Role of white rot fungus Funalia trogii in detoxification of textile dyes

Toxic and genotoxic effects of the textile dyes on organisms suggest the need for remediation of dyes before discharging them into the environment. For this reason, the ability of Funalia trogii pellets to detoxify textile dyes was investigated and evaluated. Although, textile dyes are toxic substances for many microorganisms, the pellets were able to decolorize and detoxify the azo dyes used. Astrazon Blue and Red dyes inhibit growth of F. trogii and S. aureus on solid medium in a concentration dependent manner. The toxicity of these dyes on a fungus, F. trogii and a bacterium, S. aureus was significantly decreased after pretreatment with fungal pellets.     

Screening of filamentous fungi for the decolorization of a commercial reactive dye

The aim of this work is to verify the ability of 19 isolates of 13 different fungal species to decolorize the reactive dye blue‐BF‐R. The isolates of Pleurotus pulmonarius, P. ostreatus, P. ëous, P. citrinopileatus, Lentinus edodes, Phanerochaete chrysosporium, Schizophyllum commune, Agaricus blazei, Ganoderma sp. and four isolates obtained from textile effluent were evaluated in minimum liquid medium. In addition, seven of them were also evaluated on solid medium, and both media were both added 0.5 g dye/l. All isolates evaluated on solid medium decolorized the dye. The isolates Phanerochaete chrysosporium CCB478 and Lentinus edodes CCB047 were the ones that presented the fastest and slowest growth, respectively. Despite the isolate of the textile effluent had grown on solid medium, it did not decolorize the dye. All the isolates of the genus Pleurotus, except the isolate Pleurotus ëous CCB440, decolorized the dye in liquid medium. They presented decolorization percentage ranging from 39% to 51%. The absorbance ratio (Abs₅₉₀/Abs₄₅₅) of the culture medium inoculated with these isolates decreased throughout the experiment indicating the fungal dye degradation. The others presented decolorization percent below 8%. The isolates of Pleurotus, except the isolate Pleurotus ëous CCB440, were able to decolorize and to degrade the commercial reactive dye blue‐BF‐R. The results indicate their potential to be used in the treatment of effluents containing this dye. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Decolorization of diazo-dye Reactive Blue 172 by Pseudomonas aeruginosa NBAR12

A novel bacterial strain capable of decolorizing textile dyes was isolated from dye contaminated soil obtained from industrial estate of Ahmedabad, Gujarat, India. The bacterial isolate Pseudomonas aeruginosa NBAR12 was capable of decolorizing 12 different dyes tested with decolorization efficiency varying in the range of 80 to 95%. Maximum extent as well as rate of Reactive Blue 172 (RB 172) decolorization was observed when glucose (2 g x l(-1)) and yeast extract (2.5 g x l(-1)) were supplemented in the medium. The optimum dye pH and temperature for dye decolorization was found to be 7 and 40 degrees C, respectively. The decolorizing activity was found to increase with increasing the dye concentration from 50 to 400 mg x l(-1). The dye decolorization was strongly inhibited at 500 mg dye l(-1) in the medium. High performance thin layer chromatography analysis indicated that dye decolorization occurred due to the breakdown of dye molecules into colorless end products.     

Soluble Cytostatic Factor(s) Released from Human Monocytes

Human monocytes release a stable cytostatic factor during in vitro culture after stimulation with lymphokine and endotoxin. The cell cycle time of synchronized NHTK 3025 cells increased from 20.3 to 23.2 h in the first cell cycle when the target cells were exposed to the factor during the whole cell cycle. In exponentially growing NHIK 3025 cell cultures the cell doubling time increased from 18.9 h to 23. l h under continuous factor exposure for 70 h. These cells regained normal cell division rate when fresh culture medium replaced the cytostatic factor. Continuous exposure to the cytostatic factor for 96 h increased the cell doubling time of asynchronous K-562 cells from 19.7 to 31.8 h. The target cell DNA synthesis, evaluated by thymidine incorporation. was markedly depressed after culture with the factor for 24 h, and this depression was detectable already within 4 h of culture. The factor showed no cytolytic effect on the two cell lines tested. The cytostatic factor influenced the cell cycle distribution of both target cells tested, since cell cycle analysis by DNA flow cytometry demonstrated a reversible inhibition of factor-exposed NHIK 3025 cells in G₁- and early S-phase, whereas K-562 cells accumulated in G₁-phase.     

