Same but different: ontogeny and evolution of the Musculus adductor mandibulae in the Tetraodontiformes

The morphological diversity of fishes provides a rich source to address questions regarding the evolution of complex and novel forms. The Tetraodontiformes represent an order of highly derived teleosts including fishes, such as the pelagic ocean sunfishes, triggerfishes, and pufferfishes. This makes the order attractive for comparative analyses to understand the role of development in generating new forms during evolution. The adductor mandibulae complex, the main muscle associated with jaw closure, represents an ideal model system within the Tetraodontiformes. The adductor mandibulae differs in terms of partitions and their attachment sites between members of the different tetraodontiform families. In order to understand the evolution of the jaws among the Tetraodontiformes, we investigate the development of the adductor mandibulae in pufferfishes and triggerfishes as representatives of two different suborders (Balistoidei and Tetraodontoidei) that follows two different adaptations to a durophagous feeding mode. We show that the varied patterns of the adductor mandibulae derive from similar developmental sequence of subdivision of the partitions. We propose a conserved developmental program for partitioning of the adductor mandibulae as a foundation for the evolution of different patterns of subdivisions in Tetraodontiformes. Furthermore, we argue that derived conditions in the higher taxa are realized by supplementary subdivisions and altered attachment sites. These findings support a reinterpretation of homology of different muscle partitions among the Tetraodontiformes, as muscle partitions previously thought to be disparate, are now clearly related.     

The adductor mandibulae muscle complex in lower teleostean fishes (Osteichthyes: Actinopterygii): comparative anatomy,synonymy, and phylogenetic implications

Bony fishes of the morphologically diverse infraclass Teleostei include more than 31 000 species, encompassing almost one‐half of all extant vertebrates. A remarkable anatomical complex in teleosts is the adductor mandibulae, the primary muscle in mouth closure and whose subdivisions vary in number and complexity. Difficulties in recognizing homologies amongst adductor mandibulae subdivisions across the Teleostei have hampered the understanding of the evolution of this system and consequently its application in phylogenetic analyses. The adductor mandibulae in representatives of all lower teleost orders is described, illustrated, and compared based on broad taxonomic sampling complemented by extensive literature information. Muscle division homologies are clarified via the application of a standardized homology‐driven anatomical terminology with synonymies provided to the myological terminologies of previous studies. Phylogenetic implications of the observed variations in the adductor mandibulae are discussed and new possible synapomorphies are proposed for the Notacanthiformes, Ostariophysi, Cypriniformes, Siluriphysi, Gymnotiformes, and Alepocephaloidei. New characters corroborate the putative monophyly of the clades Albuliformes plus Notacanthiformes (Elopomorpha), Argentinoidei plus Esocoidei plus Salmonoidei (Protacanthopterygii) and Hemiodontidae plus Parodontidae (Characiformes). We further confirm the validity of characters from the adductor mandibulae previously proposed to support the monophyly of the Esocoidei and the gonorynchiform clade Gonorynchoidei plus Knerioidei. © 2014 The Linnean Society of London     

Homologies among different adductor mandibulae sections of teleostean fishes, with special regard to catfishes (Teleostei: siluriformes)

The adductor mandibulae complex has been a subject of discussion and uncertainties due to a wide range of differentiations and fusions that have occurred during teleost evolution. The adductor mandibulae of numerous catfishes was studied in detail and compared with that of several other teleosts described in the literature. Our observations and comparisons demonstrate that: 1) the adductors mandibulae Aomega, A2, and A3 of acanthopterygians correspond, respectively, to the Aomega, A2, and A3 of ostariophysines; 2) the antero-dorso-lateral (A1) and the antero-ventro-lateral (A1-OST) sections of the adductor mandibulae present, respectively, in acanthopterygians and in basal ostariophysines are the result of two different patterns of differentiation of this muscle; 3) some derived ostariophysines present a lateral section of the adductor mandibulae attached to the upper jaw (A0) that is not homologous with any other section of this muscle present in any other ostariophysine or acanthopterygian fish; 4) the configuration of the adductor mandibulae present in Diplomystes seems to be the plesiomorphic condition for catfishes; and 5) the muscle retractor tentaculi, present in a large number of catfishes, is derived from the inner section of the adductor mandibulae (A3) and, thus, is not homologous with the lateral bundle of this muscle (A0) that inserts on the upper jaw in some derived ostariophysine fishes.     

