Enhanced CO2 fixation and lipid production of Chlorella vulgaris through the carbonic anhydrase complex.

Photosynthesis of C. vulgaris shows slow growth and low lipid production due to the low solubility of CO2, and it is thus necessary to increase the dissolved inorganic carbon source to solve this problem. In this study, carbonic anhydrase (CA) was fused with dockerin to form a CA complex by cohesion-dockerin interaction. The CA complex was displayed on the surface of C. vulgaris by a cellulose binding module. The CA complex increased activity and stability compared to those of a single enzyme. Additionally, C. vulgaris showed an average of 1.6-fold rapid growth during log phase through the influence of the CA complex. The bicarbonate produced by the CA complex increased the lipid production about 1.7-fold (23.3%), compared to 13.6% for the control group. The present results suggest that the CA complex successfully enhances the CO2 fixation, which should be an essential study for 4th generation biofuels.

Synergistic effect of the enzyme complexes comprising agarase, carrageenase and neoagarobiose hydrolase on degradation of the red algae.

In the practice of converting red algae biomass into biofuel or valuable biomaterials, the critical step is the decomposition process of the agarose to give fermentable monomeric sugars. In this study, we selected three enzymes such as agarase, carrageenase and neoagarobiose hydrolase to inducible the simultaneous hydrolysis of the major substrates such as agar and carrageenan constituting the pretreated red algae, and expressed the chimeric enzymes and formed a complexes through optimization of addition ratio. As a result, hydrolysis by enzyme complexes showed a maximum sugar release of 679 mg L-1 with 67.9% saccharification yield from G. verrucosa natural substrate. The difference in the reducing sugar by the enzyme complexes was 3.6-fold higher than that of the monomer enzyme (cAgaB yield 188.6 mg L-1). The synergistic effect of producing sugars from red algae biomass through these enzyme complexes can be a very important biological tools aimed at bioenergy production.

Enhancing Fatty Acid Production of Saccharomyces cerevisiae as an Animal Feed Supplement.

Saccharomyces cerevisiae is used for edible purposes, such as human food or as an animal feed supplement. Fatty acids are also beneficial as feed supplements, but S. cerevisiae produces small amounts of fatty acids. In this study, we enhanced fatty acid production of S. cerevisiae by overexpressing acetyl-CoA carboxylase, thioesterase, and malic enzyme associated with fatty acid metabolism. The enhanced strain pAMT showed 2.4-fold higher fatty acids than the wild-type strain. To further increase the fatty acids, various nitrogen sources were analyzed and calcium nitrate was selected as an optimal nitrogen source for fatty acid production. By concentration optimization, 672 mg/L of fatty acids was produced, which was 4.7-fold higher than wild-type strain. These results complement the low level fatty acid production and make it possible to obtain the benefits of fatty acids as an animal feed supplement while, simultaneously, maintaining the advantages of S. cerevisiae.

Meta-analysis of genome-wide association studies of adult height in East Asians identifies 17 novel loci.

Human height is associated with risk of multiple diseases and is profoundly determined by an individual's genetic makeup and shows a high degree of ethnic heterogeneity. Large-scale genome-wide association (GWA) analyses of adult height in Europeans have identified nearly 180 genetic loci. A recent study showed high replicability of results from Europeans-based GWA studies in Asians; however, population-specific loci may exist due to distinct linkage disequilibrium patterns. We carried out a GWA meta-analysis in 93 926 individuals from East Asia. We identified 98 loci, including 17 novel and 81 previously reported loci, associated with height at P < 5 × 10(-8), together explaining 8.89% of phenotypic variance. Among the newly identified variants, 10 are commonly distributed (minor allele frequency, MAF > 5%) in Europeans, with comparable frequencies with in Asians, and 7 single-nucleotide polymorphisms are with low frequency (MAF < 5%) in Europeans. In addition, our data suggest that novel biological pathway such as the protein tyrosine phosphatase family is involved in regulation of height. The findings from this study considerably expand our knowledge of the genetic architecture of human height in Asians.

Efficient enzymatic degradation process for hydrolysis activity of the Carrageenan from red algae in marine biomass.

