.e. UHPLC-QuadrupoleTime-of-Flight-MS (QqToF-MS)), able to exploit both full scan HR and MS/MS capabilities within a single analytical platform, was evaluated for confirmatory analysis of anabolic steroids (gestagens, estrogens including stilbenes and androgens) in meat. The validation data was compared to previously obtained results (CD 2002/657/EC) for QqQ-MS and single stage Orbitrap-MS. Additionally, a fractional factorial design was used to shorten and optimize the sample extraction. Validation according to CD 2002/657/EC demonstrated that steroid analysis using QqToF has a higher competing value towards QqQ-MS in terms of selectivity/specificity, compared to single stage Orbitrap-MS. While providing excellent linearity, based on lack-of-fit calculations (F-test, α=0.05 for all steroids except 17β-ethinylestradiol: α=0.01), the sensitivity of QqToF-MS proved for 61.8% and 85.3% of the compounds more sensitive compared to QqQ-MS and Orbitrap-MS, respectively. Indeed, the CCα values, obtained upon ToF-MS/MS detection, ranged from 0.02 to 1.74μgkg(-1) for the 34 anabolic steroids, while for QqQ-MS and Orbitrap-MS values ranged from 0.04 to 0.88μgkg(-1) and from 0.07 to 2.50μgkg(-1), respectively. Using QqToF-MS and QqQ-MS, adequate precision was obtained as relative standard deviations for repeatability and within-laboratory reproducibility, were below 20%. In case of Orbitrap-MS, some compounds (i.e. some estrogens) displayed poor precision, which was possibly caused by some lack of sensitivity at lower concentrations and the absence of MRM-like experiments. Overall, it can be

  7. A Survey of Eyespot Sexual Dimorphism across Nymphalid Butterflies

    PubMed Central

    Tokita, Christopher K.; Oliver, Jeffrey C.; Monteiro, Antónia

    2013-01-01

    Differences between sexes of the same species are widespread and are variable in nature. While it is often assumed that males are more ornamented than females, in the nymphalid butterfly genus Bicyclus, females have, on average, more eyespot wing color patterns than males. Here we extend these studies by surveying eyespot pattern sexual dimorphism across the Nymphalidae family of butterflies. Eyespot presence or absence was scored from a total of 38 wing compartments for two males and two females of each of 450 nymphalid species belonging to 399 different genera. Differences in eyespot number between sexes of each species were tallied for each wing surface (e.g., dorsal and ventral) of forewings and hindwings. In roughly 44% of the species with eyespots, females had more eyespots than males, in 34%, males had more eyespots than females, and, in the remaining 22% of the species, there was monomorphism in eyespot number. Dorsal and forewing surfaces were less patterned, but proportionally more dimorphic, than ventral and hindwing surfaces, respectively. In addition, wing compartments that frequently displayed eyespots were among the least sexually dimorphic. This survey suggests that dimorphism arises predominantly in “hidden” or “private” surfaces of a butterfly's wing, as previously demonstrated for the genus Bicyclus. PMID:24381783

  8. Modeling the Process of Science: Investigating Sexual Dimorphism in Crayfish.

    ERIC Educational Resources Information Center

    Mullen, Dennis M.; Rutledge, Michael L.; Swain, Sarah H.

    2003-01-01

    Describes a scientific investigation of sexual dimorphism with regard to chela size in crayfish in which students utilize the skills, tools, and techniques associated with the formulation and testing of scientific hypotheses. Indicates that students find the investigation effective in aiding their understanding of fundamental aspects of scientific…

  9. A Survey of Eyespot Sexual Dimorphism across Nymphalid Butterflies.

    PubMed

    Tokita, Christopher K; Oliver, Jeffrey C; Monteiro, Antónia

    2013-01-01

    Differences between sexes of the same species are widespread and are variable in nature. While it is often assumed that males are more ornamented than females, in the nymphalid butterfly genus Bicyclus, females have, on average, more eyespot wing color patterns than males. Here we extend these studies by surveying eyespot pattern sexual dimorphism across the Nymphalidae family of butterflies. Eyespot presence or absence was scored from a total of 38 wing compartments for two males and two females of each of 450 nymphalid species belonging to 399 different genera. Differences in eyespot number between sexes of each species were tallied for each wing surface (e.g., dorsal and ventral) of forewings and hindwings. In roughly 44% of the species with eyespots, females had more eyespots than males, in 34%, males had more eyespots than females, and, in the remaining 22% of the species, there was monomorphism in eyespot number. Dorsal and forewing surfaces were less patterned, but proportionally more dimorphic, than ventral and hindwing surfaces, respectively. In addition, wing compartments that frequently displayed eyespots were among the least sexually dimorphic. This survey suggests that dimorphism arises predominantly in "hidden" or "private" surfaces of a butterfly's wing, as previously demonstrated for the genus Bicyclus. PMID:24381783

  10. Seasonal dimorphism in the horny bills of sparrows

    EPA Science Inventory

    Bill shape and size are often viewed as species-specific adaptations for feeding, but they sometimes vary between sexes, suggesting that sexual selection or inter-sexual competition may also be important. Hypotheses to explain sexual bill size dimorphism in birds avian bill size...

  11. Zasp52, a Core Z-disc Protein in Drosophila Indirect Flight Muscles, Interacts with α-Actinin via an Extended PDZ Domain

    PubMed Central

    Liao, Kuo An; González-Morales, Nicanor

    2016-01-01

    Z-discs are organizing centers that establish and maintain myofibril structure and function. Important Z-disc proteins are α-actinin, which cross-links actin thin filaments at the Z-disc and Zasp PDZ domain proteins, which directly interact with α-actinin. Here we investigate the biochemical and genetic nature of this interaction in more detail. Zasp52 is the major Drosophila Zasp PDZ domain protein, and is required for myofibril assembly and maintenance. We show by in vitro biochemistry that the PDZ domain plus a C-terminal extension is the only area of Zasp52 involved in the interaction with α-actinin. In addition, site-directed mutagenesis of 5 amino acid residues in the N-terminal part of the PDZ domain, within the PWGFRL motif, abolish binding to α-actinin, demonstrating the importance of this motif for α-actinin binding. Rescue assays of a novel Zasp52 allele demonstrate the crucial importance of the PDZ domain for Zasp52 function. Flight assays also show that a Zasp52 mutant suppresses the α-actinin mutant phenotype, indicating that both proteins are core structural Z-disc proteins required for optimal Z-disc function. PMID:27783625

  12. Muscle Cramps

    MedlinePlus

    Muscle cramps are sudden, involuntary contractions or spasms in one or more of your muscles. They often occur after exercise or at night, ... to several minutes. It is a very common muscle problem. Muscle cramps can be caused by nerves ...

  13. Muscle Disorders

    MedlinePlus

    Your muscles help you move and help your body work. Different types of muscles have different jobs. There are many problems that can affect muscles. Muscle disorders can cause weakness, pain or even ...

  14. Muscle atrophy

    MedlinePlus

    Muscle wasting; Wasting; Atrophy of the muscles ... There are two types of muscle atrophy: disuse and neurogenic. Disuse atrophy is caused by not using the muscles enough . This type of atrophy can often be ...

  15. Muscle biopsy

    MedlinePlus

    ... the removal of a small piece of muscle tissue for examination. ... dystrophy Myopathic changes (destruction of the muscle) Necrosis (tissue death) of muscle Necrotizing vasculitis Traumatic muscle damage Polymyositis Additional conditions ...

  16. Sexual Size Dimorphism and Body Condition in the Australasian Gannet.

    PubMed

    Angel, Lauren P; Wells, Melanie R; Rodríguez-Malagón, Marlenne A; Tew, Emma; Speakman, John R; Arnould, John P Y

    2015-01-01

    Sexual size dimorphism is widespread throughout seabird taxa and several drivers leading to its evolution have been hypothesised. While the Australasian Gannet (Morus serrator) has previously been considered nominally monomorphic, recent studies have documented sexual segregation in diet and foraging areas, traits often associated with size dimorphism. The present study investigated the sex differences in body mass and structural size of this species at two colonies (Pope's Eye, PE; Point Danger, PD) in northern Bass Strait, south-eastern Australia. Females were found to be 3.1% and 7.3% heavier (2.74 ± 0.03, n = 92; 2.67 ± 0.03 kg, n = 43) than males (2.66 ± 0.03, n = 92; 2.48 ± 0.03 kg, n = 43) at PE and PD, respectively. Females were also larger in wing ulna length (0.8% both colonies) but smaller in bill depth (PE: 2.2%; PD: 1.7%) than males. Despite this dimorphism, a discriminant function provided only mild accuracy in determining sex. A similar degree of dimorphism was also found within breeding pairs, however assortative mating was not apparent at either colony (R2 < 0.04). Using hydrogen isotope dilution, a body condition index was developed from morphometrics to estimate total body fat (TBF) stores, where TBF(%) = 24.43+1.94*(body mass/wing ulna length) - 0.58*tarsus length (r2 = 0.84, n = 15). This index was used to estimate body composition in all sampled individuals. There was no significant difference in TBF(%) between the sexes for any stage of breeding or in any year of the study at either colony suggesting that, despite a greater body mass, females were not in a better condition than males. While the driving mechanism for sexual dimorphism in this species is currently unknown, studies of other Sulids indicate segregation in foraging behaviour, habitat and diet may be a contributing factor.

  17. Sexual Size Dimorphism and Body Condition in the Australasian Gannet.

    PubMed

    Angel, Lauren P; Wells, Melanie R; Rodríguez-Malagón, Marlenne A; Tew, Emma; Speakman, John R; Arnould, John P Y

    2015-01-01

    Sexual size dimorphism is widespread throughout seabird taxa and several drivers leading to its evolution have been hypothesised. While the Australasian Gannet (Morus serrator) has previously been considered nominally monomorphic, recent studies have documented sexual segregation in diet and foraging areas, traits often associated with size dimorphism. The present study investigated the sex differences in body mass and structural size of this species at two colonies (Pope's Eye, PE; Point Danger, PD) in northern Bass Strait, south-eastern Australia. Females were found to be 3.1% and 7.3% heavier (2.74 ± 0.03, n = 92; 2.67 ± 0.03 kg, n = 43) than males (2.66 ± 0.03, n = 92; 2.48 ± 0.03 kg, n = 43) at PE and PD, respectively. Females were also larger in wing ulna length (0.8% both colonies) but smaller in bill depth (PE: 2.2%; PD: 1.7%) than males. Despite this dimorphism, a discriminant function provided only mild accuracy in determining sex. A similar degree of dimorphism was also found within breeding pairs, however assortative mating was not apparent at either colony (R2 < 0.04). Using hydrogen isotope dilution, a body condition index was developed from morphometrics to estimate total body fat (TBF) stores, where TBF(%) = 24.43+1.94*(body mass/wing ulna length) - 0.58*tarsus length (r2 = 0.84, n = 15). This index was used to estimate body composition in all sampled individuals. There was no significant difference in TBF(%) between the sexes for any stage of breeding or in any year of the study at either colony suggesting that, despite a greater body mass, females were not in a better condition than males. While the driving mechanism for sexual dimorphism in this species is currently unknown, studies of other Sulids indicate segregation in foraging behaviour, habitat and diet may be a contributing factor. PMID:26637116

  18. Control-oriented reduced order modeling of dipteran flapping flight

    NASA Astrophysics Data System (ADS)

    Faruque, Imraan

    Flying insects achieve flight stabilization and control in a manner that requires only small, specialized neural structures to perform the essential components of sensing and feedback, achieving unparalleled levels of robust aerobatic flight on limited computational resources. An engineering mechanism to replicate these control strategies could provide a dramatic increase in the mobility of small scale aerial robotics, but a formal investigation has not yet yielded tools that both quantitatively and intuitively explain flapping wing flight as an "input-output" relationship. This work uses experimental and simulated measurements of insect flight to create reduced order flight dynamics models. The framework presented here creates models that are relevant for the study of control properties. The work begins with automated measurement of insect wing motions in free flight, which are then used to calculate flight forces via an empirically-derived aerodynamics model. When paired with rigid body dynamics and experimentally measured state feedback, both the bare airframe and closed loop systems may be analyzed using frequency domain system identification. Flight dynamics models describing maneuvering about hover and cruise conditions are presented for example fruit flies (Drosophila melanogaster) and blowflies (Calliphorids). The results show that biologically measured feedback paths are appropriate for flight stabilization and sexual dimorphism is only a minor factor in flight dynamics. A method of ranking kinematic control inputs to maximize maneuverability is also presented, showing that the volume of reachable configurations in state space can be dramatically increased due to appropriate choice of kinematic inputs.

  19. Sexually Dimorphic Effects of Cannabinoid Compounds on Emotion and Cognition

    PubMed Central

    Rubino, Tiziana; Parolaro, Daniela

    2011-01-01

    This review addresses the issue of sex differences in the response to cannabinoid compounds focusing mainly on behaviors belonging to the cognitive and emotional sphere. Sexual dimorphism exists in the different components of the endocannabinoid system. Males seem to have higher CB1 receptor binding sites than females, but females seem to possess more efficient CB1 receptors. Differences between sexes have been also observed in the metabolic processing of THC, the main psychoactive ingredient of marijuana. The consistent dimorphism in the endocannabinoid system and THC metabolism may justify at least in part the different sensitivity observed between male and female animals in different behavioral paradigms concerning emotion and cognition after treatment with cannabinoid compounds. On the basis of these observations, we would like to emphasize the need of including females in basic research and to analyze results for sex differences in epidemiological studies. PMID:21991251

  20. Human preferences for sexually dimorphic faces may be evolutionarily novel

    PubMed Central

    Scott, Isabel M.; Clark, Andrew P.; Josephson, Steven C.; Boyette, Adam H.; Cuthill, Innes C.; Fried, Ruby L.; Gibson, Mhairi A.; Hewlett, Barry S.; Jamieson, Mark; Jankowiak, William; Honey, P. Lynne; Huang, Zejun; Liebert, Melissa A.; Purzycki, Benjamin G.; Shaver, John H.; Snodgrass, J. Josh; Sosis, Richard; Sugiyama, Lawrence S.; Swami, Viren; Yu, Douglas W.; Zhao, Yangke; Penton-Voak, Ian S.

    2014-01-01

    A large literature proposes that preferences for exaggerated sex typicality in human faces (masculinity/femininity) reflect a long evolutionary history of sexual and social selection. This proposal implies that dimorphism was important to judgments of attractiveness and personality in ancestral environments. It is difficult to evaluate, however, because most available data come from large-scale, industrialized, urban populations. Here, we report the results for 12 populations with very diverse levels of economic development. Surprisingly, preferences for exaggerated sex-specific traits are only found in the novel, highly developed environments. Similarly, perceptions that masculine males look aggressive increase strongly with development and, specifically, urbanization. These data challenge the hypothesis that facial dimorphism was an important ancestral signal of heritable mate value. One possibility is that highly developed environments provide novel opportunities to discern relationships between facial traits and behavior by exposing individuals to large numbers of unfamiliar faces, revealing patterns too subtle to detect with smaller samples. PMID:25246593

  1. Human preferences for sexually dimorphic faces may be evolutionarily novel.

    PubMed

    Scott, Isabel M; Clark, Andrew P; Josephson, Steven C; Boyette, Adam H; Cuthill, Innes C; Fried, Ruby L; Gibson, Mhairi A; Hewlett, Barry S; Jamieson, Mark; Jankowiak, William; Honey, P Lynne; Huang, Zejun; Liebert, Melissa A; Purzycki, Benjamin G; Shaver, John H; Snodgrass, J Josh; Sosis, Richard; Sugiyama, Lawrence S; Swami, Viren; Yu, Douglas W; Zhao, Yangke; Penton-Voak, Ian S

    2014-10-01

    A large literature proposes that preferences for exaggerated sex typicality in human faces (masculinity/femininity) reflect a long evolutionary history of sexual and social selection. This proposal implies that dimorphism was important to judgments of attractiveness and personality in ancestral environments. It is difficult to evaluate, however, because most available data come from large-scale, industrialized, urban populations. Here, we report the results for 12 populations with very diverse levels of economic development. Surprisingly, preferences for exaggerated sex-specific traits are only found in the novel, highly developed environments. Similarly, perceptions that masculine males look aggressive increase strongly with development and, specifically, urbanization. These data challenge the hypothesis that facial dimorphism was an important ancestral signal of heritable mate value. One possibility is that highly developed environments provide novel opportunities to discern relationships between facial traits and behavior by exposing individuals to large numbers of unfamiliar faces, revealing patterns too subtle to detect with smaller samples. PMID:25246593

  2. Human preferences for sexually dimorphic faces may be evolutionarily novel.

    PubMed

    Scott, Isabel M; Clark, Andrew P; Josephson, Steven C; Boyette, Adam H; Cuthill, Innes C; Fried, Ruby L; Gibson, Mhairi A; Hewlett, Barry S; Jamieson, Mark; Jankowiak, William; Honey, P Lynne; Huang, Zejun; Liebert, Melissa A; Purzycki, Benjamin G; Shaver, John H; Snodgrass, J Josh; Sosis, Richard; Sugiyama, Lawrence S; Swami, Viren; Yu, Douglas W; Zhao, Yangke; Penton-Voak, Ian S

    2014-10-01

    A large literature proposes that preferences for exaggerated sex typicality in human faces (masculinity/femininity) reflect a long evolutionary history of sexual and social selection. This proposal implies that dimorphism was important to judgments of attractiveness and personality in ancestral environments. It is difficult to evaluate, however, because most available data come from large-scale, industrialized, urban populations. Here, we report the results for 12 populations with very diverse levels of economic development. Surprisingly, preferences for exaggerated sex-specific traits are only found in the novel, highly developed environments. Similarly, perceptions that masculine males look aggressive increase strongly with development and, specifically, urbanization. These data challenge the hypothesis that facial dimorphism was an important ancestral signal of heritable mate value. One possibility is that highly developed environments provide novel opportunities to discern relationships between facial traits and behavior by exposing individuals to large numbers of unfamiliar faces, revealing patterns too subtle to detect with smaller samples.

  3. Gene duplication in the evolution of sexual dimorphism.

    PubMed

    Wyman, Minyoung J; Cutter, Asher D; Rowe, Locke

    2012-05-01

    Males and females share most of the same genes, so selection in one sex will typically produce a correlated response in the other sex. Yet, the sexes have evolved to differ in a multitude of behavioral, morphological, and physiological traits. How did this sexual dimorphism evolve despite the presence of a common underlying genome? We investigated the potential role of gene duplication in the evolution of sexual dimorphism. Because duplication events provide extra genetic material, the sexes each might use this redundancy to facilitate sex-specific gene expression, permitting the evolution of dimorphism. We investigated this hypothesis at the genome-wide level in Drosophila melanogaster, using the presence of sex-biased expression as a proxy for the sex-specific specialization of gene function. We expected that if sexually antagonistic selection is a potent force acting upon individual genes, duplication will result in paralog families whose members differ in sex-biased expression. Gene members of the same duplicate family can have different expression patterns in males versus females. In particular, duplicate pairs containing a male-biased gene are found more frequently than expected, in agreement with previous studies. Furthermore, when the singleton ortholog is unbiased, duplication appears to allow one of the paralog copies to acquire male-biased expression. Conversely, female-biased expression is not common among duplicates; fewer duplicate genes are expressed in the female-soma and ovaries than in the male-soma and testes. Expression divergence exists more in older than in younger duplicates pairs, but expression divergence does not correlate with protein sequence divergence. Finally, genomic proximity may have an effect on whether paralogs differ in sex-biased expression. We conclude that the data are consistent with a role of gene duplication in fostering male-biased, but not female-biased, gene expression, thereby aiding the evolution of sexual dimorphism.

  4. Measuring sexual dimorphism with a race-gender face space.

    PubMed

    Hopper, William J; Finklea, Kristin M; Winkielman, Piotr; Huber, David E

    2014-10-01

    Faces are complex visual objects, and faces chosen to vary in 1 regard may unintentionally vary in other ways, particularly if the correlation is a property of the population of faces. Here, we present an example of a correlation that arises from differences in the degree of sexual dimorphism. In Experiment 1, paired similarity ratings were collected for a set of 40 real face images chosen to vary in terms of gender and race (Asian vs. White). Multidimensional scaling (MDS) placed these stimuli in a "face space," with different attributes corresponding to different dimensions. Gender was found to vary more for White faces, resulting in a negative or positive correlation between gender and race when only considering male or only considering female faces. This increased sexual dimorphism for White faces may provide an alternative explanation for differences in face processing between White and Asian faces (e.g., the own-race bias, face attractiveness biases, etc.). Studies of face processing that are unconfounded by this difference in the degree of sexual dimorphism require stimuli that are decorrelated in terms of race and gender. Decorrelated faces were created using a morphing technique, spacing the morphs uniformly around a ring in the 2-dimensional (2D) race-gender plane. In Experiment 2, paired similarity ratings confirmed the 2D positions of the morph faces. In Experiment 3, race and gender category judgments varied uniformly for these decorrelated stimuli. Our results and stimuli should prove useful for studying sexual dimorphism and for the study of face processing more generally.

  5. Skeletal muscle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are approximately 650-850 muscles in the human body these include skeletal (striated), smooth and cardiac muscle. The approximation is based on what some anatomists consider separate muscle or muscle systems. Muscles are classified based on their anatomy (striated vs. smooth) and if they are v...

  6. The effects of age and lifetime flight behavior on flight capacity in Drosophila melanogaster.

    PubMed

    Lane, Steven J; Frankino, W Anthony; Elekonich, Michelle M; Roberts, Stephen P

    2014-05-01

    The effects of flight behavior on physiology and senescence may be profound in insects because of the extremely high metabolic costs of flight. Flight capacity in insects decreases with age; in contrast, limiting flight behavior extends lifespan and slows the age-related loss of antioxidant capacity and accumulation of oxidative damage in flight muscles. In this study, we tested the effects of age and lifetime flight behavior on flight capacity by measuring wingbeat frequency, the ability to fly in a hypo-dense gas mixture, and metabolic rate in Drosophila melanogaster. Specifically, 5-day-old adult flies were separated into three life-long treatments: (1) those not allowed to fly (no flight), (2) those allowed - but not forced - to fly (voluntary flight) and (3) those mechanically stimulated to fly (induced flight). Flight capacity senesced earliest in flies from the no-flight treatment, followed by the induced-flight group and then the voluntary flight group. Wingbeat frequency senesced with age in all treatment groups, but was most apparent in the voluntary- and induced-flight groups. Metabolic rate during agitated flight senesced earliest and most rapidly in the induced flight group, and was low and uniform throughout age in the no-flight group. Early senescence in the induced-flight group was likely due to the acceleration of deleterious aging phenomena such as the rapid accumulation of damage at the cellular level, while the early loss of flight capacity and low metabolic rates in the no-flight group demonstrate that disuse effects can also significantly alter senescence patterns of whole-insect performance.

  7. Unpredictable food and sexual size dimorphism in insects.

    PubMed

    Leimar, O; Karlsson, B; Wiklund, C

    1994-11-22

    The evolution of sexual size dimorphism is likely to be affected by the amount of resources each sex invests in offspring. Male nuptial gifts, occurring in many insect species, might reduce the value of large size in females and increase the value for males. For large nuptial gifts and an accompanying shift in dimorphism to evolve, males with larger gifts should be rewarded, in effect trading the larger gift for more offspring. We suggest that food variability, causing some males to have much to provide and some females to be in great need, would be conducive to the evolution of such a mating system, and we present comparative data on butterflies supporting the suggestion. In a gift-giving mating system, growing male and female juveniles should react differently to food shortage. A female maturing at small size can to some extent buffer her disadvantage through nuptial gifts, whereas a male maturing at small size will suffer from his inability to provide substantial gifts. Thus, males benefit more than females from continued growth in the face of food shortage, leading to a shift in size dimorphism. Here we confirm this prediction in a butterfly, Pieris napi, with large nuptial gifts.

  8. Sexual dimorphism in the feeding mechanism of threespine stickleback.

    PubMed

    McGee, Matthew D; Wainwright, Peter C

    2013-03-01

    Sexual dimorphism is common in nature and has the potential to increase intraspecific variation in performance and patterns of resource use. We sought to determine whether anadromous threespine stickleback, Gasterosteus aculeatus, exhibit sexual dimorphism in feeding kinematics. We filmed four males and four females consuming live prey in a total of 51 sequences filmed at 500 Hz, then tested for differences in cranial kinematics using a combination of principal component analysis and linear mixed models. We document, for the first time in fishes, divergence between males and females in both the timing of key movements and the magnitude of excursions reached by the hyoid, jaws and neurocranium during prey capture. Some of the largest differences are in jaw protrusion, with males exhibiting faster time to peak jaw protrusion but females exhibiting greater maximum jaw protrusion. Measurements of morphological jaw protrusion on cleared and stained specimens significantly predict jaw protrusion in kinematics. This morphological divergence could reflect ecological divergence between the sexes, or the demands of nest building and territory defense compromising male feeding performance. Remarkably, the morphological jaw protrusion divergence in anadromous males and females is similar to jaw protrusion divergence between ecomorphs in a benthic-limnetic species pair, with limnetics exhibiting female-like patterns of protrusion and benthics exhibiting male-like patterns. These results suggest that sexual dimorphism in feeding functional morphology exists in nature and may have played an important role in the radiation of threespine stickleback. PMID:23408802

  9. Sexual dimorphism in tooth morphometrics: An evaluation of the parameters

    PubMed Central

    Banerjee, Abhishek; Kamath, Venkatesh V.; Satelur, Krishnanand; Rajkumar, Komali; Sundaram, Lavanya

    2016-01-01

    Aims and Objectives: Sexual dimorphism refers to the variations in tooth size and shape between the sexes. The consistency of these variations is valuable in the identification of the sex of an individual in times of mass disaster when whole body parts get destroyed or are unavailable. There exist differences in the expression of these variables across races and regions. This study aims to tabulate and identify the variations in tooth measurements using standarized reference points in an attempt to establish parameters of sexual dimorphism. Materials and Methods: 100 individuals (50 of each sex) in the age group 19-23 years were assessed for standard morphometric parameters of the maxillary central incisor, canine, premolar and molar. Odontometric measurements of established parameters were recorded from impression casts of the maxillary jaws. The mesiodistal width (MDW), the bucco-ligual width (BLW), the crown length (CL) and the cervical angle (CA) were charted among the teeth. The consistency of the variations was statistically analyzed and a logistic regression table was prepared to identify the sex of the individual from the tooth measurements. Results and Conclusions: The BLW, MDW and CL reflected significant variations among all the teeth to be effective in establishing sexual dimorphism. CA as a parameter was inadequate across all the teeth. The permanent maxillary canine was the most important tooth to be reflective of the gender and statistically significant to be utilized for gender determination. PMID:27051219

  10. Active pollination favours sexual dimorphism in floral scent.

    PubMed

    Okamoto, Tomoko; Kawakita, Atsushi; Goto, Ryutaro; Svensson, Glenn P; Kato, Makoto

    2013-12-01

    Zoophilous flowers often transmit olfactory signals to attract pollinators. In plants with unisexual flowers, such signals are usually similar between the sexes because attraction of the same animal to both male and female flowers is essential for conspecific pollen transfer. Here, we present a remarkable example of sexual dimorphism in floral signal observed in reproductively highly specialized clades of the tribe Phyllantheae (Phyllanthaceae). These plants are pollinated by species-specific, seed-parasitic Epicephala moths (Gracillariidae) that actively collect pollen from male flowers and pollinate the female flowers in which they oviposit; by doing so, they ensure seeds for their offspring. We found that Epicephala-pollinated Phyllanthaceae plants consistently exhibit major qualitative differences in scent between male and female flowers, often involving compounds derived from different biosynthetic pathways. In a choice test, mated female Epicephala moths preferred the scent of male flowers over that of female flowers, suggesting that male floral scent elicits pollen-collecting behaviour. Epicephala pollination evolved multiple times in Phyllantheae, at least thrice accompanied by transition from sexual monomorphism to dimorphism in floral scent. This is the first example in which sexually dimorphic floral scent has evolved to signal an alternative reward provided by each sex, provoking the pollinator's legitimate altruistic behaviour.

  11. Retinol and retinyl palmitate in fetal mice liver: sexual dimorphism.

    PubMed

    Carvalho, Olga; Gonçalves, Carlos

    2014-01-01

    We determined retinoids liver content in male and female mice fetuses to study a possible sex difference during prenatal development, and to ascertain if vitamin A metabolism is similar in both sexes. The study was performed between developmental days E15-E19, and the fetuses were collected from two main groups: control (no manipulation) and vitamin A (administration of vitamin A on developmental day E14). Each group was subdivided by sex and retinoids were analyzed by high performance liquid chromatography (HPLC). The control group did not have any retinol in the liver of both sexes. Fetuses from the vitamin A group began to accumulate retinol on day E16, until E19 and sexual dimorphism was exhibited. Retinyl palmitate content in the control group showed sexual dimorphism on some developmental days, and in the vitamin A group these differences were more significant. In conclusion, our study showed sexual dimorphism in the retinoids liver content during mice development and evidences a sex difference in vitamin A metabolism, with different capacities to store and metabolize retinoids. PMID:23945125

  12. Retinol and retinyl palmitate in foetal lung mice: sexual dimorphism.

    PubMed

    Carvalho, Olga; Gonçalves, Carlos

    2013-01-01

    In this work, we evaluate the lung retinoids content to study the possible difference between male and female mice during prenatal development and to comprehend if the vitamin A metabolism is similar in both genders. The study occurred between developmental days E15 and E19, and the retinol and retinyl palmitate lung contents were determined by HPLC analysis. We established two main groups: the control, consisting of foetuses obtained from pregnant females without any manipulation, and vitamin A, composed of foetuses from pregnant females submitted to vitamin A administration on developmental day E14. Each of these groups was subdivided by gender, establishing the four final groups. In the lung of control group, retinol was undetected in both genders and retinyl palmitate levels exhibited a sexual dimorphism. In the vitamin A group, we detected retinol and retinyl palmitate in both genders, and we observed a more evident sexual dimorphism for both retinoids. Our study also indicates that, from developmental day E15 to E19, there is an increase in the retinoids content in foetal lung and a gender difference in the retinoids metabolism. In conclusion, there is a sexual dimorphism in the lung retinoids content and in its metabolism during mice development. PMID:23365730

  13. Sexual Dimorphism in the Dimensions of Teeth in Serbian Population.

    PubMed

    Filipovic, Gordana; Kanjevac, Tatjana; Cetenovic, Bojana; Ajdukovic, Zorica; Petrovic, Nenad

    2016-04-01

    The study of teeth is of great interest to anthropologists, biologists, orthodontists and forensic scientists. The existence of sexual dimorphism in permanent teeth is a known phenomenon. Aim of this study was to analyze the presence of sexual dimorphism in the mesiodistal and vestibulolingual diameter of permanent teeth in the sample of Serbian population. Measurements were taken on plaster casts of 201 individuals of both sexes, ages between 18-25 years, using a digital caliper with 0.01 mm precision. The mesiodistal and vestibulolingual diameter of each permanent tooth was determined. A Student's t-test and a Mann-Whitney U test were used to statistically analyze the obtained results. There were no statistically significant differences in the teeth crown diameter between the right and left side of the same dental arch. Majority of the teeth examined were larger in male than in female patients. Statistically significant difference in the mesiodistal diameter of male and female maxillary and mandibular canines was found. The results of this study indicate that there are significant differences in teeth size between sexes in Serbian population. Males have larger diameters in teeth crowns than females. Canines show the greatest dimorphism.

  14. Do birds sleep in flight?

    NASA Astrophysics Data System (ADS)

    Rattenborg, Niels C.

    2006-09-01

    The following review examines the evidence for sleep in flying birds. The daily need to sleep in most animals has led to the common belief that birds, such as the common swift ( Apus apus), which spend the night on the wing, sleep in flight. The electroencephalogram (EEG) recordings required to detect sleep in flight have not been performed, however, rendering the evidence for sleep in flight circumstantial. The neurophysiology of sleep and flight suggests that some types of sleep might be compatible with flight. As in mammals, birds exhibit two types of sleep, slow-wave sleep (SWS) and rapid eye-movement (REM) sleep. Whereas, SWS can occur in one or both brain hemispheres at a time, REM sleep only occurs bihemispherically. During unihemispheric SWS, the eye connected to the awake hemisphere remains open, a state that may allow birds to visually navigate during sleep in flight. Bihemispheric SWS may also be possible during flight when constant visual monitoring of the environment is unnecessary. Nevertheless, the reduction in muscle tone that usually accompanies REM sleep makes it unlikely that birds enter this state in flight. Upon landing, birds may need to recover the components of sleep that are incompatible with flight. Periods of undisturbed postflight recovery sleep may be essential for maintaining adaptive brain function during wakefulness. The recent miniaturization of EEG recording devices now makes it possible to measure brain activity in flight. Determining if and how birds sleep in flight will contribute to our understanding of a largely unexplored aspect of avian behavior and may also provide insight into the function of sleep.

  15. Aspects of the development of flight-muscle sarcosomes in the sheep blowfly, Lucilia cuprina, in relation to changes in the distribution of protein and some respiratory enzymes during metamorphosis

    PubMed Central

    Lennie, R. W.; Birt, L. M.