Ontogeny of the jaw and maxillary barbel musculature in the armoured catfish families Loricariidae and Callichthyidae (Loricarioidea,Siluriformes), with a discussion on muscle homologies

The neotropical loricarioid catfishes include six families, the most species‐rich of which are the Callichthyidae and the Loricariidae. Loricariidae (suckermouth armoured catfishes) have a highly specialized head morphology, including an exceptionally large number of muscles derived from the adductor mandibulae complex and the adductor arcus palatini. Terminology of these muscles varies among the literature, and no data exist on their ontogenetic origin. A detailed examination of the ontogeny of both a callichthyid and a loricariid representative now reveals the identity of the jaw and maxillary barbel musculature, and supports new hypotheses concerning homologies. The adductor mandibulae muscle itself is homologous to the A1‐OST and A3′ of basal catfishes, and the A3′ has given rise to the newly evolved loricariid retractor veli as well. The A2 and A3″ have resulted in the retractor tentaculi of Callichthyidae and the retractor premaxillae of Loricariidae. Thus, these two muscles are shown to be homologous. In Loricariidae, the extensor tentaculi consists of two separate muscles inserting on the autopalatine, and evidence is given on the evolutionary origin of the loricariid levator tentaculi (previously and erroneously known as retractor tentaculi) from the extensor tentaculi, and not the adductor mandibulae complex. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 76–96.     

Ontogeny of cranial musculature in Clarias gariepinus (Siluroidei: Clariidae): The adductor mandibulae complex

The adductor mandibulae complex has been a subject of discussion and uncertainties due to a wide range of differentiations that have occurred in teleosts during evolution. In Siluroidei a specific modification of a part of the muscle complex has resulted in the formation of a retractor muscle of the maxillary barbel. The main part of the muscle complex, responsible for the closure of the mouth, has undergone some changes as well, which are at the base of the homology problems encountered by different authors. In this paper the muscles have been studied in three ontogenetic stages of the siluroid Clarias gariepinus (Clariidae); two of them have been described. Based on the ontogenetic evidence and the literature, the following muscles are recognized: 1) the very weakly differentiated adductor mandibulae A₂A'₃, where only little distinction can be made between the A₂ and the A'₃ muscle parts, and 2) the adductor mandibulae A“₃. Caudally, both muscles are separated from each other by the levator arcus palatini, but are fused together anteriorly, inserting onto the lower jaw. In juvenile C. gariepinus, a differentiation has occurred in the A”₃ muscle, thereby forming a distinct pars superficialis and a pars profunda. No A₁ nor an A_ω muscle is present. © 1996 Wiley-Liss, Inc.     

Homologies of the adductor mandibulae muscles in Tetraodontiformes as indicated by nerve branching patterns

Homologies of the adductor mandibulae muscles in eight families of Tetraodontiformes were hypothesized from the branching patterns of ramus mandibularis trigeminus. Insertions of the muscles to the upper or lower jaw were weak indicators of homology, migrations of the sites occurring frequently in A1, A2, A2, and A3. In monacanthids, tetraodontids, and diodontids, A1 tended to be split into numerous subsections, whereas in aracanids and ostraciids, A3 was highly developed, comprising three or four subsections. In tetraodontids, A2 was found to be a composite of A1 subsection and A2. The methods of and limits to applying nerve branching patterns to muscle homology are discussed. A new naming system that reflects both muscle homologies and insertions is proposed.     

Two New Saponins from Lysimachia capillipes Hemsl.

To investigate the saponins from whole plants of Lysimachia capillipes Hemsl., two new saponins, named capilliposide E (1) and capilliposide F (2), were isolated. The structures of the new sa ponins were elucidated as 3 β, 22α-dihydroxy- 16α-acetat-28→ 13 -lactone-oleanane-3 -O- [β-D-glucopyranosyl(1→2)-α-L-arabinpyranoyl]-22-O-β-D-glucopyranoside (1) and 3 β, 22α-dihydroxy- 16α-acetat-28→ 13-1actone-oleanane-3-O- { [β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl-(1→4)]-α-L-arabinpyranoyl }-22-O-βD-glucopyranoside (2). The structures of these compounds were determined by 1D- and 2D-NMR, MS techniques, and chemical methods.     

