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41.
Young-Rae?Chae Keun-Garp?RyuEmail author 《Biotechnology and Bioprocess Engineering》2004,9(5):379-382
Entomopathogenic nematodes are used for insect control. Herein, an extracellular protease was partially purified from a culture
supernatant ofXenorhabdus nematophilus, a symbiotic bacterium of an entomopathogenic nematode,Steinernema glaseri, using precipitation with 80% v/v isopropyl alcohol followed by gel permeation chromatography with a packed Sephacryl S-300
HR media. The partially purified protease exhibited maximal activity at pH 7 in the presence of 1 mM CaCl2. The protease was identified as a metallo-protease based on the inhibition of its activity by the metal chelating agent,
EDTA. 相似文献
42.
RIPK 2 is adapter molecule in the signal pathway involved in Toll-like receptors. However, there has been no reported association between receptor-interacting serine/threonine kinase 2 (RIPK 2) expression and the infectious diseases involving mycobacterial infection. This study found that its expression was down-regulated in the footpads and skin but was up-regulated in the liver of Mycobacterium leprae-infected nu/nu mice compared with those of the M. leprae non-infected nu/nu mice. It was observed that the interlukin-12p40 and interferon-gamma genes involved in the susceptibility of M. leprae were down-regulated in the skin but were up-regulated in the liver. Overall, this suggests that regulation of RIPK 2 expression is tissue-specifically associated with M. leprae infection. 相似文献
43.
44.
Lee CK Lee CU Kim JH Son BC Kim DH Lee CH Kim HD Kim JW Yoon YD Kang SG Moon DH 《Molecules and cells》2003,15(1):114-121
This study was performed to investigate the effects of Aroclor 1254 (A1254), a commercial polychlorinated biphenyl mixture, on the expression of rat placental prolactin (PRL) family genes and reproductive activity. Placental lactogen-Iv and -II, and prolactin-like protein-A and -C mRNA levels were significantly decreased in the placentas of A1254-treated rats in a dose-dependent manner. The mRNA levels of Pit-1alpha and beta isotypes, which are involved in the regulation of PRL family gene expression, were also decreased in the A1254-treated rat placenta. In the rat placental junctional zone, high-dose A1254 (25 mg/kg B.W.) treatment reduced the number of spongiotrophoblasts, cells in which the PRL family genes are expressed. Finally, maternal exposure to A1254 was shown to have significant toxic effects on reproductive activity, including embryonic and placental growth retardation, delay of parturition, and reduction of the number of pups per litter. The results of the present study indicated that A1254 has an inhibitory effect on PRL family, Pit-1alpha, and beta gene expression in the rat placenta, leading to significant toxic effects on reproductive activity in rats. 相似文献
45.
Hwang DY Cho JS Chae KR Kang TS Hwang JH Lim CH Lee SH Lim HJ Min SH Sheen YY Jang IS Kim YK 《Archives of biochemistry and biophysics》2003,415(2):137-145
Differential expression of the tetracycline-controlled transactivator (tTA)-driven human cytochrome p450 (CYP) 1B1 gene was found in the livers of male mice, at high levels in neonates, but at low levels in adults. The goals of this study were to determine whether the differential expression of the tTA-driven human CYP1B1 (hCYP1B1) gene in neonates and adults was testosterone dependent and whether flutamide, a representative potent antiandrogen, led to the induction of hCYP1B1. This was tested by treating castrated transgenic mice with testosterone propionate and musk extracts. It was concluded that: (i). the levels of expression of both tTA and hCYP1B1 gradually declined, with clear changes being apparent between 2 and 4 weeks of age, (ii). castration of adult males resulted in the increased expressions of both tTA and hCYP1B1 to levels similar to those found in adult females, (iii). treatment of castrated male and adult female mice with testosterone propionate and musk extracts led to the restoration of the levels of expression of hCYP1B1 in the adult males, and (iv). treatment of adult males with flutamide caused an increase in the levels of expression of hCYP1B1 in the adult females, as indicated by the antiandrogenic activity. Thus, the differential expression of the tTA-driven hCYP1B1 gene in the transgenic mice was caused by androgen, and it is possible that castrated male and adult female mice expressing the tTA-controlled hCYP1B1 could be used as the basis for a strategy for the detection of androgens and antiandrogens. 相似文献
46.