A study on significant microbial interaction leading to decolorization and degradation of textile dye Rubine 3GP

The present study evaluates an obligatory interaction between the yeast Saccharomyces cerevisiae NCIM 3312 and the bacterium Pseudomonas sp. strain BCH3 for the biodegradation of the dye Rubin 3GP (R3GP). No significant degradation of R3GP was observed either by Saccharomyces cerevisiae NCIM 3312 or by Pseudomonas sp. strain BCH3, when both the cultures were tested individually under their respective optimum medium conditions. However, when both of them were allowed to intermingle with each other, R3GP was found to be degraded within 72 h, with a steady increase in β -1,3-glucanase, chitinase and protease activity in the culture supernatant; indicating the possible role of Pseudomonas sp. strain BCH3 in cell wall lysis of S. cerevisiae NCIM 3312. The present study elucidates a rare microbial interaction where the bacterium Pseudomonas sp. strain BCH3 utilizes lysed yeast cells as the sole source of nutrients for its own growth and subsequently performs decolorization and degradation of R3GP. Enzymatic status showed involvement of various oxidoreductive enzymes like lignin peroxidase, laccase, DCIP reductase and azo reductase, indicating their role in decolorization and degradation of R3GP. Degradation was confirmed using HPLC, FTIR analysis and the biochemical pathway of degradation was elucidated by using GC-MS analysis.     

Depression of Con A proliferative response of immune cells by in vitro hyperoxic exposure--protective effects of thiol compounds

Time dependent response for hyperoxic exposure was determined in vitro on ConA proliferative response of rat splenocytes, peripheral blood mononuclear cells and thymocytes. The proliferative responses were evaluated after different lengths of hyperoxic exposure (12-72 h, FiO2 = 0.95). After 24 h oxygen exposure, the spleen cell viability assessed by dye exclusion was normal but DNA synthesis was markedly suppressed in the above three types of cells. Total or partial protection of the mitogenic response to ConA was obtained by 2-mercaptoethanol, reduced glutathione or L-cysteine addition in culture medium; only selenomethionine had no protective effect. Thymic cells showed a different response-curve: after 6 h exposure to normobaric oxygen DNA synthesis was decreased and was not restored by any of the thiol compounds tested. In this respect, these cells demonstrated different susceptibility to an oxidant injury, i.e. exposure to high oxygen concentration. From a pharmacological point of view O2 exposure and altered immune response could be proposed as a useful model for screening the antioxidant drug activity.     

Enhancing bioremoval of textile dyes by eight fungal strains from media supplemented with gelatine wastes and sucrose

Eight Aspergillus strains were found to be successful in removing textile dyes from liquid media. These fungal strains were grown on medium containing: gelatine wastes and sucrose, as sources of nitrogen and carbon to test the possible speed up of the dyes removing while fungus biomass is building up in the media. The growth of fungal strains ranged from 10 to 110 mg biomass dry weight/100 ml medium. This growth induced high decolorization percentages, which ranged 33-95% within eight days. Two textile dyes Direct brown and Polar red were included in the study. The growth of the fungal strains as well as decolorization percentage of the dyes increased after 5, 6, and 8 days from incubation time with most tested strains. With Direct brown dye the strains number 2, 5, 31 and 37 recorded the highest percentage of decolorization (91, 92, 93 and 95 respectively) after incubation for 6 days. Fungal strains Aspergillus 5 and 31 gave the highest mycelium dry weight being 110 mg. Most of fungal strains induced 86 to 95 percentage of decolorization after 6 days incubation with Polar red dye. The possible toxicity of the remaining supernatant media after fungal biomass removal was tested by Ames test to assess the residual mutagenic agents remaining after dye removal, using three strains of Salmonella typhimurium (TA 1535, TA 1537, TA 1538). The results showed that the toxicity of the dyes, measured by Ames test could be removed by the dye absorption on the fungal biomass.     

Adsorptive removal of textile dyes from aqueous solutions by dead fungal biomass

Dead fungal biomass prepared from Phanerochaete chrysosporium and Funalia trogii was tested for their efficiency in removal of textile dyes. The effects of contact time, initial dye concentration, amount of dead biomass and agitation rate on dye removal have been determined. Removal of all dyes required a very short time (60 min). Experimental results show that, P. chrysosporium was more effective than F. trogii . An increase in the amount of dead biomass positively affected of the dye removal. The removal efficiency of different amount of biomass was in order 1 g > 0.5 g > 0.2 g > 0.1 g. The highest removal was obtained at 150-200 rpm. Slightly lower removing activities were found at lower agitation rates. This study showed that it was possible to remove textile dyes by dead biomass of P. chrysosporium .     

