What isIvanantonia efremovi (Rodentia, Mammalia)?

Ivanantonia efremovi Shevyreva 1989, known from the Tsagan Khushu locality (Early Eocene of Mongolia), erroneously has been described asOrogomys obscurus Dashzeveg 1990. This form shows an interesting association of primitive and derived characters: the enamel of the incisors is two-layered and has pauciserial Hunter-Schreger bands in portio interna; the lower tooth row has only three jugal teeth; the tooth pattern of lower molars is primitive and looks very similar to that ofAlagomys, but the trigonid is less reduced with regards to the talonid. It also differs from other primitive rodents in the distribution of wear facets, suggesting that mandibular propalineal movement was pre-eminent during chewing. Comparisons ofIvanantonia with several Eocene-Oligocene rodents indicate possible relationships to the Early Oligocene North American genusNonomys.     

A new middle Eocene insectivore from the Mongolian People's Republic

A new genus and species, Bogdia orientalis, (Mammalia,Proteutheria, Pantolestidae) is described from the middle Eocene site of Tsagan-Khutel, from the valley of Lakes of the People's Republic of Mongolia. It is the first pantolestid species described from Asia.     

The Arabidopsis At1g45130 and At3g52840 genes encode beta-galactosidases with activity toward cell wall polysaccharides

The Arabidopsis genes At1g45130 and At3g52840 encode the β-galactosidase isozymes Gal-5 and Gal-2 that belong to Glycosyl Hydrolase Family 35 (GH 35). The two enzymes share 60% sequence identity with each other and 38–81% with other plant β-galactosidases that are reported to be involved in cell wall modification. We studied organ-specific expression of the two isozymes. According to our western blot analysis using peptide-specific antibodies, Gal-5 and Gal-2 are most highly expressed in stem and rosette leaves. We show by dot-immunoblotting that Gal-5 and Gal-2 are associated with the cell wall in Arabidopsis. We also report expression of the recombinant enzymes in P. pastoris and describe their substrate specificities. Both enzymes hydrolyze the synthetic substrate para-nitrophenyl-β-d-galactopyranoside and display optimal enzyme activity between pH 4.0 and 4.5, similar to the pH optimum reported for other well-characterized plant β-galactosidases. Both Gal-5 and Gal-2 show a broad specificity for the aglycone moiety and a strict specificity for the glycone moiety in that they prefer galactose and its 6-deoxy analogue, fucose. Both enzymes cleave β-(1, 4) and β-(1, 3) linkages in galacto-oligosaccharides and hydrolyze the pectic fraction of Arabidopsis cell wall. These findings suggest that Gal-5 and Gal-2 could be involved in the modification of cell wall polysaccharides.