In the yeast Saccharomyces cerevisiae, a mild heat treatment strongly induces Hsp104p which provides acquisition of thermotolerance. The mechanism by which Hsp104p protects cells from the severe heat shock has not yet been completely elucidated. In this study, a pivotal role of Hsp104p as an efficient scavenger of the reactive oxygen species (ROS) is investigated. In our previous study, we reported that Hsp104p acted as a regulator in the mitochondrial respiration pathway. In this report, the recombinant wild-type and hypersensitive ras mutants (ira2Delta) with the extrachromosomal plasmids wild-type and mutant hsp104 genes were studied. The resulting strains successfully expressed both wild-type and mutant Hsp104p and showed the thermotolerance phenotype in the strain with the functional wild-type Hsp104p expressed. Upon treatment with H2O2 and menadione, the strains with the functional Hsp104p expressed showed higher survival rates than the other mutants, indicating the protective role of Hsp104p from the oxidative stress. Fluorescence measurement of the oxidation-dependent probe, 2',7'-dichlorofluoroscein diacetate (H2DCFDA), also indicated that Hsp104p significantly reduced the amount of ROS. Resistance to the oxidative stress was independent of the amount of the glutathione in the hyperactivated ras mutants. Taken all together, this study confirms that Hsp104p plays a crucial role in keeping cells from being damaged by the oxidative stress, thus acting as a modulator of the intracellular redox state. 相似文献
47.
Lee KY Kim HG Hwang MR Chae JI Yang JM Lee YC Choo YK Lee YI Lee SS Do SI 《The Journal of biological chemistry》2002,277(51):49341-49351
The mammalian Galbeta1,3GalNAc-specific alpha2,3-sialyltransferase (ST3Gal I) was expressed as a secreted glycoprotein in High Five (Trichoplusia ni) cells. Using this recombinant ST3Gal I, we screened the synthetic hexapeptide combinatorial library to explore a sialyltransferase inhibitor. We found that the hexapeptide, NH(2)-GNWWWW, exhibited the most strong inhibition of ST3Gal I among five different hexapeptides that were finally selected. The kinetic analysis of ST3Gal I inhibition demonstrated that this hexapeptide could act as a competitive inhibitor (K(i) = 1.1 microm) on CMP-NeuAc binding to the enzyme. Moreover, the hexapeptide was shown to strongly inhibit both N-glycan-specific alpha2,3- and alpha2,6-sialyltranferase in vitro, suggesting that this peptide may inhibit the broad range of sialyltransferases regardless of their linkage specificity. The inhibitory activity in vivo was investigated by RCA-I lectin blot analyses and by metabolic d-[6-(3)H]GlcNH(2) radiolabeling analyses of N- and O-linked oligosaccharides in Chines hamster ovary cells. Our results demonstrate that the hexapeptide can act as a generic inhibitor of the N- and O-glycan-specific sialyltransferases in mammalian cells, which results in the significantly reduced NeuAc expression on cellular glycoproteins in vivo. 相似文献
48.