    1967-01-01

    1. Changes in the amounts and distribution of protein and respiratory enzymes have been estimated during the life cycle of the fly Lucilia cuprina. 2. The fully fed larva contains about 7mg. of protein, the pupa and newly emerged fly about 4mg., and the mature adult about 3mg. 3. There are two periods of incorporation of protein into particles at the expense of the soluble protein; the first, immediately after pupation, may store protein (0·5mg./insect) for use in adult development; the second, over the period of emergence, was due mainly to the development of the thoracic mitochondria of the adult (0·7mg./insect). 4. In the thorax, cytochrome c oxidase and the dehydrogenases for glycerophosphate, isocitrate (NAD-dependent), succinate and malate appeared initially in small particles (less than 1μ in diameter). 5. In adult development these enzymes were redistributed so that in the mature fly most of the activity was present in larger particles (1–10μ in diameter). 6. During this redistribution the specific activity (μl. of oxygen/hr./mg. of protein) of glycerophosphate dehydrogenase in the small particles was 690 at 1½ days before emergence, 955 at emergence and 980 at 7 days after emergence; the corresponding values for the large particles were 164, 760 and 1220. 7. In the mature fly the highest specific activities (μl. of oxygen/hr./mg. of protein) estimated were: glycerophosphate dehydrogenase 1380, isocitrate dehydrogenase (NAD-dependent and requiring ADP and Mg2+) 408, succinate dehydrogenase 122, malate dehydrogenase 190, and cytochrome c oxidase 1360. 8. The results are considered in relation to the development of the flight-muscle sarcosomes. PMID:4291561

  16. Flight Planning

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Seagull Technology, Inc., Sunnyvale, CA, produced a computer program under a Langley Research Center Small Business Innovation Research (SBIR) grant called STAFPLAN (Seagull Technology Advanced Flight Plan) that plans optimal trajectory routes for small to medium sized airlines to minimize direct operating costs while complying with various airline operating constraints. STAFPLAN incorporates four input databases, weather, route data, aircraft performance, and flight-specific information (times, payload, crew, fuel cost) to provide the correct amount of fuel optimal cruise altitude, climb and descent points, optimal cruise speed, and flight path.

  17. Muscle Deoxygenation Causes Muscle Fatigue

    NASA Technical Reports Server (NTRS)

    Murthy, G.; Hargens, A. R.; Lehman, S.; Rempel, D.

    1999-01-01

    Muscle fatigue is a common musculoskeletal disorder in the work place, and may be a harbinger for more disabling cumulative trauma disorders. Although the cause of fatigue is multifactorial, reduced blood flow and muscle oxygenation may be the primary factor in causing muscle fatigue during low intensity muscle exertion. Muscle fatigue is defined as a reduction in muscle force production, and also occurs among astronauts who are subjected to postural constraints while performing lengthy, repetitive tasks. The objectives of this research are to: 1) develop an objective tool to study the role of decreased muscle oxygenation on muscle force production, and 2) to evaluate muscle fatigue during prolonged glovebox work.

  18. Muscle disorder

    MedlinePlus

    Myopathic changes; Myopathy; Muscle problem ... Blood tests sometimes show abnormally high muscle enzymes. If a muscle disorder might also affect other family members, genetic testing may be done. When someone has symptoms and signs ...

  19. Sexual Size Dimorphism and Body Condition in the Australasian Gannet

    PubMed Central

    Angel, Lauren P.; Wells, Melanie R.; Rodríguez-Malagón, Marlenne A.; Tew, Emma; Speakman, John R.; Arnould, John P. Y.

    2015-01-01

    Sexual size dimorphism is widespread throughout seabird taxa and several drivers leading to its evolution have been hypothesised. While the Australasian Gannet (Morus serrator) has previously been considered nominally monomorphic, recent studies have documented sexual segregation in diet and foraging areas, traits often associated with size dimorphism. The present study investigated the sex differences in body mass and structural size of this species at two colonies (Pope’s Eye, PE; Point Danger, PD) in northern Bass Strait, south-eastern Australia. Females were found to be 3.1% and 7.3% heavier (2.74 ± 0.03, n = 92; 2.67 ± 0.03 kg, n = 43) than males (2.66 ± 0.03, n = 92; 2.48 ± 0.03 kg, n = 43) at PE and PD, respectively. Females were also larger in wing ulna length (0.8% both colonies) but smaller in bill depth (PE: 2.2%; PD: 1.7%) than males. Despite this dimorphism, a discriminant function provided only mild accuracy in determining sex. A similar degree of dimorphism was also found within breeding pairs, however assortative mating was not apparent at either colony (R2 < 0.04). Using hydrogen isotope dilution, a body condition index was developed from morphometrics to estimate total body fat (TBF) stores, where TBF(%) = 24.43+1.94*(body mass/wing ulna length) – 0.58*tarsus length (r2 = 0.84, n = 15). This index was used to estimate body composition in all sampled individuals. There was no significant difference in TBF(%) between the sexes for any stage of breeding or in any year of the study at either colony suggesting that, despite a greater body mass, females were not in a better condition than males. While the driving mechanism for sexual dimorphism in this species is currently unknown, studies of other Sulids indicate segregation in foraging behaviour, habitat and diet may be a contributing factor. PMID:26637116

  20. Understanding Flight

    SciTech Connect

    Anderson, David

    2001-01-31

    Through the years the explanation of flight has become mired in misconceptions that have become dogma. Wolfgang Langewiesche, the author of 'Stick and Rudder' (1944) got it right when he wrote: 'Forget Bernoulli's Theorem'. A wing develops lift by diverting (from above) a lot of air. This is the same way that a propeller produces thrust and a helicopter produces lift. Newton's three laws and a phenomenon called the Coanda effect explain most of it. With an understanding of the real physics of flight, many things become clear. Inverted flight, symmetric wings, and the flight of insects are obvious. It is easy to understand the power curve, high-speed stalls, and the effect of load and altitude on the power requirements for lift. The contribution of wing aspect ratio on the efficiency of a wing, and the true explanation of ground effect will also be discussed.

  1. Wild geese do not increase flight behaviour prior to migration.

    PubMed

    Portugal, Steven J; Green, Jonathan A; White, Craig R; Guillemette, Magella; Butler, Patrick J

    2012-06-23

    Hypertrophy of the flight muscles is regularly observed in birds prior to long-distance migrations. We tested the hypothesis that a large migratory bird would increase flight behaviour prior to migration, in order to cause hypertrophy of the flight muscles, and upregulate key components of the aerobic metabolic pathways. Implantable data loggers were used to record year-round heart rate in six wild barnacle geese (Branta leucopsis), and the amount of time spent in flight each day was identified. Time in flight per day did not significantly increase prior to either the spring or the autumn migration, both between time periods prior to migration (5, 10 and 15 days), or when compared with a control period of low activity during winter. The lack of significant increase in flight prior to migration suggests that approximately 22 min per day is sufficient to maintain the flight muscles in condition for prolonged long-distance flight. This apparent lack of a requirement for increased flight activity prior to migration may be attributable to pre-migratory mass gains in the geese increasing workload during short flights, potentially prompting hypertrophy of the flight muscles.

  2. Flight (Children's Books).

    ERIC Educational Resources Information Center

    Matthews, Susan; Reid, Rebecca; Sylvan, Anne; Woolard, Linda; Freeman, Evelyn B.

    1997-01-01

    Presents brief annotations of 43 children's books, grouped around the theme of flight: flights of imagination, flights across time and around the globe, flights of adventure, and nature's flight. (SR)

  3. Effect of spaceflight on skeletal muscle: Mechanical properties and myosin isoform content of a slow muscle

    NASA Technical Reports Server (NTRS)

    Caiozzo, Vincent J.; Baker, Michael J.; Herrick, Robert E.; Tao, Ming; Baldwin, Kenneth M.

    1994-01-01

    This study examined changes in contractile, biochemical, and histochemical properties of slow antigravity skeletal muscle after a 6-day spaceflight mission. Twelve male Sprague-Dawley rats were randomly divided into two groups: flight and ground-based control. Approximately 3 h after the landing, in situ contractile measurements were made on the soleus muscles of the flight animals. The control animals were studied 24 h later. The contractile measurements included force-velocity relationship, force-frequency relationship, and fatigability. Biochemical measurements focused on the myosin heavy chain (MHC) and myosin light chain profiles. Adenosinetriphosphatase histochemistry was performed to identify cross-sectional area of slow and fast muscle fibers and to determine the percent fiber type distribution. The force-velocity relationships of the flight muscles were altered such that maximal isometric tension P(sub o) was decreased by 24% and maximal shortening velocity was increased by 14% (P less than 0.05). The force-frequency relationship of the flight muscles was shifted to the right of the control muscles. At the end of the 2-min fatigue test, the flight muscles generated only 34% of P(sub o), whereas the control muscles generated 64% of P(sub o). The flight muscles exhibited de novo expression of the type IIx MHC isoform as well as a slight decrease in the slow type I and fast type IIa MHC isoforms. Histochemical analyses of flight muscles demonstrated a small increase in the percentage of fast type II fibers and a greater atrophy of the slow type I fibers. The results demonstrate that contractile properties of slow antigravity skeletal muscle are sensitive to the microgravity environment and that changes begin to occur within the 1st wk. These changes were at least, in part, associated with changes in the amount and type of contractile protein expressed.

  4. Sexual dimorphism of canine volume: a pilot study.

    PubMed

    De Angelis, Danilo; Gibelli, Daniele; Gaudio, Daniel; Cipriani Noce, Filippo; Guercini, Nicola; Varvara, Giuseppe; Sguazza, Emanuela; Sforza, Chiarella; Cattaneo, Cristina

    2015-05-01

    Sex assessment is a crucial part of the biological profile in forensic and archaeological context, but it can be hardly performed in cases of commingled and charred human remains where DNA tests often are not applicable. With time literature have analyzed the sexual dimorphism of teeth (and especially canines), but very few articles take into consideration the teeth volume, although with time several technologies have been introduced in order to assess 3D volume (CT-scan, laser scanner, etc.). This study aims at assessing the sexual dimorphism of dental and pulp chamber volumes of a sample of canines. Cone beam computed tomography analyses were performed by 87 patients (41 males and 46 females, aged between 15 and 83 years) for clinical purposes, and were acquired in order to measure canine volumes. Results show that the dental volume amounted to 0.745 cm(3) (SD 0.126 cm(3)) in males, 0.551 cm(3) (SD 0.130 cm(3)) with a statistically significant difference (p<0.01). A diagnostic threshold of 0.619 cm(3) was stated, which provides a percentage of correct answer of 80.5% in the chosen sample. The novel method was then applied with success to 7 archaeological: where in all the cases the results were concordant with those provided by the assessment of the cranium and pelvis. The study adds a contribution to the wide analysis of dental sexual dimorphism confirming the statistically significant differences of volume between males and females and providing a method for the diagnosis of sex applicable to forensic cases. PMID:25556039

  5. Sexual dimorphism of canine volume: a pilot study.

    PubMed

    De Angelis, Danilo; Gibelli, Daniele; Gaudio, Daniel; Cipriani Noce, Filippo; Guercini, Nicola; Varvara, Giuseppe; Sguazza, Emanuela; Sforza, Chiarella; Cattaneo, Cristina

    2015-05-01

    Sex assessment is a crucial part of the biological profile in forensic and archaeological context, but it can be hardly performed in cases of commingled and charred human remains where DNA tests often are not applicable. With time literature have analyzed the sexual dimorphism of teeth (and especially canines), but very few articles take into consideration the teeth volume, although with time several technologies have been introduced in order to assess 3D volume (CT-scan, laser scanner, etc.). This study aims at assessing the sexual dimorphism of dental and pulp chamber volumes of a sample of canines. Cone beam computed tomography analyses were performed by 87 patients (41 males and 46 females, aged between 15 and 83 years) for clinical purposes, and were acquired in order to measure canine volumes. Results show that the dental volume amounted to 0.745 cm(3) (SD 0.126 cm(3)) in males, 0.551 cm(3) (SD 0.130 cm(3)) with a statistically significant difference (p<0.01). A diagnostic threshold of 0.619 cm(3) was stated, which provides a percentage of correct answer of 80.5% in the chosen sample. The novel method was then applied with success to 7 archaeological: where in all the cases the results were concordant with those provided by the assessment of the cranium and pelvis. The study adds a contribution to the wide analysis of dental sexual dimorphism confirming the statistically significant differences of volume between males and females and providing a method for the diagnosis of sex applicable to forensic cases.

  6. Sexually Monomorphic Maps and Dimorphic Responses in Rat Genital Cortex.

    PubMed

    Lenschow, Constanze; Copley, Sean; Gardiner, Jayne M; Talbot, Zoe N; Vitenzon, Ariel; Brecht, Michael

    2016-01-11

    Mammalian external genitals show sexual dimorphism [1, 2] and can change size and shape upon sexual arousal. Genitals feature prominently in the oldest pieces of figural art [3] and phallic depictions of penises informed psychoanalytic thought about sexuality [4, 5]. Despite this longstanding interest, the neural representations of genitals are still poorly understood [6]. In somatosensory cortex specifically, many studies did not detect any cortical representation of genitals [7-9]. Studies in humans debate whether genitals are represented displaced below the foot of the cortical body map [10-12] or whether they are represented somatotopically [13-15]. We wondered what a high-resolution mapping of genital representations might tell us about the sexual differentiation of the mammalian brain. We identified genital responses in rat somatosensory cortex in a region previously assigned as arm/leg cortex. Genital responses were more common in males than in females. Despite such response dimorphism, we observed a stunning anatomical monomorphism of cortical penis and clitoris input maps revealed by cytochrome-oxidase-staining of cortical layer 4. Genital representations were somatotopic and bilaterally symmetric, and their relative size increased markedly during puberty. Size, shape, and erect posture give the cortical penis representation a phallic appearance pointing to a role in sexually aroused states. Cortical genital neurons showed unusual multi-body-part responses and sexually dimorphic receptive fields. Specifically, genital neurons were co-activated by distant body regions, which are touched during mounting in the respective sex. Genital maps indicate a deep homology of penis and clitoris representations in line with a fundamentally bi-sexual layout [16] of the vertebrate brain. PMID:26725197

  7. Isolation of UmRrm75, a gene involved in dimorphism and virulence of Ustilago maydis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ustilago maydis displays dimorphic growth, alternating between a saprophytic haploid yeast form and a filamentous dikaryon, generated by mating of haploid cells and which is an obligate parasite. Induction of the dimorphic transition of haploid strains in vitro by change in ambient pH has been used...

  8. Masculinization of Gene Expression Is Associated with Exaggeration of Male Sexual Dimorphism

    PubMed Central

    Pointer, Marie A.; Harrison, Peter W.; Wright, Alison E.; Mank, Judith E.

    2013-01-01

    Gene expression differences between the sexes account for the majority of sexually dimorphic phenotypes, and the study of sex-biased gene expression is important for understanding the genetic basis of complex sexual dimorphisms. However, it has been difficult to test the nature of this relationship due to the fact that sexual dimorphism has traditionally been conceptualized as a dichotomy between males and females, rather than an axis with individuals distributed at intermediate points. The wild turkey (Meleagris gallopavo) exhibits just this sort of continuum, with dominant and subordinate males forming a gradient in male secondary sexual characteristics. This makes it possible for the first time to test the correlation between sex-biased gene expression and sexually dimorphic phenotypes, a relationship crucial to molecular studies of sexual selection and sexual conflict. Here, we show that subordinate male transcriptomes show striking multiple concordances with their relative phenotypic sexual dimorphism. Subordinate males were clearly male rather than intersex, and when compared to dominant males, their transcriptomes were simultaneously demasculinized for male-biased genes and feminized for female-biased genes across the majority of the transcriptome. These results provide the first evidence linking sexually dimorphic transcription and sexually dimorphic phenotypes. More importantly, they indicate that evolutionary changes in sexual dimorphism can be achieved by varying the magnitude of sex-bias in expression across a large proportion of the coding content of a genome. PMID:23966876

  9. Linear versus geometric morphometric approaches for the analysis of head shape dimorphism in lizards.

    PubMed

    Fabre, Anne-Claire; Cornette, Raphäel; Huyghe, Katleen; Andrade, Denis V; Herrel, Anthony

    2014-09-01

    Differences between the sexes may arise because of differences in reproductive strategy, with females investing more in traits related to reproductive output and males investing more in traits related to resource holding capacity and territory defence. Sexual dimorphism is widespread in lizards and in many species males and females also differ in head shape. Males typically have bigger heads than females resulting in intersexual differences in bite force. Whereas most studies documenting differences in head dimensions between sexes use linear dimensions, the use of geometric morphometrics has been advocated as more appropriate to characterize such differences. This method may allow the characterization of local shape differences that may have functional consequences, and provides unbiased indicators of shape. Here, we explore whether the two approaches provide similar results in an analyses of head shape in Tupinambis merianae. The Argentine black and white tegu differs dramatically in body size, head size, and bite force between the sexes. However, whether the intersexual differences in bite force are simply the result of differences in head size or whether more subtle modifications (e.g., in muscle insertion areas) are involved remains currently unknown. Based on the crania and mandibles of 19 lizards with known bite force, we show intersexual differences in the shape of the cranium and mandible using both linear and geometric morphometric approaches. Although both types of analyses showed generally similar results for the mandible, this was not the case for the cranium. Geometric morphometric approaches provided better insights into the underlying functional relationships between the cranium and the jaw musculature, as illustrated by shape differences in muscle insertion areas not detected using linear morphometric data.

  10. Linear versus geometric morphometric approaches for the analysis of head shape dimorphism in lizards.

    PubMed

    Fabre, Anne-Claire; Cornette, Raphäel; Huyghe, Katleen; Andrade, Denis V; Herrel, Anthony

    2014-09-01

    Differences between the sexes may arise because of differences in reproductive strategy, with females investing more in traits related to reproductive output and males investing more in traits related to resource holding capacity and territory defence. Sexual dimorphism is widespread in lizards and in many species males and females also differ in head shape. Males typically have bigger heads than females resulting in intersexual differences in bite force. Whereas most studies documenting differences in head dimensions between sexes use linear dimensions, the use of geometric morphometrics has been advocated as more appropriate to characterize such differences. This method may allow the characterization of local shape differences that may have functional consequences, and provides unbiased indicators of shape. Here, we explore whether the two approaches provide similar results in an analyses of head shape in Tupinambis merianae. The Argentine black and white tegu differs dramatically in body size, head size, and bite force between the sexes. However, whether the intersexual differences in bite force are simply the result of differences in head size or whether more subtle modifications (e.g., in muscle insertion areas) are involved remains currently unknown. Based on the crania and mandibles of 19 lizards with known bite force, we show intersexual differences in the shape of the cranium and mandible using both linear and geometric morphometric approaches. Although both types of analyses showed generally similar results for the mandible, this was not the case for the cranium. Geometric morphometric approaches provided better insights into the underlying functional relationships between the cranium and the jaw musculature, as illustrated by shape differences in muscle insertion areas not detected using linear morphometric data. PMID:24740578

  11. Ancient balancing selection at tan underlies female colour dimorphism in Drosophila erecta.

    PubMed

    Yassin, Amir; Bastide, Héloïse; Chung, Henry; Veuille, Michel; David, Jean R; Pool, John E

    2016-01-01

    Dimorphic traits are ubiquitous in nature, but the evolutionary factors leading to dimorphism are largely unclear. We investigate a potential case of sexual mimicry in Drosophila erecta, in which females show contrasting resemblance to males. We map the genetic basis of this sex-limited colour dimorphism to a region containing the gene tan. We find a striking signal of ancient balancing selection at the 'male-specific enhancer' of tan, with exceptionally high sequence divergence between light and dark alleles, suggesting that this dimorphism has been adaptively maintained for millions of years. Using transgenic reporter assays, we confirm that these enhancer alleles encode expression differences that are predicted to generate this pigmentation dimorphism. These results are compatible with the theoretical prediction that divergent phenotypes maintained by selection can evolve simple genetic architectures.

  12. Sexual dimorphism in two subspecies of Ethiopian Baboons (Papio Hamadryas) and their hybrids.

    PubMed

    Phillips-Conroy, J E; Jolly, C J

    1981-10-01

    Sexual dimorphism in mammals has been related to such variables as absolute body size, ecology, and various aspects of social behavior. Attempts to relate dimorphism to any of these variables have necessarily used small heterogeneous samples to represent the relevant species. We are concerned by the inevitable exclusion of any measure of variability in dimorphism and the consequent impossibility of assessing the significance of observed interspecific differences. In this paper we describe aspects of sexual dimorphism in anubis, hamadryas, and hybrid baboons from Ethiopia. Samples are large enough to permit a measure of intrapopulational variability. Hamadryas baboons are more dimorphic than anubis in epigamic features, but not in postcanine dentition, nor, contrary to previous reports, in body weight or canine tooth size. Hybrid males are more hamadryas-like and hybrid females more anubis-like, as would be predicted by the proposed mechanism for the establishment of the hybrid zone, namely the capture of anubis females by hamadryas males.

  13. Ancient balancing selection at tan underlies female colour dimorphism in Drosophila erecta

    PubMed Central

    Yassin, Amir; Bastide, Héloïse; Chung, Henry; Veuille, Michel; David, Jean R.; Pool, John E.

    2016-01-01

    Dimorphic traits are ubiquitous in nature, but the evolutionary factors leading to dimorphism are largely unclear. We investigate a potential case of sexual mimicry in Drosophila erecta, in which females show contrasting resemblance to males. We map the genetic basis of this sex-limited colour dimorphism to a region containing the gene tan. We find a striking signal of ancient balancing selection at the ‘male-specific enhancer' of tan, with exceptionally high sequence divergence between light and dark alleles, suggesting that this dimorphism has been adaptively maintained for millions of years. Using transgenic reporter assays, we confirm that these enhancer alleles encode expression differences that are predicted to generate this pigmentation dimorphism. These results are compatible with the theoretical prediction that divergent phenotypes maintained by selection can evolve simple genetic architectures. PMID:26778363

  14. Nutritional Biochemistry of Space Flight

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.

    2000-01-01

    Adequate nutrition is critical for maintenance of crew health during and after extended-duration space flight. The impact of weightlessness on human physiology is profound, with effects on many systems related to nutrition, including bone, muscle, hematology, fluid and electrolyte regulation. Additionally, we have much to learn regarding the impact of weightlessness on absorption, mtabolism , and excretion of nutrients, and this will ultimately determine the nutrient requirements for extended-duration space flight. Existing nutritional requirements for extended-duration space flight have been formulated based on limited flight research, and extrapolation from ground-based research. NASA's Nutritional Biochemistry Laboratory is charged with defining the nutritional requirements for space flight. This is accomplished through both operational and research projects. A nutritional status assessment program is included operationally for all International Space Station astronauts. This medical requirement includes biochemical and dietary assessments, and is completed before, during, and after the missions. This program will provide information about crew health and nutritional status, and will also provide assessments of countermeasure efficacy. Ongoing research projects include studies of calcium and bone metabolism, and iron absorption and metabolism. The calcium studies include measurements of endocrine regulation of calcium homeostasis, biochemical marker of bone metabolism, and tracer kinetic studies of calcium movement in the body. These calcium kinetic studies allow for estimation of intestinal absorption, urinary excretion, and perhaps most importantly - deposition and resorption of calcium from bone. The Calcium Kinetics experiment is currently being prepared for flight on the Space Shuttle in 2001, and potentially for subsequent Shuttle and International Space Station missions. The iron study is intended to assess whether iron absorption is down-regulated dUl1ng

  15. The Ontogeny of Sexual Size Dimorphism of a Moth: When Do Males and Females Grow Apart?

    PubMed Central

    Stillwell, R. Craig; Daws, Andrew; Davidowitz, Goggy

    2014-01-01

    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. PMID:25184664

  16. Variation in Craniomandibular Morphology and Sexual Dimorphism in Pantherines and the Sabercat Smilodon fatalis

    PubMed Central

    Christiansen, Per; Harris, John M.

    2012-01-01

    Sexual dimorphism is widespread among carnivorans, and has been an important evolutionary factor in social ecology. However, its presence in sabertoothed felids remains contentious. Here we present a comprehensive analysis of extant Panthera and the sabertoothed felid Smilodon fatalis. S. fatalis has been reported to show little or no sexual dimorphism but to have been intraspecifically variable in skull morphology. We found that large and small specimens of S. fatalis could be assigned to male and female sexes with similar degrees of confidence as Panthera based on craniomandibular shape. P. uncia is much less craniomandibularly variable and has low levels of sexual size-dimorphism. Shape variation in S. fatalis probably reflects sexual differences. Craniomandibular size-dimorphism is lower in S. fatalis than in Panthera except P. uncia. Sexual dimorphism in felids is related to more than overall size, and S. fatalis and the four large Panthera species show marked and similar craniomandibular and dental morphometric sexual dimorphism, whereas morphometric dimorphism in P. uncia is less. Many morphometric-sexually dimorphic characters in Panthera and Smilodon are related to bite strength and presumably to killing ecology. This suggests that morphometric sexual dimorphism is an evolutionary adaptation to intraspecific resource partitioning, since large males with thicker upper canines and stronger bite forces would be able to hunt larger prey than females, which is corroborated by feeding ecology in P. leo. Sexual dimorphism indicates that S. fatalis could have been social, but it is unlikely that it lived in fusion-fission units dominated by one or a few males, as in sub-Saharan populations of P. leo. Instead, S. fatalis could have been solitary and polygynous, as most extant felids, or it may have lived in unisexual groups, as is common in P. leo persica. PMID:23110232

  17. Masticatory muscles of mouse do not undergo atrophy in space.

    PubMed

    Philippou, Anastassios; Minozzo, Fabio C; Spinazzola, Janelle M; Smith, Lucas R; Lei, Hanqin; Rassier, Dilson E; Barton, Elisabeth R

    2015-07-01

    Muscle loading is important for maintaining muscle mass; when load is removed, atrophy is inevitable. However, in clinical situations such as critical care myopathy, masticatory muscles do not lose mass. Thus, their properties may be harnessed to preserve mass. We compared masticatory and appendicular muscles responses to microgravity, using mice aboard the space shuttle Space Transportation System-135. Age- and sex-matched controls remained on the ground. After 13 days of space flight, 1 masseter (MA) and tibialis anterior (TA) were frozen rapidly for biochemical and functional measurements, and the contralateral MA was processed for morphologic measurements. Flight TA muscles exhibited 20 ± 3% decreased muscle mass, 2-fold decreased phosphorylated (P)-Akt, and 4- to 12-fold increased atrogene expression. In contrast, MAs had no significant change in mass but a 3-fold increase in P-focal adhesion kinase, 1.5-fold increase in P-Akt, and 50-90% lower atrogene expression compared with limb muscles, which were unaltered in microgravity. Myofibril force measurements revealed that microgravity caused a 3-fold decrease in specific force and maximal shortening velocity in TA muscles. It is surprising that myofibril-specific force from both control and flight MAs were similar to flight TA muscles, yet power was compromised by 40% following flight. Continued loading in microgravity prevents atrophy, but masticatory muscles have a different set point that mimics disuse atrophy in the appendicular muscle. PMID:25795455

  18. Masticatory muscles of mouse do not undergo atrophy in space.

    PubMed

    Philippou, Anastassios; Minozzo, Fabio C; Spinazzola, Janelle M; Smith, Lucas R; Lei, Hanqin; Rassier, Dilson E; Barton, Elisabeth R

    2015-07-01

    Muscle loading is important for maintaining muscle mass; when load is removed, atrophy is inevitable. However, in clinical situations such as critical care myopathy, masticatory muscles do not lose mass. Thus, their properties may be harnessed to preserve mass. We compared masticatory and appendicular muscles responses to microgravity, using mice aboard the space shuttle Space Transportation System-135. Age- and sex-matched controls remained on the ground. After 13 days of space flight, 1 masseter (MA) and tibialis anterior (TA) were frozen rapidly for biochemical and functional measurements, and the contralateral MA was processed for morphologic measurements. Flight TA muscles exhibited 20 ± 3% decreased muscle mass, 2-fold decreased phosphorylated (P)-Akt, and 4- to 12-fold increased atrogene expression. In contrast, MAs had no significant change in mass but a 3-fold increase in P-focal adhesion kinase, 1.5-fold increase in P-Akt, and 50-90% lower atrogene expression compared with limb muscles, which were unaltered in microgravity. Myofibril force measurements revealed that microgravity caused a 3-fold decrease in specific force and maximal shortening velocity in TA muscles. It is surprising that myofibril-specific force from both control and flight MAs were similar to flight TA muscles, yet power was compromised by 40% following flight. Continued loading in microgravity prevents atrophy, but masticatory muscles have a different set point that mimics disuse atrophy in the appendicular muscle.

  19. Stamen dimorphism in Rhododendron ferrugineum (Ericaceae): development and function.

    PubMed

    Escaravage, Nathalie; Flubacker, Elisabeth; Pornon, André; Doche, Bernard; Till-Bottraud, Irène

    2001-01-01

    The function of stamen dimorphism in the breeding system of the alpine shrub Rhododendron ferrugineum was studied in two populations in the French Alps. This species has pentameric flowers with two whorls of stamens: an inner whorl of five long stamens and an outer whorl of short stamens. We studied the development of stamens from buds to mature flowers (measurement of the filament, anther, and style lengths at five successive phenological stages) and compared the size and position of reproductive organs at maturity in control and partially emasculated flowers (removal of long-level stamens) to determine whether the presence of long-level stamens constitutes a constraint for the development of the short-level ones. Stamen dimorphism can be observed early in stamen development, from the bud stage of the year prior to flowering. At this early stage, meiosis had already occurred. Emasculation of the long-level stamens induced the short-level ones to grow longer than in normal conditions. We also performed seven pollination treatments on ten randomly chosen individuals in each population, and the number of seeds following each treatment was recorded. Results from these treatments showed that R. ferrugineum produced spontaneous selfed seeds in the absence of pollinators. However, no seed was produced when short-level stamens were emasculated and pollinators excluded, suggesting that long-level stamens are not responsible for selfing in the absence of pollinators and that reproductive assurance is promoted by short-level stamens. PMID:11159128

  20. A brain sexual dimorphism controlled by adult circulating androgens.

    PubMed

    Cooke, B M; Tabibnia, G; Breedlove, S M

    1999-06-22

    Reports of structural differences between the brains of men and women, heterosexual and homosexual men, and male-to-female transsexuals and other men have been offered as evidence that the behavioral differences between these groups are likely caused by differences in the early development of the brain. However, a possible confounding variable is the concentration of circulating hormones seen in these groups in adulthood. Evaluation of this possibility hinges on the extent to which circulating hormones can alter the size of mammalian brain regions as revealed by Nissl stains. We now report a sexual dimorphism in the volume of a brain nucleus in rats that can be completely accounted for by adult sex differences in circulating androgen. The posterodorsal nucleus of the medial amygdala (MePD) has a greater volume in male rats than in females, but adult castration of males causes the volume to shrink to female values within four weeks, whereas androgen treatment of adult females for that period enlarges the MePD to levels equivalent to normal males. This report demonstrates that adult hormone manipulations can completely reverse a sexual dimorphism in brain regional volume in a mammalian species. The sex difference and androgen responsiveness of MePD volume is reflected in the soma size of neurons there. PMID:10377450

  1. Is Sexual Size Dimorphism Inherent in the Scallop Patinopecten yessoensis?

    PubMed Central

    Silina, Alla V.

    2016-01-01

    Studies on sexual size dimorphism in Pectinidae are limited. This work deals with the mobile long-lived scallop Patinopecten yessoensis, a common (fished and cultured) species in the subtidal benthos of the Sea of Japan. A previously developed method of age determination in P. yessoensis allowed me to compare the parameters of same aged males and females in scallop populations. The shell growth rates and sizes of both sexes were similar; therefore, it was only possible to visually identify the sex of live specimens during the breeding period (May-June). Statistical analyses showed female-biased dimorphism in the gonad weight for age groups that are >4 years old. Gonad weight (in the prespawning period) increased with age, until a threshold age was attained, which varied between populations; and then gonad weight remained virtually unchanged. The fecundity advantage hypothesis for P. yessoensis with group mating and external fertilization is at least partly realized by physiological mechanisms, which cause older females to have larger gonads than those of same aged males in the population in order to produce a larger brood. Gregarious settlement of this bivalve contributes to the reproductive success of the population so that the energetically costly ovaries may all be fertilized. PMID:27293980

  2. Sexually dimorphic effects of hippocampal cholinergic deafferentation in rats.

    PubMed

    Jonasson, Zachariah; Cahill, Jonathan F X; Tobey, Rachel E; Baxter, Mark G

    2004-12-01

    To determine whether the basal forebrain-hippocampal cholinergic system supports sexually dimorphic functionality, male and female Long-Evans rats were given either selective medial septum/vertical limb of the diagonal band (MS/VDB) cholinergic lesions using the neurotoxin 192 IgG-saporin or a control surgery and then postoperatively tested in a set of standard spatial learning tasks in the Morris water maze. Lesions were highly specific and effective as confirmed by both choline acetyltransferase/parvalbumin immunostaining and acetylcholinesterase histochemistry. Female controls performed worse than male controls in place learning and MS/VDB lesions failed to impair spatial learning in male rats, both consistent with previous findings. In female rats, MS/VDB cholinergic lesions facilitated spatial reference learning. A subsequent test of learning strategy in the water maze revealed a female bias for a response, relative to a spatial, strategy; MS/VDB cholinergic lesions enhanced the use of a spatial strategy in both sexes, but only significantly so in males. Together, these results indicate a sexually dimorphic function associated with MS/VDB-hippocampal cholinergic inputs. In female rats, these neurons appear to support sex-specific spatial learning processes.

  3. Energetics, scaling and sexual size dimorphism of spiders.

    PubMed

    Grossi, B; Canals, M

    2015-03-01

    The extreme sexual size dimorphism in spiders has motivated studies for many years. In many species the male can be very small relative to the female. There are several hypotheses trying to explain this fact, most of them emphasizing the role of energy in determining spider size. The aim of this paper is to review the role of energy in sexual size dimorphism of spiders, even for those spiders that do not necessarily live in high foliage, using physical and allometric principles. Here we propose that the cost of transport or equivalently energy expenditure and the speed are traits under selection pressure in male spiders, favoring those of smaller size to reduce travel costs. The morphology of the spiders responds to these selective forces depending upon the lifestyle of the spiders. Climbing and bridging spiders must overcome the force of gravity. If bridging allows faster dispersal, small males would have a selective advantage by enjoying more mating opportunities. In wandering spiders with low population density and as a consequence few male-male interactions, high speed and low energy expenditure or cost of transport should be favored by natural selection. Pendulum mechanics show the advantages of long legs in spiders and their relationship with high speed, even in climbing and bridging spiders. Thus small size, compensated by long legs should be the expected morphology for a fast and mobile male spider.