Evolutionary trend in feeding habits of <Emphasis Type="Italic">Girella</Emphasis> (Perciformes: Girellidae)

Although some Girella species are herbivorous, having basically tricuspid teeth, some are omnivorous. To determine the evolutionary trends in feeding habits of Girella, the phylogenetic relationships of several species of Girella were estimated by partially sequencing the mitochondrially encoded NADH dehydrogenase subunit 2 gene, and the dentition and adductor mandibulae complex of each species were examined. The cladogram determined from the mitochondrial DNA analysis indicated that multiple tooth-rows containing incisor-like teeth existed in adults of the ancestral species of Girella, species with a single tooth-row of tricuspid teeth in the adult stage having diverged subsequently on several occasions. The tendinous connections between each section of the adductor mandibulae complex are believed to have been simple in the ancestral species, more complicated connections also having diverged later on several occasions. Multiple tooth-rows containing incisor-like teeth and the simple adductor mandibulae complex are deduced as adaptations to herbivory; on the other hand, a single tooth-row of tricuspid teeth and the complicated adductor mandibulae complex are deduced as adaptations to omnivory. Therefore, the ancestral species of Girella is suggested as having been adapted to herbivory, with species adapted to omnivory having diverged on several subsequent occasions.     

Comments on the evolution of the jaw adductor musculature of snakes

The aim of this study is to provide a general view of the adductor musculature of the alethinophidian snakes. The aponeurotic system present in anilioid snakes is here described as being also present in colubroid and booid snakes. Although modified in various groups, this aponeurotic system retains the same topographical pattern in the anilioids, booids and colubroids, and is thus hypothesized to be homologous. An analysis of the aponeurotic system and related muscular bundles within the alethinophidian snakes is given. A new terminology is proposed for the jaw adductor muscles where the muscles levator anguli oris and adductor mandibulae externus superficialis (proper) of snakes (sensu Lakjer, 1926; Haas, 1962) retain these names even if this fails to reflect the presumed homologies with the bundles of the same name in lizards (see Rieppel, 1988b); the fibres originating from the temporal tendon in the Anilioidea, and presumed to form a bundle of composite nature (Rieppel, 1980b), are named the M. adductor mandibulae externus temporalis (lost by the Macrostomata); the M. adductor mandibulae externus medialis is a composite muscle in the Anilioidea (Rieppel, 1980b) which give rise to two different muscles in the ‘booids’, the M. adductor mandibulae externus medialis, pars anterior and the M. adductor mandibulae externus profundus, the former being secondarily lost by the Caenophidia which retains only fibres homologues of the 3b and 3c heads of the profundus layer of lizards; the so-called M. adductor mandibular externus profundus of snakes (sensu Lackjer, 1926; Haas, 1962) is also a composite muscle in the Anilioidea (Rieppel, 1980b), in the alethinophidians it is essentially made of fibres homologous with the posterior pinnate part of the medialis layer of lizards, and is here named the M. adductor mandibulae externus medialis, pars posterior. As a result from this analysis it follows that: (1) the Macrostomata are characterized by the downward extension of the fibres forming the M. adductor mandibulae externus medialis, pars anterior and the loss of the M. adductor mandibulae externus temporalis: (2) the Xenopeltidae are set apart from the remaining macrostomatan snakes by the retention of the M. levator anguli oris and of a well developed lateral sheet of the quadrate aponeurosis; (3) the ‘booids’ form a monophyletic group comprising only the Boidae and Bolyeriidae (with the exclusion of the Xenopeltidae and Tropidophiidae) which is characterized by a differentiated M. adductor mandibulae externus medialis, pars anterior inserting on the lateral surface of the compound bone via its own aponeurosis; (4) the Tropidophiidae are set apart from all other snakes by the peculiar course of their lateral head vein; however, they belong to the Caenophidia as they show a facial carotid artery which passes dorsally to the mandibular and maxillary branches of the trigeminus; (5) a possible additional character in favour of an Acrochordoidea + Colubroidea monophyletic unit may be given by the pattern of innervation of the jaw adductor muscles in these two taxa; (6) a new interpretation of the compressor glandulae muscular complex of Atractaspis resulted in a morphologically similar pattern to that of the viperids; the phylogenetic implications of such similarity are discussed in detail.     