A flow-cytometry based cytotoxicity assay using stained effector cells in combination with native target cells

Flow-cytometry based assays for cellular cytotoxicity have established themselves widely over the last years. Discrimination of target and effector cells is critical for such assays. If scatter properties are not informative, the standard approach until now has been to label the target cells with a suitable fluorescent dye. However, this cannot be applied to a number of experimental settings, e.g. if one effector cell type is tested against several target cells, or if target cells do not incorporate the dye properly. Therefore, our goal was to develop a protocol based on the labelling of effector cells. For this purpose, we came around to using a membrane dye, DIOC18, which is not commonly used for flow-cytometric applications. This dye showed very stable membrane integration properties that allowed long-term coincubation periods (24 h) without leakage to neighbouring cells. The vitality and cytotoxic activity of the effector cells were not altered by staining. For the detection of dead cells, the intercalating DNA-dye 7-AAD was used. The spectral emission wavelengths of this combination also enable the additional use of PE-conjugated antibodies to surface antigens in three-color cytometry devices. Cytotoxicity values obtained by our protocol were highly correlated with values obtained by the chromium release assay at different E/T ratios and using several target cell lines. All in all, we present here an easy to handle protocol, which enables the precise determination of cellular cytotoxicity in various experimental settings.     

Rhamnolipid from Pseudomonas desmolyticum NCIM-2112 and its role in the degradation of Brown 3REL

The biosurfactant produced by Pseudomonas desmolyticum NCIM 2112 (Pd 2112) was confirmed as rhamnolipid based on the formation of dark blue halos around the colonies in CTAB-methylene blue agar plates and the content of rhamnose sugar. The average yield of rhamnolipid was 0.398 g/l/day when grown on hexadecane as sole carbon source. Pd 2112 emulsification potential associated with cell free culture broth was stable for 72 h using various hydrocarbons and vegetable oils. Chemical structure of the biosurfactant was identified as mono-rhamnolipid (Rha-C(6) -C(8) ) using HPTLC, fourier transform infrared spectroscopy, (1) H and (13) C NMR and gas chromatography-mass spectroscopy analysis. Pd 2112 mono-rhamnolipid (1 mg/ml) had increased permeabilization of Bacillus sp VUS NCIM 5342 and increased decolorization rate of textile dye Brown 3REL by 50%. Extracellular activities of lignin peroxidase and veratryl alcohol oxidase, enzymes involved in dye degradation, were significantly increased in the presence of mono-rhamnolipid by 324.52% and 100% respectively. Scanning electron micro-scopy observations revealed that rhamnolipid did not exert any disruptive action on Bacillus cells as compared to Tween 80. The mono-rhamnolipid of Pd 2112 has potential for its application in biodegradation of textile dyes.     

An osteogenic cell culture system to evaluate the cytocompatibility of Osteoset, a calcium sulfate bone void filler

The purpose of the study was to describe a convenient, reliable and quantitative in vitro assay system to assess the cytocompatibility of a calcium sulfate bone filler on two osteogenic cell lines and primary osteoblasts. The hypothesis was that the bone void filler, OsteoSet pellets, would not impact adversely on cell proliferation kinetics or osteogenic potential of selected cells. The hypothesis was tested by standard in vitro methodology of placing OsteoSet pellets either directly in contact with osteogenic cells, or by compartmentalizing within transwell - clear microporous membrane inserts. Data analyses were accomplished with appropriate post hoc statistics (p < or = 0.05). In the presence of the OsteoSet pellets, the cell lines exhibited a decrease in cell proliferation at days 4 and 7, independent of either cell type or tissue culture medium. A decrease in the alkaline phosphatase enzyme activity occurred in the osteogenic cell lines maintained for 9 and 16 days in the presence of the OsteoSet pellets. However, with the exception of the MC3T3E-1 line, no differences were observed with respect to calcium deposition (mineralization) by day 16. Intact human osteocalcin release data for the human-derived OPC1 line and the primary osteoblasts was inconclusive as the OsteoSet pellets may interact with the osteocalcin secreted into the tissue culture medium. The present studies describe a cell culture system to assess the cytocompatibility of bone-graft substitutes with osteogenic cells by compartmentalizing material from direct cell contact (in transwells), and additionally, by evaluating direct cell/biomaterial interactions.     