  4. Sexually dimorphic proteinuria in Wistar rats: Relevance to clinical models.

    PubMed

    Imafidon, Eseigbe Christian; Akomolafe, Rufus Ojo; Oladele, Abraham Ayodele

    2016-03-01

    The study investigated the relationship between physiological proteinuria and the histomorphometry of the renal corpuscles in apparently healthy Wistar rats of both sexes, belonging to the same age group. This was with a view to appraise any possible connection between potential expression of sexual dimorphism and the histomorphometry of some integral parts of the glomerular filtration barrier. Twenty Wistar rats of both sexes between ages 9 and 10 weeks were used for this study. This comprised 10 male and 10 female rats weighing 110-200g which were housed in separate metabolic cages for the collection of urine samples.They were sacrificed 24h and 7 days after 2 weeks of acclimatization, respectively. The rats were fasted for 24h during the collection of urine samples. The results showed 74.75% significantly higher urine total protein (p<0.0001), 187.29% significantly higher mg protein/100g body weight (p<0.0001), 32.34% significantly higher Bowman's capsular thickness (p<0.0001), 30.64% significantly higher glomerular thickness (p=0.0002), 59.47% significantly higher Bowman's capsular space (p=0.003), 5.30% insignificantly lower creatinine clearance (p=0.24) and 28.05% significantly higher level of urine protein to creatinine ratio (p<0.0001) in the male when compared with their female counterpart. In conclusion, Wistar rats express sexually dimorphic proteinuria which is structural in origin. PMID:26896858

  5. Patterns of sexual dimorphism in Mexican alligator lizards, Barisia imbricata

    PubMed Central

    Dashevsky, Daniel; Meik, Jesse M; Mociño-Deloya, Estrella; Setser, Kirk; Schaack, Sarah

    2013-01-01

    We compare morphological characteristics of male and female Barisia imbricata, Mexican alligator lizards, and find that mass, head length, coloration, incidence of scars from conspecifics, tail loss, and frequency of bearing the color/pattern of the opposite sex are all sexually dimorphic traits. Overall size (measured as snout–vent length), on the other hand, is not different between the two sexes. We use data on bite scar frequency and fecundity to evaluate competing hypotheses regarding the selective forces driving these patterns. We contend that sexual selection, acting through male-male competition, may favor larger mass and head size in males, whereas large females are likely favored by natural selection for greater fecundity. In addition, the frequency of opposite-sex patterning in males versus females may indicate that the costs of agonistic interactions among males are severe enough to allow for an alternative mating strategy. Finally, we discuss how sexual and natural selective forces may interact to drive or mask the evolution of sexually dimorphic traits. PMID:23467394

  6. Regulation of transcription factors on sexual dimorphism of fig wasps.

    PubMed

    Sun, Bao-Fa; Li, Yong-Xing; Jia, Ling-Yi; Niu, Li-Hua; Murphy, Robert W; Zhang, Peng; He, Shunmin; Huang, Da-Wei

    2015-06-02

    Fig wasps exhibit extreme intraspecific morphological divergence in the wings, compound eyes, antennae, body color, and size. Corresponding to this, behaviors and lifestyles between two sexes are also different: females can emerge from fig and fly to other fig tree to oviposit and pollinate, while males live inside fig for all their lifetime. Genetic regulation may drive these extreme intraspecific morphological and behavioral divergence. Transcription factors (TFs) involved in morphological development and physiological activity may exhibit sex-specific expressions. Herein, we detect 865 TFs by using genomic and transcriptomic data of the fig wasp Ceratosolen solmsi. Analyses of transcriptomic data indicated that up-regulated TFs in females show significant enrichment in development of the wing, eye and antenna in all stages, from larva to adult. Meanwhile, TFs related to the development of a variety of organs display sex-specific patterns of expression in the adults and these may contribute significantly to their sexual dimorphism. In addition, up-regulated TFs in adult males exhibit enrichment in genitalia development and circadian rhythm, which correspond with mating and protandry. This finding is consistent with their sex-specific behaviors. In conclusion, our results strongly indicate that TFs play important roles in the sexual dimorphism of fig wasps.

  7. DWnt-2, a Drosophila Wnt gene required for the development of the male reproductive tract, specifies a sexually dimorphic cell fate

    PubMed Central

    Kozopas, Karen M.; Samos, Cindy Harryman; Nusse, Roel

    1998-01-01

    The sexually dimorphic characteristics of the reproductive tract in Drosophila require that cells of the gonad and the genital disc be assigned sex-specific fates. We report here that DWnt-2, a secreted glycoprotein related to wingless, is a signal required for cell fate determination and morphogenesis in the developing male reproductive tract. Testes from DWnt-2 null mutant flies lack the male-specific pigment cells of the reproductive tract sheath and the muscle precursors of the sheath fail to migrate normally. However, other cell types of the testis are unaffected. DWnt-2 is expressed in somatic cells of the gonad throughout development, implicating it as a signal that can influence pigment cell fate directly. Indeed, the ectopic expression of DWnt-2 in females results in the appearance of male-specific pigment cells in otherwise morphologically normal ovaries. Thus, the presence of pigment cells is a sexually dimorphic trait that is controlled by DWnt-2 expression. DWnt-2 is also expressed in regions of the male genital disc and gonad, which we have identified as sites of contact with muscle precursor cells, suggesting that secreted DWnt-2 protein is a signal for the migration or attachment of these cells. PMID:9553045

  8. Human tolerance to space flight

    NASA Technical Reports Server (NTRS)

    Huntoon, C. L.

    1989-01-01

    Medical studies of astronauts and cosmonauts before, during, and after space missions have identified several effects of weightlessness and other factors that influence the ability of humans to tolerate space flight. Weightlessness effects include space motion sickness, cardiovascular abnormalities, reduction in immune system function, loss of red blood cells, loss of bone mass, and muscle atrophy. Extravehicular activity (EVA) increases the likelihood that decompression sickness may occur. Radiation also gives reason for concern about health of crewmembers, and psychological factors are important on long-term flights. Countermeasures that have been used include sensory preadaptation, prebreathing and use of various air mixtures for EVA, loading with water and electrolytes, exercise, use of pharmacological agents and special diets, and psychological support. It appears that humans can tolerate and recover satisfactorily from at least one year of space flight, but a number of conditions must be further ameliorated before long-duration missions can be considered routine.

  9. Poor flight performance in deep-diving cormorants.

    PubMed

    Watanabe, Yuuki Y; Takahashi, Akinori; Sato, Katsufumi; Viviant, Morgane; Bost, Charles-André

    2011-02-01

    Aerial flight and breath-hold diving present conflicting morphological and physiological demands, and hence diving seabirds capable of flight are expected to face evolutionary trade-offs regarding locomotory performances. We tested whether Kerguelen shags Phalacrocorax verrucosus, which are remarkable divers, have poor flight capability using newly developed tags that recorded their flight air speed (the first direct measurement for wild birds) with propeller sensors, flight duration, GPS position and depth during foraging trips. Flight air speed (mean 12.7 m s(-1)) was close to the speed that minimizes power requirement, rather than energy expenditure per distance, when existing aerodynamic models were applied. Flights were short (mean 92 s), with a mean summed duration of only 24 min day(-1). Shags sometimes stayed at the sea surface without diving between flights, even on the way back to the colony, and surface durations increased with the preceding flight durations; these observations suggest that shags rested after flights. Our results indicate that their flight performance is physiologically limited, presumably compromised by their great diving capability (max. depth 94 m, duration 306 s) through their morphological adaptations for diving, including large body mass (enabling a large oxygen store), small flight muscles (to allow for large leg muscles for underwater propulsion) and short wings (to decrease air volume in the feathers and hence buoyancy). The compromise between flight and diving, as well as the local bathymetry, shape the three-dimensional foraging range (<26 km horizontally, <94 m vertically) in this bottom-feeding cormorant. PMID:21228200

  10. Impact of weightlessness on muscle function

    NASA Technical Reports Server (NTRS)

    Tischler, M. E.; Slentz, M.

    1995-01-01

    The most studied skeletal muscles which depend on gravity, "antigravity" muscles, are located in the posterior portion of the legs. Antigravity muscles are characterized generally by a different fiber type composition than those which are considered nonpostural. The gravity-dependent function of the antigravity muscles makes them particularly sensitive to weightlessness (unweighting) resulting in a substantial loss of muscle protein, with a relatively greater loss of myofibrillar (structural) proteins. Accordingly alpha-actin mRNA decreases in muscle of rats exposed to microgravity. In the legs, the soleus seems particularly responsive to the lack of weight-bearing associated with space flight. The loss of muscle protein leads to a decreased cross-sectional area of muscle fibers, particularly of the slow-twitch, oxidative (SO) ones compared to fast-twitch glycolytic (FG) or oxidative-glycolytic (FOG) fibers. In some muscles, a shift in fiber composition from SO to FOG has been reported in the adaptation to spaceflight. Changes in muscle composition with spaceflight have been associated with decreased maximal isometric tension (Po) and increased maximal shortening velocity. In terms of fuel metabolism, results varied depending on the pathway considered. Glucose uptake, in the presence of insulin, and activities of glycolytic enzymes are increased by space flight. In contrast, oxidation of fatty acids may be diminished. Oxidation of pyruvate, activity of the citric acid cycle, and ketone metabolism in muscle seem to be unaffected by microgravity.

  11. The flight planning - flight management connection

    NASA Technical Reports Server (NTRS)

    Sorensen, J. A.

    1984-01-01

    Airborne flight management systems are currently being implemented to minimize direct operating costs when flying over a fixed route between a given city pair. Inherent in the design of these systems is that the horizontal flight path and wind and temperature models be defined and input into the airborne computer before flight. The wind/temperature model and horizontal path are products of the flight planning process. Flight planning consists of generating 3-D reference trajectories through a forecast wind field subject to certain ATC and transport operator constraints. The interrelationships between flight management and flight planning are reviewed, and the steps taken during the flight planning process are summarized.

  12. Dragonfly flight. III. Lift and power requirements.

    PubMed

    Wakeling, JM; Ellington, CP

    1997-02-01

    A mean lift coefficient quasi-steady analysis has been applied to the free flight of the dragonfly Sympetrum sanguineum and the damselfly Calopteryx splendens. The analysis accommodated the yaw and accelerations involved in free flight. For any given velocity or resultant aerodynamic force (thrust), the damselfly mean lift coefficient was higher than that for the dragonfly because of its clap and fling. For both species, the maximum mean lift coefficient L was higher than the steady CL,max. Both species aligned their strokes planes to be nearly normal to the thrust, a strategy that reduces the L required for flight and which is different from the previously published hovering and slow dragonfly flights with stroke planes steeply inclined to the horizontal. Owing to the relatively low costs of accelerating the wing, the aerodynamic power required for flight represents the mechanical power output from the muscles. The maximum muscle mass-specific power was estimated at 156 and 166 W kg-1 for S. sanguineum and C. splendens, respectively. Measurements of heat production immediately after flight resulted in mechanical efficiency estimates of 13 % and 9 % for S. sanguineum and C. splendens muscles, respectively.

  13. Sexual dimorphism in venom chemistry in Tetragnatha spiders is not easily explained by adult niche differences.

    PubMed

    Binford, Greta J; Gillespie, Rosemary G; Maddison, Wayne P

    2016-05-01

    Spider venom composition typically differs between sexes. This pattern is anecdotally thought to reflect differences in adult feeding biology. We used a phylogenetic approach to compare intersexual venom dimorphism between species that differ in adult niche dimorphism. Male and female venoms were compared within and between related species of Hawaiian Tetragnatha, a mainland congener, and outgroups. In some species of Hawaiian Tetragnatha adult females spin orb-webs and adult males capture prey while wandering, while in other species both males and females capture prey by wandering. We predicted that, if venom sexual dimorphism is primarily explained by differences in adult feeding biology, species in which both sexes forage by wandering would have monomorphic venoms or venoms with reduced dimorphism relative to species with different adult feeding biology. However, we found striking sexual dimorphism in venoms of both wandering and orb-weaving Tetragnatha species with males having high molecular weight components in their venoms that were absent in females, and a reduced concentration of low molecular weight components relative to females. Intersexual differences in venom composition within Tetragnatha were significantly larger than in non-Tetragnatha species. Diet composition was not different between sexes. This striking venom dimorphism is not easily explained by differences in feeding ecology or behavior. Rather, we hypothesize that the dimorphism reflects male-specific components that play a role in mating biology possibly in sexual stimulation, nuptial gifts and/or mate recognition.

  14. From Lucy to Kadanuumuu: balanced analyses of Australopithecus afarensis assemblages confirm only moderate skeletal dimorphism

    PubMed Central

    Lovejoy, C. Owen

    2015-01-01

    Sexual dimorphism in body size is often used as a correlate of social and reproductive behavior in Australopithecus afarensis. In addition to a number of isolated specimens, the sample for this species includes two small associated skeletons (A.L. 288-1 or “Lucy” and A.L. 128/129) and a geologically contemporaneous death assemblage of several larger individuals (A.L. 333). These have driven both perceptions and quantitative analyses concluding that Au. afarensis was markedly dimorphic. The Template Method enables simultaneous evaluation of multiple skeletal sites, thereby greatly expanding sample size, and reveals that A. afarensis dimorphism was similar to that of modern humans. A new very large partial skeleton (KSD-VP-1/1 or “Kadanuumuu”) can now also be used, like Lucy, as a template specimen. In addition, the recently developed Geometric Mean Method has been used to argue that Au. afarensis was equally or even more dimorphic than gorillas. However, in its previous application Lucy and A.L. 128/129 accounted for 10 of 11 estimates of female size. Here we directly compare the two methods and demonstrate that including multiple measurements from the same partial skeleton that falls at the margin of the species size range dramatically inflates dimorphism estimates. Prevention of the dominance of a single specimen’s contribution to calculations of multiple dimorphism estimates confirms that Au. afarensis was only moderately dimorphic. PMID:25945314

  15. Males Resemble Females: Re-Evaluating Sexual Dimorphism in Protoceratops andrewsi (Neoceratopsia, Protoceratopsidae)

    PubMed Central

    Maiorino, Leonardo; Farke, Andrew A.; Kotsakis, Tassos; Piras, Paolo

    2015-01-01

    Background Protoceratops andrewsi (Neoceratopsia, Protoceratopsidae) is a well-known dinosaur from the Upper Cretaceous of Mongolia. Some previous workers hypothesized sexual dimorphism in the cranial shape of this taxon, using qualitative and quantitative observations. In particular, width and height of the frill as well as the development of a nasal horn have been hypothesized as potentially sexually dimorphic. Methodology/Principal Findings Here, we reassess potential sexual dimorphism in skulls of Protoceratops andrewsi by applying two-dimensional geometric morphometrics to 29 skulls in lateral and dorsal views. Principal Component Analyses and nonparametric MANOVAs recover no clear separation between hypothetical “males” and “females” within the overall morphospace. Males and females thus possess similar overall cranial morphologies. No differences in size between “males” and “females” are recovered using nonparametric ANOVAs. Conclusions/Significance Sexual dimorphism within Protoceratops andrewsi is not strongly supported by our results, as previously proposed by several authors. Anatomical traits such as height and width of the frill, and skull size thus may not be sexually dimorphic. Based on PCA for a data set focusing on the rostrum and associated ANOVA results, nasal horn height is the only feature with potential dimorphism. As a whole, most purported dimorphic variation is probably primarily the result of ontogenetic cranial shape changes as well as intraspecific cranial variation independent of sex. PMID:25951329

  16. Modeling Muscles

    ERIC Educational Resources Information Center

    Goodwyn, Lauren; Salm, Sarah

    2007-01-01

    Teaching the anatomy of the muscle system to high school students can be challenging. Students often learn about muscle anatomy by memorizing information from textbooks or by observing plastic, inflexible models. Although these mediums help students learn about muscle placement, the mediums do not facilitate understanding regarding integration of…

  17. Sexual dimorphism in the Atapuerca-SH hominids: the evidence from the mandibles.

    PubMed

    Rosas, Antonio; Bastir, Markus; Martínez-Maza, Cayetana; Bermúdez de Castro, Jose María

    2002-04-01

    The pattern of sexual dimorphism in 15 mandibles from the Atapuerca-SH Middle Pleistocene site, attributed to Homo heidelbergensis, is explored. Two modern human samples of known sex are used as a baseline for establishing sexing criteria. The mandible was divided for analysis into seven study regions and differential expression of sexual dimorphism in these regions is analysed. A total of 40 continuous and 32 discrete variables were scored on the mandibles. The means method given in Regh & Leigh (Am. J. phys. Anthrop.110, 95-104, 1999) was followed for evaluating the potential of correct sex attribution for each variable. On average, the mandibles from the Atapuerca-SH site present a degree of sexual dimorphism about eight points higher than in H. sapiens samples. However, mandibular anatomy of the European Middle Pleistocene hominid records sexual dimorphism differentially. Different areas of the Atapuerca-SH mandibles exhibit quite distinct degrees of sexual dimorphism. For instance, variables of the alveolar arcade present very low or practically no sexual dimorphism. Variables related to overall size of the mandible and symphysis region present a medium degree of sex differences. Finally, ramus height, and gonion and coronoid process present a high degree of sexual dimorphism (indexes of sexual dimorphism are all above 130%). Whether this marked sexual dimorphism in specific anatomical systems affects sexual differences in body size is not completely clear and further studies are needed. Sexual differences detected in the mandible of modern humans have at least two components: differences related to musculo-skeletal development and differences related to a different growth trajectory in males and females (relative development of some of the basal border features). The Atapuerca-SH mandibles display little variation in the basal border, however. The limited variation of this mandibular region may indicate that the pattern of sexual variation in H

  18. Sexual dimorphism in the bed nucleus of the accessory olfactory tract in the rat.

    PubMed

    Collado, P; Guillamón, A; Valencia, A; Segovia, S

    1990-11-01

    This work investigates the existence of sex differences in the volume and number of neurons and glial cells in the bed nucleus of the accessory olfactory tract (BAOT). Males showed larger volume and number of cells than female rats. Early postnatal (day 1 after birth) orchidectomy in males, and androgenization in females, reversed these differences. No sex differences were found in BAOT glial cells. The sexual dimorphism found in the neuron/glial cell ratio reflects sex differences in neuron number. The existence of sexual dimorphism in the BAOT supports our earlier hypothesis which states that the vomeronasal system (VNS) is sexually dimorphic.

  19. Sexual dimorphism in the vomeronasal pathway and sex differences in reproductive behaviors.

    PubMed

    Segovia, S; Guillamón, A

    1993-01-01

    Several years ago we hypothesized that the vomeronasal system (VNS), a complex neural network involved in the control of reproductive behavior, might be sexually dimorphic. This hypothesis sprung from several facts; (a) the existence of steroid receptors in the VNS; (b) sexual dimorphism was already described in some structures that receive vomeronasal input, such as the medial preoptic area, the ventromedial hypothalamic nucleus, the ventral region of the premammillary nucleus and the medial amygdaloid nucleus; and (c) the vomeronasal organ, which is the receptor organ of the VNS, was also sexually dimorphic. After that point, the accessory olfactory bulb (AOB), the bed nucleus of the accessory olfactory tract (BAOT) and the bed nucleus of the stria terminalis were found to be sexually dimorphic. The aim of the present review is to show the experimental facts that confirm our earlier hypothesis and, consequently, to present the existence of a sexually dimorphic multisynaptic pathway for the first time in mammals. Sexual dimorphism in the VNS might provide a comprehensive approach to understanding the neural bases of sexually dimorphic reproductive behavior and it is suggested here that the greater number of neurons which male rats present in relation to females in most VNS structures might contribute to the inhibition of the expression of feminine copulatory behavior (lordosis) and maternal behavior in males. In addition, the mechanisms that control the development of sexual dimorphism in the VNS are discussed. The discussion takes into account the two patterns of sexual dimorphism found in the rat brain. Estrogens seem to promote the development of sexual dimorphism in both male and female rats. However, an inhibitory role of androgens might be necessary to hypothesize when males or females present a lower number of neurons and/or volume than the opposite sex. There are experimental data supporting this hypothesis in the female, since dihydrotestosterone seems to

  20. Sexual Dimorphism and Population Differences in Structural Properties of Barn Swallow (Hirundo rustica) Wing and Tail Feathers.

    PubMed

    Pap, Péter L; Osváth, Gergely; Aparicio, José Miguel; Bărbos, Lőrinc; Matyjasiak, Piotr; Rubolini, Diego; Saino, Nicola; Vágási, Csongor I; Vincze, Orsolya; Møller, Anders Pape

    2015-01-01

    Sexual selection and aerodynamic forces affecting structural properties of the flight feathers of birds are poorly understood. Here, we compared the structural features of the innermost primary wing feather (P1) and the sexually dimorphic outermost (Ta6) and monomorphic second outermost (Ta5) tail feathers of barn swallows (Hirundo rustica) from a Romanian population to investigate how sexual selection and resistance to aerodynamic forces affect structural differences among these feathers. Furthermore, we compared structural properties of Ta6 of barn swallows from six European populations. Finally, we determined the relationship between feather growth bars width (GBW) and the structural properties of tail feathers. The structure of P1 indicates strong resistance against aerodynamic forces, while the narrow rachis, low vane density and low bending stiffness of tail feathers suggest reduced resistance against airflow. The highly elongated Ta6 is characterized by structural modifications such as large rachis width and increased barbule density in relation to the less elongated Ta5, which can be explained by increased length and/or high aerodynamic forces acting at the leading tail edge. However, these changes in Ta6 structure do not allow for full compensation of elongation, as reflected by the reduced bending stiffness of Ta6. Ta6 elongation in males resulted in feathers with reduced resistance, as shown by the low barb density and reduced bending stiffness compared to females. The inconsistency in sexual dimorphism and in change in quality traits of Ta6 among six European populations shows that multiple factors may contribute to shaping population differences. In general, the difference in quality traits between tail feathers cannot be explained by the GBW of feathers. Our results show that the material and structural properties of wing and tail feathers of barn swallows change as a result of aerodynamic forces and sexual selection, although the result of these

  1. Sexual Dimorphism and Population Differences in Structural Properties of Barn Swallow (Hirundo rustica) Wing and Tail Feathers

    PubMed Central

    Pap, Péter L.; Osváth, Gergely; Aparicio, José Miguel; Bărbos, Lőrinc; Matyjasiak, Piotr; Rubolini, Diego; Saino, Nicola; Vágási, Csongor I.; Vincze, Orsolya; Møller, Anders Pape

    2015-01-01

    Sexual selection and aerodynamic forces affecting structural properties of the flight feathers of birds are poorly understood. Here, we compared the structural features of the innermost primary wing feather (P1) and the sexually dimorphic outermost (Ta6) and monomorphic second outermost (Ta5) tail feathers of barn swallows (Hirundo rustica) from a Romanian population to investigate how sexual selection and resistance to aerodynamic forces affect structural differences among these feathers. Furthermore, we compared structural properties of Ta6 of barn swallows from six European populations. Finally, we determined the relationship between feather growth bars width (GBW) and the structural properties of tail feathers. The structure of P1 indicates strong resistance against aerodynamic forces, while the narrow rachis, low vane density and low bending stiffness of tail feathers suggest reduced resistance against airflow. The highly elongated Ta6 is characterized by structural modifications such as large rachis width and increased barbule density in relation to the less elongated Ta5, which can be explained by increased length and/or high aerodynamic forces acting at the leading tail edge. However, these changes in Ta6 structure do not allow for full compensation of elongation, as reflected by the reduced bending stiffness of Ta6. Ta6 elongation in males resulted in feathers with reduced resistance, as shown by the low barb density and reduced bending stiffness compared to females. The inconsistency in sexual dimorphism and in change in quality traits of Ta6 among six European populations shows that multiple factors may contribute to shaping population differences. In general, the difference in quality traits between tail feathers cannot be explained by the GBW of feathers. Our results show that the material and structural properties of wing and tail feathers of barn swallows change as a result of aerodynamic forces and sexual selection, although the result of these

  2. [Spanish version of Adonis Complex Questionnaire. A questionnaire to test the muscle dimorphism and vigorexy].

    PubMed

    Latorre-Román, Pedro Ángel; Garrido-Ruiz, Antonio; García-Pinillos, Felipe

    2014-11-08

    Objetivo: Validar la versión española del cuestionario del complejo de Adonis en deportistas de musculación. Método: La muestra está compuesta por 99 deportistas de musculación que entrenan regularmente (Edad: 25.45±5.19 años; IMC=24.53±1.89 kg/m2). Los instrumentos utilizados para valorar la validez discriminante y convergente son la escala revisada de dependencia del ejercicio (Exercise Dependence Scale-Revised, EDS-R) y la escala de autoinformes de actitudes y síntomas de los trastornos alimenticios (Eating Attitudes Test, EAT-26). Las propiedades psicométricas de la escala se obtuvieron mediante un proceso de validez convergente, análisis factorial de los componentes principales, consistencia interna y fiabilidad test-retest. Resultados: La consistencia interna del instrumento muestra un alfa de Cronbach de 0.880 en la escala total. El coeficiente de correlación intraclase (CCI) para valorar la consistencia temporal del instrumento fue de CCI= 0.707, (95% intervalo de confianza=0.336-0.871). El instrumento muestra validez convergente con la escala EDS-R (r=0.613, p.

  3. Climate change and sexual size dimorphism in an Arctic spider.

    PubMed

    Høye, Toke Thomas; Hammel, Jörg U; Fuchs, Thomas; Toft, Søren

    2009-08-23

    Climate change is advancing the onset of the growing season and this is happening at a particularly fast rate in the High Arctic. However, in most species the relative fitness implications for males and females remain elusive. Here, we present data on 10 successive cohorts of the wolf spider Pardosa glacialis from Zackenberg in High-Arctic, northeast Greenland. We found marked inter-annual variation in adult body size (carapace width) and this variation was greater in females than in males. Earlier snowmelt during both years of its biennial maturation resulted in larger adult body sizes and a skew towards positive sexual size dimorphism (females bigger than males). These results illustrate the pervasive influence of climate on key life-history traits and indicate that male and female responses to climate should be investigated separately whenever possible. PMID:19435831

  4. General metabolism of the dimorphic and pathogenic fungus Paracoccidioides brasiliensis.

    PubMed

    Arraes, Fabrício B M; Benoliel, Bruno; Burtet, Rafael T; Costa, Patrícia L N; Galdino, Alexandro S; Lima, Luanne H A; Marinho-Silva, Camila; Oliveira-Pereira, Luciana; Pfrimer, Pollyanna; Procópio-Silva, Luciano; Reis, Viviane Castelo-Branco; Felipe, Maria Sueli S

    2005-06-30

    Annotation of the transcriptome of the dimorphic fungus Paracoccidioides brasiliensis has set the grounds for a global understanding of its metabolism in both mycelium and yeast forms. This fungus is able to use the main carbohydrate sources, including starch, and it can store reduced carbons in the form of glycogen and trehalose; these provide energy reserves that are relevant for metabolic adaptation, protection against stress and infectivity mechanisms. The glyoxylate cycle, which is also involved in pathogenicity, is present in this fungus. Classical pathways of lipid biosynthesis and degradation, including those of ketone body and sterol production, are well represented in the database of P. brasiliensis. It is able to synthesize de novo all nucleotides and amino acids, with the sole exception of asparagine, which was confirmed by the fungus growth in minimal medium. Sulfur metabolism, as well as the accessory synthetic pathways of vitamins and co-factors, are likely to exist in this fungus.

  5. Climate change and sexual size dimorphism in an Arctic spider.

    PubMed

    Høye, Toke Thomas; Hammel, Jörg U; Fuchs, Thomas; Toft, Søren

    2009-08-23

    Climate change is advancing the onset of the growing season and this is happening at a particularly fast rate in the High Arctic. However, in most species the relative fitness implications for males and females remain elusive. Here, we present data on 10 successive cohorts of the wolf spider Pardosa glacialis from Zackenberg in High-Arctic, northeast Greenland. We found marked inter-annual variation in adult body size (carapace width) and this variation was greater in females than in males. Earlier snowmelt during both years of its biennial maturation resulted in larger adult body sizes and a skew towards positive sexual size dimorphism (females bigger than males). These results illustrate the pervasive influence of climate on key life-history traits and indicate that male and female responses to climate should be investigated separately whenever possible.

  6. Status-dependent selection in the dimorphic beetle Onthophagus taurus.

    PubMed Central

    Hunt, J; Simmons, L W

    2001-01-01

    The occurrence of alternative reproductive phenotypes is widespread in most animal taxa. The majority of known examples best fit the notion of alternative tactics within a conditional strategy where the fitness pay-offs depend on an individual's competitive ability or status. Individuals are proposed as "choosing" the tactic that maximizes their fitness, given their status relative to others in the population. Theoretically, status-dependent selection should determine when an animal should switch between alternative tactics. While a number of studies have demonstrated unequal fitness pay-offs associated with alternative tactics, none, to our knowledge, have examined the fitness functions necessary for predicting when individuals should switch between tactics. Here, we use a dimorphic male beetle in order to provide the first empirically derived fitness function across alternative reproductive phenotypes. Our data provide empirical support for a game-theoretic conditional strategy that has evolved under status-dependent selection. PMID:11747558

  7. Dmrt genes in the development and evolution of sexual dimorphism

    PubMed Central

    Kopp, Artyom

    2012-01-01

    Most animals are sexually dimorphic, yet different taxa have different sex-specific traits. Despite major differences in the genetic control of sexual development among animal lineages, the Dmrt family of transcription factors has been shown to be involved in sex-specific differentiation in all animals studied so far. In recent years, the functions of Dmrt genes have been characterized in many animal groups, opening the way for a broad comparative perspective. In this review, I focus on the similarities and differences in the functions of Dmrt genes across the animal kingdom. I highlight a number of common themes in the sexual development of different taxa, discuss how Dmrt genes have acquired new roles during animal evolution, and show how they contributed to the origin of novel sex-specific traits. PMID:22425532

  8. The neuronal control of hypoxic ventilation: erythropoietin and sexual dimorphism.

    PubMed

    Gassmann, Max; Tissot van Patot, Martha; Soliz, Jorge

    2009-10-01

    Using mice, we demonstrated that when oxygen supply is lowered, erythropoietin (Epo), the main regulator of red blood cell production, modulates the ventilatory response by interacting with central (brainstem) and peripheral (carotid bodies) respiratory centers. We showed that enhanced Epo levels in the brainstem increased the hypoxic ventilatory response, and that intracerebroventricular injection of an Epo antagonist (soluble Epo receptor) abolished the ventilatory acclimatization to hypoxia. More recently, we have found that the impact of Epo on ventilation occurs in a sex-dependent manner. Keeping in mind that women are less susceptible to several respiratory sicknesses and syndromes than men, we suggest that Epo plays a key role in sexually-dimorphic hypoxic ventilation. Accordingly, we foresee that Epo has a potential therapeutic use as treatment for hypoxia-associated ventilatory diseases. PMID:19845617

  9. An analysis of sexual size dimorphism in goose.

    PubMed

    Parés-Casanova, P M

    2014-01-01

    1. Sexual size dimorphism (SSD) is a common phenomenon in animals. Rensch's rule states that larger species generally exhibit a higher male to female body size ratio than smaller ones. 2. Domesticated animals offer excellent opportunities for testing predictions of the functional explanations of Rensch's rule and this was tested in a meta-analysis of SSD in 38 breeds of domestic geese compared among themselves and with their wild relatives (subfamily Anserinae, 35 species). 3. Domestic geese and wild Anser species taken together supported Rench's rule but the wild species did not. 4. The non-targeted sex selection hypothesis seems to provide the best intuitive explanation for the lack of SSD in geese.

