Dataset Information

Analysis of immunoglobulin transcripts in the ostrich Struthio camelus, a primitive avian species.

ABSTRACT: Previous studies on the immunoglobulin (Ig) genes in avian species are limited (mainly to galliformes and anseriformes) but have revealed several interesting features, including the absence of the IgD and Ig? encoding genes, inversion of the IgA encoding gene and the use of gene conversion as the primary mechanism to generate an antibody repertoire. To better understand the Ig genes and their evolutionary development in birds, we analyzed the Ig genes in the ostrich (Struthio camelus), which is one of the most primitive birds. Similar to the chicken and duck, the ostrich expressed only three IgH chain isotypes (IgM, IgA and IgY) and ? light chains. The IgM and IgY constant domains are similar to their counterparts described in other vertebrates. Although conventional IgM, IgA and IgY cDNAs were identified in the ostrich, we also detected a transcript encoding a short membrane-bound form of IgA (lacking the last two C(H) exons) that was undetectable at the protein level. No IgD or ? encoding genes were identified. The presence of a single leader peptide in the expressed heavy chain and light chain V regions indicates that gene conversion also plays a major role in the generation of antibody diversity in the ostrich. Because the ostrich is one of the most primitive living aves, this study suggests that the distinct features of the bird Ig genes appeared very early during the divergence of the avian species and are thus shared by most, if not all, avian species.

SUBMITTER: Huang T

PROVIDER: S-EPMC3315531 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Analysis of immunoglobulin transcripts in the ostrich Struthio camelus, a primitive avian species.

Huang Tian T Zhang Min M Wei Zhiguo Z Wang Ping P Sun Yi Y Hu Xiaoxiang X Ren Liming L Meng Qingyong Q Zhang Ran R Guo Ying Y Hammarstrom Lennart L Li Ning N Zhao Yaofeng Y

PloS one 20120329 3

Previous studies on the immunoglobulin (Ig) genes in avian species are limited (mainly to galliformes and anseriformes) but have revealed several interesting features, including the absence of the IgD and Igκ encoding genes, inversion of the IgA encoding gene and the use of gene conversion as the primary mechanism to generate an antibody repertoire. To better understand the Ig genes and their evolutionary development in birds, we analyzed the Ig genes in the ostrich (Struthio camelus), which is ...[more]

PMID: 22479606

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Project description:BackgroundThe ostrich Struthio camelus reaches the highest speeds of any extant biped, and has been an extraordinary subject for studies of soft-tissue anatomy and dynamics of locomotion. An elongate tarsometatarsus in adult ostriches contributes to their speed. The internal osteology of the tarsometatarsus, and its mechanical response to forces of running, are potentially revealing about ostrich foot function.Methods/principal findingsComputed tomography (CT) reveals anatomy and bone densities in tarsometatarsi of an adult and a young juvenile ostrich. A finite element (FE) model for the adult was constructed with properties of compact and cancellous bone where these respective tissues predominate in the original specimen. The model was subjected to a quasi-static analysis under the midstance ground reaction and muscular forces of a fast run. Anatomy-Metatarsals are divided proximally and distally and unify around a single internal cavity in most adult tarsometatarsus shafts, but the juvenile retains an internal three-part division of metatarsals throughout the element. The juvenile has a sparsely ossified hypotarsus for insertion of the m. fibularis longus, as part of a proximally separate third metatarsal. Bone is denser in all regions of the adult tarsometatarsus, with cancellous bone concentrated at proximal and distal articulations, and highly dense compact bone throughout the shaft. Biomechanics-FE simulations show stress and strain are much greater at midshaft than at force applications, suggesting that shaft bending is the most important stressor of the tarsometatarsus. Contraction of digital flexors, inducing a posterior force at the TMT distal condyles, likely reduces buildup of tensile stresses in the bone by inducing compression at these locations, and counteracts bending loads. Safety factors are high for von Mises stress, consistent with faster running speeds known for ostriches.Conclusions/significanceHigh safety factors suggest that bone densities and anatomy of the ostrich tarsometatarsus confer strength for selectively critical activities, such as fleeing and kicking predators. Anatomical results and FE modeling of the ostrich tarsometatarsus are a useful baseline for testing the structure's capabilities and constraints for locomotion, through ontogeny and the full step cycle. With this foundation, future analyses can incorporate behaviorally realistic strain rates and distal joint forces, experimental validation, and proximal elements of the ostrich hind limb.

Dataset Information

Analysis of immunoglobulin transcripts in the ostrich Struthio camelus, a primitive avian species.

Publications

Analysis of immunoglobulin transcripts in the ostrich Struthio camelus, a primitive avian species.

Similar Datasets

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