Role of BMP, betaig-h3, and chitosan in early bony consolidation in distraction osteogenesis in a dog model 总被引:12,自引:0,他引:12
The purpose of this investigation was to study the effect of bone morphogenetic protein (BMP), transforming growth factor beta-induced gene h3 (betaig-h3), and chitosan on early bony consolidation in distraction osteogenesis in a dog model. Sixteen dogs were used for this study. The lateral surface of the mandibular body was exposed in the subperiosteal plane and the vertical osteotomy on the mandibular body was extended downward. An external distraction device was applied to the mandibular body, and the mandibular distraction was started 5 days after the operation at a rate of 2 mm/day up to a 10-mm distraction after 5 days. The experimental group was then divided into a control group, a BMP group, a betaig-h3 group, and a chitosan group, depending on the type of implantation material used in the distracted area. On the same day after completing the distraction, BMP, betaig-h3, or chitosan was implanted into the distracted area. No material was implanted into the distracted area in the control group. After implanting the materials, the distraction device was left in place for 7 weeks to allow for bony consolidation. Four dogs were allocated to each group. Two dogs in each group, a total of eight dogs, were killed 4 weeks after completing the distraction and the other eight dogs were killed after 7 weeks. Serial radiographs were obtained every week after completing the distraction. New bone was generated in the distracted zone in all groups. In the BMP group, the formation of active woven bone was observed throughout the distracted zone, and the new bone appeared to be nearly normal cortical bone 7 weeks after implantation. In the betaig-h3 and chitosan groups, the development of new bone was observed in the distracted zone after 7 weeks; however, the amount was less than that in the BMP group. In the control group, the new bone was observed at the edges of the distracted zone. These findings suggest that BMP seems to be very effective in early bony consolidation in distraction osteogenesis. 相似文献
49.
To improve the success rate of microsurgical flap transfers into a buried area, it is important to monitor the circulation of the flap during the early stage. A monitoring flap includes such advantages as simplicity, reliability, noninvasiveness, and the ability to continuously monitor the vascular status of various buried flaps. This article describes experiences related to the importance and reliability of a monitoring flap. A total of 109 flaps in 99 patients were treated with buried free flaps, including a monitoring flap, between 1990 and 1999. Forty-nine patients received a tubed free radial forearm flap with a skin-monitoring flap, and six received a free jejunal flap with a jejunal segment monitoring flap for the reconstruction of the esophagus. Vascularized fibular grafts with a skin monitoring flap or peroneus longus muscle monitoring flap were used for reconstructing the mandible in six patients and for treating osteonecrosis of the femoral head in 48 flaps in 38 patients. Monitoring flap abnormalities were indicated in 14 flaps; therefore, immediate revisions were performed on the pedicle of the monitoring flap and microanastomosis site. Among these 14 flaps, nine showed true thrombosis and five showed false-positive thrombosis. Among the nine flaps that showed true thrombosis, five were salvaged and four were finally lost. The false-positive thrombosis in the five flaps was attributed to torsion or tension of the perforator of the monitoring flap in three flaps, an unclear determination in one flap because the monitoring flap size was too small, and damage to the perforator in the last flap. The total thrombosis rate was 8.3 percent (nine of 109), and the failure rate of the free tissue transfer was 3.7 percent (four of 109). The overall sensitivity of the monitoring flap was 100 percent, the predictive value of a positive test was 64 percent (nine of 14), and false-positive results occurred in 36 percent (five of 14). The salvage rate was 55.6 percent. To improve the reliability of a monitoring flap, it is recommended that the size of the flap be larger than 1 x 2 cm to assess the arterial status, and that a perforator with the appropriate caliber be selected. When a monitoring flap is fixed to a previous incision line or a newly created wound, any torsion or tension of the perforator should be avoided. In conclusion, the current results suggest that a monitoring flap is a simple, extremely useful, and reliable method for assessing the vascular status of a buried free flap. 相似文献
50.
A prion determining 7-mer peptide derived from Sup35 was fused to glutathione S transferase (GST). The fusion protein was successfully overexpressed in Escherichia coli, and purified by employing affinity chromatography. Upon incubation, it showed substantial aggregation suggesting the formation of amyloid-like fibrils. Congo Red binding strongly suggested that the fusion protein formed amyloid-like fibrils. By considering the steric hindrance of GST, the beta-sheet formation should be in the anti-parallel fashion. 相似文献