Phytoestrogens inhibit aromatase but not 17beta-hydroxysteroid dehydrogenase (HSD) type 1 in human granulosa-luteal cells: evidence for FSH induction of 17beta-HSD

BACKGROUND: Studies using purified enzyme preparations, placental microsomes or cell lines have shown that certain phytoestrogens can inhibit the enzymes that convert androgens to estrogens, namely aromatase and 17beta-hydroxysteroid dehydrogenase (HSD) type 1 and type 5. The study aim was to investigate the effects of selected phytoestrogens on aromatase and 17beta-HSD type 1 activity in primary cultures of human granulosa-luteal (GL) cells. METHODS AND RESULTS: GL cells, cultured for 48 h in medium containing 5% fetal calf serum and for a further 24 h in serum-free medium with or without hFSH or hCG, were exposed to steroid substrates during the last 1-4 h of the experiment. The production of progesterone in the presence of pregnenolone or estradiol synthesis from androstenedione, estrone or testosterone showed dose- and time-dependent increases. Whilst hCG priming had no effect on progesterone production, FSH priming induced mean 68 and 56% increases in the production of estradiol from androstenedione (A-dione) and estrone respectively, but had no significant effect on the metabolism of testosterone to estradiol. None of the phytoestrogens investigated had any acute effects on enzyme activity. In contrast, when GL cells were exposed to the compounds for 24 h prior to exposure to steroid substrates for 4 h, 10 micro mol/l apigenin and zearalenone significantly inhibited aromatase activity, whilst biochanin A and quercetin had no effect. None of the phytoestrogens inhibited FSH-induced 17beta-HSD type 1 activity, and only quercetin significantly inhibited progesterone production. CONCLUSIONS: The inability of phytoestrogens to acutely inhibit steroidogenic enzymes in human GL cells (as has been shown in cell-free models) suggests that they are either rapidly metabolized to relatively inactive compounds or that the high enzyme activity in human GL cells masks any inhibitory effects of the compounds at the concentration tested.     

Potential difference and the distribution of ions across the human red blood cell membrane; a study of the mechanism by which the fluorescent cation, diS-C3-(5) reports membrane potential.

1. The mechanism by which the fluorescent, cationic dye diS-C3-(5) responds to the membrane potential of red blood cells has been investigated. 2. The dye in aqueous solution absorbs most strongly at 650 nm. Addition of white, haemoglobin-free membranes red shifts the absorption maximum ca. 20 nm, while addition of membrane-free cell lysate results in the appearance of a new dye absorption peak at 590 nm. Thus the dye binds both to cell membranes and to cell contents. The component of the cytoplasm which binds the dye is non-dialysable, presumably haemoglobin. 3. Dye added to a suspension of intact cells shows a strong absorption at 590 nm indicating that the dye has bound to the cell contents and that the membrane is permeable to the dye. 4. The amount of dye which partitions into (and on to) the cells can be determined, as reported by Sims, Waggoner, Wang & Hoffman (1974), from the fluorescence of the dye remaining in the supernatant after the cells are centrifuged to the bottom of the suspension. In most conditions the proportion of the cell associated dye which is either free inside the cell or bound to the outside face of the membrane is negligible compared to the proportion bound to the cell contents. 5. On the assumption that the dye is not actively transported, the ratio of the equilibrium dye activities inside and outside the cell, ai/ao, is determined by the membrane potential according to the Nernst relation. Driving the membrane potenial negative then increases the cell associated dye by increasing the activity ratio and hence ai and the amount of dye bound to cell contents. 6. At the known Donnan equilibrium potential the internal dye activity can be calculated from the external activity. An empirical relation between cell associated dye and internal activity has been determined by measuring the dye partition between cells and medium at different external activities. 7. Using this empirial relation, and providing that any changes in cell composition do not affect the dye binding, the internal activity at any potential can be calculated from the measured amount of cell associated dye. The external activity can be estimated fluorimetrically. The membrane potential is then calculated from the activity ratio. 8. The membrane potenial of cells has been altered by adding valinomycin in the presence of different K gradients. Under the conditions used, the 'constant field' permeability for K-Val is 15-20 times that of Cl. 9. Dye binding to haemoglobin is influenced by pH and thus dye partitioning into cells changes with intracellular pH. Increasing intracellular pH increases the amount of dye partitioned, while decreasing pH decreases this amount. 10. When large potentials are produced with valinomycin there is no change in intracellular pH. This result indicates that in red blood cells intracellular pH is determined by the external pH and the Cl concentration ratio and not by the membrane potentials. 11. DiS-C3-(5) can be used to estimate potentials across resealed ghost membranes...     