  10. Discovery of Sexual Dimorphisms in Metabolic and Genetic Biomarkers

    PubMed Central

    Krumsiek, Jan; Gieger, Christian; Prehn, Cornelia; Roemisch-Margl, Werner; Polonikov, Alexey; Peters, Annette; Theis, Fabian J.; Meitinger, Thomas; Kronenberg, Florian; Weidinger, Stephan; Wichmann, Heinz Erich; Suhre, Karsten; Wang-Sattler, Rui; Adamski, Jerzy; Illig, Thomas

    2011-01-01

    Metabolomic profiling and the integration of whole-genome genetic association data has proven to be a powerful tool to comprehensively explore gene regulatory networks and to investigate the effects of genetic variation at the molecular level. Serum metabolite concentrations allow a direct readout of biological processes, and association of specific metabolomic signatures with complex diseases such as Alzheimer's disease and cardiovascular and metabolic disorders has been shown. There are well-known correlations between sex and the incidence, prevalence, age of onset, symptoms, and severity of a disease, as well as the reaction to drugs. However, most of the studies published so far did not consider the role of sexual dimorphism and did not analyse their data stratified by gender. This study investigated sex-specific differences of serum metabolite concentrations and their underlying genetic determination. For discovery and replication we used more than 3,300 independent individuals from KORA F3 and F4 with metabolite measurements of 131 metabolites, including amino acids, phosphatidylcholines, sphingomyelins, acylcarnitines, and C6-sugars. A linear regression approach revealed significant concentration differences between males and females for 102 out of 131 metabolites (p-values<3.8×10−4; Bonferroni-corrected threshold). Sex-specific genome-wide association studies (GWAS) showed genome-wide significant differences in beta-estimates for SNPs in the CPS1 locus (carbamoyl-phosphate synthase 1, significance level: p<3.8×10−10; Bonferroni-corrected threshold) for glycine. We showed that the metabolite profiles of males and females are significantly different and, furthermore, that specific genetic variants in metabolism-related genes depict sexual dimorphism. Our study provides new important insights into sex-specific differences of cell regulatory processes and underscores that studies should consider sex-specific effects in design and interpretation. PMID

  11. Macroevolutionary patterns of sexual size dimorphism in copepods.

    PubMed

    Hirst, Andrew G; Kiørboe, Thomas

    2014-09-22

    Major theories compete to explain the macroevolutionary trends observed in sexual size dimorphism (SSD) in animals. Quantitative genetic theory suggests that the sex under historically stronger directional selection will exhibit greater interspecific variance in size, with covariation between allometric slopes (male to female size) and the strength of SSD across clades. Rensch's rule (RR) also suggests a correlation, but one in which males are always the more size variant sex. Examining free-living pelagic and parasitic Copepoda, we test these competing predictions. Females are commonly the larger sex in copepod species. Comparing clades that vary by four orders of magnitude in their degree of dimorphism, we show that isometry is widespread. As such we find no support for either RR or for covariation between allometry and SSD. Our results suggest that selection on both sexes has been equally important. We next test the prediction that variation in the degree of SSD is related to the adult sex ratio. As males become relatively less abundant, it has been hypothesized that this will lead to a reduction in both inter-male competition and male size. However, the lack of such a correlation across diverse free-living pelagic families of copepods provides no support for this hypothesis. By comparison, in sea lice of the family Caligidae, there is some qualitative support of the hypothesis, males may suffer elevated mortality when they leave the host and rove for sedentary females, and their female-biased SSD is greater than in many free-living families. However, other parasitic copepods which do not appear to have obvious differences in sex-based mate searching risks also show similar or even more extreme SSD, therefore suggesting other factors can drive the observed extremes. PMID:25100692

  12. Differential Juvenile Hormone Variations in Scale Insect Extreme Sexual Dimorphism

    PubMed Central

    Vea, Isabelle Mifom; Tanaka, Sayumi; Shiotsuki, Takahiro; Jouraku, Akiya; Tanaka, Toshiharu; Minakuchi, Chieka

    2016-01-01

    Scale insects have evolved extreme sexual dimorphism, as demonstrated by sedentary juvenile-like females and ephemeral winged males. This dimorphism is established during the post-embryonic development; however, the underlying regulatory mechanisms have not yet been examined. We herein assessed the role of juvenile hormone (JH) on the diverging developmental pathways occurring in the male and female Japanese mealybug Planococcus kraunhiae (Kuwana). We provide, for the first time, detailed gene expression profiles related to JH signaling in scale insects. Prior to adult emergence, the transcript levels of JH acid O-methyltransferase, encoding a rate-limiting enzyme in JH biosynthesis, were higher in males than in females, suggesting that JH levels are higher in males. Furthermore, male quiescent pupal-like stages were associated with higher transcript levels of the JH receptor gene, Methoprene-tolerant and its co-activator taiman, as well as the JH early-response genes, Krüppel homolog 1 and broad. The exposure of male juveniles to an ectopic JH mimic prolonged the expression of Krüppel homolog 1 and broad, and delayed adult emergence by producing a supernumeral pupal stage. We propose that male wing development is first induced by up-regulated JH signaling compared to female expression pattern, but a decrease at the end of the prepupal stage is necessary for adult emergence, as evidenced by the JH mimic treatments. Furthermore, wing development seems linked to JH titers as JHM treatments on the pupal stage led to wing deformation. The female pedomorphic appearance was not reflected by the maintenance of high levels of JH. The results in this study suggest that differential variations in JH signaling may be responsible for sex-specific and radically different modes of metamorphosis. PMID:26894583

  13. Differential Juvenile Hormone Variations in Scale Insect Extreme Sexual Dimorphism.

    PubMed

    Vea, Isabelle Mifom; Tanaka, Sayumi; Shiotsuki, Takahiro; Jouraku, Akiya; Tanaka, Toshiharu; Minakuchi, Chieka

    2016-01-01

    Scale insects have evolved extreme sexual dimorphism, as demonstrated by sedentary juvenile-like females and ephemeral winged males. This dimorphism is established during the post-embryonic development; however, the underlying regulatory mechanisms have not yet been examined. We herein assessed the role of juvenile hormone (JH) on the diverging developmental pathways occurring in the male and female Japanese mealybug Planococcus kraunhiae (Kuwana). We provide, for the first time, detailed gene expression profiles related to JH signaling in scale insects. Prior to adult emergence, the transcript levels of JH acid O-methyltransferase, encoding a rate-limiting enzyme in JH biosynthesis, were higher in males than in females, suggesting that JH levels are higher in males. Furthermore, male quiescent pupal-like stages were associated with higher transcript levels of the JH receptor gene, Methoprene-tolerant and its co-activator taiman, as well as the JH early-response genes, Krüppel homolog 1 and broad. The exposure of male juveniles to an ectopic JH mimic prolonged the expression of Krüppel homolog 1 and broad, and delayed adult emergence by producing a supernumeral pupal stage. We propose that male wing development is first induced by up-regulated JH signaling compared to female expression pattern, but a decrease at the end of the prepupal stage is necessary for adult emergence, as evidenced by the JH mimic treatments. Furthermore, wing development seems linked to JH titers as JHM treatments on the pupal stage led to wing deformation. The female pedomorphic appearance was not reflected by the maintenance of high levels of JH. The results in this study suggest that differential variations in JH signaling may be responsible for sex-specific and radically different modes of metamorphosis.

  14. Head shape dimorphism in European glass eels (Anguilla anguilla).

    PubMed

    De Meyer, J; Ide, C; Belpaire, C; Goemans, G; Adriaens, D

    2015-12-01

    The life cycle of the European eel (Anguilla anguilla) remained a mystery until the 20th century, when Schmidt discovered that the Sargasso Sea was its spawning area. However, many aspects of the eel's life cycle remain poorly understood. Among these is the bimodal distribution in head shape, with broad- and narrowheaded phenotypes reported in the yellow eel stage. Although this has been linked to dietary preferences of the yellow eels, very little is known about why, how and when this dimorphism arises during their ontogeny. To determine whether this dimorphism indeed appears in relation to trophic niche segregation, we examined head shape variation at an earlier ontogenetic stage, the glass eel stage, as at this stage eels are considered to be non-feeding. Head shape was studied in a large dataset, containing glass eels captured from the Yser river mouth, the Leopold Canal (Belgium) and from the rivers Severn, Trent and Parret (UK), by both taking measurements (head width/head length) and using an outline analysis. Our results show that there is already considerable variation in broadness and bluntness of the head at the glass eel stage. In most cases, equal support for a unimodal and bimodal head shape distribution is found, whereas some cases support head shape bimodality in glass eels, suggesting that glass eel head shape might be shifting from a unimodal to a bimodal distribution. This, in combination with the observation that variation in head width/head length ratios in non-feeding glass eels shows a similar range as in feeding yellow eels, indicates that head shape in European eel might be at least partially determined through other mechanisms than trophic segregation. PMID:26265585

  15. The Proximate Causes of Sexual Size Dimorphism in Phrynocephalus przewalskii

    PubMed Central

    Zhao, Wei; Liu, Nai-fa

    2014-01-01

    Sexual size dimorphism (SSD) is a common phenomenon and is a central topic in evolutionary biology. Recently, the importance of pursuing an ontogenetic perspective of SSD has been emphasized, to elucidate the proximate physiological mechanisms leading to its evolution. However, such research has seldom focused on the critical periods when males and females diverge. Using mark-recapture data, we investigated the development of SSD, sex-specific survivorship, and growth rates in Phrynocephalus przewalskii (Agamidae). We demonstrated that both male and female lizards are reproductively mature at age 10–11 months (including 5 months hibernation). Male-biased SSD in snout-vent length (SVL) was only found in adults and was fully expressed at age 11 months (June of the first full season of activity), just after sexual maturation. However, male-biased SSD in tail length (TL), hind-limb length (LL), and head width (HW) were fully expressed at age 9–10 months, just before sexual maturation. Analysis of age-specific linear growth rates identified sexually dimorphic growth during the fifth growth month (age 10–11 months) as the proximate cause of SSD in SVL. The males experienced higher mortality than females in the first 2 years and only survived better than females after SSD was well developed. This suggests that the critical period of divergence in the sizes of male and female P. przewalskii occurs between 10 and 11 months of age (May to June during the first full season of activity), and that the sexual difference in growth during this period is the proximate cause. However, the sexual difference in survivorship cannot explain the male-biased SSD in SVL. Our results indicate that performance-related characteristics, such as TL, HW, and LL diverged earlier than SVL. The physiological mechanisms underlying the different growth patterns of males and females may reflect different energy allocations associated with their different reproductive statuses. PMID:24465815

  16. Head shape dimorphism in European glass eels (Anguilla anguilla).

    PubMed

    De Meyer, J; Ide, C; Belpaire, C; Goemans, G; Adriaens, D

    2015-12-01

    The life cycle of the European eel (Anguilla anguilla) remained a mystery until the 20th century, when Schmidt discovered that the Sargasso Sea was its spawning area. However, many aspects of the eel's life cycle remain poorly understood. Among these is the bimodal distribution in head shape, with broad- and narrowheaded phenotypes reported in the yellow eel stage. Although this has been linked to dietary preferences of the yellow eels, very little is known about why, how and when this dimorphism arises during their ontogeny. To determine whether this dimorphism indeed appears in relation to trophic niche segregation, we examined head shape variation at an earlier ontogenetic stage, the glass eel stage, as at this stage eels are considered to be non-feeding. Head shape was studied in a large dataset, containing glass eels captured from the Yser river mouth, the Leopold Canal (Belgium) and from the rivers Severn, Trent and Parret (UK), by both taking measurements (head width/head length) and using an outline analysis. Our results show that there is already considerable variation in broadness and bluntness of the head at the glass eel stage. In most cases, equal support for a unimodal and bimodal head shape distribution is found, whereas some cases support head shape bimodality in glass eels, suggesting that glass eel head shape might be shifting from a unimodal to a bimodal distribution. This, in combination with the observation that variation in head width/head length ratios in non-feeding glass eels shows a similar range as in feeding yellow eels, indicates that head shape in European eel might be at least partially determined through other mechanisms than trophic segregation.

  17. Sexual dimorphism in the osmopressor response following water ingestion.

    PubMed

    Mendonca, Goncalo V; Teodósio, Carolina; Lucena, Rui; Pereira, Fernando D

    2016-07-01

    There is conflicting evidence as to whether water drinking elicits a pressor response in healthy young adults. The inclusion of a variable number of women may have contributed to the discrepancies found in past research. Thus, we aimed at exploring whether the osmopressor response follows a sexually dimorphic pattern. In a randomized fashion, 31 healthy adults (16 men; 15 women, aged 18-40 years) ingested 50 and 500 ml of water before completing a resting protocol on two separate days. Arterial blood pressure, heart rate and spectral heart rate variability were measured in the seated position at pre- and post-25 min of water ingestion. Women responded to 500 ml of water with a greater proportion of change in diastolic and mean arterial pressure (MAP) (P<0.05). Conversely, the percent change in systolic blood pressure (SBP) and heart rate was not different between sexes after 500 ml of water. Overall, women demonstrated lower blood pressure, but higher resting heart rate compared with men (P<0.05). In contrast, heart rate variability was similar between sexes before and after ingesting either volume of water. There was a bradycardic effect of water and, irrespectively of sex; this was accompanied by increased high frequency power (HF) (P<0.05). We conclude that women display a greater magnitude of pressor response than men post-water ingestion. Accordingly, we provide direct evidence of sexual dimorphism in the haemodynamic response to water intake in young healthy adults.

  18. Sexual dimorphism in cranial morphology among modern South Africans.

    PubMed

    Krüger, Gabriele Christa; L'Abbé, Ericka N; Stull, Kyra E; Kenyhercz, Michael W

    2015-07-01

    Pattern expressions of morphoscopic cranial traits vary across populations with classification accuracies being highly dependent on the reference collection to which unknown skulls are compared. Despite recent developments in population-specific standards for South Africans, researchers have not addressed the accuracy of morphological methods. Several studies demonstrate differences in sexual dimorphism between South Africans and North Americans, warranting a need to re-evaluate sex estimation methods in South Africa. The purposes of this study were to test the reliability and accuracy of the Walker (2008) method and to examine patterns of sexual dimorphism among South Africans. A total of 245 modern Black and White South African male and female crania from the Pretoria Bone Collection, University of Pretoria, were scored using the Walker (2008) methodology. Cohen's kappa was used to evaluate reliability of the method, and percent correct assessed validity of the method. Logistic regression was utilised to create modified population-specific formulae. Inter- and intra-observer agreement was moderate to excellent (0.60-0.90), except for the mental eminence (0.40). The percent correct results for sex were 80% or higher for combinations of glabella, mastoid and menton and between 68% and 73% for menton, mastoid, orbital and nuchal margin using logistic equations of Walker (2008). White males had the highest (94-97%) and White females had the lowest (31-62%) percent correct. The low accuracies obtained when using Walker's (2008) equations emphasised the need for population-specific sex estimation models. Modified formulae for South Africans were created, yielding higher classification rates (84-93%) than when North American standards were employed. PMID:25394745

  19. Synchronous monitoring of muscle dynamics and muscle force for maximum isometric tetanus

    NASA Astrophysics Data System (ADS)

    Zakir Hossain, M.; Grill, Wolfgang

    2010-03-01

    Skeletal muscle is a classic example of a biological soft matter . At both macro and microscopic levels, skeletal muscle is exquisitely oriented for force generation and movement. In addition to the dynamics of contracting and relaxing muscle which can be monitored with ultrasound, variations in the muscle force are also expected to be monitored. To observe such force and sideways expansion variations synchronously for the skeletal muscle a novel detection scheme has been developed. As already introduced for the detection of sideways expansion variations of the muscle, ultrasonic transducers are mounted sideways on opposing positions of the monitored muscle. To detect variations of the muscle force, angle of pull of the monitored muscle has been restricted by the mechanical pull of the sonic force sensor. Under this condition, any variation in the time-of-flight (TOF) of the transmitted ultrasonic signals can be introduced by the variation of the path length between the transducers. The observed variations of the TOF are compared to the signals obtained by ultrasound monitoring for the muscle dynamics. The general behavior of the muscle dynamics and muscle force shows almost an identical concept. Since muscle force also relates the psychological boosting-up effects, the influence of boosting-up on muscle force and muscle dynamics can also be quantified form this study. Length-tension or force-length and force-velocity relationship can also be derived quantitatively with such monitoring.

  20. Remote radio control of insect flight.

    PubMed

    Sato, Hirotaka; Berry, Christopher W; Peeri, Yoav; Baghoomian, Emen; Casey, Brendan E; Lavella, Gabriel; Vandenbrooks, John M; Harrison, Jon F; Maharbiz, Michel M

    2009-01-01

    We demonstrated the remote control of insects in free flight via an implantable radio-equipped miniature neural stimulating system. The pronotum mounted system consisted of neural stimulators, muscular stimulators, a radio transceiver-equipped microcontroller and a microbattery. Flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and free-flight trajectories elicited by our neural control systems in remotely controlled beetles. We believe this type of technology will open the door to in-flight perturbation and recording of insect flight responses.

  1. Remote Radio Control of Insect Flight

    PubMed Central

    Sato, Hirotaka; Berry, Christopher W.; Peeri, Yoav; Baghoomian, Emen; Casey, Brendan E.; Lavella, Gabriel; VandenBrooks, John M.; Harrison, Jon F.; Maharbiz, Michel M.

    2009-01-01

    We demonstrated the remote control of insects in free flight via an implantable radio-equipped miniature neural stimulating system. The pronotum mounted system consisted of neural stimulators, muscular stimulators, a radio transceiver-equipped microcontroller and a microbattery. Flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Turns were triggered through the direct muscular stimulus of either of the basalar muscles. We characterized the response times, success rates, and free-flight trajectories elicited by our neural control systems in remotely controlled beetles. We believe this type of technology will open the door to in-flight perturbation and recording of insect flight responses. PMID:20161808

  2. Quantitative genetics of costly neonatal sexual size dimorphism in squirrel monkeys (Saimiri boliviensis)

    PubMed Central

    BLOMQUIST, G. E.; WILLIAMS, L. E.

    2015-01-01

    Offspring size is often an intimate link between the fitness of parents and offspring. Among mammals, neonate mass is also related to adult levels of dimorphism and intrasexual competitive mating. We describe the sex-specific genetic architecture of neonate mass in captive squirrel monkeys (Saimiri boliviensis), a small Neotropical primate. Best fitting quantitative genetic models show strong maternal genetic effects with little difference between sexes offering limited opportunity for neonatal dimorphism to respond to observed or hypothetical selection. Heritabilities that are approximately zero also imply it is unlikely that neonatal dimorphism can evolve as a correlated response to selection on adult size. However, male mass is also more dependent on maternal condition (age and parity) making dimorphism plastic. Finally, we hypothesize that large maternal genetic effects reflect income breeding and tightly synchronized seasonal reproduction in squirrel monkeys, both of which require strong maternal control of offspring growth and timing of birth. PMID:23437981

  3. Dioecious Silene latifolia plants show sexual dimorphism in the vegetative stage

    PubMed Central

    2010-01-01

    Background Prior to this study, no differences in gene expression between male and female dioecious plants in the vegetative state had been detected. Among dioecious plants displaying sexual dimorphism, Silene latifolia is one of the most studied species. Although many sexually dimorphic traits have been described in S. latifolia, all of them are quantitative, and they usually become apparent only after the initiation of flowering. Results We present RT-PCR-based evidence that in S. latifolia, sexual dimorphism in gene expression is present long before the initiation of flowering. We describe three ESTs that show sex-specific (two male specific and one female specific) transcription at the rosette stage before the first flowering season. Conclusions To our knowledge, this study provides the first molecular evidence of early pre-flowering sexual dimorphism in angiosperms. PMID:20854681

  4. Range extension of Lepidocephalichthys alkaia (Teleostei: Cobitidae) and notes on its sexual dimorphism

    PubMed Central

    ENDRUWEIT, Marco

    2016-01-01

    The natural distributional range of the cobitid loach Lepidocephalichthys alkaia is extended into Yunnan Province,China. The modified sexually dimorphic pectoral fin in males of L. alkaia is described. PMID:27265657

  5. Estrogenic support of motoneuron dendritic growth via the neuromuscular periphery in a sexually dimorphic motor system.

    PubMed

    Nowacek, Ari S; Sengelaub, Dale R

    2006-08-01

    The lumbar spinal cord of rats contains the sexually dimorphic, steroid-sensitive spinal nucleus of the bulbocavernosus (SNB). In males, the growth of SNB dendrites is steroid-dependent: dendrites fail to grow after castration, but grow in castrates treated with androgens or estrogens. Blocking estradiol synthesis or estrogen receptors in gonadally intact males attenuates SNB dendritic growth, suggesting that estrogens are required and must be able to act at their receptors to support normal masculine dendritic growth. However, SNB motoneurons do not accumulate estrogens, suggesting that estrogens act indirectly to support SNB dendritic growth. In this experiment, we examined whether local estrogen action in the neuromuscular periphery was involved in the postnatal development of SNB motoneurons. Motoneuron morphology was assessed in gonadally intact and castrated males. Gonadally intact males were left untreated or given either blank or tamoxifen implants sutured to the target musculature, or tamoxifen interscapular implants. Castrated males were left untreated or were given estradiol by muscle or interscapular implants or systemic injection during the period of SNB dendritic growth. At postnatal day 28, when SNB dendritic length is normally maximal, SNB motoneurons were retrogradely labeled with cholera toxin-HRP and reconstructed in three dimensions. While interscapular tamoxifen implants were ineffective, blocking estrogen receptors at the target musculature resulted in attenuation of SNB dendritic growth. In contrast, while interscapular implants of estradiol were ineffective, local treatment with estradiol at the target musculature in castrated males resulted in masculinization of dendritic growth. Thus, estrogens may act by an indirect action in the neuromuscular periphery to support SNB dendritic growth.

  6. Nutrition in Space Flight: Some Thoughts

    NASA Technical Reports Server (NTRS)

    Johnson, P. C., Jr.

    1985-01-01

    Space flight causes physiological changes related to microgravity and on which nutrition has a bearing. Examples are: muscle atrophy-protein; bone atrophy-calcium; phosphorus, and vitamin D; space sickness-fat; cardiovascular deconditioning-sodium; water, and potassium. The physiological changes are discussed which relate to living in space.

  7. Muscle Stimulation Technology

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Under a Goddard Space Flight Center contract, Electrologic of America was able to refine the process of densely packing circuitry on personal computer boards, providing significant contributions to the closed-loop systems for the Remote Manipulator System Simulator. The microcircuitry work was then applied to the StimMaster FES Ergometer, an exercise device used to stimulate muscles suffering from paralysis. The electrical stimulation equipment was developed exclusively for V-Care Health Systems, Inc. Product still commercially available as of March 2002.

  8. Sexual dimorphism of the Eurasian otter (Lutra lutra) in South Korea: Craniodental geometric morphometry

    PubMed Central

    LAU, Alice Ching Ching; ASAHARA, Masakazu; HAN, Sung Yong; KIMURA, Junpei

    2016-01-01

    Sexual dimorphism of the craniodental morphology of the Eurasian otter in South Korea was studied with geometric morphometrics. 29 adult skulls (15 males and 14 females) were used. Images of the dorsal and ventral view of the cranium and right lateral view of the mandible were taken and then digitized, and measurements were taken on the right side. Results showed that size difference between males and females was significant. Correlations between the size and shape variations have not been observed in this study. The bivariate plots with centroid size showed size dimorphism between males and females with some overlapping. Most relative warp (RW) scores were not significantly different between males and females. We observed only RW2 for dorsal and ventral view of the skull, and only RW1 for mandible was significantly different between the sexes. Shape dimorphisms were revealed at the postorbital constriction, temporal-mandibular joint, coronoid process, mandibular condyle and angular process of the skull. Based on our study, sexual dimorphism exists in Eurasian otter from the South Korean population in terms of both the size and shape. Furthermore, the degree of size dimorphism is greater than shape dimorphism. PMID:26983684

  9. Sexual dimorphism and speciation on two ecological coins: patterns from nature and theoretical predictions.

    PubMed

    Cooper, Idelle A; Gilman, R Tucker; Boughman, Janette Wenrick

    2011-09-01

    Adaptive divergence of phenotypes, such as sexual dimorphism or adaptive speciation, can result from disruptive selection via competition for limited resources. Theory indicates that speciation and sexual dimorphism can result from identical ecological conditions, but co-occurrence is unlikely because whichever evolves first should dissipate the disruptive selection necessary to drive evolution of the other. Here, we consider ecological conditions in which disruptive selection can act along multiple ecological axes. Speciation in lake populations of threespine sticklebacks (Gasterosteus aculeatus) has been attributed to disruptive selection due to competition for resources. Head shape in sticklebacks is thought to reflect adaptation to different resource acquisition strategies. We measure sexual dimorphism and species variation in head shape and body size in stickleback populations in two lakes in British Columbia, Canada. We find that sexual dimorphism in head shape is greater than interspecific differences. Using a numerical simulation model that contains two axes of ecological variation, we show that speciation and sexual dimorphism can readily co-occur when the effects of loci underlying sexually dimorphic traits are orthogonal to those underlying sexually selected traits.

  10. Effect of Real and Simulated Microgravity on Muscle Function

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In this session, Session JA3, the discussion focuses on the following topics: Changes in Calf Muscle Performance, Energy Metabolism, and Muscle Volume Caused by Long Term Stay on Space Station MIR; Vibrografic Signs of Autonomous Muscle Tone Studied in Long Term Space Missions; Reduction of Muscle Strength After Long Duration Space Flights is Associated Primarily with Changes in Neuromuscular Function; The Effects of a 115-Day Spaceflight on Neuromuscular Function in Crewman; Effects of 17-Day Spaceflight on Human Triceps Surae Electrically-Evoked Contractions; Effects of Muscle Unloading on EMG Spectral Parameters; and Myofiber Wound-Mediated FGF Release and Muscle Atrophy During Bedrest.

  11. Introducing the refined gravity hypothesis of extreme sexual size dimorphism

    PubMed Central

    2010-01-01

    Background Explanations for the evolution of female-biased, extreme Sexual Size Dimorphism (SSD), which has puzzled researchers since Darwin, are still controversial. Here we propose an extension of the Gravity Hypothesis (i.e., the GH, which postulates a climbing advantage for small males) that in conjunction with the fecundity hypothesis appears to have the most general power to explain the evolution of SSD in spiders so far. In this "Bridging GH" we propose that bridging locomotion (i.e., walking upside-down under own-made silk bridges) may be behind the evolution of extreme SSD. A biomechanical model shows that there is a physical constraint for large spiders to bridge. This should lead to a trade-off between other traits and dispersal in which bridging would favor smaller sizes and other selective forces (e.g. fecundity selection in females) would favor larger sizes. If bridging allows faster dispersal, small males would have a selective advantage by enjoying more mating opportunities. We predicted that both large males and females would show a lower propensity to bridge, and that SSD would be negatively correlated with sexual dimorphism in bridging propensity. To test these hypotheses we experimentally induced bridging in males and females of 13 species of spiders belonging to the two clades in which bridging locomotion has evolved independently and in which most of the cases of extreme SSD in spiders are found. Results We found that 1) as the degree of SSD increased and females became larger, females tended to bridge less relative to males, and that 2) smaller males and females show a higher propensity to bridge. Conclusions Physical constraints make bridging inefficient for large spiders. Thus, in species where bridging is a very common mode of locomotion, small males, by being more efficient at bridging, will be competitively superior and enjoy more mating opportunities. This "Bridging GH" helps to solve the controversial question of what keeps males small

  12. Biometrical studies upon hominoid teeth: the coefficient of variation, sexual dimorphism and questions of phylogenetic relationship.

    PubMed

    Blumenberg, B

    1985-01-01

    Sexual dimorphism as a function of variation in hominoid tooth metrics has been investigated for four groups of taxa: Recent great apes (two subfamilies), Dryopiths (one subfamily), Ramapiths (one subfamily) and hominids (one family). Gorilla, and to a lesser extent Pan, appear characterized by very high levels of sexual dimorphism and meet several criteria for statistical outliers. Recent great apes are the only group exhibiting consistently high levels of sexual dimorphism. Ramapiths are the only group characterized by low levels of sexual dimorphism and their relative canine length is most similar to Dryopiths. Both Dryopiths and hominids contain taxa with low and intermediate levels of sexual dimorphism. The Gingerich and Shoeninger hypothesis relating coefficients of variation to occlusal complexity is supported. Non-parametric statistics suggest that homogeneity of coefficient of variation profiles over most of the tooth row is characteristic of only the Dryopiths and a composite data set composed of the Dryopith plus Ramapith tooth measurements. Oxnard's model for the multifactorial basis of multiple sexual dimorphisms is also supported. The Dryopith and hominid patterns of sexual dimorphism are similar, an observation that suggests phylogenetic relationship. At the taxonomic level of subfamily or family, sexual dimorphism is a character of cladistic usefulness and possible phylogenetic valence. Assuming that breeding system and sexual dimorphism are functional correlates as many workers suggest, then Ramapithecus sp. China, Sivapithecus indicus and possibly Australopithecus boisei are good candidates for having possessed monogamous breeding/social structures. All Dryopith taxa, S. sivalensis, Sivapithecus sp. China, A. afarensis, Homo habilis and H. erectus emerge as the best candidates for having possessed a polygynous breeding/social structure. No biometrical affinities of Ramapiths with hominids can be demonstrated and some phylogenetic relationship with

  13. Green Flight Challenge

    NASA Video Gallery

    The CAFE Green Flight Challenge sponsored by Google will be held at the CAFE Foundation Flight Test Center at Charles M. Schulz Sonoma County Airport in Santa Rosa, Calif. The Green Flight Challeng...

  14. Magnetorheology of dimorphic magnetorheological fluids based on nanofibers

    NASA Astrophysics Data System (ADS)

    Bombard, Antonio J. F.; Gonçalves, Flavia R.; Morillas, Jose R.; de Vicente, Juan

    2014-12-01

    We report a systematic experimental investigation on the use of nanofibers to enhance the magnetorheological (MR) effect in conventional (microsphere-based) MR fluids formulated in polyalphaolefin oil/1-octanol. Two kinds of nanofibers are employed that have very similar morphology but very different magnetic properties. On the one hand we use non-magnetic goethite nanofibers. On the other hand we employ magnetic chromium dioxide nanofibers. For appropriate concentrations the on-state relative yield stress increases up to 80% when incorporating the nanofibers in the formulation. A similar yield stress enhancement is found for both nanofibers investigated (magnetic and non-magnetic) suggesting that the main factor behind this MR enhancement is the particle shape anisotropy. The relative yield stresses obtained by partial substitution of carbonyl iron particles with nanofibers are significantly larger than those measured in previous works on MR fluids formulated by partial substitution with non-magnetic micronsized spherical particles. We also demonstrate that these dimorphic MR fluids also exhibit remarkably larger long-term sedimentation stability while keeping the same penetration and redispersibility characteristics.

  15. Two sexually dimorphic cell groups in the human brain.

    PubMed

    Allen, L S; Hines, M; Shryne, J E; Gorski, R A

    1989-02-01

    A quantitative analysis of the volume of 4 cell groups in the preoptic-anterior hypothalamic area (PO-AHA) and of the supraoptic nucleus (SON) of the human brain was performed in 22 age-matched male and female individuals. We suggest the term Interstitial Nuclei of the Anterior Hypothalamus (INAH 1-4) to identify these 4 previously undescribed cell groups in the PO-AHA. While 2 INAH and the SON were not sexually dimorphic, gender-related differences were found in the other 2 cell groups. One nucleus (INAH-3) was 2.8 times larger in the male brain than in the female brain irrespective of age. The other cell group (INAH-2) was twice as large in the male brain, but also appeared to be related in women to circulating steroid hormone levels. Since the PO-AHA influences gonadotropin secretion, maternal behavior, and sexual behavior in several mammalian species, these results suggest that functional sex differences in the hypothalamus may be related to sex differences in neural structure.

  16. Evidence of sexually dimorphic introgression in Pinaleno Mountain Apache trout

    USGS Publications Warehouse

    Porath, M.T.; Nielsen, J.L.

    2003-01-01

    The high-elevation headwater streams of the Pinaleno Mountains support small populations of threatened Apache trout Oncorhynchus apache that were stocked following the chemical removal of nonnative salmonids in the 1960s. A fisheries survey to assess population composition, growth, and size structure confirmed angler reports of infrequent occurrences of Oncorhynchus spp. exhibiting the external morphological characteristics of both Apache trout and rainbow trout O. mykiss. Nonlethal tissue samples were collected from 50 individuals in the headwaters of each stream. Mitochondrial DNA (mtDNA) sequencing and amplification of nuclear microsatellite loci were used to determine the levels of genetic introgression by rainbow trout in Apache trout populations at these locations. Sexually dimorphic introgression from the spawning of male rainbow trout with female Apache trout was detected using mtDNA and microsatellites. Estimates of the degree of hybridization based on three microsatellite loci were 10-88%. The use of nonlethal DNA genetic analyses can supplement information obtained from standard survey methods and be useful in assessing the relative importance of small and sensitive populations with a history of nonnative introductions.

  17. Sexually dimorphic RB inactivation underlies mesenchymal glioblastoma prevalence in males

    PubMed Central

    Sun, Tao; Warrington, Nicole M.; Luo, Jingqin; Brooks, Michael D.; Dahiya, Sonika; Snyder, Steven C.; Sengupta, Rajarshi; Rubin, Joshua B.

    2014-01-01

    The prevalence of brain tumors in males is common but unexplained. While sex differences in disease are typically mediated through acute sex hormone actions, sex-specific differences in brain tumor rates are comparable at all ages, suggesting that factors other than sex hormones underlie this discrepancy. We found that mesenchymal glioblastoma (Mes-GBM) affects more males as the result of cell-intrinsic sexual dimorphism in astrocyte transformation. We used astrocytes from neurofibromin-deficient (Nf1–/–) mice expressing a dominant-negative form of the tumor suppressor p53 (DNp53) and treated them with EGF as a Mes-GBM model. Male Mes-GBM astrocytes exhibited greater growth and colony formation compared with female Mes-GBM astrocytes. Moreover, male Mes-GBM astrocytes underwent greater tumorigenesis in vivo, regardless of recipient mouse sex. Male Mes-GBM astrocytes exhibited greater inactivation of the tumor suppressor RB, higher proliferation rates, and greater induction of a clonogenic, stem-like cell population compared with female Mes-GBM astrocytes. Furthermore, complete inactivation of RB and p53 in Mes-GBM astrocytes resulted in equivalent male and female tumorigenic transformation, indicating that intrinsic differences in RB activation are responsible for the predominance of tumorigenic transformation in male astrocytes. Together, these results indicate that cell-intrinsic sex differences in RB regulation and stem-like cell function may underlie the predominance of GBM in males. PMID:25083989

  18. Glucocorticoid receptor exhibits sexually dimorphic expression in the medaka brain.

    PubMed

    Kikuchi, Yukiko; Hosono, Kohei; Yamashita, Junpei; Kawabata, Yukika; Okubo, Kataaki

    2015-11-01

    The differential impact of stress on brain functions of males and females has been widely observed in vertebrates. Recent evidence suggests that stress-induced glucocorticoid signaling affects sexual differentiation and sex changes in teleost fish. These facts led us to postulate that there were sex differences in glucocorticoid signaling in the teleost brain that underlie some sex differences in their physiological and behavioral traits. Here we found sexually dimorphic expression of a glucocorticoid receptor gene (gr1) in the brain of medaka fish (Oryzias latipes), with females having greater expression in several preoptic and thalamic nuclei. Further, gr1 exhibits female-biased expression in neurons of the anterior parvocellular preoptic nucleus that produce the neuropeptides vasotocin and gonadotropin-releasing hormone 1 (these neuropeptides have been implicated in the regulation of neuroendocrine and behavioral functions). These findings suggest that glucocorticoids have a greater influence on physiology and behavior mediated by these neuropeptides in females than in males, which may contribute to sex differences in the brain's response to stress. PMID:26433060

  19. Environmental Health Factors and Sexually Dimorphic Differences in Behavioral Disruptions

    PubMed Central

    Rosenfeld, Cheryl S.; Trainor, Brian C.

