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151.
Lee DG Jeon JH Jang MK Kim NY Lee JH Lee JH Kim SJ Kim GD Lee SH 《Biotechnology letters》2007,29(3):465-472
A metagenomic library was constructed using total genomic DNA extracted from the mud in the west coast of Korea and was used
together with a fosmid vector, pCC1FOS in order to uncover novel gene sources. One clone from approximately 30,000 recombinant
Escherichia coli clones was identified that showed proteolytic activity. The gene for the proteolytic enzyme was subcloned into pUC19 and
sequenced, and a database search for homologies revealed it to be a zinc-dependent metalloprotease. The cloned gene included
the intact coding gene for a novel metalloproteinase and its own promoter. It comprised an open reading frame of 1,080 base
pairs, which encodes a protein of 39,490 Da consisting of 359 amino acid residues. A His-Glu-X-X-His sequence, which is a
conserved sequence in the active site of zinc-dependent metalloproteases, was found in the deduced amino acid sequence of
the gene, suggesting that the enzyme is a zinc-dependent metalloprotease. The purified enzyme showed optimal activity at 50°C
for 1 h and pH 7.0. The enzyme activity was inhibited by metal-chelating reagents, such as EDTA, EGTA and 1,10-phenanthroline.
The enzyme hydrolyzed azocasein as well as fibrin. Thus, the enzyme could be useful as a therapeutic agent to treat thrombosis.
The sequence reported in this paper has been deposited in the GenBank database (Accession number: EF100137). 相似文献
152.
153.
Nam Jin Noh Yowhan Son Jin Woo Koo Kyung Won Seo Rae Hyun Kim Yoon Young Lee Kyung Seun Yoo 《Journal of Plant Biology》2010,53(1):61-69
The nitrogenase activity, root nodule biomass, and rates of nitrogen (N) fixation were measured in 25-year-old pure north-
and south-facing Robinia pseudoacacia stands in an urban forest of Seoul (Kkachisan Mountain) in central Korea. The nitrogenase activity was estimated using an
acetylene reduction (AR) assay, which showed an increasing trend during the early growing season, with sustained high rates
from June through to September with a decrease thereafter. July had the highest nitrogenase activity rate (micromoles C2H4 per gram dry nodule per hour), averaging 95.8 and 115.1 for the north- and south-facing stands, respectively. The maximum
root nodule biomass (kilograms per hectare) was 45.7 and 9.1 for the north- and south-facing stands in July, respectively.
The AR rate appeared to be strongly correlated to the soil temperature (r
2 = 0.68, P < 0.001) and soil pH (r
2 = 0.59, P < 0.001) while root nodule biomass was correlated to the soil temperature (r
2 = 0.36, P < 0.01) and water content (r
2 = 0.35, P < 0.05). The soil temperature showed clear differences between seasons, while there was a significant difference in soil pH,
organic matter, total N concentrations, and available phosphorus between the north- and south-facing stands. The N2 fixation rates during the growing season varied from 0.1 to 37.5 kg N ha−1 month−1 depending on the sampling location and time. The annual N2 fixation rate (kg N per hectare per year) was 112.3 and 23.2 for the north- and south-facing stands, respectively. The differences
in N2 fixation rate between the two stands were due mainly to the differences in total nodule biomass. 相似文献
154.
Creatine kinase is a member of the phosphagen kinase family, which catalyzes the reversible phosphoryl transfer reaction that occurs between ATP and creatine to produce ADP and phosphocreatine. Here, three structural aspects of human-brain-type-creatine-kinase (hBB-CK) were identified by X-ray crystallography: the ligand-free-form at 2.2 Å; the ADP-Mg2+, nitrate, and creatine complex (transition-state-analogue complex; TSAC); and the ADP-Mg2+-complex at 2.0 Å. The structures of ligand-bound hBB-CK revealed two different monomeric states in a single homodimer. One monomer is a closed form, either bound to TSAC or the ADP-Mg2+-complex, and the second monomer is an unliganded open form. These structural studies provide a detailed mechanism indicating that the binding of ADP-Mg2+ alone may trigger conformational changes in hBB-CK that were not observed with muscle-type-CK. 相似文献
155.
