Low oxygen and nutrient depletion play critical roles in tumorigenesis, but little is known about how they interact to produce tumor survival and tumor malignancy. In the present study, we investigated the mechanism underlying hypoxia-modulated apoptosis of serum-deprived HepG2 cells. Our results showed that hypoxia blocked the apoptosis, which was accompanied with decreased Bax/ Bcl-2 ratio, inhibited cytochrome c release, and reduced caspase-3 activity. More importantly, increased expressions of VEGF and its receptor-2 (KDR) under hypoxic/ serum-deprived condition suggest that VEGF may act as a survival factor in a self-promoting manner. Data were further supported by results that recombinant human VEGF (rhVEGF) suppressed the serum deprivationinduced apoptosis, and anti-VEGF neutralizing antibody block anti-apoptotic activity of hypoxia. In addition, inhibitors of receptor tyrosine kinase blocked antiapoptosis of hypoxia. Our study further showed that rhVEGF or hypoxia induced ERK phosphorylation in serum-deprived cells, and that a speci®c inhibitor of MAPK/ERK, PD98059 eliminated the anti-apoptotic activity of rhVEGF or hypoxia by increasing Bax/Bcl-2 ratio and caspase-3 activity. Our data led us to conclude that induction of ERK phosphorylation and decrease of Bax/Bcl-2 ratio by rhVEGF implies that hypoxiainduced VEGF prevents apoptosis of serum-deprived cells by activating the MAPK/ERK pathway. Taken together, we propose that hypoxia enhances survival of nutrient-depleted tumor cells by reducing susceptibility to apoptosis, which consequently leads to tumor malignancy. Oncogene (2000) 19, 4621 ± 4631.

ABSTRACT:The breast cancer resistance protein (BCRP) is a member of the ATP-binding cassette transporters. The aim of the present study was to identify genetic variants of BCRP in Koreans and to assess the functional consequences of BCRP polymorphisms. Twenty single nucleotide polymorphisms (SNP), including four nonsynonymous SNP, were identified by DNA sequencing of the BCRP gene in 92 Korean subjects. BCRP V12M, Q141K, P269S, and Q126Stop were detected at frequencies of 23, 28, 0.2, and 1.9%, respectively. These four coding variants were also screened in Chinese and Vietnamese subjects; the allelic frequencies among the three populations were compared; and predictions were made as to the potential frequency of each variant.

To develop a technique for efficient management of fertility for cucumber in greenhouse, a quick test method to quantify nitrate (NO 3 -) content in soil solution and leaf petiole juice using a simple instrument that are easy to use for farmers was investigated. N fertilizer (urea) was applied at 0, 50, 100 and 200% levels of the recommended application rate from 30 days after transplanting to harvest by soil fertigation treatments. 147±14 at 55 DAT, 67±4 ㎎ L -1 at 65 DAT, respectively. The cucumber yield at 50% N fertigation was not different from 1,697 ㎏ 10a -1 of 100% N fertigation level and even with that of the 200% N fertigation. However, there was 21% decrease in yield at 0% N fertigation.

Livestock waste compost tea is a liquid extract of compost obtained by mixing livestock compost. In this study, some chemical and microbiological characteristics of compost tea depending on the kind of raw materials used were examined, and several experiments to investigate the practical effects on Chinese cabbage cultivation were conducted. This experiment showed that livestock composts needed to be added into aerated water at the ratio between 1:100 and 1:10 (1 part compost to 10~100 parts water) to produce the high quality compost tea. Compost teas must be aerated more than 24 to 48 hours to be able to support aerobic organisms. In cultivation test with compost teas, swine manure compost teas were made by the extracting ratio of 50x, in the aerated condition for 24 hours in water and oil cake in the extracting ratio of 100x were added as supplements. Following the input of oil cake, the concentration of nitrogen and aerobic bacteria increased. Another experiment was conducted to determine the effect of different swine manure compost teas on plant growth and yield of Chinese cabbage. The fresh yield of Chinese cabbage was higher in the fertigated plots by compost tea with oil cake compared to those of N, P 2 O 5 , K 2 O fertilization plot with chemical fertilizer by soil test recommendation (Fert. NPK). The effect of compost tea on growth of Chinese cabbage was largely attributable to the increased number of microorganisms as well as nutrients.

Jungdream' is an early maturing, high-quality rice cultivar developed in 2017 by the crop breeding team at Crop Research Division, GARES, Hwaseong, Korea. 'Jungdream' was first developed in 2008 from crossing a medium-late maturity cultivar 'Chilbo' and an early maturity cultivar 'Ungwang'. The heading date of this cultivar is July 28 th in the Gyeonggido Province. Its culm length is 63 cm, and it has 19 panicles per hill and 82 spikelets per panicle. It is a medium-small grain brown rice cultivar with a 1000-grain weight of 20.6 g. Its cold tolerance is lower than that of 'Hwaseong', which is the standard cultivar in the central region, as is its degree of lodging tolerance. 'Jungdream' is resistant to rice blast and stripe virus diseases but is susceptible to bacterial leaf blight and other viral diseases and pests. The appearance of milled 'Jungdream' rice is clear, and its amylose content is 16.5%, which is lower than that of 'Hwaseong'. The palatability of cooked 'Jungdream' rice is better than that of 'Chucheong', which is the main cultivated crop in Gyeonggido. Its milling ratio is 75.0%, which is lower than that of 'Hwaseong'. The yield of milled 'Jungdream' rice was 5.42 MT/ha in the local adaptability tests during standard cultivation in four regions from 2015 to 2017. 'Jungdream' is highly adaptable to the environmental conditions in the Gyeonggido Province (Registration No. 8236).