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Nuclear receptors (NR) are ligand-activated transcription factors that regulate different metabolic pathways by influencing the expression of target genes. The current study examined mRNA abundance of NR and NR target genes at different sites of the gastrointestinal tract (GIT) and the liver of healthy dogs (Beagles; n = 11). Samples of GIT and liver were collected postmortem and homogenized, total RNA was extracted and reverse transcribed, and gene expression was quantified by real-time reverse-transcription PCR relative to the mean of 3 housekeeping genes (β-actin, glyceraldehyde-3-phosphate dehydrogenase, and ubi-quitin). Differences were observed (P≤ 0.05) in the mRNA abundance among stomach (St), duodenum (Du), jejunum (Je), ileum (Il), and colon (Col) for NR [pregnane X receptor (Du, Je > Il, Col > St), peroxisome proliferator-associated receptor γ (St, Du, Col > Je, Il), constitutive androstane receptor (Je, Du > Il, Col), and retinoid × receptor α (Du > Il)] and NR target genes [glutathione-S-transferase A3-3 (Du > Je > St, Il; St > Col), phenol-sulfating phenol sulfotransferase 1A1 (Du, Je > Il, St; Col > St), cytochrome P450 3A12 (Du, Je > St, Il, Col), multiple drug resistance gene 1 (Du, Je, Il, Col > St), multiple drug resistance-associated protein 2 (Je, Du > Il > St, Col), multiple drug resistance-associated protein 3 (Col > St > Il; Du > Je, Il; St > Il), NR corepressor 2 (St > Il, Col), and cytochrome P450 reductase (St, Du, Je > Il, Col)], but not for peroxisome proliferator-associated receptor α. Differences (P> 0.05) in mRNA abundance in the liver relative to the GIT were also observed. In conclusion, the presence of numerous differences in expression of NR and NR target genes in different parts of the GIT and in liver of healthy dogs may be associated with location-specific functions and regulation of GIT regions.

The centromeric heterochromatin of all human chromosomes is composed of tandemly repeated alpha satellite DNA. Here we describe another alphoid subfamily that maps to human chromosome 22 as determined by FISH. The alphoid sequences were isolated from three YAC-clones carrying DNA from the pericentromeric region of the short arm of human chromosome 22 and limited amounts of alphoid DNA. This property enabled us to map the members of the subfamily to the border of the centromeric region and the short arm of the chromosome. The new alphoid subfamily may contribute to the closure of the gap remaining between the centromeric and short-arm maps of human chromosome 22.

THE series of minute, adherent species of Brachiopoda brought together in the following discussion are usually assigned by American pal?ontologists to the genus Strophalosia, but recent writers have come to recognize the fact that, in America at least, the genus Strophalosiais a polyphyletic group. Dr. Stuart Weller, in his monograph on the Mississippian Brachiopoda (1914), all but recognizes the generic value of these minute shells when he points out the lack of harmony in the series of forms which he places in the genus Strophalosia.

Scaphopods are of rare occurrence in the Paleozoic of North America. Dentaliumand Plagioglyptahave been recorded from formations as old as Middle Devonian; however, their occurrence is always sporadic and it is only in the Upper Carboniferous rocks that they are met with in any number. The form here described is the first Devonian occurrence of the Class that has come to the writer’s notice throughout a period of thirty-five years’ active collecting in the Devonian of the Mississippi Valley.

Through the kindness of a correspondent in Southern California, the writer recently acquired a series of 320 superb examples of Dentalium neohexagonumS. and P. collected from the Fernando formation of that state. The following somewhat detailed account of the variations occurring in the collection may prove of interest to students of the Scaphopoda. Our study of this series is supplemented by the addition of other material of the species, collected by Charles Sternberg, from the Pleistocene in the vicinity of San Quintin, Baja California, Mexico, and a few examples of the species, now found living off the California coast, dredged by Henry Hemphill.