RESUMO
The vertebrate immune system provides an impressively effective defense against parasites and pathogens. However, these benefits must be balanced against a range of costly side-effects including energy loss and risks of auto-immunity. These costs might include biomechanical impairment of movement, but little is known about the intersection between immunity and biomechanics. Here, we show that a fibrosis immune response to Schistocephalus solidus infection in freshwater threespine stickleback (Gasterosteus aculeatus) has collateral effects on their locomotion. Although fibrosis is effective at reducing infection, some populations of stickleback actively suppress this immune response, possibly because the costs of fibrosis outweigh the benefits. We quantified the locomotor effects of the fibrosis immune response in the absence of parasites to investigate whether there are incidental costs of fibrosis that could help explain why some fish forego this effective defense. To do this, we induced fibrosis in stickleback and then tested their C-start escape performance. Additionally, we measured the severity of fibrosis, body stiffness and body curvature during the escape response. We were able to estimate performance costs of fibrosis by including these variables as intermediates in a structural equation model. This model revealed that among control fish without fibrosis, there is a performance cost associated with increased body stiffness. However, fish with fibrosis did not experience this cost but rather displayed increased performance with higher fibrosis severity. This result demonstrates that the adaptive landscape of immune responses can be complex with the potential for wide-reaching and unexpected fitness consequences.
Assuntos
Cestoides , Infecções por Cestoides , Doenças dos Peixes , Parasitos , Smegmamorpha , Animais , Doenças dos Peixes/parasitologia , Peixes , Cestoides/fisiologia , Imunidade , Interações Hospedeiro-Parasita , Infecções por Cestoides/parasitologiaRESUMO
The vertebrate immune system provides an impressively effective defense against parasites and pathogens. However, these benefits must be balanced against a range of costly side-effects including energy loss and risks of auto-immunity. These costs might include biomechanical impairment of movement, but little is known about the intersection between immunity and biomechanics. Here, we show that a fibrosis immune response in threespine stickleback (Gasterosteus aculeatus) has collateral effects on their locomotion. When freshwater stickleback are infected with the tapeworm parasite Schistocephalus solidus, they face an array of fitness consequences ranging from impaired body condition and fertility to an increased risk of mortality. To fight the infection, some stickleback will initiate a fibrosis immune response in which they produce excess collagenous tissue in their coelom. Although fibrosis is effective at reducing infection, some populations of stickleback actively suppress this immune response, possibly because the costs of fibrosis outweigh the benefits. Here we quantify the locomotor effects of the fibrosis immune response in the absence of parasites to investigate whether there are collateral costs of fibrosis that could help explain why some fish forego this effective defense. To do this, we induce fibrosis in stickleback and then test their C-start escape performance. Additionally, we measure the severity of fibrosis, body stiffness, and body curvature during the escape response. We were able to estimate performance costs of fibrosis by including these variables as intermediates in a structural equation model. This model reveals that among control fish without fibrosis, there is a performance cost associated with increased body stiffness. However, fish with fibrosis did not experience this cost but rather displayed increased performance with higher fibrosis severity. This result demonstrates that the adaptive landscape of immune responses can be complex with the potential for wide reaching and unexpected fitness consequences.
RESUMO
Shark skin is covered in dermal denticles-tooth-like structures consisting of enameloid, dentine, and a central pulp cavity. Previous studies have demonstrated differences in denticle morphology both among species and across different body regions within a species, including one report of extreme morphological variation within a 1 cm distance on the skin covering the branchial pouches, a region termed "interbranchial skin." We used gel-based profilometry, histology, and scanning electron microscopy to quantify differences in denticle morphology and surface topography of interbranchial skin denticles among 13 species of sharks to better understand the surface structure of this region. We show that (1) interbranchial skin denticles differ across shark species, and (2) denticles on the leading edge of the skin covering each gill pouch have different morphology and surface topography compared with denticles on the trailing edge. Across all species studied, there were significant differences in denticle length (P = 0.01) and width (P = 0.002), with shorter and wider leading edge denticles compared with trailing edge denticles. Surface skew was also higher in leading edge denticles (P = 0.009), though most values were still negative, indicating a surface texture more dominated by valleys than peaks. Overall, leading edge denticles were smoother-edged than trailing edge denticles in all of the species studied. These data suggest two hypotheses: (1) smoother-edged leading edge denticles protect the previous gill flap from abrasion during respiration, and (2) ridged denticle morphology at the trailing edge might alter water turbulence exiting branchial pouches after passing over the gills. Future studies will focus on determining the relationship between denticle morphology and water flow by visualizing fluid motion over interbranchial denticles during in vivo respiration.
