The gene encoding a 40-kDa protein, previously studied as a substrate and inhibitor of the yeast cyclin-dependent protein kinase, Cdc28, has been cloned. The DNA sequence reveals that p40 is a highly charged protein of 32,187 Da with no significant homology to other proteins. Overexpression of the gene encoding p40, SIC], produces cells with an elongated bud morphology similar to that of cells with depleted levels of the CLB gene products, suggesting that p40 acts as an inhibitor of Cdc28-Clb complexes in vivo. A SIC] deletion is viable and has highly increased frequencies of broken and lost chromosomes. The deletion strain segregates out many dead cells that are primarily arrested at the G2 checkpoint in an asymmetric fashion. Only daughters and young mothers display the lethal defect, while experienced mothers appear to grow normally. These results suggest that negative regulation of Cdc28 protein kinase activity by p40 is important for faithful segregation of chromosomes to daughter cells.

No abstract

The gene encoding a 40-kDa protein, previously studied as a substrate and inhibitor of the yeast cyclin-dependent protein kinase, Cdc28, has been cloned. The DNA sequence reveals that p40 is a highly charged protein of 32,187 Da with no significant homology to other proteins. Overexpression of the gene encoding p40, SIC1, produces cells with an elongated but morphology similar to that of cells with depleted levels of the CLB gene products, suggesting that p40 acts as an inhibitor of Cdc28-Clb complexes in vivo. A SIC1 deletion is viable and has highly increased frequencies of broken and lost chromosomes. The deletion strain segregates out many dead cells that are primarily arrested at the G2 checkpoint in an asymmetric fashion. Only daughters and young mothers display the lethal defect, while experienced mothers appear to grow normally. These results suggest that negative regulation of Cdc28 protein kinase activity by p40 is important for faithful segregation of chromosomes to daughter cells.

Background: Lithocarpus bancanus or commonly called as mempening in Talang Mamak Tribe, Indonesia is a plant that is used as a traditional medicine. Objective: This study aim to evaluated antioxidant and antidiabetic activities of L. bancanus leaves extract. Material and Methods: The methanol extract was obtained by maceration of the leaves. The n-hexane, dichloromethane and ethyl acetate fractions were prepared by successive partition process of the methanol extract. Antioxidant activities were evaluated by various antioxidant assays, including DPPH (1,1-diphenyl-2-picrylhydrazyl), FRAP (ferric reducing antioxidant power), CUPRAC (cupric reducing antioxidant capacity), and ABTS (2,2'-azonobis 3-ethylbenzothiazoline-6-sulfonic acid) method. Total phenolics were estimated based on the Folin-Ciocalteu method, while, aluminum chloride methods were employed to estimate total flavonoids. Antidiabetic activies was determined by inhibiting the activity of α-glucosidase method. Results: antioxidant activity assay against DPPH radical as well as the total phenolic and flavonoid content of L. bancanus leaves showed that the methanol extract possessed IC 50 value of 39.469 ± 0.273 μg/mL with total phenol and flavonoid were 11.426 ± 0.432 mg GAE/g dry weight sample and 15.423 ± 0.213 mg QE/g respectively. The FRAP, CUPRAC and ABTS values of methanol extract were 3494.302 ±0.456 , 26665.501 ± 5.940 and 2857.977 ± 0.715 μM TE/g dry weight sample respectively. Antidiabetic activity of methanol extract with IC 50 value of 30.565 ± 0.331 µg/mL. Conclusion: It could be concluded that leaves of L. bancanus have antioxidant and antidiabetic properties.

Laccase is an important industrial enzyme used in the paper, food and textile industry. It is produced by many different organisms, including filamentous fungi. Trichoderma asperellum LBKURCC1 is a strain isolated from Riau soil, which can produce laccase by solid state fermentation (SSF) of rice husk and rice straw. The aim of this work was to optimize SSF production of laccase from rice straw, through optimizing Nitrogen, Carbon and surfactant supplements to the fermentation media. Effect of surfactant, nitrogen supplement, and carbon supplement were evaluated by using a Central Composite Design (CCD) and surface response analysis. The concentration of the surfactant, Tween-20, at all concentration levels tested had no significant effect to the model. In contrast, the nitrogen and carbon supplement concentrations were significant factors (P-Value<0.05) enhancing laccase production. Optimum conditions for laccase production were 23 g/L nitrogen and 1% carbon supplement, giving a maximum laccase activity of 56.8 U/L enzyme extracted, equivalent to 0.7 U per g rice straw fermented. Optimizing the nitrogen and carbon supplement increased yields up to 3 times the level obtained in a non-optimized media.