Mantle xenoliths from Kimberley, South Africa, contain texturally distinct peridotites; coarse granular to extensively sheared peridotites. Mineral chemistries of the textually distinct peridotite xenoliths indicate that these mantle rocks were equilibrated at similar P-T conditions: 44-54 kbar and 970-1130 o C for granular peridotites, and 41-50 kbar and 950-1080 o C for sheared peridotites. The Kimberley peridotites showing various deformation textures are restricted to a relatively narrow depth range (120-160km). They display no systematic correlation between texture and estimated equilibrium pressure and temperature, whereas sheared peridotites in the Lesotho kimberlites commonly originated from greater depths and higher temperature. The large local variations in the degree of deformation in the cratonic lithosphere beneath Kimberley require pronounced weakening due to localized high water flux that can be associated with mantle metasomatism. Sheared peridotites have more depleted compositions in FeO and CaO compositions than those of granular peridotites, but have a higher orthopyroxene modal abundance and contain sodium-rich clinopyroxene, which are consistent with that extensive deformations associated with Si-rich fluid/melt metasomatism. We therefore conclude that mantle metasomatism has an important role in facilitating deformation locally within the cratonic lithosphere, and is responsible for the textural variations of peridotite xenoliths from the cratonic roots.

The complete primary structure of a base non-specific and adenylic acid preferential RNase (RNase M) from Aspergillus saitoi was determined. The sequence was determined by analysis of the peptides generated by digestion of heat-denatured RNase M with lysylendopeptidase, and the peptides generated from RCM RNase M by digestion with staphylococcal V8 protease or chemical cleavage with BrCN. It consisted of 238 amino acid residues and carbohydrate moiety attached to the 74th asparagine residue. The molecular weight of the protein moiety deduced from the sequence was 26,596. The locations of 10 half cystine residues are almost superimposable on those of RNase Rh from Rhizopus niveus and RNase T2 from Aspergillus oryzae which have similar base specificity. The homology between RNase M and RNase Rh and RNase T2 amounted to 97 and 160 amino acid residues, respectively. The amino acid sequences conserved in the three RNases are concentrated around the three histidine residues, which are supposed to form part of the active sites of these RNases.

Leptin resistance is one of the mechanisms involved in the pathophysiology of obesity. The present study showed that glucose deprivation inhibited leptin-induced phosphorylation of signal transducer and activator of transcription 3 (STAT3) and signal transducer and activator of transcription 5 (STAT5) in neuronal cells. Flurbiprofen reversed glucose deprivation-mediated attenuation of STAT3, but not STAT5 activation, in leptin-treated cells. Glucose deprivation increased C/EBP-homologous protein and glucose regulated protein 78 induction, indicating the activation of unfolded protein responses (UPR). Flurbiprofen did not affect the glucose deprivation-induced activation of UPR, but did attenuate the glucose deprivation-mediated induction of AMP-activated protein kinase phosphorylation. Flurbiprofen may ameliorate glucose deprivation-induced leptin resistance in neuronal cells.