小鼠白细胞介素23基因在毕赤酵母中的诱导表达及初步活性研究

目的:克隆小鼠白细胞介素23(mice interlecukin-23,mIL-23)基因,构建高效稳定的毕赤酵母表达菌株,并对得到的蛋白进行生物活性的初步测定。方法:采用聚合酶链式反应(PCR)技术从pcDNA3-mIL-23上分别扩增获得IL-23的两亚基p19和p40,并通过重叠PCR(over-lap PCR)技术获得含有连接子的p1940,构建pPICZαA-IL-23重组质粒;采用甲醇诱导毕赤酵母表达重组蛋白,MTT方法检测诱导表达蛋白的促淋巴细胞增殖情况。结果:SDS-PAGE分析显示在诱导24小时和36小时后的上清及24～96小时的沉淀中均可以检测到约70 kD的诱导条带。Western blot印迹法证实了重组蛋白为特异性蛋白。上清和沉淀中表达的重组蛋白IL-23能促进外周血单个核细胞的增殖,OD570 nm分别达到(0.235±0.029)和(0.216±0.035),而未刺激的对照组只有(0.135±0.008)和(0.164±0.017)。结论:成功构建出mIL-23的酵母表达载体,诱导产生的蛋白可以明显地促进外周血单个核细胞的增殖。     

Antibacterial nanosized silver substituted hydroxyapatite: synthesis and characterization

The silver (0.5-3 at %) substituted nanosize hydroxyapatites (AgHAs) were synthesized by microwave processing. The X-ray diffraction (XRD) peaks are very broad, indicating that the AgHAs were of nanosize (30 nm). Transmission electron microscopy analysis shows needle-like morphology of AgHA, having length 60-70 nm and width 15-20 nm. The AgHA phase was stable up to 700 degrees C without any secondary phases. The antibacterial effect of AgHA against Escherichia coli and Staphylococcus aureus was observed by spread plate method, even for low concentration of silver ions (0.5%) with 1 x 10(5) cells/mL of respective bacterial culture, after a 48 h incubation period. However, some colonies of E. coli were seen with a high dose of 1 x 10(8) cells/mL after 24 h. The zone of inhibition by disc diffusion test method was found to vary with the amount of silver in the sintered AgHA pellets, for both the bacteria, after 24 h of inoculation. Osteoblast cell attachment in varying density was noticed on AgHA samples with 0.5, 1.0, and 1.5% silver substitution. However, osteoblast spreading was significantly greater on 0.5% AgHA compared to 1.0 or 1.5% substituted AgHA samples. Thus, the low amount of AgHA has a potential of minimizing the risk of bacterial contamination, without compromising the bioactivity, and is expected to display greater biological efficacy in terms of osseointegration.     

HSV-2 disrupts gap junctional intercellular communication between mammalian cells in vitro

Infection by herpes simplex virus-2 (HSV-2) disrupts both dye and electrical coupling in Vero (African green monkey kidney) cell cultures. Vero cells in vitro were iontophoretically injected with the fluorescent dye Lucifer yellow CH, the spread of which revealed that cells throughout the confluent sheet shared open gap junctions. However, 24 h after infection with the virus (but before cells became rounded), dye always remained only within the target cell. Intracellular electrophysiological measurements of ionic coupling revealed a 0.4 coupling coefficient for adjacent cells in uninfected control cultures. By 3 h following infection significant down-regulation of gap junctions had begun, preceding by many hours any signs of infection visible with the light microscope. Measurements between adjacent cells 3 h post-infection, a period when HSV-2 gene expression is known to be at a maximum, yielded an average coupling coefficient of 0.35. By 6 h post-infection (a period of known viral DNA replication) average coupling coefficient for adjacent cells was 0.25, while by 24 h post-infection the average fill still further to <0.08. A coupling coefficient of <0.08 suggests that infection by HSV-2 completely disabled the gap junctions.     

Sodium pyruvate protects against H(2)O(2) mediated apoptosis in human neuroblastoma cell line-SK-N-MC

Free radicals are involved in neuronal damage. The present study was aimed to investigate the protective effect of sodium pyruvate-a free radical scavenger against hydrogen peroxide (H(2)O(2)) induced apoptosis in human neuroblastoma cell line-SK-N-MC. On exposure to H(2)O(2) (0.025 mM) cells exhibited apoptosis within 24 h, demonstrating a high caspase 3 activity by 3 h followed by cleavage of PARP that was maximum at 24 h. A break down in the mitochondrial membrane potential was observed 3 h onwards. Sodium pyruvate protected cells significantly (P<0.05) against apoptosis in a dose dependent manner as assessed for cell viability by dye exclusion method and apoptosis by TUNEL. Sodium pyruvate significantly inhibited caspase 3 activity, cleavage of PARP and breakdown of mitochondrial membrane potential. These data suggest that sodium pyruvate protects neuronal damage caused by H(2)O(2).     