    2015-01-01

    Mounting evidence suggests that environmental factors—in particular, those that we are exposed to during perinatal life—can dramatically shape the organism’s risk for later diseases, including neurobehavioral disorders. However, depending on the environmental insult, one sex may demonstrate greater vulnerability than the other sex. Herein, we focus on two well-defined extrinsic environmental factors that lead to sexually dimorphic behavioral differences in animal models and linkage in human epidemiological studies. These include maternal or psychosocial stress (such as social stress) and exposure to endocrine-disrupting compounds (such as one of the most prevalent, bisphenol A [BPA]). In general, the evidence suggests that early environmental exposures, such as BPA and stress, lead to more pronounced behavioral deficits in males than in females, whereas female neurobehavioral patterns are more vulnerable to later in life stress. These findings highlight the importance of considering sex differences and developmental timing when examining the effects of environmental factors on later neurobehavioral outcomes. PMID:25705580

  20. Genetic constraints on dishonesty and caste dimorphism in an ant.

    PubMed

    Holman, Luke; Linksvayer, Timothy A; d'Ettorre, Patrizia

    2013-02-01

    The ultimate causes of honest signaling remain a subject of debate, with questions remaining over the relative importance of costs and constraints. Signal costs may make dishonesty prohibitively expensive, while genetic constraints could make it impossible. We investigated honest signaling using full-sib analysis and parent-offspring regression in the ant Lasius niger, in which queens produce a cuticular hydrocarbon-based pheromone that signals fertility and inhibits worker reproduction and aggression. We found multiple lines of evidence that cuticular hydrocarbon production is genetically correlated with oogenesis and that the queen pheromone 3-methylhentriacontane and other 3-methylalkanes have strong genetic links with fertility relative to other cuticular hydrocarbons. These genetic correlations may maintain honesty in the face of directional selection on signaling and explain the putatively widespread use of cuticular hydrocarbons in fertility signaling across the social insects. We also found evidence for a positive genetic correlation for fertility between the castes; that is, the most fertile queens produced especially fertile workers. These results highlight that intercaste genetic correlations could constrain the evolution of queen-worker dimorphism, such that worker reproduction may sometimes reflect a nonadaptive "caste load" rather than positively selected cheating. PMID:23348771

  1. Sexual Dimorphism in the Response of Mercurialis annua to Stress

    PubMed Central

    Orlofsky, Ezra M.; Kozhoridze, Giorgi; Lyubenova, Lyudmila; Ostrozhenkova, Elena; Winkler, J. Barbro; Schröder, Peter; Bacher, Adelbert; Eisenreich, Wolfgang; Guy, Micha; Golan-Goldhirsh, Avi

    2016-01-01

    The research presented stemmed from the observations that female plants of the annual dioecious Mercurialis annua outlive male plants. This led to the hypothesis that female plants of M. annua would be more tolerant to stress than male plants. This hypothesis was addressed in a comprehensive way, by comparing morphological, biochemical and metabolomics changes in female and male plants during their development and under salinity. There were practically no differences between the genders in vegetative development and physiological parameters. However, under salinity conditions, female plants produced significantly more new reproductive nodes. Gender-linked differences in peroxidase (POD) and glutathione transferases (GSTs) were involved in anti-oxidation, detoxification and developmental processes in M. annua. 1H NMR metabolite profiling of female and male M. annua plants showed that under salinity the activity of the TCA cycle increased. There was also an increase in betaine in both genders, which may be explainable by its osmo-compatible function under salinity. The concentration of ten metabolites changed in both genders, while ‘Female-only-response’ to salinity was detected for five metabolites. In conclusion, dimorphic responses of M. annua plant genders to stress may be attributed to female plants’ capacity to survive and complete the reproductive life cycle. PMID:27128954

  2. Sexually antagonistic epigenetic marks that canalize sexually dimorphic development.

    PubMed

    Rice, William R; Friberg, Urban; Gavrilets, Sergey

    2016-04-01

    The sexes share the same autosomal genomes, yet sexual dimorphism is common due to sex-specific gene expression. When present, XX and XY karyotypes trigger alternate regulatory cascades that determine sex-specific gene expression profiles. In mammals, secretion of testosterone (T) by the testes during foetal development is the master switch influencing the gene expression pathways (male vs. female) that will be followed, but many genes have sex-specific expression prior to T secretion. Environmental factors, like endocrine disruptors and mimics, can interfere with sexual development. However, sex-specific ontogeny can be canalized by the production of epigenetic marks (epimarks) generated during early ontogeny that increase sensitivity of XY embryos to T and decrease sensitivity of XX embryos. Here, we integrate and synthesize the evidence indicating that canalizing epimarks are produced during early ontogeny. We will also describe the evidence that such epimarks sometimes carry over across generations and produce mosaicism in which some traits are discordant with the gonad. Such carryover epimarks are sexually antagonistic because they benefit the individual in which they were formed (via canalization) but harm opposite-sex offspring when they fail to erase across generations and produce gonad-trait discordances. SA-epimarks have the potential to: i) magnify phenotypic variation for many sexually selected traits, ii) generate overlap along many dimensions of the masculinity/femininity spectrum, and iii) influence medically important gonad-trait discordances like cryptorchidism, hypospadias and idiopathic hirsutism. PMID:26600375

  3. Microgravity Flight - Accommodating Non-Human Primates

    NASA Technical Reports Server (NTRS)

    Dalton, Bonnie P.; Searby, Nancy; Ostrach, Louis

    1994-01-01

    Spacelab Life Sciences-3 (SLS-3) was scheduled to be the first United States man-tended microgravity flight containing Rhesus monkeys. The goal of this flight as in the five untended Russian COSMOS Bion flights and an earlier American Biosatellite flight, was to understand the biomedical and biological effects of a microgravity environment using the non-human primate as human surrogate. The SLS-3/Rhesus Project and COSMOS Primate-BIOS flights all utilized the rhesus monkey, Macaca mulatta. The ultimate objective of all flights with an animal surrogate has been to evaluate and understand biological mechanisms at both the system and cellular level, thus enabling rational effective countermeasures for future long duration human activity under microgravity conditions and enabling technical application to correction of common human physiological problems within earth's gravity, e.g., muscle strength and reloading, osteoporosis, immune deficiency diseases. Hardware developed for the SLS-3/Rhesus Project was the result of a joint effort with the French Centre National d'Etudes Spatiales (CNES) and the United States National Aeronautics and Space Administration (NASA) extending over the last decade. The flight hardware design and development required implementation of sufficient automation to insure flight crew and animal bio-isolation and maintenance with minimal impact to crew activities. A variety of hardware of varying functional capabilities was developed to support the scientific objectives of the original 22 combined French and American experiments, along with 5 Russian co-investigations, including musculoskeletal, metabolic, and behavioral studies. Unique elements of the Rhesus Research Facility (RRF) included separation of waste for daily delivery of urine and fecal samples for metabolic studies and a psychomotor test system for behavioral studies along with monitored food measurement. As in untended flights, telemetry measurements would allow monitoring of

  4. NASA's Flight Opportunities Program

    NASA Video Gallery

    NASA's Flight Opportunities Program is facilitating low-cost access to suborbital space, where researchers can test technologies using commercially developed vehicles. Suborbital flights can quickl...

  5. [Relationship between simulated weightlessness-induced muscle spindle change and muscle atrophy].

    PubMed

    Zhao, Xue-Hong; Fan, Xiao-Li

    2013-02-25

    One of the most important and urgent issues in the field of space medicine is to reveal the potential mechanism underlying the disused muscle atrophy during the weightlessness or microgravity environment. It will conduce to find out effective methods for the prevention and treatment of muscle atrophy during a long-term space flight. Increasing data show that muscle spindle discharges are significantly altered following the hindlimb unloading, suggesting a vital role in the progress of muscle atrophy. In the last decades, we have made a series of studies on changes in the morphological structure and function of muscle spindle following simulated weightlessness. This review will discuss our main results and related researches for understanding of muscle spindle activities during microgravity environment, which may provide a theoretic basis for effective prevention and treatment of muscle atrophy induced by weightlessness. PMID:23426520

  6. Sexual shape dimorphism accelerated by male–male competition, but not prevented by sex-indiscriminate parental care in dung beetles (Scarabaeidae)

    PubMed Central

    Kishi, Shigeki; Takakura, Koh-Ichi; Nishida, Takayoshi

    2015-01-01

    Dimorphic sexual differences in shape and body size are called sexual dimorphism and sexual size dimorphism, respectively. The degrees of both dimorphisms are considered to increase with sexual selection, represented by male–male competition. However, the degrees of the two dimorphisms often differ within a species. In some dung beetles, typical sexual shape dimorphisms are seen in male horns and other exaggerated traits, although sexual size dimorphism looks rare. We hypothesized that the evolution of this sexual shape dimorphism without sexual size dimorphism is caused by male–male competition and their crucial and sex-indiscriminate provisioning behaviors, in which parents provide the equivalent size of brood ball with each of both sons and daughters indiscriminately. As a result of individual-based model simulations, we show that parents evolve to provide each of sons and daughters with the optimal amount of resource for a son when parents do not distinguish the sex of offspring and males compete for mates. This result explains why crucial and sex-indiscriminate parental provisioning does not prevent the evolution of sexual shape dimorphism. The model result was supported by empirical data of Scarabaeidae beetles. In some dung beetles, sexual size dimorphism is absent, compared with significant sexual size dimorphism in other horned beetles, although both groups exhibit similar degrees of sexual shape dimorphism in male horns and other exaggerated traits. PMID:26306164

  7. Influence of spaceflight on rat skeletal muscle

    NASA Technical Reports Server (NTRS)

    Martin, Thomas P.; Edgerton, V. Reggie; Grindeland, Richard E.

    1988-01-01

    The effect of a 7-day spaceflight (aboard NASA's SL-3) on the size and the metabolism of single fibers from several rat muscles was investigated along with the specificity of these responses as related to the muscle type and the size of fibers. It was found that the loss of mass after flight was varied from 36 percent in the soleus to 15 percent in the extensor digitorum longus. Results of histochemical analyses showed that the succinate dehydrogenase (SDH) activity in muscles of flight-exposed rats was maintained at the control levels, whereas the alpha-glycerol phosphate dehydrogenase (GPD) activity was either maintained or increased. The analyses of the metabolic profiles of ATPase, SDH, and GPD indicated that, in some muscles, there was an increase in the poportion of fast oxidative-glycolytic fibers.

  8. Masticatory muscles of mouse do not undergo atrophy in space

    PubMed Central

    Philippou, Anastassios; Minozzo, Fabio C.; Spinazzola, Janelle M.; Smith, Lucas R.; Lei, Hanqin; Rassier, Dilson E.; Barton, Elisabeth R.

    2015-01-01

    Muscle loading is important for maintaining muscle mass; when load is removed, atrophy is inevitable. However, in clinical situations such as critical care myopathy, masticatory muscles do not lose mass. Thus, their properties may be harnessed to preserve mass. We compared masticatory and appendicular muscles responses to microgravity, using mice aboard the space shuttle Space Transportation System-135. Age- and sex-matched controls remained on the ground. After 13 days of space flight, 1 masseter (MA) and tibialis anterior (TA) were frozen rapidly for biochemical and functional measurements, and the contralateral MA was processed for morphologic measurements. Flight TA muscles exhibited 20 ± 3% decreased muscle mass, 2-fold decreased phosphorylated (P)-Akt, and 4- to 12-fold increased atrogene expression. In contrast, MAs had no significant change in mass but a 3-fold increase in P-focal adhesion kinase, 1.5-fold increase in P-Akt, and 50–90% lower atrogene expression compared with limb muscles, which were unaltered in microgravity. Myofibril force measurements revealed that microgravity caused a 3-fold decrease in specific force and maximal shortening velocity in TA muscles. It is surprising that myofibril-specific force from both control and flight MAs were similar to flight TA muscles, yet power was compromised by 40% following flight. Continued loading in microgravity prevents atrophy, but masticatory muscles have a different set point that mimics disuse atrophy in the appendicular muscle.—Philippou, A., Minozzo, F. C., Spinazzola, J. M., Smith, L. R., Lei, H., Rassier, D. E., Barton, E. R. Masticatory muscles of mouse do not undergo atrophy in space. PMID:25795455

  9. Muscle sarcomere lesions and thrombosis after spaceflight and suspension unloading

    SciTech Connect

    Riley, D.A.; Ellis, S.; Giometti, C.S.; Hoh, J.F.Y.; Ilyina-Kakueva, E.I.; Oganov, V.S.; Slocum, G.R.; Bain, J.L.W.; Sedlak, F.R. )

    1992-08-01

    Extended exposure of humans to spaceflight produces a progressive loss of skeletal muscle strength. This process must be understood to design effective countermeasures. The present investigation examined hindlimb muscles from flight rats killed as close to landing as possible. Spaceflight and tail suspension-hindlimb unloading (unloaded) produced significant decreases in fiber cross-sectional areas of the adductor longus (AL), a slow-twitch antigravity muscle. However, the mean wet weight of the flight AL muscles was near normal, whereas that of the suspension unloaded AL muscles was significantly reduced. Interstitial edema within the flight AL, but not in the unloaded AL, appeared to account for this apparent disagreement.In both conditions, the slow-twitch oxidative fibers atrophied more than the fast-twitch oxidative-glycolytic fibers. Microcirculation was also compromised by spaceflight, such that there was increased formation of thrombi in the postcapillary venules and capillaries.

  10. Reproductive skew drives patterns of sexual dimorphism in sponge-dwelling snapping shrimps.

    PubMed

    Chak, Solomon Tin Chi; Duffy, J Emmett; Rubenstein, Dustin R

    2015-06-22

    Sexual dimorphism is typically a result of strong sexual selection on male traits used in male-male competition and subsequent female choice. However, in social species where reproduction is monopolized by one or a few individuals in a group, selection on secondary sexual characteristics may be strong in both sexes. Indeed, sexual dimorphism is reduced in many cooperatively breeding vertebrates and eusocial insects with totipotent workers, presumably because of increased selection on female traits. Here, we examined the relationship between sexual dimorphism and sociality in eight species of Synalpheus snapping shrimps that vary in social structure and degree of reproductive skew. In species where reproduction was shared more equitably, most members of both sexes were physiologically capable of breeding. However, in species where reproduction was monopolized by a single individual, a large proportion of females--but not males--were reproductively inactive, suggesting stronger reproductive suppression and conflict among females. Moreover, as skew increased across species, proportional size of the major chela--the primary antagonistic weapon in snapping shrimps--increased among females and sexual dimorphism in major chela size declined. Thus, as reproductive skew increases among Synalpheus, female-female competition over reproduction appears to increase, resulting in decreased sexual dimorphism in weapon size.

  11. Reproductive skew drives patterns of sexual dimorphism in sponge-dwelling snapping shrimps

    PubMed Central

    Chak, Solomon Tin Chi; Duffy, J. Emmett; Rubenstein, Dustin R.

    2015-01-01

    Sexual dimorphism is typically a result of strong sexual selection on male traits used in male–male competition and subsequent female choice. However, in social species where reproduction is monopolized by one or a few individuals in a group, selection on secondary sexual characteristics may be strong in both sexes. Indeed, sexual dimorphism is reduced in many cooperatively breeding vertebrates and eusocial insects with totipotent workers, presumably because of increased selection on female traits. Here, we examined the relationship between sexual dimorphism and sociality in eight species of Synalpheus snapping shrimps that vary in social structure and degree of reproductive skew. In species where reproduction was shared more equitably, most members of both sexes were physiologically capable of breeding. However, in species where reproduction was monopolized by a single individual, a large proportion of females—but not males—were reproductively inactive, suggesting stronger reproductive suppression and conflict among females. Moreover, as skew increased across species, proportional size of the major chela—the primary antagonistic weapon in snapping shrimps—increased among females and sexual dimorphism in major chela size declined. Thus, as reproductive skew increases among Synalpheus, female–female competition over reproduction appears to increase, resulting in decreased sexual dimorphism in weapon size. PMID:26041357

  12. Deep sexual dimorphism in adult medaka fish liver highlighted by multi-omic approach

    PubMed Central

    Qiao, Qin; Le Manach, Séverine; Sotton, Benoit; Huet, Hélène; Duvernois-Berthet, Evelyne; Paris, Alain; Duval, Charlotte; Ponger, Loïc; Marie, Arul; Blond, Alain; Mathéron, Lucrèce; Vinh, Joelle; Bolbach, Gérard; Djediat, Chakib; Bernard, Cécile; Edery, Marc; Marie, Benjamin

    2016-01-01

    Sexual dimorphism describes the features that discriminate between the two sexes at various biological levels. Especially, during the reproductive phase, the liver is one of the most sexually dimorphic organs, because of different metabolic demands between the two sexes. The liver is a key organ that plays fundamental roles in various physiological processes, including digestion, energetic metabolism, xenobiotic detoxification, biosynthesis of serum proteins, and also in endocrine or immune response. The sex-dimorphism of the liver is particularly obvious in oviparous animals, as the female liver is the main organ for the synthesis of oocyte constituents. In this work, we are interested in identifying molecular sexual dimorphism in the liver of adult medaka fish and their sex-variation in response to hepatotoxic exposures. By developing an integrative approach combining histology and different high-throughput omic investigations (metabolomics, proteomics and transcriptomics), we were able to globally depict the strong sexual dimorphism that concerns various cellular and molecular processes of hepatocytes comprising protein synthesis, amino acid, lipid and polysaccharide metabolism, along with steroidogenesis and detoxification. The results of this work imply noticeable repercussions on the biology of oviparous organisms environmentally exposed to chemical or toxin issues. PMID:27561897

  13. Deep sexual dimorphism in adult medaka fish liver highlighted by multi-omic approach.

    PubMed

    Qiao, Qin; Le Manach, Séverine; Sotton, Benoit; Huet, Hélène; Duvernois-Berthet, Evelyne; Paris, Alain; Duval, Charlotte; Ponger, Loïc; Marie, Arul; Blond, Alain; Mathéron, Lucrèce; Vinh, Joelle; Bolbach, Gérard; Djediat, Chakib; Bernard, Cécile; Edery, Marc; Marie, Benjamin

    2016-01-01

    Sexual dimorphism describes the features that discriminate between the two sexes at various biological levels. Especially, during the reproductive phase, the liver is one of the most sexually dimorphic organs, because of different metabolic demands between the two sexes. The liver is a key organ that plays fundamental roles in various physiological processes, including digestion, energetic metabolism, xenobiotic detoxification, biosynthesis of serum proteins, and also in endocrine or immune response. The sex-dimorphism of the liver is particularly obvious in oviparous animals, as the female liver is the main organ for the synthesis of oocyte constituents. In this work, we are interested in identifying molecular sexual dimorphism in the liver of adult medaka fish and their sex-variation in response to hepatotoxic exposures. By developing an integrative approach combining histology and different high-throughput omic investigations (metabolomics, proteomics and transcriptomics), we were able to globally depict the strong sexual dimorphism that concerns various cellular and molecular processes of hepatocytes comprising protein synthesis, amino acid, lipid and polysaccharide metabolism, along with steroidogenesis and detoxification. The results of this work imply noticeable repercussions on the biology of oviparous organisms environmentally exposed to chemical or toxin issues. PMID:27561897

  14. Sex chromosome linked genetic variance and the evolution of sexual dimorphism of quantitative traits.

    PubMed

    Husby, Arild; Schielzeth, Holger; Forstmeier, Wolfgang; Gustafsson, Lars; Qvarnström, Anna

    2013-03-01

    Theory predicts that sex chromsome linkage should reduce intersexual genetic correlations thereby allowing the evolution of sexual dimorphism. Empirical evidence for sex linkage has come largely from crosses and few studies have examined how sexual dimorphism and sex linkage are related within outbred populations. Here, we use data on an array of different traits measured on over 10,000 individuals from two pedigreed populations of birds (collared flycatcher and zebra finch) to estimate the amount of sex-linked genetic variance (h(2)z ). Of 17 traits examined, eight showed a nonzero h(2)Z estimate but only four were significantly different from zero (wing patch size and tarsus length in collared flycatchers, wing length and beak color in zebra finches). We further tested how sexual dimorphism and the mode of selection operating on the trait relate to the proportion of sex-linked genetic variance. Sexually selected traits did not show higher h(2)Z than morphological traits and there was only a weak positive relationship between h(2)Z and sexual dimorphism. However, given the relative scarcity of empirical studies, it is premature to make conclusions about the role of sex chromosome linkage in the evolution of sexual dimorphism.

  15. The geography of sex-specific selection, local adaptation, and sexual dimorphism.

    PubMed

    Connallon, Tim

    2015-09-01

    Local adaptation and sexual dimorphism are iconic evolutionary scenarios of intraspecific adaptive differentiation in the face of gene flow. Although theory has traditionally considered local adaptation and sexual dimorphism as conceptually distinct processes, emerging data suggest that they often act concurrently during evolutionary diversification. Here, I merge theories of local adaptation in space and sex-specific adaptation over time, and show that their confluence yields several new predictions about the roles of context-specific selection, migration, and genetic correlations, in adaptive diversification. I specifically revisit two influential predictions from classical studies of clinal adaptation and sexual dimorphism: (1) that local adaptation should decrease with distance from the species' range center and (2) that opposing directional selection between the sexes (sexual antagonism) should inevitably accompany the evolution of sexual dimorphism. I show that both predictions can break down under clinally varying selection. First, the geography of local adaptation can be sexually dimorphic, with locations of relatively high local adaptation differing profoundly between the sexes. Second, the intensity of sexual antagonism varies across the species' range, with subpopulations near the range center representing hotspots for antagonistic selection. The results highlight the context-dependent roles of migration versus sexual conflict as primary constraints to adaptive diversification.

  16. Deep sexual dimorphism in adult medaka fish liver highlighted by multi-omic approach.

    PubMed

    Qiao, Qin; Le Manach, Séverine; Sotton, Benoit; Huet, Hélène; Duvernois-Berthet, Evelyne; Paris, Alain; Duval, Charlotte; Ponger, Loïc; Marie, Arul; Blond, Alain; Mathéron, Lucrèce; Vinh, Joelle; Bolbach, Gérard; Djediat, Chakib; Bernard, Cécile; Edery, Marc; Marie, Benjamin

    2016-08-26

    Sexual dimorphism describes the features that discriminate between the two sexes at various biological levels. Especially, during the reproductive phase, the liver is one of the most sexually dimorphic organs, because of different metabolic demands between the two sexes. The liver is a key organ that plays fundamental roles in various physiological processes, including digestion, energetic metabolism, xenobiotic detoxification, biosynthesis of serum proteins, and also in endocrine or immune response. The sex-dimorphism of the liver is particularly obvious in oviparous animals, as the female liver is the main organ for the synthesis of oocyte constituents. In this work, we are interested in identifying molecular sexual dimorphism in the liver of adult medaka fish and their sex-variation in response to hepatotoxic exposures. By developing an integrative approach combining histology and different high-throughput omic investigations (metabolomics, proteomics and transcriptomics), we were able to globally depict the strong sexual dimorphism that concerns various cellular and molecular processes of hepatocytes comprising protein synthesis, amino acid, lipid and polysaccharide metabolism, along with steroidogenesis and detoxification. The results of this work imply noticeable repercussions on the biology of oviparous organisms environmentally exposed to chemical or toxin issues.

  17. Flight Test Series 3: Flight Test Report

    NASA Technical Reports Server (NTRS)

    Marston, Mike; Sternberg, Daniel; Valkov, Steffi

    2015-01-01

    This document is a flight test report from the Operational perspective for Flight Test Series 3, a subpart of the Unmanned Aircraft System (UAS) Integration in the National Airspace System (NAS) project. Flight Test Series 3 testing began on June 15, 2015, and concluded on August 12, 2015. Participants included NASA Ames Research Center, NASA Armstrong Flight Research Center, NASA Glenn Research Center, NASA Langley Research center, General Atomics Aeronautical Systems, Inc., and Honeywell. Key stakeholders analyzed their System Under Test (SUT) in two distinct configurations. Configuration 1, known as Pairwise Encounters, was subdivided into two parts: 1a, involving a low-speed UAS ownship and intruder(s), and 1b, involving a high-speed surrogate ownship and intruder. Configuration 2, known as Full Mission, involved a surrogate ownship, live intruder(s), and integrated virtual traffic. Table 1 is a summary of flights for each configuration, with data collection flights highlighted in green. Section 2 and 3 of this report give an in-depth description of the flight test period, aircraft involved, flight crew, and mission team. Overall, Flight Test 3 gathered excellent data for each SUT. We attribute this successful outcome in large part from the experience that was acquired from the ACAS Xu SS flight test flown in December 2014. Configuration 1 was a tremendous success, thanks to the training, member participation, integration/testing, and in-depth analysis of the flight points. Although Configuration 2 flights were cancelled after 3 data collection flights due to various problems, the lessons learned from this will help the UAS in the NAS project move forward successfully in future flight phases.

  18. Analysis of muscle fatigue in helicopter pilots.

    PubMed

    Balasubramanian, Venkatesh; Dutt, Ashwani; Rai, Shobhit

    2011-11-01

    Helicopter pilots espouse ergonomically unfavourable postures and endure vibration which result in low back pain. The objective of this study was to investigate the effects of a helicopter flight on pilots back and shoulder muscles using surface Electromyography (sEMG) analysis. This study also correlates low back pain symptoms from Rehabilitation Bioengineering Group Pain Scale (RBGPS) questionnaire with muscle fatigue rates obtained. RBGPS was administered on 20 Coast Guard helicopter pilots. sEMG was acquired before and after flight from erector spinae and trapezius muscles in 8 of these 20 pilots. Statistical analysis of time and frequency domain parameters indicated significant fatigue in right trapezius muscle due to flying. Muscle fatigue correlated with average duration of flight (r² = 0.913), total service as pilot (r² = 0.825), pain (r² = 0.463) and total flying hours (r² = 0.507). However, muscle fatigue weakly correlated with Body Mass Index (BMI) (r² = 0.000144) and age (r² = 0.033).

  19. Analysis of muscle fatigue in helicopter pilots.

    PubMed

    Balasubramanian, Venkatesh; Dutt, Ashwani; Rai, Shobhit

    2011-11-01

    Helicopter pilots espouse ergonomically unfavourable postures and endure vibration which result in low back pain. The objective of this study was to investigate the effects of a helicopter flight on pilots back and shoulder muscles using surface Electromyography (sEMG) analysis. This study also correlates low back pain symptoms from Rehabilitation Bioengineering Group Pain Scale (RBGPS) questionnaire with muscle fatigue rates obtained. RBGPS was administered on 20 Coast Guard helicopter pilots. sEMG was acquired before and after flight from erector spinae and trapezius muscles in 8 of these 20 pilots. Statistical analysis of time and frequency domain parameters indicated significant fatigue in right trapezius muscle due to flying. Muscle fatigue correlated with average duration of flight (r² = 0.913), total service as pilot (r² = 0.825), pain (r² = 0.463) and total flying hours (r² = 0.507). However, muscle fatigue weakly correlated with Body Mass Index (BMI) (r² = 0.000144) and age (r² = 0.033). PMID:21411058

  20. A comparative, developmental, and clinical perspective of neurobehavioral sexual dimorphisms.

    PubMed

    Viveros, Maria-Paz; Mendrek, Adriana; Paus, Tomáš; López-Rodríguez, Ana Belén; Marco, Eva Maria; Yehuda, Rachel; Cohen, Hagit; Lehrner, Amy; Wagner, Edward J

    2012-01-01

    Women and men differ in a wide variety of behavioral traits and in their vulnerability to developing certain mental disorders. This review endeavors to explore how recent preclinical and clinical research findings have enhanced our understanding of the factors that underlie these disparities. We start with a brief overview of some of the important genetic, molecular, and hormonal determinants that contribute to the process of sexual differentiation. We then discuss the importance of animal models in studying the mechanisms responsible for sex differences in neuropsychiatric disorders (e.g., drug dependence) - with a special emphasis on experimental models based on the neurodevelopmental and "three hits" hypotheses. Next, we describe the most common brain phenotypes observed in vivo with magnetic resonance imaging. We discuss the challenges in interpreting these phenotypes vis-à-vis the underlying neurobiology and revisit the known sex differences in brain structure from birth, through adolescence, and into adulthood. This is followed by a presentation of pertinent clinical and epidemiological data that point to important sex differences in the prevalence, course, and expression of psychopathologies such as schizophrenia, and mood disorders including major depression and posttraumatic stress disorder. Recent evidence implies that mood disorders and psychosis share some common genetic predispositions and neurobiological bases. Therefore, modern research is emphasizing dimensional representation of mental disorders and conceptualization of schizophrenia and major depression as a continuum of cognitive deficits and neurobiological abnormalities. Herein, we examine available evidence on cerebral sexual dimorphism to verify if sex differences vary quantitatively and/or qualitatively along the psychoses-depression continuum. Finally, sex differences in the prevalence of posttraumatic disorder and drug abuse have been described, and we consider the genomic and molecular

  1. A Comparative, Developmental, and Clinical Perspective of Neurobehavioral Sexual Dimorphisms

    PubMed Central

    Viveros, Maria-Paz; Mendrek, Adriana; Paus, Tomáš; López-Rodríguez, Ana Belén; Marco, Eva Maria; Yehuda, Rachel; Cohen, Hagit; Lehrner, Amy; Wagner, Edward J.

    2012-01-01

    Women and men differ in a wide variety of behavioral traits and in their vulnerability to developing certain mental disorders. This review endeavors to explore how recent preclinical and clinical research findings have enhanced our understanding of the factors that underlie these disparities. We start with a brief overview of some of the important genetic, molecular, and hormonal determinants that contribute to the process of sexual differentiation. We then discuss the importance of animal models in studying the mechanisms responsible for sex differences in neuropsychiatric disorders (e.g., drug dependence) – with a special emphasis on experimental models based on the neurodevelopmental and “three hits” hypotheses. Next, we describe the most common brain phenotypes observed in vivo with magnetic resonance imaging. We discuss the challenges in interpreting these phenotypes vis-à-vis the underlying neurobiology and revisit the known sex differences in brain structure from birth, through adolescence, and into adulthood. This is followed by a presentation of pertinent clinical and epidemiological data that point to important sex differences in the prevalence, course, and expression of psychopathologies such as schizophrenia, and mood disorders including major depression and posttraumatic stress disorder. Recent evidence implies that mood disorders and psychosis share some common genetic predispositions and neurobiological bases. Therefore, modern research is emphasizing dimensional representation of mental disorders and conceptualization of schizophrenia and major depression as a continuum of cognitive deficits and neurobiological abnormalities. Herein, we examine available evidence on cerebral sexual dimorphism to verify if sex differences vary quantitatively and/or qualitatively along the psychoses-depression continuum. Finally, sex differences in the prevalence of posttraumatic disorder and drug abuse have been described, and we consider the genomic and

  2. Sexual Dimorphism in Bite Performance Drives Morphological Variation in Chameleons

    PubMed Central

    da Silva, Jessica M.; Herrel, Anthony; Measey, G. John; Tolley, Krystal A.

    2014-01-01

    Phenotypic performance in different environments is central to understanding the evolutionary and ecological processes that drive adaptive divergence and, ultimately, speciation. Because habitat structure can affect an animal’s foraging behaviour, anti-predator defences, and communication behaviour, it can influence both natural and sexual selection pressures. These selective pressures, in turn, act upon morphological traits to maximize an animal’s performance. For performance traits involved in both social and ecological activities, such as bite force, natural and sexual selection often interact in complex ways, providing an opportunity to understand the adaptive significance of morphological variation with respect to habitat. Dwarf chameleons within the Bradypodion melanocephalum-Bradypodion thamnobates species complex have multiple phenotypic forms, each with a specific head morphology that could reflect its use of either open- or closed-canopy habitats. To determine whether these morphological differences represent adaptations to their habitats, we tested for differences in both absolute and relative bite performance. Only absolute differences were found between forms, with the closed-canopy forms biting harder than their open-canopy counterparts. In contrast, sexual dimorphism was found for both absolute and relative bite force, but the relative differences were limited to the closed-canopy forms. These results indicate that both natural and sexual selection are acting within both habitat types, but to varying degrees. Sexual selection seems to be the predominant force within the closed-canopy habitats, which are more protected from aerial predators, enabling chameleons to invest more in ornamentation for communication. In contrast, natural selection is likely to be the predominant force in the open-canopy habitats, inhibiting the development of conspicuous secondary sexual characteristics and, ultimately, enforcing their overall diminutive body size and

  3. Genome update of the dimorphic human pathogenic fungi causing paracoccidioidomycosis.

    PubMed

    Muñoz, José F; Gallo, Juan E; Misas, Elizabeth; Priest, Margaret; Imamovic, Alma; Young, Sarah; Zeng, Qiandong; Clay, Oliver K; McEwen, Juan G; Cuomo, Christina A

    2014-12-01

    Paracoccidiodomycosis (PCM) is a clinically important fungal disease that can acquire serious systemic forms and is caused by the thermodimorphic fungal Paracoccidioides spp. PCM is a tropical disease that is endemic in Latin America, where up to ten million people are infected; 80% of reported cases occur in Brazil, followed by Colombia and Venezuela. To enable genomic studies and to better characterize the pathogenesis of this dimorphic fungus, two reference strains of P. brasiliensis (Pb03, Pb18) and one strain of P. lutzii (Pb01) were sequenced [1]. While the initial draft assemblies were accurate in large scale structure and had high overall base quality, the sequences had frequent small scale defects such as poor quality stretches, unknown bases (N's), and artifactual deletions or nucleotide duplications, all of which caused larger scale errors in predicted gene structures. Since assembly consensus errors can now be addressed using next generation sequencing (NGS) in combination with recent methods allowing systematic assembly improvement, we re-sequenced the three reference strains of Paracoccidioides spp. using Illumina technology. We utilized the high sequencing depth to re-evaluate and improve the original assemblies generated from Sanger sequence reads, and obtained more complete and accurate reference assemblies. The new assemblies led to improved transcript predictions for the vast majority of genes of these reference strains, and often substantially corrected gene structures. These include several genes that are central to virulence or expressed during the pathogenic yeast stage in Paracoccidioides and other fungi, such as HSP90, RYP1-3, BAD1, catalase B, alpha-1,3-glucan synthase and the beta glucan synthase target gene FKS1. The improvement and validation of these reference sequences will now allow more accurate genome-based analyses. To our knowledge, this is one of the first reports of a fully automated and quality-assessed upgrade of a genome

  4. [Sexual dimorphism in the XXI(st) century].