La piel de los tiburones está cubierta de dentículos dérmicos, estructuras similares a los dientes que constan de un tejido esmaltado, una dentina y una cavidad pulpar central. Estudios anteriores han demostrado diferencias en la morfología de los dentículos tanto entre especies como entre diferentes regiones del cuerpo dentro de una misma especie, incluyendo un informe sobre la extrema variación morfológica dentro de una distancia de 1 cm en la piel que cubre las bolsas branquiales, una región denominada "piel interbranquial." Hemos utilizado perfilometría basada en gel, histología y microscopía electrónica de barrido, para cuantificar las diferencias en la morfología de los dentículos y la topografía de la superficie de la piel interbranquial de los dentículos en 13 especies de tiburones, para comprender mejor la estructura de la superficie de esta región. Demostramos que (1) los dentículos de la piel interbranquial difieren entre las especies de tiburones, y (2) los dentículos del borde anterior de la piel que cubre cada bolsa branquial tienen una morfología y una topografía superficial diferentes en comparación con los dentículos del borde posterior. En todas las especies estudiadas, hubo diferencias significativas en la longitud (P = 0.01) y en el ancho (P = 0.002), con dentículos del borde anterior más cortos y anchos que los del borde posterior. La inclinación de la superficie también era mayor en los dentículos del borde anterior (P = 0.009) aunque la mayoría de los valores seguían siendo negativos, lo que indicaba más valles que picos. En general, los dentículos de la parte anterior tenian los bordes mas lisos que los de la parte posterior en todas las especies estudiadas. Estos datos sugieren dos hipótesis: (1) los dentículos del borde anterior con bordes más lisos protegen la aleta branquial previa de la abrasión durante la respiración, y (2) la morfología de los dentículos con crestas en el borde posterior podría alterar la turbulencia del agua que sale de las bolsas branquiales después de pasar por las branquias. Futuros estudios se centrarán en determinar la relación entre la morfología de los dentículos y el flujo de agua mediante la visualización del movimiento del fluido sobre los dentículos interbranquiales durante la respiración in vivo.Translated by Laura Paez, Ph.D. studentSwiss Federal Institute of Technology Lausanne.
ìì´ì ë¹ëì ì ë²ëì§, ììì§, ì¹ìê°ì¼ë¡ ì´ë£¨ì´ì¡ì¼ë©°, ë±ê°ë¡ ë³´ë©´ ìê¹ìê° ì´ë¹¨ì ë®ìë¤. 기존ì ì°êµ¬ììë ìì´ ë¹ëì íííì 구조를 ì¢ ê° ë° ëì¢ ë´ ë¤ë¥¸ ì´ì²´ ë¶ìì ë¤ìí ê°ëìì ë¶ìíëë°, ê·¸ ì¤ììë ìê°ë¯¸êµ¬ë© ì¬ì´ì 1cmì ë¶ê³¼í ë²ììì ìì ì¸ì í면미ì¸êµ¬ì¡° ë¤ìì±ì ë°ê²¬í ì°êµ¬ê° 주목ëë¤. ìì´ ë¹ëì íííì ì´í´ë¥¼ ë기 ìíì¬, 본 ì°êµ¬ììë ì ¤ì ì¬ì©í íë¡íë¡ë©í¸ë¦¬(gel-based profilometry), ì¡°ì§íì ê¸°ë² ë° ì£¼ì¬ì ìí미경ë²ì íµíì¬, ìì´ë¥ 13ì¢ ìì ìê°ë¯¸êµ¬ë© ì¬ì´ í¼ë¶ì ë¹ë ííì í면미ì¸êµ¬ì¡°ë¥¼ ë¶ìíë¤. 본 ì°êµ¬ì ê²°ê³¼ë (1) ìê°ë¯¸êµ¬ë© ì¬ì´ í¼ë¶ì íë©´ííìë ì¢ ê° ì°¨ì´ê° ìê³ , (2) ìê°ë¯¸êµ¬ë© ì¬ì´ í¼ë¶ì ì ë°© (머리 ë°©í¥) ë¹ëì íë°© (꼬리 ë°©í¥) ì ë¹ëì ë¹íì¬ í¨ì¬ ë í° ìì¤ì ë¤ìì±ì ë³´ìë¤ë ê²ì´ë¤. ë¶ìí 13ì¢ ëª¨ë를 íµíì´, ìê°ë¯¸êµ¬ë© ì¬ì´ í¼ë¶ì ì ë°© ë¹ëì íë°©ì ë¹ë ë³´ë¤ í¨ì¬ ëê³ (P = 0.01) 길ìë¤ (P = 0.002). 본 ì°êµ¬ììë (1) ë¶ëë¬ì´ 머리 쪽 ë¹ëì´ ìì´ê° ì¨ ì´ ëë§ë¤ ìê°ë¯¸êµ¬ë©ì íµí´ ë¹ ì ¸ëì¨ ë¬¼ íë¦ì ì íì ì¤ì¬ì¤ë¤ë ê², ê·¸ë¦¬ê³ (2) 꼬리 쪽 ê°ì¥ì리ì ë¹ëìì ëëë¬ì§ë ë¤ìë ìí ê°ì¥ì리ë ìë§ë ë¹ì·í ì리ìì ìê°ë¯¸êµ¬ë©ì íµí´ ë¹ ì ¸ëì¨ ë¬¼ì ìì©ëì´ë¥¼ ì¤ì¬ ì¤ë¤ë ê°ì¤ì ì¸ì¸ ì ììë¤. 미ëì ì°êµ¬ììë ì¤íì¤ ë´ì ì¡°ê±´ìì ìê°ë¯¸êµ¬ë©ì íµí´ í르ë 물ì ìíì ì¸ ì¸¡ë©´ì ìì´ ë¹ëì íííì 측면과 ì°ê´ì§ì´ ì ê·¼í´ì¼ í ê²ì´ë¤.Translated by Daemin Kim, Ph.D. studentYale University.