Carrageenan is a generic name for a family of polysaccharides obtained from certain species of red algae. New methods to produce useful cost-efficiently materials from red algae are needed to convert enzymatic processes into fermentable sugars. In this study, we constructed chimeric genes cCgkA and cCglA containing the catalytic domain of κ-carrageenase CgkA and λ-carrageenase CglA from Pseudoalteromonas carrageenovora fused with a dockerin domain. Recombinant strains expressing the chimeric carrageenase resulted in a halo formation on the carrageenan plate by alcian blue staining. The recombinant cCgkA and cCglA were assembled with scaffoldin miniCbpA via cohesin and dockerin interaction. Carbohydrate binding module (CBM) in scaffoldin was used as a tag for cellulose affinity purification using cellulose as a support. The hydrolysis process was monitored by the amount of reducing sugar released from carrageenan. Interestingly, these results indicated that miniCbpA, cCgkA and cCglA assembled into a complex and that the dockerin-fused enzymes on the scaffoldin had synergistic activity in the degradation of carrageenan. The observed enhancement of activity by carrageenolytic complex was 3.1-fold-higher compared with the corresponding enzymes alone. Thus, the assemblies of advancement of active enzyme complexes will facilitate the commercial production of useful products from red algae biomass which represents inexpensive and sustainable feed-stocks.

Signal amplification by a self-assembled biosensor system designed on the principle of dockerin-cohesin interactions in a cellulosome complex.

To construct a self-assembled biosensor with signal amplification, a cellulosome system, comprising type I and type II dockerin-cohesin interactions with different specificities, from the anaerobic Clostridia bacterium was applied. The self-assembled biosensor was highly sensitive and achieved 128.1-fold increase in detection levels compared to the control.

GntR-type transcriptional regulator PckR negatively regulates the expression of phosphoenolpyruvate carboxykinase in Corynebacterium glutamicum.

The pck (cg3169) gene of Corynebacterium glutamicum encodes a phosphoenolpyruvate carboxykinase (PEPCK). Here, a candidate transcriptional regulator that binds to the promoter region of pck was detected using a DNA affinity purification approach. An isolated protein was identified to be PckR (Cg0196), a GntR family transcriptional regulator which consists of 253 amino acids with a mass of 27 kDa as measured by peptide mass fingerprinting. The results of electrophoretic mobility shift assays verified that PckR specifically binds to the pck promoter. The putative regulator binding region extended from position -44 to -27 (an 18-bp sequence) relative to the transcriptional start point of the pck gene. We measured the expression of pck in a pckR deletion mutant by using quantitative real-time reverse transcription-PCR. The expression level of pck in the pckR mutant was 7.6 times higher than that in wild-type cells grown in glucose. Comparative DNA microarray hybridizations and bioinformatic searches revealed the gene composition of the transcriptional regulon of C. glutamicum. Based on these results, PckR seemed to play an important role in the regulation of PEPCK in C. glutamicum grown in glucose. In particular, these assays revealed that PckR acts as a repressor of pck expression during glucose metabolism.

Protective role of CYP1A1*2A in the development of multiple myeloma.

We had previously reported the association of the NQO1*2/*2 polymorphism with a decreased risk for multiple myeloma (MM) in Koreans (odds ratio, OR, 0.24; 95% confidence interval, CI, 0.01-0.68). The associations of polymorphisms of other metabolizing enzymes (CYP1A1, GSTM1 and GSTT1) with the MM risk were investigated in 116 Korean MM patients and 176 Korean controls using TaqMan allelic discrimination and multiplex polymerase chain reaction. The ORs for CYP1A1*1/*2A and CYP1A1*1/*2B genotypes were 0.43 (95% CI, 0.19-0.98) and 0.51 (95% CI, 0.26-0.98), respectively, which was significantly associated with a decreased MM risk. With regard to CYP1A1 alleles, the OR for the CYP1A1*2A allele was 0.57 (95% CI, 0.326-0.995), which was also significantly associated with a decreased MM risk. However, null types of GSTM1 and GSTT1 polymorphisms were not associated with the MM risk. These results were different from those of a previous report on Caucasians which suggested the association of the GSTT1 polymorphism with an increased MM risk and no association of CYP1A1 with the MM risk. The associations of polymorphisms of metabolizing enzymes with the risk for MM differed between Koreans and Caucasians, suggesting an ethnic variation in the susceptibility to MM.

Association of estrogen receptor alpha gene microsatellite polymorphism with annual changes in bone mineral density in Korean women with hormone replacement therapy.