    PubMed

    Junien, Claudine; Gabory, Anne; Attig, Linda

    2012-02-01

    A new definition of sexual dimorphism is required. The divergent biology of the sexes is still largely ignored, overshadowed by sociocultural considerations and confined to its hormonal organizational and activational effects, while the genes unequally expressed by the sex chromosomes play an important role much earlier, after conception, to set the stage and throughout life. These different components have independent and parallel effects that can interact in a synergistic or antagonistic manner on differentiation and response processes to trigger or erase sex-specific differences. The epigenetic marks and machinery represent the perfect tools to keep the memory of which sex is ours from the very beginning of life. Within the context of the developmental origin of adult health and diseases (DOHaD), owing to their flexibility to the environment, epigenetic marks also represent a support to archive the effects of environments during development, according to the sex of the parent, in a sex-specific mode. In all tissues, including gonads and brain, different trajectories of genes and pathways are used at the basal levels and to modulate/dictate responses according to sex and gender. It is urgent to emphasize the need to take into consideration this new knowledge and to apply less sex-biased approaches in research, medicine and society, to enhance women health and well-being. A critical review and realization of gender-specific social constraints, an indeniably but slowly on-going process, should allow us to "set free our sex biology" while detracting the delusion of hierarchy of the complex mechanisms involved. PMID:22377307

  5. Flight projects overview

    NASA Technical Reports Server (NTRS)

    Levine, Jack

    1988-01-01

    Information is given in viewgraph form on the activities of the Flight Projects Division of NASA's Office of Aeronautics and Space Technology. Information is given on space research and technology strategy, current space flight experiments, the Long Duration Exposure Facility, the Orbiter Experiment Program, the Lidar In-Space Technology Experiment, the Ion Auxiliary Propulsion System, the Arcjet Flight Experiment, the Telerobotic Intelligent Interface Flight Experiment, the Cryogenic Fluid Management Flight Experiment, the Industry/University In-Space Flight Experiments, and the Aeroassist Flight Experiment.

  6. Differential adaptation to weightlessness of functional and structural characteristics of rat hindlimb muscles.

    PubMed

    Stevens, L; Picquet, F; Catinot, M P; Mounier, Y

    1996-09-01

    Soleus, vastus intermedius, tibialis anterior, and extensor digitorum longus muscles were removed from rats following space flight onboard the SLS-2 mission and from control animals. Muscle tissues were studied for their calcium and strontium activated tension characteristics and for structural changes. Muscles were also examined for myosin composition using electrophoresis. Results indicate that changes occurred in structural and functional muscle characteristics in both slow and fast muscle fiber types. These results are detailed and discussed.

  7. Studies on the Flight Mechanism of Insects

    PubMed Central

    McCann, Frances V.; Boettiger, Edward G.

    1961-01-01

    Fibrillar type flight muscle powers the flight machinery of the more phylogenetically advanced groups of flying insects. A comparison of responses from single fibers in insects from various orders having fibrillar muscle reveals fundamental differences. In single fibers of flies and wasps the response to a single threshold stimulus is an all-or-none, uniformly rising, in most cases overshooting action potential. Beetles give variable responses, some of which appear similar to the type mentioned above, and others which summate and facilitate. Some of the latter responses vary with time in a cyclic manner, and some are altered by the intensity of the stimulus. Further differences appear when the two types of muscle are exposed to ether and carbon dioxide. In the wasp and fly ether produces a neuromuscular block, while CO2 effects a rapid depolarization of the resting fiber membrane. Both reactions are completely reversible. The electrical responses of beetle muscle are somewhat affected but only by massive doses. The implications of these data are discussed relative to the existence of fibrillar muscle "types." PMID:13773753

  8. Sexual dimorphism in Australopithecus afarensis was similar to that of modern humans.

    PubMed

    Reno, Philip L; Meindl, Richard S; McCollum, Melanie A; Lovejoy, C Owen

    2003-08-01

    The substantial fossil record for Australopithecus afarensis includes both an adult partial skeleton [Afar Locality (A.L.) 288-1, "Lucy"] and a large simultaneous death assemblage (A.L. 333). Here we optimize data derived from both to more accurately estimate skeletal size dimorphism. Postcranial ratios derived from A.L. 288-1 enable a significant increase in sample size compared with previous studies. Extensive simulations using modern humans, chimpanzees, and gorillas confirm that this technique is accurate and that skeletal size dimorphism in A. afarensis was most similar to that of contemporary Homo sapiens. These data eliminate some apparent discrepancies between the canine and skeletal size dimorphism in hominoids, imply that the species was not characterized by substantial sexual bimaturation, and greatly increase the probability that the reproductive strategy of A. afarensis was principally monogamy.

  9. Human skin-color sexual dimorphism: a test of the sexual selection hypothesis.

    PubMed

    Madrigal, Lorena; Kelly, William

    2007-03-01

    Applied to skin color, the sexual selection hypothesis proposes that male preference for light-skinned females explains the presence of light skin in areas of low solar radiation. According to this proposal, in areas of high solar radiation, natural selection for dark skin overrides the universal preference of males for light females. But in areas in which natural selection ceases to act, sexual selection becomes more important, and causes human populations to become light-skinned, and females to be lighter than males. The sexual selection hypothesis proposes that human sexual dimorphism of skin color should be positively correlated with distance from the equator. We tested the prediction that sexual dimorphism should increase with increasing latitude, using adult-only data sets derived from measurements with standard reflectance spectrophotometric devices. Our analysis failed to support the prediction of a positive correlation between increasing distance from the equator and increased sexual dimorphism. We found no evidence in support of the sexual selection hypothesis.

  10. Different on the inside: extreme swimbladder sexual dimorphism in the South Asian torrent minnows.

    PubMed

    Conway, Kevin W; Britz, Ralf; Siegel, Dustin S

    2014-07-01

    The swimbladder plays an important role in buoyancy regulation but is typically reduced or even absent in benthic freshwater fishes that inhabit fast flowing water. Here, we document, for the first time, a remarkable example of swimbladder sexual dimorphism in the highly rheophilic South Asian torrent minnows (Psilorhynchus). The male swimbladder is not only much larger than that of the female (up to five times the diameter and up to 98 times the volume in some cases), but is also structurally more complex, with multiple internal septa dividing it into smaller chambers. Males also exhibit a strange organ of unknown function or homology in association with the swimbladder that is absent in females. Extreme sexual dimorphism of non-gonadal internal organs is rare among vertebrates and the swimbladder sexual dimorphisms that we describe for Psilorhynchus are unique among fishes.

  11. Different on the inside: extreme swimbladder sexual dimorphism in the South Asian torrent minnows

    PubMed Central

    Conway, Kevin W.; Britz, Ralf; Siegel, Dustin S.

    2014-01-01

    The swimbladder plays an important role in buoyancy regulation but is typically reduced or even absent in benthic freshwater fishes that inhabit fast flowing water. Here, we document, for the first time, a remarkable example of swimbladder sexual dimorphism in the highly rheophilic South Asian torrent minnows (Psilorhynchus). The male swimbladder is not only much larger than that of the female (up to five times the diameter and up to 98 times the volume in some cases), but is also structurally more complex, with multiple internal septa dividing it into smaller chambers. Males also exhibit a strange organ of unknown function or homology in association with the swimbladder that is absent in females. Extreme sexual dimorphism of non-gonadal internal organs is rare among vertebrates and the swimbladder sexual dimorphisms that we describe for Psilorhynchus are unique among fishes. PMID:25009242

  12. Cognitive impairment but preservation of sexual dimorphism in cognitive abilities in chronic schizophrenia.

    PubMed

    Halari, Rozmin; Mehrotra, Ravi; Sharma, Tonmoy; Ng, Virginia; Kumari, Veena

    2006-02-28

    Neurocognitive impairment in schizophrenia is well established, though sex differences on cognitive tasks have produced equivocal findings. The present study was designed to examine performance of schizophrenia patients on a sexually dimorphic cognitive battery. The cognitive battery comprising tests of spatial (mental rotation, computerized version of the Benton Judgment of Line Orientation) and verbal abilities (phonological and semantic fluency) was administered to men (n = 22) and women (n = 21) with schizophrenia and healthy controls (n = 21 men and 21 women). A series of multivariate analyses showed that the patient group performed worse than controls on all the cognitive tasks. Cognitive sexual dimorphism on all spatial tasks favoring men and verbal tasks favoring women remained. Within the patient sample, correlational data demonstrated that earlier age at onset of illness related to poorer spatial performance. It is concluded that normal sexual dimorphism is undisturbed on both spatial and verbal tasks by the schizophrenia disease process.

  13. A new viewpoint on the evolution of sexually dimorphic human faces.

    PubMed

    Burke, Darren; Sulikowski, Danielle

    2010-01-01

    Human faces show marked sexual shape dimorphism, and this affects their attractiveness. Humans also show marked height dimorphism, which means that men typically view women's faces from slightly above and women typically view men's faces from slightly below. We tested the idea that this perspective difference may be the evolutionary origin of the face shape dimorphism by having males and females rate the masculinity/femininity and attractiveness of male and female faces that had been manipulated in pitch (forward or backward tilt), simulating viewing the face from slightly above or below. As predicted, tilting female faces upwards decreased their perceived femininity and attractiveness, whereas tilting them downwards increased their perceived femininity and attractiveness. Male faces tilted up were judged to be more masculine, and tilted down judged to be less masculine. This suggests that sexual selection may have embodied this viewpoint difference into the actual facial proportions of men and women. PMID:22947821

  14. Space travel directly induces skeletal muscle atrophy

    NASA Technical Reports Server (NTRS)

    Vandenburgh, H.; Chromiak, J.; Shansky, J.; Del Tatto, M.; Lemaire, J.

    1999-01-01

    Space travel causes rapid and pronounced skeletal muscle wasting in humans that reduces their long-term flight capabilities. To develop effective countermeasures, the basis of this atrophy needs to be better understood. Space travel may cause muscle atrophy indirectly by altering circulating levels of factors such as growth hormone, glucocorticoids, and anabolic steroids and/or by a direct effect on the muscle fibers themselves. To determine whether skeletal muscle cells are directly affected by space travel, tissue-cultured avian skeletal muscle cells were tissue engineered into bioartificial muscles and flown in perfusion bioreactors for 9 to 10 days aboard the Space Transportation System (STS, i.e., Space Shuttle). Significant muscle fiber atrophy occurred due to a decrease in protein synthesis rates without alterations in protein degradation. Return of the muscle cells to Earth stimulated protein synthesis rates of both muscle-specific and extracellular matrix proteins relative to ground controls. These results show for the first time that skeletal muscle fibers are directly responsive to space travel and should be a target for countermeasure development.

  15. Space travel directly induces skeletal muscle atrophy.

    PubMed

    Vandenburgh, H; Chromiak, J; Shansky, J; Del Tatto, M; Lemaire, J

    1999-06-01

    Space travel causes rapid and pronounced skeletal muscle wasting in humans that reduces their long-term flight capabilities. To develop effective countermeasures, the basis of this atrophy needs to be better understood. Space travel may cause muscle atrophy indirectly by altering circulating levels of factors such as growth hormone, glucocorticoids, and anabolic steroids and/or by a direct effect on the muscle fibers themselves. To determine whether skeletal muscle cells are directly affected by space travel, tissue-cultured avian skeletal muscle cells were tissue engineered into bioartificial muscles and flown in perfusion bioreactors for 9 to 10 days aboard the Space Transportation System (STS, i.e., Space Shuttle). Significant muscle fiber atrophy occurred due to a decrease in protein synthesis rates without alterations in protein degradation. Return of the muscle cells to Earth stimulated protein synthesis rates of both muscle-specific and extracellular matrix proteins relative to ground controls. These results show for the first time that skeletal muscle fibers are directly responsive to space travel and should be a target for countermeasure development.

  16. Changes in recruitment of Rhesus soleus and gastrocnemius muscles following a 14 day spaceflight

    NASA Technical Reports Server (NTRS)

    Hodgson, J. A.; Bodine-Fowler, S. C.; Roy, R. R.; De Leon, R. D.; De Guzman, C. P.; Koslovskaia, I.; Sirota, M.; Edgerton, V. R.

    1991-01-01

    The effect of microgravity on the recruitment patterns of the soleus, gastrocnemius, and tibialis-anterior muscles was investigated by comparing electromyograms (EMGs) of these muscles of Rhesus monkeys implanted with EMG electrodes, taken before and after a 14-day flight on board Cosmos 2044. It was found that the EMG amplitude values in the soleus muscle decreased after the spaceflight but returned to normal values over the 2-wk recovery period. The medial amplitudes of gastrocnemius and tibialis anterior were not changed by flight. Joint probability density distributions displayed changes after flight in both the soleus and gastrocnemius muscles, but not in tibialis anterior.

  17. Specialization for aggression in sexually dimorphic skeletal morphology in grey wolves (Canis lupus).

    PubMed

    Morris, Jeremy S; Brandt, Ellissa K

    2014-07-01

    Aggressive behaviour is important in the life history of many animals. In grey wolves (Canis lupus), territory defence through direct competition with conspecifics is severe and often lethal. Thus, performance in aggressive encounters may be under strong selection. Additionally, grey wolves frequently kill large dangerous prey species. Because both sexes actively participate in aggressive activities and prey capture, wolves are expected to exhibit a low level of musculoskeletal sexual dimorphism. However, male wolves more often lead in agonistic encounters with conspecifics and must provision the nursing female during the pup-rearing period of the breeding season. These behaviours may select for males that exhibit a higher degree of morphological adaptation associated with aggression and prey capture performance. To test this prediction, we assessed skeletal sexual dimorphism in three subspecies of grey wolves using functional indices reflecting morphological specialization for aggression. As expected, sexual dimorphism in skeletal shape was limited. However, in two of three subspecies, we found sexually dimorphic traits in the skull, forelimbs and hindlimbs that are consistent with the hypothesis that males are more specialized for aggression. These characters may also be associated with selection for improved prey capture performance by males. Thus, the sexually dimorphic functional traits identified by our analysis may be adaptive in the contexts of both natural and sexual selection. Several of these traits may conflict with locomotor economy, indicating the importance of aggression in the life history of male grey wolves. The presence of functional specialization for aggression in a generally monogamous species indicates that sexual dimorphism in specific musculoskeletal traits may be widespread among mammals. PMID:24810384

  18. Effect of the MC1R gene on sexual dimorphism in melanin-based colorations.

    PubMed

    San-Jose, Luis M; Ducrest, Anne-Lyse; Ducret, Valérie; Béziers, Paul; Simon, Céline; Wakamatsu, Kazumasa; Roulin, Alexandre

    2015-06-01

    Variants of the melanocortin-1 receptor (MC1R) gene result in abrupt, naturally selected colour morphs. These genetic variants may differentially affect sexual dimorphism if one morph is naturally selected in the two sexes but another morph is naturally or sexually selected only in one of the two sexes (e.g. to confer camouflage in reproductive females or confer mating advantage in males). Therefore, the balance between natural and sexual selections can differ between MC1R variants, as suggest studies showing interspecific correlations between sexual dimorphism and the rate of nonsynonymous vs. synonymous amino acid substitutions at the MC1R. Surprisingly, how MC1R is related to within-species sexual dimorphism, and thereby to sex-specific selection, has not yet been investigated. We tackled this issue in the barn owl (Tyto alba), a species showing pronounced variation in the degree of reddish pheomelanin-based coloration and in the number and size of black feather spots. We found that a valine (V)-to-isoleucine (I) substitution at position 126 explains up to 30% of the variation in the three melanin-based colour traits and in feather melanin content. Interestingly, MC1R genotypes also differed in the degree of sexual colour dimorphism, with individuals homozygous for the II MC1R variant being 2 times redder and 2.5 times less sexually dimorphic than homozygous individuals for the VV MC1R variant. These findings support that MC1R interacts with the expression of sexual dimorphism and suggest that a gene with major phenotypic effects and weakly influenced by variation in body condition can participate in sex-specific selection processes. PMID:25857339

  19. Specialization for aggression in sexually dimorphic skeletal morphology in grey wolves (Canis lupus).

    PubMed

    Morris, Jeremy S; Brandt, Ellissa K

    2014-07-01

    Aggressive behaviour is important in the life history of many animals. In grey wolves (Canis lupus), territory defence through direct competition with conspecifics is severe and often lethal. Thus, performance in aggressive encounters may be under strong selection. Additionally, grey wolves frequently kill large dangerous prey species. Because both sexes actively participate in aggressive activities and prey capture, wolves are expected to exhibit a low level of musculoskeletal sexual dimorphism. However, male wolves more often lead in agonistic encounters with conspecifics and must provision the nursing female during the pup-rearing period of the breeding season. These behaviours may select for males that exhibit a higher degree of morphological adaptation associated with aggression and prey capture performance. To test this prediction, we assessed skeletal sexual dimorphism in three subspecies of grey wolves using functional indices reflecting morphological specialization for aggression. As expected, sexual dimorphism in skeletal shape was limited. However, in two of three subspecies, we found sexually dimorphic traits in the skull, forelimbs and hindlimbs that are consistent with the hypothesis that males are more specialized for aggression. These characters may also be associated with selection for improved prey capture performance by males. Thus, the sexually dimorphic functional traits identified by our analysis may be adaptive in the contexts of both natural and sexual selection. Several of these traits may conflict with locomotor economy, indicating the importance of aggression in the life history of male grey wolves. The presence of functional specialization for aggression in a generally monogamous species indicates that sexual dimorphism in specific musculoskeletal traits may be widespread among mammals.

  20. Signature gene expression reveals novel clues to the molecular mechanisms of dimorphic transition in Penicillium marneffei.

    PubMed

    Yang, Ence; Chow, Wang-Ngai; Wang, Gang; Woo, Patrick C Y; Lau, Susanna K P; Yuen, Kwok-Yung; Lin, Xiaorong; Cai, James J

    2014-10-01

    Systemic dimorphic fungi cause more than one million new infections each year, ranking them among the significant public health challenges currently encountered. Penicillium marneffei is a systemic dimorphic fungus endemic to Southeast Asia. The temperature-dependent dimorphic phase transition between mycelium and yeast is considered crucial for the pathogenicity and transmission of P. marneffei, but the underlying mechanisms are still poorly understood. Here, we re-sequenced P. marneffei strain PM1 using multiple sequencing platforms and assembled the genome using hybrid genome assembly. We determined gene expression levels using RNA sequencing at the mycelial and yeast phases of P. marneffei, as well as during phase transition. We classified 2,718 genes with variable expression across conditions into 14 distinct groups, each marked by a signature expression pattern implicated at a certain stage in the dimorphic life cycle. Genes with the same expression patterns tend to be clustered together on the genome, suggesting orchestrated regulations of the transcriptional activities of neighboring genes. Using qRT-PCR, we validated expression levels of all genes in one of clusters highly expressed during the yeast-to-mycelium transition. These included madsA, a gene encoding MADS-box transcription factor whose gene family is exclusively expanded in P. marneffei. Over-expression of madsA drove P. marneffei to undergo mycelial growth at 37°C, a condition that restricts the wild-type in the yeast phase. Furthermore, analyses of signature expression patterns suggested diverse roles of secreted proteins at different developmental stages and the potential importance of non-coding RNAs in mycelium-to-yeast transition. We also showed that RNA structural transition in response to temperature changes may be related to the control of thermal dimorphism. Together, our findings have revealed multiple molecular mechanisms that may underlie the dimorphic transition in P. marneffei

  1. Comparison of sexual dimorphism of permanent mandibular canine with mandibular first molar by odontometrics

    PubMed Central

    Agrawal, Aditi; Manjunatha, Bhari Shranesha; Dholia, Bhavik; Althomali, Yousef

    2015-01-01

    Background and Objectives: Sexual dimorphism is one of important tool of forensic science. The objective of this study is to assess the dimorphic status of mesio-distal (MD) and bucco-lingual (BL) diameter of mandibular canine with mandibular first molar among the students of dental college. This study is of definite significance as sex chromosomes and hormonal production influenced tooth morphology. Materials and Methods: The descriptive study adopted the purposive sampling technique, of 50 male and 50 female aged 17-25 years, using study casts for mesio-distal and bucco-lingual dimensions of mandibular canine with mandibular first molar were taken using digital Vernier caliper. The data obtained were subjected to statistical analysis using descriptive statistics and t-test to compare MD and BL dimensions in male and female populations and P ≤ 0.05 was found statistically significant. Results: Sexual dimorphism can be predicted by measuring mesiodistal dimension of mandibular canine and mandibular first molar. The left mandibular canine showed more sexual dimorphism (12.66%) in comparison to left mandibular first molar (0.824%) only. Right mandibular canine showed greater dimorphism in MD dimensions (10.94%) in comparison to right mandibular first molar (6.96%). In bucco-lingual dimensions mandibular canine showed less variability when compared with mandibular first molar, thus our study showed more significance on mesio-distal dimensions of both teeth. Conclusion: The present study concludes statistically significant sexual dimorphism in mandibular canine over mandibular first molar on study casts. The MD dimensions in mandibular canine and mandibular first molar can help in determining sex and identification of unknown person. PMID:26816466

  2. Beta 2-adrenergic receptor regulation of human neutrophil function is sexually dimorphic.

    PubMed

    de Coupade, Catherine; Gear, Robert W; Dazin, Paul F; Sroussi, Herve Y; Green, Paul G; Levine, Jon D

    2004-12-01

    While the mechanisms underlying the marked sexual dimorphism in inflammatory diseases are not well understood, the sexually dimorphic sympathoadrenal axis profoundly affects the inflammatory response. We tested whether adrenergic receptor-mediated activation of human neutrophil function is sexually dimorphic, since neutrophils provide the first line of defense in the inflammatory response. There was a marked sexual dimorphism in beta(2)-adrenergic receptor binding, using the specific beta(2)-adrenergic receptor ligand, [(3)H]-dihydroalprenolol, with almost three times more binding sites on neutrophils from females (20,878 +/- 2470) compared to males (7331 +/- 3179). There was also a marked sexual dimorphism in the effects of isoprenaline, a beta-adrenergic receptor agonist, which increased nondirected locomotion (chemokinesis) in neutrophils obtained from females, while having no effect on neutrophils from males. Isoprenaline stimulated the release of a chemotactic factor from neutrophils obtained from females, but not from males. This chemotactic factor acts on the G protein-coupled CXC chemokine receptor 2 (CXCR2) chemokine receptor, since an anti-CXCR2 antibody and the selective nonpeptide CXCR2 antagonist SB225002, inhibited chemotaxis produced by this factor. While interleukin- (IL-) 8 is a principal CXCR2 ligand, isoprenaline did not produce an increase in IL-8 release from neutrophils. IL-8-induced chemotaxis was inhibited in a sexually dimorphic manner by isoprenaline, which also stimulated release of a mediator from neutrophils that induced chemotaxis, that was inhibited by anti-CXCR2 antibodies. These findings indicate an important role for adrenergic receptors in the modulation of neutrophil trafficking, which could contribute to sex-differences in the inflammatory response. PMID:15477226

  3. Specialization for aggression in sexually dimorphic skeletal morphology in grey wolves (Canis lupus)

    PubMed Central

    Morris, Jeremy S; Brandt, Ellissa K

    2014-01-01

    Aggressive behaviour is important in the life history of many animals. In grey wolves (Canis lupus), territory defence through direct competition with conspecifics is severe and often lethal. Thus, performance in aggressive encounters may be under strong selection. Additionally, grey wolves frequently kill large dangerous prey species. Because both sexes actively participate in aggressive activities and prey capture, wolves are expected to exhibit a low level of musculoskeletal sexual dimorphism. However, male wolves more often lead in agonistic encounters with conspecifics and must provision the nursing female during the pup-rearing period of the breeding season. These behaviours may select for males that exhibit a higher degree of morphological adaptation associated with aggression and prey capture performance. To test this prediction, we assessed skeletal sexual dimorphism in three subspecies of grey wolves using functional indices reflecting morphological specialization for aggression. As expected, sexual dimorphism in skeletal shape was limited. However, in two of three subspecies, we found sexually dimorphic traits in the skull, forelimbs and hindlimbs that are consistent with the hypothesis that males are more specialized for aggression. These characters may also be associated with selection for improved prey capture performance by males. Thus, the sexually dimorphic functional traits identified by our analysis may be adaptive in the contexts of both natural and sexual selection. Several of these traits may conflict with locomotor economy, indicating the importance of aggression in the life history of male grey wolves. The presence of functional specialization for aggression in a generally monogamous species indicates that sexual dimorphism in specific musculoskeletal traits may be widespread among mammals. PMID:24810384

  4. Steroid hormones and CNS sexual dimorphisms modulate symptom expression in Tourette's syndrome.

    PubMed

    Peterson, B S; Leckman, J F; Scahill, L; Naftolin, F; Keefe, D; Charest, N J; Cohen, D J

    1992-11-01

    We present our hypothesis that various steroid hormones play an important role in the symptom expression of Gilles de la Tourette's syndrome (TS) and that androgenic hormones, in particular, are likely to exacerbate symptoms of the disorder. We review the clinical evidence supporting our hypothesis. Sex steroids establish brain sexual dimorphisms early in CNS development, and we suggest mechanisms whereby androgenic and other hormonal changes later in human development might act at dimorphic brain regions to influence the natural history of TS. Finally, we discuss the various ways in which neuroendocrine studies might assist in genetic and neurobiologic research programs in TS.

  5. Red is romantic, but only for feminine females: sexual dimorphism moderates red effect on sexual attraction.

    PubMed

    Wen, Fangfang; Zuo, Bin; Wu, Yang; Sun, Shan; Liu, Ke

    2014-01-01

    Previous researchers have documented that the color red enhances one's sexual attraction to the opposite sex. The current study further examined the moderating role of sexual dimorphism in red effects. The results indicated that red enhanced men's sexual attraction to women with more feminine facial characteristics but had no effect on ratings of perceived general attractiveness. Red clothing also had a marginally significant effect on men's sexual attractiveness. In addition, regardless of sexual dimorphism cues, male participants rated women with red as warmer and more competent. The underlying mechanisms of the red effect, the limitations of the current study, and suggestions for future directions are discussed. PMID:25300050

  6. Space flight and oxidative stress

    NASA Technical Reports Server (NTRS)

    Stein, T. P.

    2002-01-01

    Space flight is associated with an increase in oxidative stress after return to 1g. The effect is more pronounced after long-duration space flight. The effects lasts for several weeks after landing. In humans there is increased lipid peroxidation in erythrocyte membranes, reduction in some blood antioxidants, and increased urinary excretion of 8-iso-prostaglandin F(2alpha) and 8-oxo-7,8 dihydro-2 deoxyguanosine. Isoprostane 8-iso-prostaglandin F(2alpha) and 8-oxo-7,8 dihydro-2 deoxyguanosine are markers for oxidative damage to lipids and DNA, respectively. The changes have been attributed to a combination of the energy deficiency that occurs during flight and substrate competition for amino acids occurring between repleting muscle and other tissues during the recovery phase. The observations in humans have been complemented by rodent studies. Most rodent studies showed increased production of lipid peroxidation products postflight and decreased antioxidant enzyme activity postflight. The rodent observations were attributed to the stress associated with reentry into Earth's gravity. Decreasing the imbalance between the production of endogenous oxidant defenses and oxidant production by increasing the supply of dietary antioxidants may lessen the severity of the postflight increase in oxidative stress.

  7. X-33 Flight Visualization

    NASA Technical Reports Server (NTRS)

    Laue, Jay H.

    1998-01-01

    The X-33 flight visualization effort has resulted in the integration of high-resolution terrain data with vehicle position and attitude data for planned flights of the X-33 vehicle from its launch site at Edwards AFB, California, to landings at Michael Army Air Field, Utah, and Maelstrom AFB, Montana. Video and Web Site representations of these flight visualizations were produced. In addition, a totally new module was developed to control viewpoints in real-time using a joystick input. Efforts have been initiated, and are presently being continued, for real-time flight coverage visualizations using the data streams from the X-33 vehicle flights. The flight visualizations that have resulted thus far give convincing support to the expectation that the flights of the X-33 will be exciting and significant space flight milestones... flights of this nation's one-half scale predecessor to its first single-stage-to-orbit, fully-reusable launch vehicle system.

  8. Initial Observations of Fruit Fly;s Flight with its b1 Motor Neuron Altered

    NASA Astrophysics Data System (ADS)

    Wang, Z. Jane; Melfi, James, Jr.

    2015-11-01

    Recently we have suggested that one of the fly's 17 steering muscles, the first basalar muscle (b1) is responsible for maintaining flight stability. To test this, we compare the flight behavior of normal flies with genetically modified flies whose motor neuron to the b1 muscle is silenced. We report our initial observation of the difference and similarity between these two lines supplied by Janelia Farm. We also discuss the basic question for quantifying flight, what makes a good flier? Partly supported by the Visiting Scientist program at HHMI-Janelia Farm.

  9. Thermal biology of flight in a butterfly: genotype, flight metabolism, and environmental conditions.

    PubMed

    Mattila, Anniina L K

    2015-12-01

    Knowledge of the effects of thermal conditions on animal movement and dispersal is necessary for a mechanistic understanding of the consequences of climate change and habitat fragmentation. In particular, the flight of ectothermic insects such as small butterflies is greatly influenced by ambient temperature. Here, variation in body temperature during flight is investigated in an ecological model species, the Glanville fritillary butterfly (Melitaea cinxia). Attention is paid on the effects of flight metabolism, genotypes at candidate loci, and environmental conditions. Measurements were made under a natural range of conditions using infrared thermal imaging. Heating of flight muscles by flight metabolism has been presumed to be negligible in small butterflies. However, the results demonstrate that Glanville fritillary males with high flight metabolic rate maintain elevated body temperature better during flight than males with a low rate of flight metabolism. This effect is likely to have a significant influence on the dispersal performance and fitness of butterflies and demonstrates the possible importance of intraspecific physiological variation on dispersal in other similar ectothermic insects. The results also suggest that individuals having an advantage in low ambient temperatures can be susceptible to overheating at high temperatures. Further, tolerance of high temperatures may be important for flight performance, as indicated by an association of heat-shock protein (Hsp70) genotype with flight metabolic rate and body temperature at takeoff. The dynamics of body temperature at flight and factors affecting it also differed significantly between female and male butterflies, indicating that thermal dynamics are governed by different mechanisms in the two sexes. This study contributes to knowledge about factors affecting intraspecific variation in dispersal-related thermal performance in butterflies and other insects. Such information is needed for predictive

  10. Thermal biology of flight in a butterfly: genotype, flight metabolism, and environmental conditions.

    PubMed

    Mattila, Anniina L K

    2015-12-01

    Knowledge of the effects of thermal conditions on animal movement and dispersal is necessary for a mechanistic understanding of the consequences of climate change and habitat fragmentation. In particular, the flight of ectothermic insects such as small butterflies is greatly influenced by ambient temperature. Here, variation in body temperature during flight is investigated in an ecological model species, the Glanville fritillary butterfly (Melitaea cinxia). Attention is paid on the effects of flight metabolism, genotypes at candidate loci, and environmental conditions. Measurements were made under a natural range of conditions using infrared thermal imaging. Heating of flight muscles by flight metabolism has been presumed to be negligible in small butterflies. However, the results demonstrate that Glanville fritillary males with high flight metabolic rate maintain elevated body temperature better during flight than males with a low rate of flight metabolism. This effect is likely to have a significant influence on the dispersal performance and fitness of butterflies and demonstrates the possible importance of intraspecific physiological variation on dispersal in other similar ectothermic insects. The results also suggest that individuals having an advantage in low ambient temperatures can be susceptible to overheating at high temperatures. Further, tolerance of high temperatures may be important for flight performance, as indicated by an association of heat-shock protein (Hsp70) genotype with flight metabolic rate and body temperature at takeoff. The dynamics of body temperature at flight and factors affecting it also differed significantly between female and male butterflies, indicating that thermal dynamics are governed by different mechanisms in the two sexes. This study contributes to knowledge about factors affecting intraspecific variation in dispersal-related thermal performance in butterflies and other insects. Such information is needed for predictive

  11. Flight Test Engineering

    NASA Technical Reports Server (NTRS)

    Pavlock, Kate Maureen

    2013-01-01

    Although the scope of flight test engineering efforts may vary among organizations, all point to a common theme: flight test engineering is an interdisciplinary effort to test an asset in its operational flight environment. Upfront planning where design, implementation, and test efforts are clearly aligned with the flight test objective are keys to success. This chapter provides a top level perspective of flight test engineering for the non-expert. Additional research and reading on the topic is encouraged to develop a deeper understanding of specific considerations involved in each phase of flight test engineering.

