Free oligosaccharides (FOSs) in the cytosol of eukaryotic cells are mainly generated during endoplasmic reticulum (ER)-associated degradation (ERAD) of misfolded glycoproteins. We analyzed FOS of the nematode Caenorhabditis elegans to elucidate its detailed degradation pathway. The major FOSs were high mannose-type ones bearing 3-9 Man residues. About 94% of the total FOSs had one GlcNAc at their reducing end (FOS-GN1), and the remaining 6% had two GlcNAc (FOS-GN2). A cytosolic endo-␤-N-acetylglucosaminidase mutant (tm1208) accumulated FOS-GN2, indicating involvement of the enzyme in conversion of FOS-GN2 into FOS-GN1. The most abundant FOS in the wild type was Man 5 GlcNAc 1 , the M5A isomer (Man␣1-3(Man␣1-6)Man␣1-6(Man␣1-3)Man␤1-4GlcNAc), which is different from the corresponding M5B (Man␣1-2Man␣1-2Man␣1-3(Man␣1-6)Man␤1-4GlcNAc) in mammals. Analyses of FOS in worms treated with Golgi ␣-mannosidase I inhibitors revealed decreases in Man 5 GlcNAc 1 and increases in Man 7 GlcNAc 1 . These results suggested that Golgi ␣-mannosidase I-like enzyme is involved in the production of Man 5-6 -GlcNAc 1 , which is unlike in mammals, in which cytosolic ␣-mannosidase is involved. Thus, we assumed that major FOSs in C. elegans were generated through Golgi trafficking. Analysis of FOSs from a Golgi ␣-mannosidase II mutant (tm1078) supported this idea, because GlcNAc 1 Man 5 GlcNAc 1 , which is formed by the Golgi-resident GlcNAc-transferase I, was found as a FOS in the mutant. We concluded that significant amounts of misfolded glycoproteins in C. elegans are trafficked to the Golgi and are directly or indirectly retro-translocated into the cytosol to be degraded.It is known that N-linked oligosaccharides play important roles in the quality control of glycoproteins. An oligosaccharide composed of 14 sugars (Glc 3 Man 9 GlcNAc 2 ) is transferred en bloc from a dolichol-linked donor to the Asn residue of nascent polypeptide chains by oligosaccharyltransferase (OST), 2 and the oligosaccharides serve as tags indicating the folding state of glycoproteins in the endoplasmic reticulum (ER). Then, properly folded and assembled glycoproteins are transported to their destinations such as the extracellular space, plasma membrane, or inner compartments via the Golgi apparatus, with some accompanying modifications on the oligosaccharides.The presence of free oligosaccharides (FOSs) has been reported in the cytosol of several types of animal cells (1-6). These FOSs were thought to be generated from the ER by the following pathways. First, ER-associated degradation (ERAD) of glycoproteins is involved in generation of FOS. Misfolded or unassembled glycoproteins are recognized by ER degradationenhancing ␣-mannosidase-like protein (EDEM), retro-translocated into the cytosol through the Sec61 translocon (7) or the Hrd1 complex (8), and subjected to ubiquitin-proteasome degradation. The N-glycans on the misfolded glycoproteins are released by peptide:N-glycanase (PNGase) in the cytosol before the degradation by the proteasome (9, 10). Second, FOS...

Skeletal muscle is an important organ for controlling the development of type 2 diabetes. We discovered Panax notoginseng roots as a candidate to improve hyperglycemia through in vitro muscle cells screening test. Saponins are considered as the active ingredients of ginseng. However, in the body, saponins are converted to dammarane-type triterpenes, which may account for the anti-hyperglycemic activity. We developed a method for producing a dammarane-type triterpene extract (DTE) from Panax notoginseng roots and investigated the extract's potential anti-hyperglycemic activity. We found that DTE had stronger suppressive activity on blood glucose levels than the saponin extract (SE) did in KK-A mice. Additionally, DTE improved oral glucose tolerance, insulin sensitivity, glucose uptake, and Akt phosphorylation in skeletal muscle. These results suggest that DTE is a promising agent for controlling hyperglycemia by enhancing glucose uptake in skeletal muscle.

Plastoquinone-9 (PQ-9)-depleted PSI1 reaction center core complex, consisting of CP47/Dl/D2/Cytb-559/I, was isolated from spinach PSI1 particles. PQ-9, lipids and several proteins were extracted from the original PSI1 particles and separated by several steps of chromatography to be reconstituted into the isolated complex. PQ-9 reconstituted in the complex with the help of thylakoid lipids (digalactosyldiglyceride) did not function as QA by itself. However, PQ-9 simultaneously reconstituted with L protein and the thylakoid lipids successfully functioned as QA in the complex. Other proteins of PSI1 origin, such as CP43, H, K, nuclear encoded 4.1 and 5.0 kDa proteins, are unable to restore the QA activity in the complex.

A B S T R A C T Surface crack growth of silicone nitride ceramic bearings under rolling contact fatigue has been investigated from the viewpoints of contact stresses (ring crack model) and fluid pressure (wedge effect model). The mechanisms of these two models have been investigated independently; however, it was impossible to separate the effects of contact stresses and fluid pressure on surface crack growth. In this paper the effects of contact stresses (ring crack model) on surface crack growth are investigated. In the ring crack model the crack growth is caused by contact stresses around the circumference of the contact circle. The growth of surface cracks located inside and outside the contact track was observed in order to obtain data from which we could reexamine the ring crack model. The outside cracks under rolling contact fatigue were propagated by contact stresses alone and also the inside cracks grew as slowly as the outside cracks. We concluded that the cracks are propagated by the single effect of contact stresses. Preliminary observations of surface crack growth showed that the cracks were unaffected by wear and residual stresses. III = normalized stress intensity factors in mode I, mode II and mode III K I 1 , K II 1 and K III 1 = stress intensity factors caused by tensile stress on unit area when calculating stress intensity factors K I 2 , K II 2 and K III 2 = stress intensity factors caused by shear stress (τ xy ) on unit area when calculating stress intensity factors K I 3 , K II 3 and K III 3 = stress intensity factors caused by shear stress (τ yz ) on unit area when calculating stress intensity factors K Ic = fracture toughness K * II = normalized stress intensity factor range in mode II K * III = normalized stress intensity factor range in mode III O = centre of contact circle O = centre of initial crack O = position of O in Y axis R a = surface roughness Correspondence: K. Kida.