• Journal of Microbiology and Biotechnology
• /
• v.8 no.6
• /
• pp.676-684
• /
• 1998

Baculovirus transfer and expression vectors with Hyphantria cunea nuclear polyhedrosis virus (HcNPV) were constructed. An initial transfer vector, pHcEV, constructed using HcNPV was previously reported (Park et al. 1993. J. Kor. Soc. Viral. 23: 141-151). Herein, the size of the vector was properly reduced, and a functionally perfect vector was constructed and named pHcEV-IV (6.7 kb). The vector has a 2.2-kb HcNPV DNA sequence in the 5'-flanking region of the vector's polyhedrin gene promoter. The 1.8-kb HcNPV DNA sequence, poly A signal sequence, T3 primer sequence, and 13 multicloning site sequences, in order, were ligated in front of the translation start codon of the polyhedrin gene. The cloning indicating marker lacZ gene was inserted into the pHcEV-IV, named pHcEV-IV-lacZ, and transferred into the wild-type virus. Recombinant expression virus, lacZ-HcNPV, was constructed by replacing the lacZ gene in the pHcEV-IV-lacZ with the polyhedrin gene of the wild-type virus. The recombinant virus was isolated from blue plaques that produce $\beta$-galactosidase without polyhedra. The lacZ gene insertion was confirmed by Southern hybridization analysis. The expression of the lacZ gene in Spodoptera frugiperda cells infected with the lacZ-HcNPV was examined by SDS-PAGE and colorimetric assay. One 116-kDa LacZ protein band appeared on the PAGE. The production rate of the $\beta$-galactosidase was approximately 50 international units (IU) per min per ml between 2 to 5 days postinfection (p.i.). The highest activity occurred at five days p.i. was 170 IU/min/$m\ell$. The enzyme activity first appeared about 20 h p.i. as measured by colorimetric assay.

• The Korean Journal of Zoology
• /
• v.38 no.4
• /
• pp.505-513
• /
• 1995

P-lement mediated enhancer detector lines (EDla) were screened for reporter gene (1acZ expression In the ovary of Drosophila mejanogaster Cell-type spedfic 1acZ expression can be grouped Into three parts such as in the geimline, soma, and both. LacZ expression In germline cells was devided into 2 types; expression in nurse cells or in both of the nurse cells and oocote. In the stage-9 to stage-lO follicles, lacZ expression was observed either In the whole follicle cells around oocote or in the subpopulation of follicle cells in egg chamber. lacZ expression in the subset of follicle cells are showed in the centripetal follicle cells or the columnar follicle cells except centripetal follicle cells. Several lines showed anterior to postedor gradient pattern of lacZ expression in the follicle cells. Interestingly there were 3 lines in which lacZ was expressed In the polar cells and/or the horder cells of egg chamber. These lacZ expression patterns in the different ovarian cells of independent EDla reflect the cell type-spedflc expression of maternal genes nesr the P-element insertion, and might provide a basis for cloning of genes involved in oogenesis of Drosophila.

• The Korean Journal of Food And Nutrition
• /
• v.17 no.1
• /
• pp.8-17
• /
• 2004

The effect of chlorella extract on the growth and acid production of yoghurt starter was investigated in order to prepare the yoghurt added with chlorella extract. The various levels of chlorella extract powder were added to skim milk medium and the medium was fermented by single or mixed culture of 4 types of lactic acid bacteria such as Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus bulgaricus. The changes in acid production(pH, titratable acidity) and number of viable cells of the medium during fermentation in skim milk added with chlorella extract powder have determined. When chlorella extract powder was added to skim milk medium at the levels of 0.5%, 1.0%, 2.0%, and 3.0%, the addition of 0.5% chlorella extract powder with the single culture of Str. thermophilus, Lac. casei, and Lac. bulgaricus showed the highest number of viable cell counts after 9 hours incubation. And also all single cultures of the yoghurt starter produced the higher amounts of acid with the addition of 0.5% chlorella extract powder. When chlorella extract powder was added to the medium at the levels of 0.25%, 0.5%, 1.0%, and 2.0%, the addition of lower lever(0.25∼0.5%) of chlorella extract powder with the mixed culture of the lactic acid bacteria showed more the acidity of pH and the number of viable cell counts. Among the treatments tested, the addition of 0.25% chlorella extract powder with the mixed culture of Str. thermophilus and Lac. casei produced the highest number of viable cell counts after 12 hours incubation. Therefore it was suggested to manufacture the yoghurt with the addition of 0.25% chlorella extract powder and the inoculation of mixed culture of Str. thermophilus and Lac. casei for on the stimulation of growth of the yoghurt starter.

