Primordial emergence of the recombination activating gene 1 (RAG1): sequence of the complete shark gene indicates homology to microbial integrases.

The rearrangement of antibody and T-cell receptor gene segments is indispensable to the vertebrate immune response. All extant jawed vertebrates can rearrange these gene segments. This ability is conferred by the recombination activating genes I and II (RAG I and RAG II). To elucidate their origin and function, the cDNA encoding RAG I from a member of the most ancient class of extant gnathostomes, the Carcharhine sharks, was characterized. Homology domains identified within shark RAG I prompted sequence comparison analyses that suggested similarity of the RAG I and II genes, respectively, to the integrase family genes and integration host factor genes of the bacterial site-specific recombination system. Thus, the apparent explosive evolution (or "big bang") of the ancestral immune system may have been initiated by a transfer of microbial site-specific recombinases.

A new high molecular weight immunoglobulin class from the carcharhine shark: implications for the properties of the primordial immunoglobulin.

All immunoglobulins and T-cell receptors throughout phylogeny share regions of highly conserved amino acid sequence. To identify possible primitive immunoglobulins and immunoglobulin-like molecules, we utilized 3' RACE (rapid amplification of cDNA ends) and a highly conserved constant region consensus amino acid sequence to isolate a new immunoglobulin class from the sandbar shark Carcharhinus plumbeus. The immunoglobulin, termed IgW, in its secreted form consists of 782 amino acids and is expressed in both the thymus and the spleen. The molecule overall most closely resembles mu chains of the skate and human and a new putative antigen binding molecule isolated from the nurse shark (NAR). The full-length IgW chain has a variable region resembling human and shark heavy-chain (VH) sequences and a novel joining segment containing the WGXGT motif characteristic of H chains. However, unlike any other H-chain-type molecule, it contains six constant (C) domains. The first C domain contains the cysteine residue characteristic of C mu1 that would allow dimerization with a light (L) chain. The fourth and sixth domains also contain comparable cysteines that would enable dimerization with other H chains or homodimerization. Comparison of the sequences of IgW V and C domains shows homology greater than that found in comparisons among VH and C mu or VL, or CL thereby suggesting that IgW may retain features of the primordial immunoglobulin in evolution.

Tooth histology and ultrastructure of a Paleozoic shark, Edestus heinrichii / Katherine Taylor -- and Thomas Adamec --.

v.33:no.24(1977)

Bandringa rayi: a new Ctenacanthoid shark from the Pennsylvania Essex fauna of Illinois / Rainer Zangerl --

v.12:no.10(1969)

A new shark of the family Edestidae, Ornithoprion hertwigi, from the Pennsylvanian Mecca and Logan quarry shales of Indiana / Rainer Zangerl --

v.16:no.1(1966)

Preservation of bull semen at sub-zero temperatures /

Cover title.

John Bull and Jonathan; or, Free trade v. protection, an address to working men.

Mode of access: Internet.

John Bull sur la sellette : le "livre bleu" en images : documents pour servir à l'histoire, présentés aux Johns Anglais /

Cover title.

John Bull and his unemployed. A plain statement on the law of England as it affects the unemployed.

Mode of access: Internet.

Theseus Taming the Bull of Marathon

Carle van Loo; 2 ft. 2 in.x 4 ft. 10 in.; oil on canvas

Evaluation of fertility in the bull and boar,

Mode of access: Internet.

The Bull of Adrian IV.

Mode of access: Internet.

Magistri Cornelij de Snekis ... Sermones XXI super confraternitate de serto Rosaceo ... Sermones duo eiusdem [et] eode[m] themate co[n]tra Ebrietatem ... ; Quibus addu[n]tur Corona super officio dicti serti Rosacei ; Bull[a]e apostolic[a]e ... , Sermones synodales ...

Mode of access: Internet.