Helicobacter pylori urease activity is toxic to human gastric epithelial cells.

A human gastric adenocarcinoma cell line was used to evaluate the contribution of urease from Helicobacter (formerly Campylobacter) pylori to its cytotoxicity. Gastric cells cultured in medium supplemented with 20 mM urea were exposed to 5 x 10(6) CFU of H. pylori per ml with or without the addition of a urease inhibitor, acetohydroxamic acid. Viabilities of cells exposed to H. pylori for 2, 24, and 48 h, assessed by incorporation of neutral red dye, were 60, 27, and 16%, respectively; however, the viabilities of cells exposed to both H. pylori and acetohydroxamic acid were 92, 46, and 20% after 2, 24, and 48 h, respectively, (P less than 0.001). Therefore, the urease activity of H. pylori may play an important role in its pathogenicity, and inhibition of this enzyme activity may have therapeutic potential.     

Quantitative determination of complement components produced by purified hepatocytes

In this report we describe, on a quantitative basis, the secretion of complement components by hepatocytes. Primary cultures were established after isolation of the cells from guinea-pig liver and the synthesis of C3, C5, C4 and C2 was measured. The cells were isolated by collagenase perfusion of the liver followed by differential centrifugation. The contamination of the hepatocyte suspension with non-parenchymal cells was less than 1%. At 24 h after plating the cells the kinetics of complement production were measured. C3 and C5 content in the culture medium harvested at different time intervals was determined by a sensitive ELISA. Secretion of C2 and C4 was measured haemolytically using C2 or C4 deficient guinea-pig serum. Under the conditions used hepatocytes secreted C3 at a rate of about 100 ng/10(6) cells/h with a plateau of secretion after 24 h of culture corresponding to about 350,000 molecules/cell/h. C5 secretion was detectable after 3-6 h of culture. The C5 secretion rate was about 15 ng/10(6) cells/24 h. The functional activity of C4 and C2 in the supernatants amounted to about 80 SFU/cell/h if the culture medium was changed every 3 h but dropped significantly if the medium was changed every 12 h. The decrease of the haemolytic activity became stronger if the medium was changed every 24 h. Cycloheximide reversibly inhibited the complement production. Our results show that guinea-pig hepatocytes synthesize considerably more C3 and C5 compared to peritoneal macrophages supporting the hypothesis that hepatocytes provide the major source of plasma complement.     

Overexpression of RGPR-p117 induces the decrease in protein and DNA contents in cloned normal rat kidney proximal tubular epithelial NRK52E cells

A novel protein RGPR-p117 was discovered as a regucalcin gene promoter region-related protein that binds to the TTGGC motif. Regucalcin is known to regulate the intracellular signaling system in many cell types. RGPR-p117 has been shown to enhance the promoter activity of the regucalcin gene in cloned normal rat kidney proximal tubular epithelial NRK52E cells. The role of RGPR-p117 in cell function remains to be elucidated, however. This study was undertaken to determine whether overexpression of RGPR-p117 has an effect on cell proliferation, protein and DNA contents in NRK52E cells. NRK52E cells (wild-type) or stable RGPR-p117/phCMV2-transfected cells (transfectants) were cultured in Dulbecco's minimum essential medium containing 5% bovine serum (BS). RGPR-p117 was markedly expressed in the transfectants. NRK52E cells (wild-type) or transfectants were cultured for 24, 48, or 72 h in a medium containing 5% BS, and after subconfluency the cells were cultured for 24, 48, or 72 h in a medium without BS. Cell proliferation was not significantly changed in the transfectants as compared with that of wild-type cells. Protein and DNA contents in NRK52E cells were significantly decreased in the transfectants with cell proliferation in the presence of BS. When NRK52E cells with subconfluency were cultured for 24, 48, or 72 h in a medium without BS, the number of transfectant cells was not significantly changed compared with that of wild-type cells. Protein and DNA contents in NRK52E cells were significantly decreased in the transfectants cultured in a medium without BS after subconfluency. This study demonstrates that overexpression of RGPR-p117 induces the decrease in protein and DNA contents in NK52E cells, indicating its role in the regulation of cell function.