Variation in drug response to hormone replacement therapy (HRT) may reflect genetic heterogeneity in the estrogen-related genes, possibly including estrogen receptor alpha (ERalpha) gene. However, only a few association studies of the drug response to HRT have been reported, focusing mainly on the intronic polymorphisms of the ERalpha gene. We therefore examined 284 postmenopausal women (mean age, 52.2 +/- 5.0 years) for the microsatellite thymine-adenine (TA) repeat polymorphism in the promoter of the ERalpha gene and its relationship to drug response by measuring changes in bone mineral density (BMD) after 1 year of HRT. In our study population, the most common number of TA repeats was 14, with a range of values between 11 and 27. At baseline, the number of TA repeats was neither associated with measured lumbar spine or femoral neck BMD nor with bone markers. When we categorized the subjects by the TA repeat numbers into an L group (n = 142), with a low mean number of repeats (TA < 16), and an H group (n = 142), with a high mean number of repeats (TA > or = 16), no significant genotypic differences were noted in spinal or femoral neck BMD or in bone markers. However, the drug response on lumbar spine BMD after 1 year of HRT correlated with the mean number of TA repeats (r = -0.131, P = 0.035) after adjustment for confounding factors such as body mass index and years since menopause. This correlation was also seen with the number of TA repeats on the shorter allele (r = -0.159, P = 0.012), which was defined as the allele with the lower number of TA repeats. However, this genotypic association was not found in the femoral neck BMD (r = 0.053, P = 0.396). When we defined the nonresponder group as women who had lost BMD even with HRT, 15.9% of the subjects were included, and this group was significantly younger and had higher initial BMD than the responder group. After further adjustment for age and initial BMD, the number of TA repeats on the shorter allele remained significantly associated with drug responsiveness (P = 0.005). These data indicate significant effects of the ERalpha TA repeat polymorphism on the estrogen responsiveness of lumbar spine BMD after 1 year of HRT in Korean women.

Cyclooxygenase-2 and p53 expressions in endometrial cancer.

Cyclooxygenase-2 (COX-2) has been known to be related with various types of carcinoma, but we have insufficient knowledge about the association between COX-2 and endometrial cancer. Many have reported a close relationship between p53 expression and a poor prognosis in endometrial cancer, but it is unclear whether p53 is an independent prognostic factor. To clarify these uncertainties, we examined the expressions of COX-2 and p53 in endometrial cancer tissues. The study was carried on 152 endometrial cancer patients who had operation at Seoul National University Hospital. Paraffin-embedded tissue blocks were sectioned and immunostained using monoclonal anti-COX-2 and anti-p53 antibodies. Twenty-seven (17.8%) specimens stained as COX-2 positive. COX-2 positivity was more frequently observed in postmenopausal patients than in premenopausal patients (8.8% versus 25.0%; P = 0.009). However, COX-2 positivity did not show a statistically significant association with any other clinicopathologic characteristic (parity, body mass index, histotype, International Federation of Gynecology and Obstetrics stage, grade, lymph node metastasis, deep myometrial invasion, or p53 overexpression). Thirty-one (20.4%) specimens showed p53 overexpression and this was significantly correlated with an advanced stage (P = 0.001), poor differentiation (P < 0.001), lymph node metastasis (P = 0.012), and deep myometrial invasion (P < 0.001). Multivariate Cox regression analysis showed that advanced stage was an independent prognostic factor of survival, but p53 overexpression was not. COX-2 may be associated with endometrial cancer carcinogenesis during the postmenopausal period but not with tumor aggressiveness and p53 overexpression. The p53 overexpression was found to be strongly associated with endometrial cancer aggressiveness.

Expression of cyclooxygenase-2 in association with clinicopathological prognostic factors and molecular markers in epithelial ovarian cancer.

OBJECTIVES: This study examines whether expression of COX-2 is associated with clinicopathological features and other molecular markers of ovarian cancer. METHODS: Sixty-four paraffin-embedded tissue specimens were obtained from patients with ovarian cancer who received cytoreductive surgery and combination chemotherapy. Tissue specimens were subjected to immunohistochemical analysis using antibodies to COX-2, p53, and VEGF. RESULTS: Increased COX-2 expression significantly correlated with histologic type (mucinous 5.6% vs. non-mucinous 65.2%, P<0.001). COX-2 expression was also significantly associated with stage, tumor grade, residual disease status, and presence of ascites. COX-2 expression correlated positively with expression of p53 (P=0.006) and VEGF (P=0.025). Although survival was lower in patients with high COX-2 expression than in those without high COX-2 expression (P<0.001), only tumor grade and stage were independent prognostic indicators. In patients with non-mucinous cancer, COX-2 expression correlated with stage (P<0.001) and presence of ascites (P=0.033). CONCLUSIONS: Our results suggest that expression of COX-2 in ovarian cancers is specific to histologic type of tumor and is associated with poor clinicopathologic prognostic factors. Expression of COX-2 also correlates well with expression of p53 and VEGF.