Comparative lever analysis and ontogenetic scaling in esocid fishes: Functional demands and constraints in feeding biomechanics

When animals grow, the functional demands that they experience often change as a consequence of their increasing body size. In this study, we examined the feeding biomechanics in esocid species that represent different size classes (small, Esox americanus; intermediate, Esox niger; large, Esox lucius), and how their bite forces and associated functional variables change as they grow. In order to evaluate bite performance through ontogeny, we dissected and measured dimensions of the feeding apparatus and the adductor mandibulae muscle complex with its segmentum facialis subdivisions such as the ricto‐malaris, stegalis and endoricto‐malaris across a wide range of body sizes. The collected morphological data was used as input variables for a published anatomical model to simulate jaw function in these fish species. Maximum bite forces for both anterior bite and posterior bite increased in isometry in E. americanus and E. niger. The posterior bite of E. lucius also increases in isometry, however, the anterior bite increases in positive allometry. Intraspecific comparison within E. lucius indicated the increase of bite forces in more developed individuals accelerated after the fish grew out of fingerling stage. In addition, our analysis indicated functional differentiation between subdivisions of the adductor mandibulae segmentum facialis, as well as interspecific differences in the pattern of contribution to the bite performance by these subdivisions. Our study provides insights into not only the musculoskeletal basis of the jaw function of esocid species, but also the feeding capacity of this species in relation to the functional demands it faces as one of the top predators in lake and river systems. J. Morphol. 277:1447–1458, 2016. © 2016 Wiley Periodicals, Inc.     

ON THE STRUCTURE OF TWO NEW GANGLIOSIDES FROM BEEF BRAIN

Abstract— Two new gangliosides were isolated in pure form from beef brain. They were provisionally named ganglioside G5a and G5b. Ganglioside GSa is a monosialoganglioside containing fucose. Its basic neutral glycosphingolipid core is the gangliotetraose ceramide: Gal (1 —> 3) GalNac (1—> 4) Gal (1 —> 4) Glc (1—>) ceramide, most likely with β-linkages. Fucose is linked to the 2-position of external galactose, N -acetylneuraminic acid to the 3- position of internal galactose. Ganglioside G5b is a mixture of at least two isomeric disialogangliosides containing N -acetylneuraminic acid and N -glycolylneura-minic acid. The major isomer has the following structure: NeuNac (α,2—>3) Gal (β,1—>3) GalNac (β, 1 —> 4) (NeuNglα, 2 —> 3) gal (β,1—>4) Glc (β,1 —>)-ceramide. The minor isomer contains N -acetylneur-aminic acid and N -glycolylneuraminic acid in an inverted linkage position.     

Steroidogenesis in the Ovarian Follicle of Medaka (Oryzias latipes, a daily spawner) during Oocyte Maturation

The metabolism of ¹⁴C-labeled steroid precursors by cell-free homogenates of medaka ( Oryzias latipes , a daily spawner) ovarian follicles at 12 different developmental stages was examined using thin layer chromatography (TLC). The radioactive metabolites produced were identified and tested for their ability to induce germinal vesicle breakdown (GVBD) in oocytes in an in vitro homologous bioassay. When homogenates of follicles isolated during oocyte maturation were incubated with ¹⁴C-labeled 17α-hydroxyprogesterone, 13 metabolites were detected in TLC. Among these metabolites, one metabolite exhibited very high maturation inducing activity by the in vitro bioassay. This metabolite was identified as 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DP) by its chromatographic mobility in TLC and recrystallization to constant specific activity. 17α,20β-DP production was high in follicles collected between 10 and 6 hr before spawning. A much less biologically active metabolite, 17α,20β-dihydroxy-5β-pregnane-3-one appeared in follicles immediately after the formation of 17α,20β-DP. A similar pattern of steroidogenesis was observed when the follicles were incubated with ¹⁴C-labeled pregnenolone and progesterone. The timely synthesis of 17α,20β-DP in medaka at the onset of oocyte maturation, together with the demonstration that this progestogen is the most potent inducer of oocyte maturation in vitro , provides further evidence that 17α,20β-DP is the naturally occurring maturation-inducing hormone in the medaka. The results also suggest that the conversion of 17α,20β-DP to its 5β-reduced metabolite may be an inactivation process.     

