The npgA1 mutation causes defects in the outer layer of the cell wall resulting in a colorless colony. In this study, a temperature-sensitive suppressor of npgA1 named snpA was isolated by UV mutagenesis. The suppressing mutant showed pleiotropic phenotypes in cellular structure and developmental processes when incubated at a temperature of 37 degrees C or above. At 37 degrees C, multiple germ tubes emerged from germinating conidia. Moreover, at 42 degrees C conidia germination was delayed more than 12h and hyphal growth was strongly inhibited. The suppressor allele, snpA6, is recessive and maps to the linkage group III. A gene complementing the mutation was identified employing the chromosome III-specific cosmid library. Sequencing analysis revealed that the snpA gene encodes the eukaryotic polypeptide release factor, eRF1. The snpA6 allele contains a G-A mutation resulting in SnpA(E117K), which may allow read-through of the nonsense mutation in the npgA1 allele in a similar manner to the yeast omni-potent suppressor SUP45 and SUP35.

Gangliosides are a family of sialic acid-containing glycosphingolipids that are abundant in neurons and have a variety of functions in developing and mature tissues. We examined the expression of ganglioside GT1b in the embryonic preimplantation stage after freezing and thawing processes to determine the regulatory roles of ganglioside GT1b in early embryonic development. ICR mouse embryos at the two-cell stage obtained by flushing the oviducts were frozen by two cryopreservation procedures, slow freezing using a programmable freezer or vitrification by direct plunging into liquid nitrogen. Slow freezing was conducted with equilibration in 1.5 M 1,2-propanediol or 5% equilibration glycerol. Vitrification was applied with a 10-15 min equilibration in 7.5% ethylene glycol (EG), 7.5% dimethylsulfoxide (DMSO), and 30 sec in a solution of 15% EG, 15% DMSO and 0.5 M sucrose. Immediately after thawing, the survival rate of the embryos was assessed by their morphology and ability to develop to blastocysts in culture. The survival rate of vitrified and thawed embryos (92%) was significantly higher than that of slow frozen and thawed embryos (76%) (P<0.05). A tendency of higher blastocyst rate was found in the vitrified and thawed embryos compared to that of the slow frozen and thawed embryos. Confocal immunofluorescence staining confirmed that surviving embryos expressed ganglioside GT1b, with the strongest expression at the compacted eight-cell or later stage embryos. Ganglioside GT1b was not observed in the TUNEL-positive, apoptotic embryos, suggesting that cryopreservation had induced DNA breaks in them. These results suggest that ganglioside GT1b may play an important role in embryo survival or development.

Context: Nardostachys chinensis Batalin (Valerianaceae) has been used in Korean traditional medicine to elicit stomachic and sedative effects. However, the anti-leukemic activities of N. chinensis have not been well examined. Objective: To investigate the effect of N. chinensis on differentiation and proliferation in the human promyelocytic leukemic HL-60 cells. Materials and methods:The dried roots and stems of N. chiensis are extracted using hot water and then freeze-dried. The yield of extract was 12.82% (w/w). The HL-60 cells were treated with 25-200 lg/ml of N. chinensis for 72 h or 100 lg/ml of N. chinensis for 24-72 h. Results: Nardostachys chinensis significantly inhibited cell viability dose dependently with an IC 50 of 100 lg/ml in HL-60 cells. Nardostachys chinensis induced differentiation of the cells as measured by reduction activity of NBT and expression of CD11b but not of CD14 as analyzed by flow cytometry, which indicates a differentiation toward the granulocytic lineage. Nardostachys chinensis also induced growth inhibition through G 0 /G 1 phase arrest in the cell cycle of HL-60 cells. Among the G 0 /G 1 phase in the cell cycle-related protein, the expression of cyclindependent kinase (CDK) inhibitor p27Kip1 was increased in N. chinensis-treated HL-60 cells, whereas the expression levels of CDK2, CDK4, CDK6, cyclin D1, cyclin D3, cyclin E, and cyclin A were decreased. Interestingly, N. chinensis markedly enhanced the binding of p27Kip1 with CDK2 and CDK6. Discussion and conclusion: This study demonstrated that N. chinensis is capable of inducing cellular differentiation and growth inhibition through p27Kip1 protein-related G 0 /G 1 phase arrest in HL-60 cells.

Abstract. The underground parts of Nardostachys chinensis (N. chinensis), which belongs the genus Valerianaceae, have been used as sedative and analgesic agents in traditional Korean medicine for centuries. The mitogen-activated protein kinases (MAPKs) are serine/threonine kinases involved in the regulation of various cellular responses, such as cell proliferation, differentiation and apoptosis. Protein kinase C (PKC) plays a key role in the regulation of proliferation and differentiation. In this study, we investigated the signaling pathways involved in the differentiation of the HL-60 human leukemic cells induced by N. chinensis extract. Treatment with N. chinensis extract resulted in the activation of the extracellular signal-regulated kinase (ERK) pathway and induced the differentiation of HL-60 cells into granulocytes. The activation of p38 MAPK was also observed 24 h after treatment; however, the activation of c-Jun N-terminal kinase (JNK) was unaffected. Treatment with an inhibitor of ERK (PD98059) blocked the nitrotetrazolium blue chloride (NBT) reducing activity and CD11b expression in the N. chinensis-treated HL-60 cells, whereas treatment with an inhibitor of p38 MAPK (SB203580) had no significant effect on NBT reducing activity and CD11b expression. In addition, N. chinensis extract increased PKC activity and the protein levels of PKCα, PKCβI and PKCβII isoforms, without a significant change in the protein levels of the PKCγ isoform. PKC inhibitors (GF 109203X, chelerythrine and H-7) inhibited the differentiation of HL-60 cells into granulocytes, as well as ERK activation in the N. chinensis-treated HL-60 cells. These results indicate that the PKC and ERK signaling pathways may be involved in the induction, by N. chinensis extract, of the differentiation of HL-60 cells into granulocytes.