• Animal cells and systems
• /
• v.2 no.2
• /
• pp.269-275
• /
• 1998

The reporter plasmid pMT-lacZ containing the metallothionein (MT) promoter region (-320∼+58 with respect to the transcription initiation site) fused to the lacZ gene in a P-element vector was constructed. Transgenic Drosophila bearing the MT-lacZ fusion gene were established by P-element mediated transformation. Expression of the MT-lacZ fusion gene in transformants was examined during development. By treatment with low concentration of cadmium (>1O uM) or paraquat (>50 uM), increased expression of B-galactosidase was shown in fat body, brain lobe, and ganglion transgenic larval tissues. The results show that transformants bearing the MT-lacZ fusion gene are useful for further studies on the mechanism of regulation of MT gene expression and for monitoring toxic metals.

• KSBB Journal
• /
• v.26 no.3
• /
• pp.199-205
• /
• 2011

Using tetrameric ${\beta}$-galactosidase as a model protein, anchoring motives were screened in Bacillus subtilis spore display system. Eleven spore coat proteins were selected considering their expression levels and the location in the spore coat layer. After chromosomal single-copy homologous integration in the amyE site of Bacillus subtilis chromosome, cotE and cotG were chosen as possible spore surface anchoring motives with their higher whole cell ${\beta}$-galactosidase activity. PAGE and Wester blot of extracted fraction of outer layer of purified spore, which express CotE-LacZ or CotG-LacZ fusion verified the existence of exact size of fusion protein and its location in outer coat layer of purified spore. ${\beta}$-galactosidase activity of spore with CotE-LacZ or CotG-LacZ fusion reached its highest value around 16~20 h of culture time in terms of whole cell and purified spore. After intensive spore purification with lysozyme treatment and renografin treatment, spore of BJH135, which expresses CotE-LacZ, retained only 1~2% of its whole cell ${\beta}$-galactosidase activity. Whereas spore of BJH136, which has cotG-lacZ cassette in the chromosome, retained 10~15% of its whole cell ${\beta}$-galactosidase activity, proving minor perturbation of CotG-LacZ, when incorporated in the spore coat layer of Bacillus subtilis compared to CotE-LacZ. Usage of Bacillus subtilis WB700, of which 7 proteases are knocked-out and thereby resulting in 99.7% decrease in protease activity of the host, did not prevent the proteolytic degradation of spore surface expressed CotG-LacZ fusion protein.

• Journal of Life Science
• /
• v.7 no.1
• /
• pp.49-58
• /
• 1997

Single P[en-lacZ] element including 5.7 kb of engrailed upstream sequences and the E. coli lacZ fusion gene, localized on 48A in rxyho25 strain was transposed to different sites in the Drosophila genome by the jumpstart technique. From 3315 individual genetic crosses, 113 new insertion lines carrying P[en-lacZ] inserted at different sites were obtained. $\beta$-Galactosidase expression in larval tissues of 113 insertion lines were detected by X-gal staining. & among 113 lines have been indentified to be for recessive lethal mutations. Among 7 lines, the #1119 line being lethal during embryogenesis was examined about the ${\beta}$$-Galactosidase expression, nuclear behavior and cellularization pattern during embryogenesis. The P[en-lacZ] insertion lines obtained in this study could be utilized for studying structure and function of the Drosophila development-related genes.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.1
• /
• pp.20-27
• /
• 2016