  12. Trehalose metabolism in the blue crab Callinectes sapidus: isolation of multiple structural cDNA isoforms of trehalose-6-phosphate synthase and their expression in muscles.

    PubMed

    Shi, Q; Chung, J Sook

    2014-02-15

    Adult blue crab Callinectes sapidus exhibit behavioral and ecological dimorphisms: females migrating from the low salinity water to the high salinity area vs. males remaining in the same areas. The flesh basal muscle of the swimming paddle shows a dimorphic color pattern in that levator (Lev) and depressor (Dep) of females tend to be much darker than those of males, while both genders have the same light colored remoter (Rem) and promoter (Pro). The full-length cDNA sequence of four structural isoforms of trehalose-6-phosphate synthase (TPS) is isolated from chela muscles of an adult female, C. sapidus. Two isoforms of the C. sapidus TPS encode functional domains of TPS and trehalose-6-phosphorylase (TPP) in tandem as a fused gene product of Escherichia coli Ost A and Ost B. The other two isoforms contain only a single TPS domain. In both males and females, the darker (Lev+Dep) muscles exhibit greater amounts of trehalose, TPS and trehalase activities than the light colored (Rem+Pro). The fact that adult females show higher levels of trehalase activity in the basal muscles and of glucose in Lev+Dep than those of adult males suggests that there may be a metabolic dimorphism. Moreover, the involvement of trehalose in energy metabolism that was examined under the condition of strenuous swimming activity mimicked in adult females demonstrates the intrinsic trehalose metabolism in Lev+Dep, which subsequently results in hemolymphatic hyperglycemia and hyperlactemia. Our data support that trehalose serves as an additional carbohydrate source of hemolymphatic hyperglycemia in this species. Behavioral and ecological dimorphisms of C. sapidus adults may be supported by a functional dimorphism in energy metabolism.

  13. Development of Sensory Receptors in Skeletal Muscle

    NASA Technical Reports Server (NTRS)

    DeSantis, Mark

    2000-01-01

    The two major goals for this project is to (1) examine the hindlimb walking pattern of offspring from the Flight dams as compared with offspring of the ground control groups from initiation of walking up to two months thereafter; and (2) examine skeletal muscle.

  14. 14 CFR 91.109 - Flight instruction; Simulated instrument flight and certain flight tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Flight instruction; Simulated instrument flight and certain flight tests. 91.109 Section 91.109 Aeronautics and Space FEDERAL AVIATION... OPERATING AND FLIGHT RULES Flight Rules General § 91.109 Flight instruction; Simulated instrument flight...

  15. 14 CFR 91.109 - Flight instruction; Simulated instrument flight and certain flight tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Flight instruction; Simulated instrument flight and certain flight tests. 91.109 Section 91.109 Aeronautics and Space FEDERAL AVIATION... OPERATING AND FLIGHT RULES Flight Rules General § 91.109 Flight instruction; Simulated instrument flight...

  16. 14 CFR 91.109 - Flight instruction; Simulated instrument flight and certain flight tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Flight instruction; Simulated instrument flight and certain flight tests. 91.109 Section 91.109 Aeronautics and Space FEDERAL AVIATION... OPERATING AND FLIGHT RULES Flight Rules General § 91.109 Flight instruction; Simulated instrument flight...

  17. 14 CFR 91.109 - Flight instruction; Simulated instrument flight and certain flight tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Flight instruction; Simulated instrument flight and certain flight tests. 91.109 Section 91.109 Aeronautics and Space FEDERAL AVIATION... OPERATING AND FLIGHT RULES Flight Rules General § 91.109 Flight instruction; Simulated instrument flight...

  18. Energy substrates for flight in the blister beetle Decapotoma lunata (Meloidae)

    PubMed

    Auerswald; GADe

    1995-01-01

    We investigated the substrates for flight in the blister beetle Decapotoma lunata by (a) establishing the patterns of maximum activities of enzymes of various metabolic pathways in the flight muscles, (b) measuring the respiratory rates of flight muscle mitochondria with various substrates and (c) determining metabolite concentrations in flight muscles and haemolymph during a flight period of up to 17 min and over a rest period of up to 2 h following 10 min of flight. Activities of enzymes involved in proline metabolism (glutamate dehydrogenase, alanine aminotransferase, malic enzyme) were much higher in the blister beetle than in the migratory locust Locusta migratoria, whereas the activity of an enzyme responsible for fatty acid oxidation (ss-hydroxyacyl-CoA dehydrogenase) was much lower. Mitochondria from flight muscles of D. lunata have a much higher capacity to oxidise proline than those from L. migratoria. The glycerophosphate shuttle, however, was equally active in both insects. Whereas lipid levels in the haemolymph did not change significantly during flight, there was a continuous decrease in proline levels from 34.8 to 6.6 micromol ml-1 and a simultaneous increase in alanine concentration; carbohydrate levels dropped from 20.1 to 12.2 mg ml-1. In the thorax (flight muscles), glycogen levels were diminished between 2 and 17 min of flight from 25.9 to 6.7 micromol glucose equivalents g-1 fresh mass. Proline concentration dropped continuously from an initial 49.5 to 10.1 micromol g-1 fresh mass, whereas alanine levels rose concomitantly from 2.9 to 17.3 micromol g-1 fresh mass. After termination of a 10 min flight, pre-flight levels of proline in the haemolymph and flight muscles were only re-established after 2 h. In contrast, glycogen levels in the thorax were restored after 1 h. Using the rates of utilisation of substrates during the first 10 min of flight to calculate rates of oxygen consumption during flight, it was shown that overall haemolymph

  19. Energy substrates for flight in the blister beetle Decapotoma lunata (Meloidae)

    PubMed

    Auerswald; GADe

    1995-01-01

    We investigated the substrates for flight in the blister beetle Decapotoma lunata by (a) establishing the patterns of maximum activities of enzymes of various metabolic pathways in the flight muscles, (b) measuring the respiratory rates of flight muscle mitochondria with various substrates and (c) determining metabolite concentrations in flight muscles and haemolymph during a flight period of up to 17 min and over a rest period of up to 2 h following 10 min of flight. Activities of enzymes involved in proline metabolism (glutamate dehydrogenase, alanine aminotransferase, malic enzyme) were much higher in the blister beetle than in the migratory locust Locusta migratoria, whereas the activity of an enzyme responsible for fatty acid oxidation (ss-hydroxyacyl-CoA dehydrogenase) was much lower. Mitochondria from flight muscles of D. lunata have a much higher capacity to oxidise proline than those from L. migratoria. The glycerophosphate shuttle, however, was equally active in both insects. Whereas lipid levels in the haemolymph did not change significantly during flight, there was a continuous decrease in proline levels from 34.8 to 6.6 micromol ml-1 and a simultaneous increase in alanine concentration; carbohydrate levels dropped from 20.1 to 12.2 mg ml-1. In the thorax (flight muscles), glycogen levels were diminished between 2 and 17 min of flight from 25.9 to 6.7 micromol glucose equivalents g-1 fresh mass. Proline concentration dropped continuously from an initial 49.5 to 10.1 micromol g-1 fresh mass, whereas alanine levels rose concomitantly from 2.9 to 17.3 micromol g-1 fresh mass. After termination of a 10 min flight, pre-flight levels of proline in the haemolymph and flight muscles were only re-established after 2 h. In contrast, glycogen levels in the thorax were restored after 1 h. Using the rates of utilisation of substrates during the first 10 min of flight to calculate rates of oxygen consumption during flight, it was shown that overall haemolymph

  20. Muscle strain (image)

    MedlinePlus

    A muscle strain is the stretching or tearing of muscle fibers. A muscle strain can be caused by sports, exercise, a ... something that is too heavy. Symptoms of a muscle strain include pain, tightness, swelling, tenderness, and the ...

  1. Adult sex ratio, sexual dimorphism and sexual selection in a Mesozoic reptile.

    PubMed

    Motani, Ryosuke; Jiang, Da-yong; Rieppel, Olivier; Xue, Yi-fan; Tintori, Andrea

    2015-09-22

    The evolutionary history of sexual selection in the geologic past is poorly documented based on quantification, largely because of difficulty in sexing fossil specimens. Even such essential ecological parameters as adult sex ratio (ASR) and sexual size dimorphism (SSD) are rarely quantified, despite their implications for sexual selection. To enable their estimation, we propose a method for unbiased sex identification based on sexual shape dimorphism, using size-independent principal components of phenotypic data. We applied the method to test sexual selection in Keichousaurus hui, a Middle Triassic (about 237 Ma) sauropterygian with an unusually large sample size for a fossil reptile. Keichousaurus hui exhibited SSD biased towards males, as in the majority of extant reptiles, to a minor degree (sexual dimorphism index -0.087). The ASR is about 60% females, suggesting higher mortality of males over females. Both values support sexual selection of males in this species. The method may be applied to other fossil species. We also used the Gompertz allometric equation to study the sexual shape dimorphism of K. hui and found that two sexes had largely homogeneous phenotypes at birth except in the humeral width, contrary to previous suggestions derived from the standard allometric equation.

  2. Sexual size dimorphism in caecilian amphibians: analysis, review and directions for future research.

    PubMed

    Kupfer, Alexander

    2009-01-01

    Sexual dimorphism, widespread in the animal kingdom, describes differences between the sexes in size, shape and many other traits. Sexual size dimorphism (SSD) plays a significant role in understanding life history evolution and mating systems. The snakelike morphology of limbless caecilian amphibians lacking obvious secondary sexual characters (in contrast to frogs and salamanders) impedes accurate intrasexual comparisons. In this study, sexual size dimorphism in the oviparous caecilian Ichthyophis cf. kohtaoensis, a phylogenetically basal caecilian, was analysed. Females were larger in all body and head characters tested. However, when adjusted to body size (total length), females differed only in their cloacal shape. Clutch volume was positively correlated to female body size, thus female fecundity increased with body size supporting the hypothesis of a fecundity-selected SSD in the oviparous Ichthyophis cf. kohtaoensis. A review of the present SSD data for caecilians shows that many species are monomorphic for body size but show dimorphism in head size, while other species demonstrate female-biased SSD. Male-biased SSD has not been reported for caecilians. To understand life history evolution in caecilians, further studies on the reproductive biology of other taxa are urgently needed, in particular for rhinatrematids and uraeotyphlids. New data will allow phylogenetically controlled comparative analyses to fully explore the pattern of SSD among caecilian lineages.

  3. Dissolved oxygen levels affect dimorphic growth by the entomopathogenic fungus Isaria fumosorosea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The entomopathogenic fungus Isaria fumosorosea is capable of dimorphic growth (hyphal or yeast-like) in submerged culture. In shake flask studies, we evaluated the impact of aeration on the mode of growth of I. fumosorosea. Using 250 mL baffled Erlenmeyer flasks, culture volumes of 50, 100, 150, a...

  4. Women's Performance on Sexually Dimorphic Tasks: The Effect of Hormonal Fluctuations

    ERIC Educational Resources Information Center

    Duell, Lanora J.

    2011-01-01

    This study examined the effect of hormonal fluctuations on women's performance on sexually dimorphic cognitive tasks. Thirty-six participants were recruited through introduction to psychology courses at three colleges. Participants were assessed using the Woodcock-Johnson Test of Cognitive Ability III (WJ III COG), which is a commonly-used, widely…

  5. Quantitative genetics of ontogeny of sexual dimorphism in red junglefowl (Gallus gallus).

    PubMed

    Parker, T H; Garant, D

    2005-11-01

    We studied phenotypic patterns and underlying quantitative genetics of development of sexual size dimorphism in red junglefowl (Gallus gallus). Using a multigenerational pedigree and the 'animal model' technique, we found significant heritability for many of the size and growth-related traits we examined, as well as significant genetic correlations among them. Despite sexual size dimorphism throughout posthatching ontogeny, the genetic correlation between males and females for all size measurements and growth parameters remained high. Significant positive phenotypic and genetic correlations between the fastest rate of growth and mass at week 26 (near asymptote) indicate that faster growth when young promotes larger adult size. However, age at which peak growth is reached does not appear to be phenotypically or genetically correlated with adult size. Positive genetic correlations within traits among ages were common, demonstrating that the genetic variance important to growth is relatively consistent among ages. However, male mass and tarsus length showed no genetic correlation between week 0 values and those from later ages. The body size traits of mass and tarsus length were genetically correlated with each other in females, but this pattern was not significant in males. Thus, despite striking sexual dimorphism in size and growth trajectories, size dimorphic traits in junglefowl show, with some exceptions, genetic integration between the sexes, among ages, and between traits. PMID:16118659

  6. Adult sex ratio, sexual dimorphism and sexual selection in a Mesozoic reptile

    PubMed Central

    Motani, Ryosuke; Jiang, Da-yong; Rieppel, Olivier; Xue, Yi-fan; Tintori, Andrea

    2015-01-01

    The evolutionary history of sexual selection in the geologic past is poorly documented based on quantification, largely because of difficulty in sexing fossil specimens. Even such essential ecological parameters as adult sex ratio (ASR) and sexual size dimorphism (SSD) are rarely quantified, despite their implications for sexual selection. To enable their estimation, we propose a method for unbiased sex identification based on sexual shape dimorphism, using size-independent principal components of phenotypic data. We applied the method to test sexual selection in Keichousaurus hui, a Middle Triassic (about 237 Ma) sauropterygian with an unusually large sample size for a fossil reptile. Keichousaurus hui exhibited SSD biased towards males, as in the majority of extant reptiles, to a minor degree (sexual dimorphism index −0.087). The ASR is about 60% females, suggesting higher mortality of males over females. Both values support sexual selection of males in this species. The method may be applied to other fossil species. We also used the Gompertz allometric equation to study the sexual shape dimorphism of K. hui and found that two sexes had largely homogeneous phenotypes at birth except in the humeral width, contrary to previous suggestions derived from the standard allometric equation. PMID:26378218

  7. Sexual size dimorphism is not associated with the evolution of parental care in frogs

    PubMed Central

    Monroe, Melanie J; Alonzo, Suzanne H

    2014-01-01

    Sex differences in parental care are thought to arise from differential selection on the sexes. Sexual dimorphism, including sexual size dimorphism (SSD), is often used as a proxy for sexual selection on males. Some studies have found an association between male-biased SSD (i.e., males larger than females) and the loss of paternal care. While the relationship between sexual selection on males and parental care evolution has been studied extensively, the relationship between female-biased SSD (i.e., females larger than males) and the evolution of parental care has received very little attention. Thus, we have little knowledge of whether female-biased SSD coevolves with parental care. In species displaying female-biased SSD, we might expect dimorphism to be associated with the evolution of paternal care or perhaps the loss of maternal care. Here, drawing on data for 99 extant frog species, we use comparative methods to evaluate how parental care and female-biased SSD have evolved over time. Generally, we find no significant correlation between the evolution of parental care and female-biased SSD in frogs. This suggests that differential selection on body size between the sexes is unlikely to have driven the evolution of parental care in these clades and questions whether we should expect sexual dimorphism to exhibit a general relationship with the evolution of sex differences in parental care. PMID:25505526

  8. Draft Genome Sequence of the Dimorphic Yeast Yarrowia lipolytica Strain W29

    PubMed Central

    Pomraning, Kyle R.

    2015-01-01

    Here, we present the draft genome sequence of the dimorphic ascomycete yeast Yarrowia lipolytica strain W29 (ATCC 20460). Y. lipolytica is a commonly employed model for the industrial production of lipases, small molecules, and more recently for its ability to accumulate lipids. PMID:26607882

  9. The energy costs of sexual dimorphism in mole-rats are morphological not behavioural

    PubMed Central

    Scantlebury, M; Speakman, J.R; Bennett, N.C

    2005-01-01

    Different reproductive strategies of males and females may lead to the evolution of differences in their energetic costs of reproduction, overall energetic requirements and physiological performances. Sexual dimorphism is often associated with costly behaviours (e.g. large males might have a competitive advantage in fighting, which is energetically expensive). However, few studies of mammals have directly compared the energy costs of reproductive activities between sexes. We compared the daily energy expenditure (DEE) and resting metabolic rate (RMR) of males and females of two species of mole-rat, Bathyergus janetta and Georychus capensis (the former is sexually dimorphic in body size and the latter is not) during a period of intense digging when males seek females. We hypothesized that large body size might be indicative of greater digging or fighting capabilities, and hence greater mass-independent DEE values in males of the sexually dimorphic species. In contrast to this prediction, although absolute values of DEE were greater in B. janetta males, mass-independent values were not. No differences were apparent between sexes in G. capensis. By comparison, although RMR values were greater in B. janetta than G. capensis, no differences were apparent between the sexes for either species. The energy cost of dimorphism is most likely to be the cost of maintenance of a large body size, and not the cost of behaviours performed when an individual is large. PMID:16519235

  10. Femur bone strength in Tyrannosaurus rex: A study of sexual dimorphism

    NASA Astrophysics Data System (ADS)

    Lee, Scott

    2012-04-01

    Tyrannosaurus rex is the iconic species of a fearsome predator and is held in fascination by virtually everyone. Like many other species, Tyrannosaurs rex displayed sexual dimorphism with the females larger than the males. The femur bones of 14 fossil specimens were examined to determine if the maximum running abilities were significantly different for the two genders. No significant difference is observed.

  11. Sexual Dimorphisms in the Dermal Denticles of the Lesser-Spotted Catshark, Scyliorhinus canicula (Linnaeus, 1758)

    PubMed Central

    Crooks, Neil; Babey, Lucy; Haddon, William J.; Love, Adrian C.; Waring, Colin P.

    2013-01-01

    The dermal layers of several elasmobranch species have been shown to be sexually dimorphic. Generally, when this occurs the females have thicker dermal layers compared to those of males. This sexual dimorphism has been suggested to occur as a response to male biting during mating. Although male biting as a copulatory behaviour in Scyliorhinus canicula has been widely speculated to occur, only relatively recently has this behaviour been observed. Male S. canicula use their mouths to bite the female’s pectoral and caudal fins as part of their pre-copulatory behaviour and to grasp females during copulation. Previous work has shown that female S. canicula have a thicker epidermis compared to that of males. The structure of the dermal denticles in females may also differ from that of males in order to protect against male biting or to provide a greater degree of friction in order to allow the male more purchase. This study reveals that the length, width and density of the dermal denticles of mature male and female S. canicula are sexually dimorphic across the integument in areas where males have been observed to bite and wrap themselves around females (pectoral fin, area posterior to the pectoral fin, caudal fin, and pelvic girdle). No significant differences in the dermal denticle dimensions were found in other body areas examined (head, dorsal skin and caudal peduncle). Sexually dimorphic dermal denticles in mature S. canicula could be a response to male biting/wrapping as part of the copulatory process. PMID:24116179

  12. The Sexual Dimorphic Association of Cardiorespiratory Fitness to Working Memory in Children

    ERIC Educational Resources Information Center

    Drollette, Eric S.; Scudder, Mark R.; Raine, Lauren B.; Davis Moore, R.; Pontifex, Matthew B.; Erickson, Kirk I.; Hillman, Charles H.

    2016-01-01

    The present investigation examined the sexual dimorphic patterns of cardiorespiratory fitness to working memory in preadolescent children (age range: 7.7-10.9). Data were collected in three separate studies (Study 1: n = 97, 42 females; Study 2: n = 95, 45 females; Study 3: n = 84, 37 females). All participants completed a cardiorespiratory…

  13. Draft Genome Sequence of the Dimorphic Yeast Yarrowia lipolytica Strain W29.

    PubMed

    Pomraning, Kyle R; Baker, Scott E

    2015-01-01

    Here, we present the draft genome sequence of the dimorphic ascomycete yeast Yarrowia lipolytica strain W29 (ATCC 20460). Y. lipolytica is a commonly employed model for the industrial production of lipases, small molecules, and more recently for its ability to accumulate lipids. PMID:26607882

  14. Sexually dimorphic regulation of the Wingless morphogen controls sex-specific segment number in Drosophila

    PubMed Central

    Wang, Wei; Kidd, Bryan J.; Carroll, Sean B.; Yoder, John H.

    2011-01-01

    Sexual dimorphism is widespread throughout the metazoa and plays important roles in mate recognition and preference, sex-based niche partitioning, and sex-specific coadaptation. One notable example of sex-specific differences in insect body morphology is presented by the higher diptera, such as Drosophila, in which males develop fewer abdominal segments than females. Because diversity in segment number is a distinguishing feature of major arthropod clades, it is of fundamental interest to understand how different numbers of segments can be generated within the same species. Here we show that sex-specific and segment-specific regulation of the Wingless (Wg) morphogen underlies the development of sexually dimorphic adult segment number in Drosophila. Wg expression is repressed in the developing terminal male abdominal segment by the combination of the Hox protein Abdominal-B (Abd-B) and the sex-determination regulator Doublesex (Dsx). The subsequent loss of the terminal male abdominal segment during pupation occurs through a combination of developmental processes including segment compartmental transformation, apoptosis, and suppression of cell proliferation. Furthermore, we show that ectopic expression of Wg is sufficient to rescue this loss. We propose that dimorphic Wg regulation, in concert with monomorphic segment-specific programmed cell death, are the principal mechanisms of sculpting the sexually dimorphic abdomen of Drosophila. PMID:21690416

  15. Organization and evolutionary trajectory of the mating type (MAT) locus in dermatophyte and dimorphic fungal pathogens.

    PubMed

    Li, Wenjun; Metin, Banu; White, Theodore C; Heitman, Joseph

    2010-01-01

    Sexual reproduction in fungi is governed by a specialized genomic region, the mating type (MAT) locus, whose gene identity, organization, and complexity are diverse. We identified the MAT locus of five dermatophyte fungal pathogens (Microsporum gypseum, Microsporum canis, Trichophyton equinum, Trichophyton rubrum, and Trichophyton tonsurans) and a dimorphic fungus, Paracoccidioides brasiliensis, and performed phylogenetic analyses. The identified MAT locus idiomorphs of M. gypseum control cell type identity in mating assays, and recombinant progeny were produced. Virulence tests in Galleria mellonella larvae suggest the two mating types of M. gypseum may have equivalent virulence. Synteny analysis revealed common features of the MAT locus shared among these five dermatophytes: namely, a small size ( approximately 3 kb) and a novel gene arrangement. The SLA2, COX13, and APN2 genes, which flank the MAT locus in other Ascomycota are instead linked on one side of the dermatophyte MAT locus. In addition, the transcriptional orientations of the APN2 and COX13 genes are reversed compared to the dimorphic fungi Histoplasma capsulatum, Coccidioides immitis, and Coccidioides posadasii. A putative transposable element, pogo, was found to have inserted in the MAT1-2 idiomorph of one P. brasiliensis strain but not others. In conclusion, the evolution of the MAT locus of the dermatophytes and dimorphic fungi from the last common ancestor has been punctuated by both gene acquisition and expansion, and asymmetric gene loss. These studies further support a foundation to develop molecular and genetic tools for dermatophyte and dimorphic human fungal pathogens. PMID:19880755

  16. Adult sex ratio, sexual dimorphism and sexual selection in a Mesozoic reptile.

    PubMed

    Motani, Ryosuke; Jiang, Da-yong; Rieppel, Olivier; Xue, Yi-fan; Tintori, Andrea

    2015-09-22

    The evolutionary history of sexual selection in the geologic past is poorly documented based on quantification, largely because of difficulty in sexing fossil specimens. Even such essential ecological parameters as adult sex ratio (ASR) and sexual size dimorphism (SSD) are rarely quantified, despite their implications for sexual selection. To enable their estimation, we propose a method for unbiased sex identification based on sexual shape dimorphism, using size-independent principal components of phenotypic data. We applied the method to test sexual selection in Keichousaurus hui, a Middle Triassic (about 237 Ma) sauropterygian with an unusually large sample size for a fossil reptile. Keichousaurus hui exhibited SSD biased towards males, as in the majority of extant reptiles, to a minor degree (sexual dimorphism index -0.087). The ASR is about 60% females, suggesting higher mortality of males over females. Both values support sexual selection of males in this species. The method may be applied to other fossil species. We also used the Gompertz allometric equation to study the sexual shape dimorphism of K. hui and found that two sexes had largely homogeneous phenotypes at birth except in the humeral width, contrary to previous suggestions derived from the standard allometric equation. PMID:26378218

  17. Sexual size dimorphism in caecilian amphibians: analysis, review and directions for future research.

    PubMed

    Kupfer, Alexander

    2009-01-01

    Sexual dimorphism, widespread in the animal kingdom, describes differences between the sexes in size, shape and many other traits. Sexual size dimorphism (SSD) plays a significant role in understanding life history evolution and mating systems. The snakelike morphology of limbless caecilian amphibians lacking obvious secondary sexual characters (in contrast to frogs and salamanders) impedes accurate intrasexual comparisons. In this study, sexual size dimorphism in the oviparous caecilian Ichthyophis cf. kohtaoensis, a phylogenetically basal caecilian, was analysed. Females were larger in all body and head characters tested. However, when adjusted to body size (total length), females differed only in their cloacal shape. Clutch volume was positively correlated to female body size, thus female fecundity increased with body size supporting the hypothesis of a fecundity-selected SSD in the oviparous Ichthyophis cf. kohtaoensis. A review of the present SSD data for caecilians shows that many species are monomorphic for body size but show dimorphism in head size, while other species demonstrate female-biased SSD. Male-biased SSD has not been reported for caecilians. To understand life history evolution in caecilians, further studies on the reproductive biology of other taxa are urgently needed, in particular for rhinatrematids and uraeotyphlids. New data will allow phylogenetically controlled comparative analyses to fully explore the pattern of SSD among caecilian lineages. PMID:19433349

  18. Chemical and Hormonal Effects on STAT5b-Dependent Sexual Dimorphism of the Liver Transcriptome.

    EPA Science Inventory

    The growth hormone (GH)-activated transcription factor signal transducer and activator of transcription 5b (STAT5b) is a key regulator of sexually dimorphic gene expression in the liver. Suppression of hepatic STAT5b signaling is associated with lipid metabolic dysfunction leadi...

  19. Autonomous Soaring Flight Results

    NASA Technical Reports Server (NTRS)

    Allen, Michael J.

    2006-01-01

    A viewgraph presentation on autonomous soaring flight results for Unmanned Aerial Vehicles (UAV)'s is shown. The topics include: 1) Background; 2) Thermal Soaring Flight Results; 3) Autonomous Dolphin Soaring; and 4) Future Plans.

  20. 'Mighty Eagle' Takes Flight

    NASA Video Gallery

    The "Mighty Eagle," a NASA robotic prototype lander, had a successful first untethered flight Aug. 8 at the Marshall Center. During the 34-second flight, the Mighty Eagle soared and hovered at 30 f...

  1. Electric flight systems, overview

    NASA Technical Reports Server (NTRS)

    Cronin, M. J.

    1982-01-01

    Materials illustrating a presentation on electric flight systems are presented. Fuel consumption, the power plant assembly, flight control technology, electromechanical actuator systems and components of possible power systems are surveyed.

  2. Toxicogenomic analysis suggests chemical-induced sexual dimorphism in the expression of metabolic genes in zebrafish liver.

    PubMed

    Zhang, Xun; Ung, Choong Yong; Lam, Siew Hong; Ma, Jing; Chen, Yu Zong; Zhang, Louxin; Gong, Zhiyuan; Li, Baowen

    2012-01-01

    Differential gene expression in two sexes is widespread throughout the animal kingdom, giving rise to sex-dimorphic gene activities and sex-dependent adaptability to environmental cues, diets, growth and development as well as susceptibility to diseases. Here, we present a study using a toxicogenomic approach to investigate metabolic genes that show sex-dimorphic expression in the zebrafish liver triggered by several chemicals. Our analysis revealed that, besides the known genes for xenobiotic metabolism, many functionally diverse metabolic genes, such as ELOVL fatty acid elongase, DNA-directed RNA polymerase, and hydroxysteroid dehydrogenase, were also sex-dimorphic in their response to chemical treatments. Moreover, sex-dimorphic responses were also observed at the pathway level. Pathways belonging to xenobiotic metabolism, lipid metabolism, and nucleotide metabolism were enriched with sex-dimorphically expressed genes. We also observed temporal differences of the sex-dimorphic responses, suggesting that both genes and pathways are differently correlated during different periods of chemical perturbation. The ubiquity of sex-dimorphic activities at different biological hierarchies indicate the importance and the need of considering the sex factor in many areas of biological researches, especially in toxicology and pathology. PMID:23272195

  3. Sexual dimorphism in the size and shape of the os coxae and the effects of microevolutionary processes.

    PubMed

    Betti, Lia

    2014-02-01

    Sexual dimorphism in the human pelvis has been studied widely for forensic purposes, but it is still unclear to what extent it varies among human populations. There is evidence that microevolutionary processes, both neutral (i.e., population history) and selective (e.g., thermoregulatory adaptation and size-related obstetrical constraints) contribute to explain pelvic variation among populations, but the extent to which these factors affect pelvic sexual dimorphism is unknown. In this study, I analyze sexual dimorphism of the os coxae in 20 globally distributed human populations, using 3D morphometric data to separate the size and shape components of sexual differences. After evaluating population differences in the degree and pattern of sexual dimorphism, I test for the effect of population history, climate, and body size in shaping global diversity. The results show that size and shape dimorphism follow different patterns. Coxal size dimorphism is generally quite consistent through populations, with males bigger than females, but it appears to be reduced in small-bodied populations, possibly in relation to obstetrically-related selective pressures for a spacious birth canal. Beyond a general species-wide pattern of shape dimorphism, commonly used for forensic sex determination, other aspects of sexual differences in coxal shape vary among human populations, reflecting the effects of neutral demographic processes and climatic adaptation. PMID:24222471

  4. Evolution of sexual dimorphism in bill size and shape of hermit hummingbirds (Phaethornithinae): a role for ecological causation.

    PubMed

    Temeles, Ethan J; Miller, Jill S; Rifkin, Joanna L

    2010-04-12

    Unambiguous examples of ecological causation of sexual dimorphism are rare, and the best evidence involves sexual differences in trophic morphology. We show that moderate female-biased sexual dimorphism in bill curvature is the ancestral condition in hermit hummingbirds (Phaethornithinae), and that it is greatly amplified in species such as Glaucis hirsutus and Phaethornis guy, where bills of females are 60 per cent more curved than bills of males. In contrast, bill curvature dimorphism is lost or reduced in a lineage of short-billed hermit species and in specialist Eutoxeres sicklebill hermits. In the hermits, males tend to be larger than females in the majority of species, although size dimorphism is typically small. Consistent with earlier studies of hummingbird feeding performance, both raw regressions of traits and phylogenetic independent contrasts supported the prediction that dimorphism in bill curvature of hermits is associated with longer bills. Some evidence indicates that differences between sexes of hermit hummingbirds are associated with differences in the use of food plants. We suggest that some hermit hummingbirds provide model organisms for studies of ecological causation of sexual dimorphism because their sexual dimorphism in bill curvature provides a diagnostic clue for the food plants that need to be monitored for studies of sexual differences in resource use.

  5. Evolution of sexual dimorphism in bill size and shape of hermit hummingbirds (Phaethornithinae): a role for ecological causation

    PubMed Central

    Temeles, Ethan J.; Miller, Jill S.; Rifkin, Joanna L.

    2010-01-01

    Unambiguous examples of ecological causation of sexual dimorphism are rare, and the best evidence involves sexual differences in trophic morphology. We show that moderate female-biased sexual dimorphism in bill curvature is the ancestral condition in hermit hummingbirds (Phaethornithinae), and that it is greatly amplified in species such as Glaucis hirsutus and Phaethornis guy, where bills of females are 60 per cent more curved than bills of males. In contrast, bill curvature dimorphism is lost or reduced in a lineage of short-billed hermit species and in specialist Eutoxeres sicklebill hermits. In the hermits, males tend to be larger than females in the majority of species, although size dimorphism is typically small. Consistent with earlier studies of hummingbird feeding performance, both raw regressions of traits and phylogenetic independent contrasts supported the prediction that dimorphism in bill curvature of hermits is associated with longer bills. Some evidence indicates that differences between sexes of hermit hummingbirds are associated with differences in the use of food plants. We suggest that some hermit hummingbirds provide model organisms for studies of ecological causation of sexual dimorphism because their sexual dimorphism in bill curvature provides a diagnostic clue for the food plants that need to be monitored for studies of sexual differences in resource use. PMID:20194168

  6. The densities of calbindin and parvalbumin, but not calretinin neurons, are sexually dimorphic in the amygdala of the guinea pig.

    PubMed

    Równiak, Maciej; Bogus-Nowakowska, Krystyna; Robak, Anna

    2015-04-16

    In the amygdala, the calcium-binding proteins (calbindin, parvalbumin or calretinin) are useful markers of specific subpopulations of γ-aminobutyric acid (GABA) containing neurons. In the rat and monkey they together mark the vast majority of GABA-containing neurons in this brain region. As GABA involvement in the control of various behaviors in a sex-specific manner and sexual dimorphism of the GABAergic system itself were recently proven, the question is how much dimorphic may be various subpopulations of this system. Thus, the present study investigates for the first time the presence/absence of sexual dimorphism among neurons expressing calbindin (CB), parvalbumin (PV) and calretinin (CR) which form in the amygdala main subsets of GABAergic system. The results show that in the amygdala of the guinea pig the densities of CB and/or PV expressing neurons are sexually dimorphic with the female>male pattern of sex differences in the basolateral amygdala. In the medial and cortical amygdala respectively CB and PV values are also sexually dimorphic, favoring males. The densities of CR expressing neurons are in the amygdala of the guinea pig sexually isomorphic. In conclusion, the results of the present study provide an evidence that in the amygdala of the guinea pig the densities of neurons expressing CB and/or PV are sexually dimorphic what supports the idea that GABA participates in the mediation of sexually dimorphic functions, controlled by this brain area.