Association between αs1-, β- and x-casein loci in two Italian cattle breeds

The genetic polymorphism α_s1-, β- and x-caseins was examined by gel electrophoresis in two Italian breeds, Valdostana and Piedmont.
The results obtained from acid and basic migration show that the gene frequencies of the two breeds are very similar.
Non independent assortment of genotypes among these milk protein loci was also studied.
Results of analyses carried out on loci pairs showed that the genetic complex αs1-Cn^B-β-Cn^A2 was the most common in both breeds. In addition, the measure of linkage disequilibrium or gametic association (denoted A) showed a close association between α_s1-Cn and β-Cn , and between β-Cn. and x-Cn. No significant association was found between α_s1-Cn and x-Cn. This is in line with the model proposed by Grosclaude et al. (1973).     

Interleukin-1 beta up-regulates TACE to enhance alpha-cleavage of APP in neurons: resulting decrease in Abeta production

The proinflammatory cytokine interleukin (IL)-1β is up-regulated in microglial cells surrounding amyloid plaques, leading to the hypothesis that IL-1β is a risk factor for Alzheimer's disease. However, we unexpectedly found that IL-1β significantly enhanced α-cleavage, indicated by increases in sAPPα and C83, but reduced β-cleavage, indicated by decreases in sAPPβ and Aβ40/42, in human neuroblastoma SK-N-SH cells. IL-1β did not significantly alter the mRNA levels of BACE1, ADAM-9, and ADAM-10, but up-regulated that of TACE by threefold. The proform and mature form of TACE protein were also significantly up-regulated. A TACE inhibitor (TAPI-2) concomitantly reversed the IL-1β-dependent increase in sAPPα and decrease in sAPPβ, suggesting that APP consumption in the α-cleavage pathway reduced its consumption in the β-cleavage pathway. IL-1Ra, a physiological antagonist for the IL-1 receptor, reversed the effects of IL-1β, suggesting that the IL-1β-dependent up-regulation of α-cleavage is mediated by the IL-1 receptor. IL-1β also induced this concomitant increase in α-cleavage and decrease in β-cleavage in mouse primary cultured neurons. Taken together we conclude that IL-1β is an anti-amyloidogenic factor, and that enhancement of its signaling or inhibition of IL-1Ra activity could represent potential therapeutic strategies against Alzheimer's disease.     

Selective Dephosphorylation of the Subunits of Skeletal Muscle Calcium Channels by Purified Phosphoprotein Phosphatases

Abstract: Multiple sites on the α1 and β subunits of purified skeletal muscle calcium channels are phosphorylated by cyclic AMP-dependent protein kinase, resulting in three different tryptic phosphopeptides derived from each subunit. Phosphoprotein phosphatases dephosphorylated these sites selectively. Phosphoprotein phosphatase 1 (PP1) and phosphoprotein phosphatase 2A (PP2A) dephosphorylated both α1 and β subunits at similar rates, whereas calcineurin dephosphorylated β subunits preferentially. PP1 dephosphorylated phosphopeptides 1 and 2 of the α1 subunit more rapidly than phosphopeptide 3. In contrast, PP2A dephosphorylated phosphopeptide 3 of the α1 subunit preferentially. All three phosphoprotein phosphatases preferentially dephosphorylated phosphopeptide 1 of the β subunit and dephosphorylated phosphopeptides 2 and 3 more slowly. Mn²⁺ increased the rate and extent of dephosphorylation of all sites by calcineurin so that >80% dephosphorylation of both α1 and β sub-units was obtained. The results demonstrate selective dephosphorylation of different phosphorylation sites on the α1 and β subunits of skeletal muscle calcium channels by the three principal serine/threonine phosphoprotein phosphatases.     

Production of monoclonal antibodies against 3α,20β-hydroxysteroid dehydrogenase from Streptomyces hydrogenans

Abstract A procedure is described for the production of monoclonal antibodies (mAbs) against 3α,20β-hydroxysteroid dehydrogenase (3α,20β-HSD) from the actinomycete Streptomyces hydrogenans ATCC 19631. Clones which were obtained after fusion of immune cells were screened by solid-phase ELISA and immunoblotting. About 5.2% of the clones secreted immunoglobulins with specificity for 3α,20β-HSD. The purified mAbs were found to belong to subclass IgG₁ and to recognize both the native enzyme as well as its identical subunits which were obtained by SDS denaturation. However, the activity of the tetrameric holoenzyme was only weakly diminished in the presence of these mAbs.