Die Haut von Haien ist mit dermalen Dentikeln bedeckt - zahnähnlichen Strukturen, die aus Schmelz, Dentin und einer zentralen Pulpahöhle bestehen. Vorhergehende Studien haben Unterschiede in der Morphologie der Dentikel sowohl zwischen den Arten als auch zwischen verschiedenen Körperregionen innerhalb einer Art gezeigt, einschließlich eines Berichts über extreme morphologische Variationen innerhalb eines Abstands von 1 cm auf der Haut, die die Kiementaschen bedeckt, eine Region, die als "Interbranchialhaut" bezeichnet wird. Um die Oberflächenstruktur dieser Region besser zu versteshen, haben wir die Unterschiede in der Morphologie und Oberflächentopographie der Dentikel der Interbranchialhaut in 13 Haiarten mit Hilfe von Gel-Profilometrie, Histologie und Rasterelektronenmikroskopie quantifiziert. Wir konnten zeigen, dass (1) sich die Dentikel der Interbranchialhaut zwischen den Haiarten unterscheiden und (2) die Dentikel an der Vorderkante der Haut, die jede Kiementasche bedeckt, eine andere Morphologie und Oberflächentopographie aufweisen als die Dentikel an der Hinterkante. Bei allen untersuchten Arten gab es signifikante Unterschiede in der Länge (P = 0.01) und Breite (P = 0.002) der Dentikel, wobei die Dentikel an der Vorderkante kürzer und breiter waren als die Dentikel an der Hinterkante. Auch die Oberflächenschiefe war bei den Dentikeln der Vorderkante höher (P = 0.009), obwohl die meisten Werte immer noch negativ waren, was auf mehr Täler als Spitzen hinweist. Insgesamt waren die Vorderkanten-Dentikel bei allen untersuchten Arten glatter als die Hinterkanten-Dentikel. Diese Daten legen zwei Hypothesen nahe: (1) Glattere Vorderkantenzähne schützen den vorhergehenden Kiemenlappen vor Abrieb während der Atmung, und (2) die Morphologie der gezackten Zähne an der Hinterkante könnte die Wasserturbulenz beim Austritt aus den Kiementaschen nach dem Passieren der Kiemen verändern. Zukünftige Studien werden sich darauf konzentrieren, die Beziehung zwischen der Morphologie der Dentikel und der Wasserströmung zu bestimmen, indem die Flüssigkeitsbewegung über die Interbranchialdentikel während der In-vivo-Atmung sichtbar gemacht wird.Translated by Robin Thandiackal, postdoctoral fellowHarvard University.
La peau des requins est recouverte de denticules dermiques - des structures semblables à des dents composées d'émail, de dentine et d'une cavité pulpaire centrale. Des études précédentes ont démontré que la morphologie des denticules diffère entre les espèces, mais également entre les différentes régions du corps au sein d'une même espèce. Il existe notamment une variation morphologique extrême sur une distance de 1 cm dans la région appelée "peau interbranchiale," soit la peau peau couvrant les poches branchiales. Nous avons utilisé la profilométrie à base de gel, l'histologie et la microscopie électronique à balayage pour quantifier les différences morphologiques et topographiques des denticules de la peau interbranchiale chez 13 espèces de requins, ceci afin de mieux comprendre la structure de la surface de cette région. Nos résultats montrent que (1) les denticules de la peau interbranchiale diffèrent selon les espèces de requins, et (2) les denticules situées sur le bord d'attaque de la peau couvrant chaque poche branchiale ont une morphologie et une topographie de surface différentes de celles des denticules situées sur le bord de fuite. Chez toutes les espèces étudiées, il y avait des différences significatives dans la longueur (P = 0.01) et la largeur (P = 0.002) des denticules, avec les denticules du bord antérieur plus courtes et plus larges que celles du bord postérieur. L'asymétrie de la surface était également plus élevée dans les denticules antérieures (P = 0.009), bien que la plupart des valeurs soient négatives, indiquant plus de vallées que de sommets.Par ailleurs, , les denticules du bord antérieur étaient plus lisses que celles du bord postérieur. Dans l'ensemble, ces données suggèrent deux hypothèses: (1) les denticules situées sur le bord d'attaque et possédant une surface plus lisse protègent le volet branchial précédent de l'abrasion pendant la respiration, et (2) la morphologie plutôt striée des denticules situées sur le bord de fuite pourrait modifier les caractéristiques turbulentes de l'écoulement sortant des poches branchiales après être passé sur les branchies. Les études futures se concentreront sur la détermination de la relation entre la morphologie des denticules et l'écoulement de l'eau en visualisant le mouvement du fluide sur les denticules interbranchiaux pendant la respiration in vivo.Translated by Elsa Goerig, postdoctoral fellowHarvard University.