Lactobacillus kefiranofaciens ZW3 was obtained from kefir grains, which have high lactose hydrolytic activity. In this study, a heterodimeric LacLM-type β-galactosidase gene (lacLM) from ZW3 was isolated, which was composed of two overlapping genes, lacL (1,884 bp) and lacM (960 bp) encoding large and small subunits with calculated molecular masses of 73,620 and 35,682 Da, respectively. LacLM, LacL, and LacM were expressed in Escherichia coli BL21(DE3) and these recombinant proteins were purified and characterized. The results showed that, compared with the recombinant holoenzyme, the recombinant large subunit exhibits obviously lower thermostability and hydrolytic activity. Moreover, the optimal temperature and pH of the holoenzyme and large subunit are 60℃ and 7.0, and 50℃ and 8.0, respectively. However, the recombinant small subunit alone has no activity. Interestingly, the activity and thermostability of the large subunit were greatly improved after mixing it with the recombinant small subunit. Therefore, the results suggest that the small subunit might play an important role in maintaining the stability of the structure of the catalytic center located in the large subunit.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.6
• /
• pp.901-906
• /
• 2013

We examined the availability of the lacZ gene (${\beta}$-galactosidase gene) as a reporter of foreign gene transfer in the cysts of Artemia franciscana (A. franciscana) to conduct a risk assessment of living genetically modified organisms (LMOs) in the marine ecosystem. The LacZ gene was transferred to decapsulated cysts by particle bombardment, and its insertion and expression were assessed by means of polymerase chain reaction (PCR) and X-gal staining. X-gal staining indicated lacZ expression in all A. franciscana examined (including the control group), which exhibited not only negative but also positive PCR amplification. Endogenous ${\beta}$-galactosidase is highly active in the whole body of A. franciscana during all stages of the life cycle. Thus, the lacZ gene is unsuitable as a reporter for foreign gene transfer in A. franciscana cysts, because it is difficult to discriminate between exogenous and endogenous ${\beta}$-galactosidase activity.

• Korean journal of food and cookery science
• /
• v.10 no.1
• /
• pp.35-38
• /
• 1994

The growth extent of Leu. mesenteroides and Lac. plantarum in the medium which contain sterilized extract of each of garlic, red pepper powder, and onion was examined. Garlic and onion decreased the growth of Leu. mesenteroides and Lac. Plantarum, and garlic represented more negative effect on the growth of Lac. plantarum than that of onion. Red pepper powder had negative effect on the growth of Lac. plantarum, and positive effect on the growth of Leu. mesenteroides in accordance with incubation processing.

• Microbiology and Biotechnology Letters
• /
• v.13 no.3
• /
• pp.265-271
• /
• 1985

The classification of bacteriophage could be followed by several criteria. In this study three criteria were used for classification of Lactobacillus casei bacteriophag. In serological classification. antiserum was prepared by rabbit and used for classification. The inactivation effect of phage by antiserum was exponential and L. casei phage was classified in to three serological groups by inactivation rate (K-values). The Lac Y group was proved as a new serological group but the Lac J and Lac S group were shown the same results as previous reports. From the comparison of restriction enzyme pattern of phage DNA, Lac J group was divided into four sub-groups. According to the difference of host range, Lac J-II group was further subdivided into three groups. These results were shown that L. casei strains S-1 bacteriophage was classified into 8 sub-groups. The phage YK of Lac Y group was shown to consist of a icosahedral head about 95nm in diameter, a contractile tail about 150nm in length and 20nm in width. The tail of YK phage is composed of stacked disks(4nm repeat)and a hexagonal baseplate. The molecular weight of YK phage DNA was approximately 85.6 Mdalton.