  7. Ecological Sexual Dimorphism and Environmental Variability within a Community of Antarctic Penguins (Genus Pygoscelis)

    PubMed Central

    Gorman, Kristen B.; Williams, Tony D.; Fraser, William R.

    2014-01-01

    Background Sexual segregation in vertebrate foraging niche is often associated with sexual size dimorphism (SSD), i.e., ecological sexual dimorphism. Although foraging behavior of male and female seabirds can vary markedly, differences in isotopic (carbon, δ13C and nitrogen, δ15N) foraging niche are generally more pronounced within sexually dimorphic species and during phases when competition for food is greater. We examined ecological sexual dimorphism among sympatric nesting Pygoscelis penguins asking whether environmental variability is associated with differences in male and female pre-breeding foraging niche. We predicted that all Pygoscelis species would forage sex-specifically, and that higher quality winter habitat, i.e., higher or lower sea ice coverage for a given species, would be associated with a more similar foraging niche among the sexes. Results P2/P8 primers reliably amplified DNA of all species. On average, male Pygoscelis penguins are structurally larger than female conspecifics. However, chinstrap penguins were more sexually dimorphic in culmen and flipper features than Adélie and gentoo penguins. Adélies and gentoos were more sexually dimorphic in body mass than chinstraps. Only male and female chinstraps and gentoos occupied separate δ15N foraging niches. Strong year effects in δ15N signatures were documented for all three species, however, only for Adélies, did yearly variation in δ15N signatures tightly correlate with winter sea ice conditions. There was no evidence that variation in sex-specific foraging niche interacted with yearly winter habitat quality. Conclusion Chinstraps were most sexually size dimorphic followed by gentoos and Adélies. Pre-breeding sex-specific foraging niche was associated with overall SSD indices across species; male chinstrap and gentoo penguins were enriched in δ15N relative to females. Our results highlight previously unknown trophic pathways that link Pygoscelis penguins with variation in Southern

  8. Cortisol, insulin and leptin during space flight and bed rest

    NASA Technical Reports Server (NTRS)

    Stein, T. P.; Schluter, M. D.; Leskiw, M. J.

    1999-01-01

    Most ground based models for studying muscle atrophy and bone loss show reasonable fidelity to the space flight situation. However there are some differences. Investigation of the reasons for these differences can provide useful information about humans during space flight and aid in the refinement of ground based models. This report discusses three such differences, the relationships between: (i) cortisol and the protein loss, (ii) cortisol and ACTH and (iii) leptin, insulin and food intake.

  9. Experiment K-7-29: Connective Tissue Studies. Part 3; Rodent Tissue Repair: Skeletal Muscle

    NASA Technical Reports Server (NTRS)

    Stauber, W.; Fritz, V. K.; Burkovskaya, T. E.; Ilyina-Kakueva, E. I.

    1994-01-01

    Myofiber injury-repair was studied in the rat gastrocnemius following a crush injury to the lower leg prior to flight in order to understand if the regenerative responses of muscles are altered by the lack of gravitational forces during Cosmos 2044 flight. After 14 days of flight, the gastrocnemius muscle was removed from the 5 injured flight rodents and various Earth-based treatment groups for comparison. The Earth-based animals consisted of three groups of five rats with injured muscles from a simulated, tail-suspended, and vivarium as well as an uninjured basal group. The gastrocnemius muscle from each was evaluated by histochemical and immunohistochemical techniques to document myofiber, vascular, and connective tissue alterations following injury. In general the repair process was somewhat similar in all injured muscle samples with regard to extracellular matrix organization and myofiber regeneration. Small and large myofibers were present with a newly organized extracellular matrix indicative of myogenesis and muscle regeneration. In the tail-suspended animals, a more complete repair was observed with no enlarged area of non-muscle cells or matrix material visible. In contrast, the muscle samples from the flight animals were less well differentiated with more macrophages and blood vessels in the repair region but small myofibers and proteoglycans, nevertheless, were in their usual configuration. Thus, myofiber repair did vary in muscles from the different groups, but for the most part, resulted in functional muscle tissue.

  10. Ornithopter flight stabilization

    NASA Astrophysics Data System (ADS)

    Dietl, John M.; Garcia, Ephrahim

    2007-04-01

    The quasi-steady aerodynamics model and the vehicle dynamics model of ornithopter flight are explained, and numerical methods are described to capture limit cycle behavior in ornithopter flight. The Floquet method is used to determine stability in forward flight, and a linear discrete-time state-space model is developed. This is used to calculate stabilizing and disturbance-rejecting controllers.

  11. In Flight, Online

    ERIC Educational Resources Information Center

    Lucking, Robert A.; Wighting, Mervyn J.; Christmann, Edwin P.

    2005-01-01

    The concept of flight for human beings has always been closely tied to imagination. To fly like a bird requires a mind that also soars. Therefore, good teachers who want to teach the scientific principles of flight recognize that it is helpful to share stories of their search for the keys to flight. The authors share some of these with the reader,…

  12. Costal process of the first sacral vertebra: sexual dimorphism and obstetrical adaptation.

    PubMed

    Tague, Robert G

    2007-03-01

    The human sacrum is sexually dimorphic, with males being larger than females in most dimensions. Previous studies, though, suggest that females may have a longer costal process of the first sacral vertebra (S1) than males. However, these studies neither quantified nor tested statistically the costal process of S1. This study compares S1 with the five lumbar vertebrae (L1 to L5) for a number of metric dimensions, including costal process length. Four issues are addressed, the: 1) hypothesis that females have a longer costal process of S1 than males; 2)hypothesis that homologous structures (i.e., costal processes of L1 to S1) differ in their direction of sexual dimorphism; 3) importance of the costal process of S1 to the obstetrical capacity of the pelvis; and 4) evolution of sexual dimorphism in costal process length of S1. One hundred ninety-seven individuals, including males and females of American blacks and whites, from the Hamann-Todd and Terry Collections were studied. Results show that males are significantly larger than females for most vertebral measurements, except that females have a significantly longer costal process of S1 than males. Costal process length of S1 is positively correlated with the transverse diameter and circumference of the pelvic inlet. The magnitude of sexual dimorphism in costal process length of S1 ranks this measure among the most highly dimorphic of the pelvis. Compared with the humans in this study, australopithecines have a relatively long costal process of S1, but their broad sacrum was not associated with obstetrical imperatives. PMID:17266155

  13. Costal process of the first sacral vertebra: sexual dimorphism and obstetrical adaptation.

    PubMed

    Tague, Robert G

    2007-03-01

    The human sacrum is sexually dimorphic, with males being larger than females in most dimensions. Previous studies, though, suggest that females may have a longer costal process of the first sacral vertebra (S1) than males. However, these studies neither quantified nor tested statistically the costal process of S1. This study compares S1 with the five lumbar vertebrae (L1 to L5) for a number of metric dimensions, including costal process length. Four issues are addressed, the: 1) hypothesis that females have a longer costal process of S1 than males; 2)hypothesis that homologous structures (i.e., costal processes of L1 to S1) differ in their direction of sexual dimorphism; 3) importance of the costal process of S1 to the obstetrical capacity of the pelvis; and 4) evolution of sexual dimorphism in costal process length of S1. One hundred ninety-seven individuals, including males and females of American blacks and whites, from the Hamann-Todd and Terry Collections were studied. Results show that males are significantly larger than females for most vertebral measurements, except that females have a significantly longer costal process of S1 than males. Costal process length of S1 is positively correlated with the transverse diameter and circumference of the pelvic inlet. The magnitude of sexual dimorphism in costal process length of S1 ranks this measure among the most highly dimorphic of the pelvis. Compared with the humans in this study, australopithecines have a relatively long costal process of S1, but their broad sacrum was not associated with obstetrical imperatives.

  14. Sexual Dimorphism in the Brain of the Monogamous California Mouse (Peromyscus californicus).

    PubMed

    Campi, Katharine L; Jameson, Chelsea E; Trainor, Brian C

    2013-01-01

    Sex differences in behavior and morphology are usually assumed to be stronger in polygynous species compared to monogamous species. A few brain structures have been identified as sexually dimorphic in polygynous rodent species, but it is less clear whether these differences persist in monogamous species. California mice are among the 5% or less of mammals that are considered to be monogamous and as such provide an ideal model to examine sexual dimorphism in neuroanatomy. In the present study we compared the volume of hypothalamic- and limbic-associated regions in female and male California mice for sexual dimorphism. We also used tyrosine hydroxylase (TH) immunohistochemistry to compare the number of dopamine neurons in the ventral tegmental area (VTA) in female and male California mice. Additionally, tract tracing was used to accurately delineate the boundaries of the VTA. The total volume of the sexually dimorphic nucleus of the preoptic area (SDN-POA), the principal nucleus of the bed nucleus of the stria terminalis (BNST), and the posterodorsal medial amygdala (MEA) was larger in males compared to females. In the SDN-POA we found that the magnitude of sex differences in the California mouse were intermediate between the large differences observed in promiscuous meadow voles and rats and the absence of significant differences in monogamous prairie voles. However, the magnitude of sex differences in MEA and the BNST were comparable to polygynous species. No sex differences were observed in the volume of the whole brain, the VTA, the nucleus accumbens or the number of TH-ir neurons in the VTA. These data show that despite a monogamous social organization, sexual dimorphisms that have been reported in polygynous rodents extend to California mice. Our data suggest that sex differences in brain structures such as the SDN-POA persist across species with different social organizations and may be an evolutionarily conserved characteristic of mammalian brains. PMID

  15. Oxygen-sensitive flight metabolism in the dragonfly erythemis simplicicollis

    PubMed

    Harrison; Lighton

    1998-06-01

    Insect flight metabolism is completely aerobic, and insect resting metabolism is quite insensitive to atmospheric oxygen level, suggesting a large safety margin in the capacity of the tracheal system to deliver oxygen during flight. We tested the sensitivity of flight initiation and metabolism to atmospheric oxygen level in the libellulid dragonfly Erythemis (Mesothemis) simplicicollis using flow-through respirometric measurements of the rate of CO2 emission (CO2). Flight initiations were unimpaired in atmospheric oxygen levels as low as 10 %. However, flight metabolic rate was affected by ambient oxygen level. Flight CO2 decreased in hypoxic mixtures (5 kPa or 10 kPa oxygen) and increased in hyperoxic atmospheres (30 kPa or 50 kPa oxygen), suggesting that ambient oxygen level influences flight muscle oxygen partial pressure (PO2) and the vigour of flight. These are the first data to show oxygen-limitation of flight metabolism in a free-flying insect. A low safety margin for oxygen delivery during dragonfly flight is consistent with a previous hypothesis that atmospheric hyperoxia facilitated gigantism in Paleozoic protodonates. However, allometric studies of tracheal morphology, and mechanisms and capacity of gas exchange in extant insects are necessary in order to test the hypothesis that the oxygen-sensitivity of aerobic metabolism increases with body size in insects.

  16. Metabolic 'engines' of flight drive genome size reduction in birds.

    PubMed

    Wright, Natalie A; Gregory, T Ryan; Witt, Christopher C

    2014-03-22

    The tendency for flying organisms to possess small genomes has been interpreted as evidence of natural selection acting on the physical size of the genome. Nonetheless, the flight-genome link and its mechanistic basis have yet to be well established by comparative studies within a volant clade. Is there a particular functional aspect of flight such as brisk metabolism, lift production or maneuverability that impinges on the physical genome? We measured genome sizes, wing dimensions and heart, flight muscle and body masses from a phylogenetically diverse set of bird species. In phylogenetically controlled analyses, we found that genome size was negatively correlated with relative flight muscle size and heart index (i.e. ratio of heart to body mass), but positively correlated with body mass and wing loading. The proportional masses of the flight muscles and heart were the most important parameters explaining variation in genome size in multivariate models. Hence, the metabolic intensity of powered flight appears to have driven genome size reduction in birds.

  17. Neuromuscular activation patterns during treadmill walking after space flight

    NASA Technical Reports Server (NTRS)

    Layne, C. S.; McDonald, P. V.; Bloomberg, J. J.

    1997-01-01

    Astronauts adopt a variety of neuromuscular control strategies during space flight that are appropriate for locomoting in that unique environment, but are less than optimal upon return to Earth. We report here the first systematic investigation of potential adaptations in neuromuscular activity patterns associated with postflight locomotion. Astronaut-subjects were tasked with walking on a treadmill at 6.4 km/h while fixating a visual target 30 cm away from their eyes after space flights of 8-15 days. Surface electromyography was collected from selected lower limb muscles and normalized with regard to mean amplitude and temporal relation to heel strike. In general, high correlations (more than 0.80) were found between preflight and postflight activation waveforms for each muscle and each subject: however relative activation amplitude around heel strike and toe off was changed as a result of flight. The level of muscle cocontraction and activation variability, and the relationship between the phasic characteristics of the ankle musculature in preparation for toe off also were altered by space flight. Subjects also reported oscillopsia during treadmill walking after flight. These findings indicate that, after space flight, the sensory-motor system can generate neuromuscular-activation strategies that permit treadmill walking, but subtle changes in lower-limb neuromuscular activation are present that may contribute to increased lower limb kinematic variability and oscillopsia also present during postflight walking.

  18. Capillary muscle

    PubMed Central

    Cohen, Caroline; Mouterde, Timothée; Quéré, David; Clanet, Christophe

    2015-01-01

    The contraction of a muscle generates a force that decreases when increasing the contraction velocity. This “hyperbolic” force–velocity relationship has been known since the seminal work of A. V. Hill in 1938 [Hill AV (1938) Proc R Soc Lond B Biol Sci 126(843):136–195]. Hill’s heuristic equation is still used, and the sliding-filament theory for the sarcomere [Huxley H, Hanson J (1954) Nature 173(4412):973–976; Huxley AF, Niedergerke R (1954) Nature 173(4412):971–973] suggested how its different parameters can be related to the molecular origin of the force generator [Huxley AF (1957) Prog Biophys Biophys Chem 7:255–318; Deshcherevskiĭ VI (1968) Biofizika 13(5):928–935]. Here, we develop a capillary analog of the sarcomere obeying Hill’s equation and discuss its analogy with muscles. PMID:25944938

  19. Relationship between reversed sexual dimorphism, breeding investment and foraging ecology in a pelagic seabird, the masked booby.

    PubMed

    Weimerskirch, Henri; Le Corre, Matthieu; Gadenne, Hélène; Pinaud, David; Kato, Akiko; Ropert-Coudert, Yan; Bost, Charles-André

    2009-09-01

    Reversed sexual dimorphism (RSD) may be related to different roles in breeding investment and/or foraging, but little information is available on foraging ecology. We studied the foraging behaviour and parental investment by male and female masked boobies, a species with RSD, by combining studies of foraging ecology using miniaturised activity and GPS data loggers of nest attendance, with an experimental study where flight costs were increased. Males attended the chick more often than females, but females provided more food to the chick than males. Males and females foraged during similar periods of the day, had similar prey types and sizes, diving depths, durations of foraging trips, foraging zones and ranges. Females spent a smaller proportion of the foraging trip sitting on the water and had higher diving rate than males, suggesting higher foraging effort by females. In females, trip duration correlated with mass at departure, suggesting a flexible investment through control by body mass. The experimental study showed that handicapped females and female partners of handicapped males lost mass compared to control birds, whereas there was no difference for males. These results indicate that the larger female is the main provisioner of the chick in the pair, and regulates breeding effort in relation to its own body mass, whereas males have a fixed investment. The different breeding investment between the sexes is associated with contrasting foraging strategies, but no clear niche differentiation was observed. The larger size of the females may be advantageous for provisioning the chick with large quantities of energy and for flexible breeding effort, while the smaller male invests in territory defence and nest guarding, a crucial task when breeding at high densities. In masked boobies, division of labour appears to be maximal during chick rearin-g-the most energy-demanding period--and may be related to evolution of RSD.

  20. Relationship between reversed sexual dimorphism, breeding investment and foraging ecology in a pelagic seabird, the masked booby.

    PubMed

    Weimerskirch, Henri; Le Corre, Matthieu; Gadenne, Hélène; Pinaud, David; Kato, Akiko; Ropert-Coudert, Yan; Bost, Charles-André

    2009-09-01

    Reversed sexual dimorphism (RSD) may be related to different roles in breeding investment and/or foraging, but little information is available on foraging ecology. We studied the foraging behaviour and parental investment by male and female masked boobies, a species with RSD, by combining studies of foraging ecology using miniaturised activity and GPS data loggers of nest attendance, with an experimental study where flight costs were increased. Males attended the chick more often than females, but females provided more food to the chick than males. Males and females foraged during similar periods of the day, had similar prey types and sizes, diving depths, durations of foraging trips, foraging zones and ranges. Females spent a smaller proportion of the foraging trip sitting on the water and had higher diving rate than males, suggesting higher foraging effort by females. In females, trip duration correlated with mass at departure, suggesting a flexible investment through control by body mass. The experimental study showed that handicapped females and female partners of handicapped males lost mass compared to control birds, whereas there was no difference for males. These results indicate that the larger female is the main provisioner of the chick in the pair, and regulates breeding effort in relation to its own body mass, whereas males have a fixed investment. The different breeding investment between the sexes is associated with contrasting foraging strategies, but no clear niche differentiation was observed. The larger size of the females may be advantageous for provisioning the chick with large quantities of energy and for flexible breeding effort, while the smaller male invests in territory defence and nest guarding, a crucial task when breeding at high densities. In masked boobies, division of labour appears to be maximal during chick rearin-g-the most energy-demanding period--and may be related to evolution of RSD. PMID:19544073

  1. Bacterial symbionts, Buchnera, and starvation on wing dimorphism in English grain aphid, Sitobion avenae (F.) (Homoptera: Aphididae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wing dimorphism in aphids can be affected by multiple cues including both biotic (nutrition, crowding, interspecific interactions, the presence of natural enemies, maternal and transgenerational effects, and alarm pheromone) and abiotic factors (temperature, humidity, and photoperiod). Virtually al...

  2. Fungal dimorphism: the switch from hyphae to yeast is a specialized morphogenetic adaptation allowing colonization of a host.

    PubMed

    Boyce, Kylie J; Andrianopoulos, Alex

    2015-11-01

    The ability of pathogenic fungi to switch between a multicellular hyphal and unicellular yeast growth form is a tightly regulated process known as dimorphic switching. Dimorphic switching requires the fungus to sense and respond to the host environment and is essential for pathogenicity. This review will focus on the role of dimorphism in fungi commonly called thermally dimorphic fungi, which switch to a yeast growth form during infection. This group of phylogenetically diverse ascomycetes includes Talaromyces marneffei (recently renamed from Penicillium marneffei), Blastomyces dermatitidis (teleomorph Ajellomyces dermatitidis), Coccidioides species (C. immitis and C. posadasii), Histoplasma capsulatum (teleomorph Ajellomyces capsulatum), Paracoccidioides species (P. brasiliensis and P. lutzii) and Sporothrix schenckii (teleomorph Ophiostoma schenckii). This review will explore both the signalling pathways regulating the morphological transition and the transcriptional responses necessary for intracellular growth. The physiological requirements of yeast cells during infection will also be discussed, highlighting recent advances in the understanding of the role of iron and calcium acquisition during infection. PMID:26253139

  3. Fungal dimorphism in the entomopathogenic fungus Metarhizium rileyi: detection of an in vivo quorum-sensing system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This investigation documents the expression of the in vivo dimorphic program exhibited by insect mycopathogen M. rileyi replicating. This insect mycopathogen represents the key mortality factor regulating various caterpillar populations in various legumes, including subtropical and tropical soybeans...

  4. Biomechanics and biomimetics in insect-inspired flight systems.

    PubMed

    Liu, Hao; Ravi, Sridhar; Kolomenskiy, Dmitry; Tanaka, Hiroto

    2016-09-26

    Insect- and bird-size drones-micro air vehicles (MAV) that can perform autonomous flight in natural and man-made environments are now an active and well-integrated research area. MAVs normally operate at a low speed in a Reynolds number regime of 10(4)-10(5) or lower, in which most flying animals of insects, birds and bats fly, and encounter unconventional challenges in generating sufficient aerodynamic forces to stay airborne and in controlling flight autonomy to achieve complex manoeuvres. Flying insects that power and control flight by flapping wings are capable of sophisticated aerodynamic force production and precise, agile manoeuvring, through an integrated system consisting of wings to generate aerodynamic force, muscles to move the wings and a control system to modulate power output from the muscles. In this article, we give a selective review on the state of the art of biomechanics in bioinspired flight systems in terms of flapping and flexible wing aerodynamics, flight dynamics and stability, passive and active mechanisms in stabilization and control, as well as flapping flight in unsteady environments. We further highlight recent advances in biomimetics of flapping-wing MAVs with a specific focus on insect-inspired wing design and fabrication, as well as sensing systems.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

  5. Biomechanics and biomimetics in insect-inspired flight systems.

    PubMed

    Liu, Hao; Ravi, Sridhar; Kolomenskiy, Dmitry; Tanaka, Hiroto

    2016-09-26

    Insect- and bird-size drones-micro air vehicles (MAV) that can perform autonomous flight in natural and man-made environments are now an active and well-integrated research area. MAVs normally operate at a low speed in a Reynolds number regime of 10(4)-10(5) or lower, in which most flying animals of insects, birds and bats fly, and encounter unconventional challenges in generating sufficient aerodynamic forces to stay airborne and in controlling flight autonomy to achieve complex manoeuvres. Flying insects that power and control flight by flapping wings are capable of sophisticated aerodynamic force production and precise, agile manoeuvring, through an integrated system consisting of wings to generate aerodynamic force, muscles to move the wings and a control system to modulate power output from the muscles. In this article, we give a selective review on the state of the art of biomechanics in bioinspired flight systems in terms of flapping and flexible wing aerodynamics, flight dynamics and stability, passive and active mechanisms in stabilization and control, as well as flapping flight in unsteady environments. We further highlight recent advances in biomimetics of flapping-wing MAVs with a specific focus on insect-inspired wing design and fabrication, as well as sensing systems.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'. PMID:27528780

  6. Regulators of Human White Adipose Browning: Evidence for Sympathetic Control and Sexual Dimorphic Responses to Sprint Interval Training

    PubMed Central

    Scalzo, Rebecca L.; Peltonen, Garrett L.; Giordano, Gregory R.; Binns, Scott E.; Klochak, Anna L.; Paris, Hunter L. R.; Schweder, Melani M.; Szallar, Steve E.; Wood, Lacey M.; Larson, Dennis G.; Luckasen, Gary J.; Hickey, Matthew S.; Bell, Christopher

    2014-01-01

    The conversion of white adipose to the highly thermogenic beige adipose tissue has been proposed as a potential strategy to counter the unfavorable consequences of obesity. Three regulators of this conversion have recently emerged but information regarding their control is limited, and contradictory. We present two studies examining the control of these regulators. Study 1: In 10 young men, the plasma concentrations of irisin and fibroblast growth factor 21 (FGF21) were determined prior to and during activation of the sympathetic nervous system via hypoxic gas breathing (FIO2 = 0.11). The measurements were performed twice, once with and once without prior/concurrent sympathetic inhibition via transdermal clonidine administration. FGF21 was unaffected by basal sympathetic inhibition (338±113 vs. 295±80 pg/mL; P = 0.43; mean±SE), but was increased during hypoxia mediated sympathetic activation (368±135); this response was abrogated (P = 0.035) with clonidine (269±93). Irisin was unaffected by sympathetic inhibition and/or hypoxia (P>0.21). Study 2: The plasma concentration of irisin and FGF21, and the skeletal muscle protein content of fibronectin type III domain containing 5 (FNDC5) was determined in 19 young adults prior to and following three weeks of sprint interval training (SIT). SIT decreased FGF21 (338±78 vs. 251±36; P = 0.046) but did not affect FNDC5 (P = 0.79). Irisin was decreased in males (127±18 vs. 90±23 ng/mL; P = 0.045) and increased in females (139±14 vs. 170±18). Collectively, these data suggest a potential regulatory role of acute sympathetic activation pertaining to the browning of white adipose; further, there appears to be a sexual dimorphic response of irisin to SIT. PMID:24603718

  7. Wing attachment position of fruit fly minimizes flight cost

    NASA Astrophysics Data System (ADS)

    Noest, Robert; Wang, Jane

    Flight is energetically costly which means insects need to find ways to reduce their energy expenditure during sustained flight. Previous work has shown that insect muscles can recover some of the energy used for producing flapping motion. Moreover the form of flapping motions are efficient for generating the required force to balance the weight. In this talk, we show that one of the morphological parameters, the wing attachment point on a fly, is suitably located to further reduce the cost for flight, while allowing the fly to be close to stable. We investigate why this is the case and attempt to find a general rule for the optimal location of the wing hinge. Our analysis is based on computations of flapping free flight together with the Floquet stability analysis of periodic flight for descending, hovering and ascending cases.

  8. Novel Analog For Muscle Deconditioning

    NASA Technical Reports Server (NTRS)

    Ploutz-Snyder, Lori; Ryder, Jeff; Buxton, Roxanne; Redd, Elizabeth; Scott-Pandorf, Melissa; Hackney, Kyle; Fiedler, James; Bloomberg, Jacob

    2010-01-01

    Existing models of muscle deconditioning are cumbersome and expensive (ex: bedrest). We propose a new model utilizing a weighted suit to manipulate strength, power or endurance (function) relative to body weight (BW). Methods: 20 subjects performed 7 occupational astronaut tasks while wearing a suit weighted with 0-120% of BW. Models of the full relationship between muscle function/BW and task completion time were developed using fractional polynomial regression and verified by the addition of pre- and post-flight astronaut performance data using the same tasks. Spline regression was used to identify muscle function thresholds below which task performance was impaired. Results: Thresholds of performance decline were identified for each task. Seated egress & walk (most difficult task) showed thresholds of: leg press (LP) isometric peak force/BW of 18 N/kg, LP power/BW of 18 W/kg, LP work/ BW of 79 J/kg, knee extension (KE) isokinetic/BW of 6 Nm/Kg and KE torque/BW of 1.9 Nm/kg. Conclusions: Laboratory manipulation of strength / BW has promise as an appropriate analog for spaceflight-induced loss of muscle function for predicting occupational task performance and establishing operationally relevant exercise targets.

  9. Sexual dimorphism in the human bony pelvis, with a consideration of the Neandertal pelvis from Kebara Cave, Israel.

    PubMed

    Tague, R G

    1992-05-01

    Sexual dimorphism of the human pelvis is inferentially related to obstetrics. However, researchers disagree in the identification and obstetric significance of pelvic dimorphisms. This study addresses three issues. First, common patterns in dimorphism are identified by analysis of pelvimetrics from six independent samples (Whites and Blacks of known sex and four Amerindian samples of unknown sex). Second, an hypothesis is tested that the index of pelvic dimorphism (female mean x 100/male mean) is inversely related to pelvic variability. Third, the pelvic dimensions of the Neandertal male from Kebara cave, Israel are compared with those of the males in this study. The results show that the pelvic inlet is the plane of least dimorphism in humans. The reason that reports often differ in the identification of dimorphisms for this pelvic plane is that both the length of the pubis and the shape of the inlet are related to nutrition. The dimensions of the pelvis that are most dimorphic (that is, female larger than male) are the measures of posterior space, angulation of sacrum, biischial breadth, and subpubic angle. Interestingly, these dimensions are also the most variable. The hypothesis that variability and dimorphism are inversely related fails to be supported. The factors that influence pelvic variability are discussed. The Kebara 2 pelvis has a spacious inlet and a confined outlet relative to modern males, though the circumferences of both planes in the Neandertal are within the range of variation of modern males. The inference is that outlet circumference in Neandertal females is also small in size, but within the range of variation of modern females. Arguments that Neandertal newborns were larger in size than those of modern humans necessarily imply that birth was more difficult in Neandertals.

  10. Testosterone-induced development of the rat levator ani muscle.

    PubMed

    Tobin, C; Joubert, Y

    1991-07-01

    The perinatal development of the levator ani (LA) muscle in male and female rats was investigated by measuring the total number of muscle units (MU) (i.e., mononucleate cells, clustered or independent myotubes, and muscle fibers) in transverse semithin sections of the entire muscle and the MU cross-sectional area in 22-day-old fetuses (F22), 1-day-old (D1 = day of birth), 3-day-old (D3), and 6-day-old (D6) newborns. Male muscle contained 350 +/- 64 MU on F22, twice that of the female. The number of MU increased markedly in males from F22, but changed little in females; the number of MU in males was 760% that of females on D6. The MU cross-sectional area was greater in males on F22 (120.8 micron(s)2 +/- 7.5) and D1 (155.2 micron(s)2 +/- 64.8) than in females (F22: 89.2 micron(s) +/- 14.2, D1: 64.1 micron(s)2 +/- 19.7) and dropped to about 30 X micron(s)2 in both sexes on D6. Female rats given a single injection of testosterone propionate (TP) before D7 showed a significant increase in the number of fibers, but no increase in cross-sectional area. TP given after D7 had no effect on the fiber number, but increased the average cross-sectional area. The increase in fiber number induced by postnatal TP treatment was a permanent effect, still quantifiable in 15-month-old females. We conclude that the sexual dimorphism of the rat LA muscle is principally due to a dramatic increase in the MU number in male muscles during the perinatal period, rather than to involution of the fibers in female muscles as it is widely accepted. This increase seems to be, at least partly, under the control of testosterone.

  11. Sex-linked inheritance, genetic correlations and sexual dimorphism in three melanin-based colour traits in the barn owl.

    PubMed

    Roulin, A; Jensen, H

    2015-03-01

    Theory states that genes on the sex chromosomes have stronger effects on sexual dimorphism than genes on the autosomes. Although empirical data are not necessarily consistent with this theory, this situation may prevail because the relative role of sex-linked and autosomally inherited genes on sexual dimorphism has rarely been evaluated. We estimated the quantitative genetics of three sexually dimorphic melanin-based traits in the barn owl (Tyto alba), in which females are on average darker reddish pheomelanic and display more and larger black eumelanic feather spots than males. The plumage traits with higher sex-linked inheritance showed lower heritability and genetic correlations, but contrary to prediction, these traits showed less pronounced sexual dimorphism. Strong offspring sexual dimorphism primarily resulted from daughters not expressing malelike melanin-based traits and from sons expressing femalelike traits to similar degrees as their sisters. We conclude that in the barn owl, polymorphism at autosomal genes rather than at sex-linked genes generate variation in sexual dimorphism in melanin-based traits. PMID:25656218

  12. Y-linked variation for autosomal immune gene regulation has the potential to shape sexually dimorphic immunity.

    PubMed

    Kutch, Ian C; Fedorka, Kenneth M

    2015-12-01

    Sexually dimorphic phenotypes arise from the differential expression of male and female shared genes throughout the genome. Unfortunately, the underlying molecular mechanisms by which dimorphic regulation manifests and evolves are unclear. Recent work suggests that Y-chromosomes may play an important role, given that Drosophila melanogaster Ys were shown to influence the regulation of hundreds of X and autosomal genes. For Y-linked regulatory variation (YRV) to facilitate sexually dimorphic evolution, however, it must exist within populations (where selection operates) and influence male fitness. These criteria have seldom been investigated, leaving the potential for dimorphic evolution via YRV unclear. Interestingly, male and female D. melanogaster differ in immune gene regulation. Furthermore, immune gene regulation appears to be influenced by the Y-chromosome, suggesting it may contribute to dimorphic immune evolution. We address this possibility by introgressing Y-chromosomes from a single wild population into an isogenic background (to create Y-lines) and assessing immune gene regulation and bacterial defence. We found that Y-line males differed in their immune gene regulation and their ability to defend against Serratia marcescens. Moreover, gene expression and bacterial defence were positively genetically correlated. These data indicate that the Y-chromosome has the potential to shape the evolution of sexually dimorphic immunity in this system.

  13. Sex-linked inheritance, genetic correlations and sexual dimorphism in three melanin-based colour traits in the barn owl.

    PubMed

    Roulin, A; Jensen, H

    2015-03-01

    Theory states that genes on the sex chromosomes have stronger effects on sexual dimorphism than genes on the autosomes. Although empirical data are not necessarily consistent with this theory, this situation may prevail because the relative role of sex-linked and autosomally inherited genes on sexual dimorphism has rarely been evaluated. We estimated the quantitative genetics of three sexually dimorphic melanin-based traits in the barn owl (Tyto alba), in which females are on average darker reddish pheomelanic and display more and larger black eumelanic feather spots than males. The plumage traits with higher sex-linked inheritance showed lower heritability and genetic correlations, but contrary to prediction, these traits showed less pronounced sexual dimorphism. Strong offspring sexual dimorphism primarily resulted from daughters not expressing malelike melanin-based traits and from sons expressing femalelike traits to similar degrees as their sisters. We conclude that in the barn owl, polymorphism at autosomal genes rather than at sex-linked genes generate variation in sexual dimorphism in melanin-based traits.

  14. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2004-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  15. Flight control actuation system

    NASA Technical Reports Server (NTRS)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2006-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  16. Flight code validation simulator

    SciTech Connect

    Sims, B.A.

    1995-08-01

    An End-To-End Simulation capability for software development and validation of missile flight software on the actual embedded computer has been developed utilizing a 486 PC, i860 DSP coprocessor, embedded flight computer and custom dual port memory interface hardware. This system allows real-time interrupt driven embedded flight software development and checkout. The flight software runs in a Sandia Digital Airborne Computer (SANDAC) and reads and writes actual hardware sensor locations in which IMU (Inertial Measurements Unit) data resides. The simulator provides six degree of freedom real-time dynamic simulation, accurate real-time discrete sensor data and acts on commands and discretes from the flight computer. This system was utilized in the development and validation of the successful premier flight of the Digital Miniature Attitude Reference System (DMARS) in January 1995 at the White Sands Missile Range on a two sta