Influence of smoking on blood cadmium concentration in university students.

OBJECTIVES: This study was performed to examine the influence of smoking on the blood cadmium concentration in university students. METHODS: The study included 300 university students. A questionnaire interview was used to collect data. The urine cotinine and blood cadmium levels were measured as biological exposure indices. The data were analyzed using t-tests ANOVA and ANCOVA. RESULTS: The median value of blood cadmium concentration was equal in both males and females (0.8microgram/liter). This level was relatively low in comparison with the reference value suggested by WHO (2001). ANCOVA showed that smoking related variables, urine cotinine and smoking amount, were significantly associated with the blood cadmium level (P=0.004, 0.015). However, the values with regard to traffic related air pollution were not significantly associated with the blood cadmium level. CONCLUSIONS: Smoking is an important source of nonoccupational cadmium exposure in young people. The Blood cadmium level is at least 10% higher in active smokers than in passive or nonsmokers. The level of urine cotinine can be used as an indicator of non-occupational exposure of respirable cadmium due to smoking, as there is a good correlation bestween smoking amount and the urine cotinine level.

Expression of cyclooxygenase-1 and -2 associated with expression of VEGF in primary cervical cancer and at metastatic lymph nodes.

OBJECTIVES: This study examines the relationship between expression of COX-1, COX-2, and vascular endothelial growth factor (VEGF), and their association with clinicopathological features in primary tumor and metastatic lymph node specimens from cervical cancer patients. The relationship between COX-2 expression and human papillomavirus (HPV) positivity was also examined. METHODS: The following samples were analyzed: 97 paraffin-embedded specimens from patients with cervical cancer (Ib-IIb), including 49 primary cervical cancer specimens without lymph node metastasis and 24 primary specimens with lymph node metastasis and their metastatic lymph nodes. Immunohistochemical analysis was performed with antibodies to COX-1, COX-2, and VEGF. HPV viratype was identified by PCR and HPVDNAChip. RESULTS: VEGF expression was strongly correlated with expression of COX-1 (P = 0.03) and not COX-2 (P = 0.12) in primary tumor and metastatic lymph nodes. COX-2 expression correlated with lymph node metastasis (P = 0.001), but not with any other clinicopathological features. The parametrial invasion showed borderline significance with COX-2 expression (P = 0.058). COX-1 or VEGF expression did not correlate with any clinicopathological features. In addition, COX-2 expression was not associated with HPV positivity.COX-1 expression is associated with VEGF expression in primary tumor tissue and at sites of metastasis to lymph nodes. CONCLUSION: COX-2 expression is associated with lymph node metastasis and possibly parametrial invasion, but expression of COX-1 and VEGF is not associated with clinicopathological features. COX-2 expression is not associated with HPV positivity.

The Estimation of Breast Cancer Disease-Probability by Difference of Individual Susceptibility.

PURPOSE: The aims were to evaluate the main risk factors (RFs) of breast cancer and to estimate the individual disease-probability from combinations of RFs in Korean female. MATERIALS AND METHODS: We conducted case-control study of 1, 687 incident cases of invasive carcinoma and 1, 238 controls during 1996~2000. A breast cancer disease-probability model was established by a general modeling process using a multivariate logistic regression model, which included the main Korean RFs and synergistic interaction-terms. RESULTS: The main Korean RFs selected were age, family history of second relatives, BMI, age at first full term pregnancy, breast-feeding, and a special test on the breasts. Two synergisms were observed between age and breast-feeding, and between special test and age at first fullterm pregnancy. The disease-probability and model are shown in Table 4, and Appendix 1. CONCLUSION: The availability of previous Western models was limited for Korean female due to the differences inhazard-rates and the characteristics of breast cancer between Asian and Western females. Due to limited basic data, i.e. incidence, hazard-rate and cancer-cohorts, the developing-probability of breast cancer for Korean females was not calculated. Therefore, the disease-probability was calculated instead. This approach might be more beneficial for Koreans, and help in the decision- making for regular screening or hospital visit-interval, counseling in breast-cancer clinics, prescribing high-risk population, and in educating for primary prevention, although it over-estimates the relative probability compared to the developing-probability and the 65% predictive validity.