Xiao-Bin Yu Joo-Heon Nam Hyun Shik Yun Yoon-Mo Koo 《Biotechnology and Bioprocess Engineering》1998,3(1):44-47
Maximum cellulase production was sought by comparing the activities of the cellulases produced by differentTrichoderma reesei strains andAspergillus niger. Trichoderma reesei Rut-C30 showed higher cellulase activity than otherTrichoderma reesei strains andAspergillus niger that was isolated from soil. By optimizing the cultivation condition during shake flask culture, higher cellulase production
could be achieved. The FP (filter paper) activity of 3.7 U/ml and CMCase (Carboxymethylcellulase) activity of 60 U/ml were
obtained from shake flask culture. When it was grown in 2.5L fermentor, where pH and DO levels are controlled, the Enzyme
activities were 133.35 U/ml (CMCase) and 11.67 U./ml (FP), respectively. Ammonium sulfate precipitation method was used to
recover enzymes from fermentation broth. The dried cellulase powder showed 3074.9 U/g of CMCase activity and 166.7 U/g of
FP activity with 83.5% CMCase recovery. 相似文献
156.
157.
Ji Eun Kim Eun Jeong Kim Won Jong Rhee Tai Hyun Park 《Biotechnology and Bioprocess Engineering》2005,10(4):353-356
The effect of silkworm hemolymph on the expression of recombinant protein inEscherichia coli was investigated. The addition of silkworm hemolymph to the culture medium increased the production of recombinant β-galactosidase
inE. coli. The production was dependent on the concentration of the added silkworm hemolymph, which increased 2-, 5-, and 8-fold in
media supplemented with 1,3, and 5% silkworm hemolymph, respectively. To identify the effective component, the silkworm hemolymph
was fractionated by gel filtration column chromatography. A fraction, with a molecular weight of about 30 K was identified
as the effective component. 相似文献
158.
YR Kim JS Kim YH Min DH Yoon HJ Shin YC Mun Y Park YR Do SH Jeong JS Park SY Oh S Lee EK Park JS Jang WS Lee HW Lee H Eom JS Ahn J Jeong SK Baek SJ Kim WS Kim C Suh 《Journal of hematology & oncology》2012,5(1):49
ABSTRACT: BACKGROUND: The objective of this study was to identify prognostic factors for survival in patients with primary diffuse large B-cell lymphoma (DLBCL) of the adrenal gland. METHODS: Thirty one patients diagnosed with primary adrenal DLBCL from 14 Korean institutions and treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) were analyzed. RESULTS: Complete remission (CR) and overall response rate after R-CHOP chemotherapy were 54.8% and 87.0%. The 2-year estimates of overall survival (OS) and progression-free survival (PFS) were 68.3% and 51.1%. In patients achieving CR, significant prolongations of OS (P = 0.029) and PFS (P = 0.005) were observed. Ann Arbor stage had no influence on OS. There was no significant difference in OS between patients with unilateral involvement of adrenal gland and those with bilateral involvement. When staging was modified to include bilateral adrenal involvement as one extranodal site, early stage (I or II) significantly correlated with longer OS (P = 0.021) and PFS (P <0.001). CONCLUSIONS: Contrary to prior reports, our data suggests that outcomes of primary adrenal DLBCL are encouraging using a regimen of R-CHOP, and that achieving CR after R-CHOP is predictive of survival. Likewise, our modified staging system may have prognostic value. 相似文献
159.
160.
Kim SY Kang JJ Lee HH Kang JJ Kim B Kim CG Park TK Kang H 《Biochemical and biophysical research communications》2011,415(2):224-228
The patients suffering from acidosis usually sign psychological deficits. The cerebral dysfunction is reportedly caused by an acid-induced functional impairment of GABAergic neurons; however, the role of pyramidal neurons in this process remains unclear. By using electrophysiological method and changing extracellular pH, we investigated the influence of acidic environment on pyramidal neurons in the cortical slices, such as their ability of firing spikes and response to synaptic inputs. A low pH of artificial cerebral spinal fluid elevates the responses of pyramidal neurons to excitatory synaptic inputs and their ability of encoding digital spikes, as well as reduces the signal transmission at GABAergic synapses. The elevated ability of neuronal spiking is associated with the decreases of refractory periods and threshold potentials. Therefore, acidosis deteriorates brain functions through making the activities between cortical pyramidal neurons and GABAergic neurons imbalanced toward the overexcitation of neural networks, a process similar to neural excitotoxicity. 相似文献