Vivo Induction Research Articles

Peptides of CD200 Modulate LPS-Induced TNF-α Induction and Mortality In Vivo

Interaction of the ubiquitously expressed molecule CD200 with its receptor(s) CD200R, expressed on cells of myeloid and lymphoid origin, delivers immunoregulatory signals that modulate inflammation in a number of diseases, including transplant rejection and arthritis. A number of isoforms of CD200R have been described in mice with distinct function. We have synthesized small (9-13 mer) peptides defining distinct regions of CD200, and asked whether different peptides would function as agonists and/or antagonists of different CD200R isoforms. The assays used to characterize these functions include a model of inflammation and tumor necrosis factor-alpha production induced following lipopolysaccharide administration in vivo, and mixed leukocyte cultures in vitro. Discrete agonist and antagonist peptides were defined for different CD200Rs, which suggests this approach may have some clinical utility.

Dendritic Cell Expression of OX40 Ligand Acts as a Costimulatory, Not Polarizing, Signal for Optimal Th2 Priming and Memory Induction In Vivo

Costimulatory cross-talk can occur at multiple cellular levels to potentiate expansion and polarization of Th responses. Although OX40L ligand (OX40L) is thought to play a key role in Th2 development, the critical cellular source of this molecule has yet to be identified. In this study, we demonstrate that OX40L expression by the initiating dendritic cell (DC) is a fundamental requirement for optimal induction of primary and memory Th2 responses in vivo. Analysis of the kinetics of the residual Th2 response primed by OX40L-deficient DC suggested a failure to stimulate appropriate expansion and/or survival of T cells, rather than an inability to polarize per se. The dependence upon OX40L was predominantly due to the provision of signaling through OX40 rather than retrograde signaling to the DC. Mechanistically, impaired Th2 priming in the absence of OX40L was not due to exaggerated regulation because there was no evidence of increased expansion or function of regulatory cell populations, suppression through IL-10 production, or hyporesponsiveness to secondary challenge. These data define a critical role for DC-derived OX40L in the induction and development of Th2 responses in vivo.

In Vivo Induction of Glial Cell Proliferation and Axonal Outgrowth and Myelination by Brain-Derived Neurotrophic Factor

Brain-derived neurotrophic factor (BDNF) belongs to the neurotrophin family of neuronal cell survival and differentiation factors but is thought to be involved in neuronal cell proliferation and myelination as well. To explore the role of BDNF in vivo, we employed the intermediate pituitary melanotrope cells of the amphibian Xenopus laevis as a model system. These cells mediate background adaptation of the animal by producing high levels of the prohormone proopiomelanocortin (POMC) when the animal is black adapted. We used stable X. transgenesis in combination with the POMC gene promoter to generate transgenic frogs overexpressing BDNF specifically and physiologically inducible in the melanotrope cells. Intriguingly, an approximately 25-fold overexpression of BDNF resulted in hyperplastic glial cells and myelinated axons infiltrating the pituitary, whereby the transgenic melanotrope cells became located dispersed among the induced tissue. The infiltrating glial cells and axons originated from both peripheral and central nervous system sources. The formation of the phenotype started around tadpole stage 50 and was induced by placing white-adapted transgenics on a black background, i.e. after activation of transgene expression. The severity of the phenotype depended on the level of transgene expression, because the intermediate pituitaries from transgenic animals raised on a white background or from transgenics with only an approximately 5-fold BDNF overexpression were essentially not affected. In conclusion, we show in a physiological context that, besides its classical role as neuronal cell survival and differentiation factor, in vivo BDNF can also induce glial cell proliferation as well as axonal outgrowth and myelination.

332. Routes of Ligand Administration That Give Efficient and Robust In Vivo Induction with the RheoSwitch® Therapeutic System

The RheoSwitch|[reg]| Therapeutic System (RTS) is used to regulate both the timing and level of gene expression in response to a systemically delivered small molecule ligand, Activator Drug. This inducible gene regulation system may have utility in human gene therapies that require a specifically regulated level of gene expression, where it is desirable to terminate the therapy when it is no longer needed, or where continuation of the therapy would be unsafe. The version of RTS used in these studies was comprised of an ecdysone receptor (EcR) fused to a GAL4 DNA binding domain, a chimeric retinoid X receptor fused to a VP16 activation domain (pVP16-Hs- LmRXR) , a human secreted alkaline phosphatase (hSEAP) reporter gene placed under the control of a 6xGAL4 response element, and a transthyretin minimal promoter (p6xGAL4-TTR-SEAP). The RTS was electroporated into the quadriceps of C57BL/6 mice and Activator Drug was administered by either intraperitoneal (IP) injection, intramuscular (IM) injection, subcutaneous injection, oral gavage, or administration in the rodent chow. Although ligand-dependent gene expression was observed by all five routes of administration, Activator Drug mixed in chow was easiest to administer, could be administered continuously and may mimic administration by capsule. As an example, six groups of mice (n = four/group) were administered various concentrations of Activator Drug in rodent chow 38 days after RTS electroporation. Activator Drug was given at a rate of 300, 150, 100, 50, 25, or 12.5 mg/kg chow for 21 days, corresponding to approximate total daily Activator Drug doses of 45, 23, 15, 8, 4 and 2 mg/kg/day, respectively. In this study, both the rate of ligand-mediated induction and the magnitude of ligand-mediated hSEAP expression were dependent on the concentration of ligand in the chow. Human SEAP reached a ligand- dose dependent plateau in mice receiving 100, 150, or 300 mg/kg chow two weeks after initiation of ligand administration. The threshold for induction was observed with 50 mg Activator Drug/kg chow, which showed a small induction of hSEAP that was slightly above background. In another long-term expression study, four groups of severe combined immunodeficient (SCID) mice (n = four/group) were administered Activator Drug in chow or by single IP injection at various times after electroporation. Activator Drug administration was started at 3, 32, or 76 days after RTS electroporation. In mice receiving Activator Drug by IP injection, gene expression could be cycled on and off by repeated IP administration. Likewise, gene expression could be similarly cycled when mice were put on and taken off chow containing Activator Drug. Gene expression remained |[ldquo]|on|[rdquo]| when mice were chronically maintained on chow containing Activator Drug. These studies establish that ligand-dependent induction of transgene expression can be obtained by various routes of ligand administration, and that gene expression can be sustained for long periods of time by chronic administration of ligand in chow. Further, the results demonstrate that transgene expression under control of RTS can be cycled on and off by repeat exposure to Activator Drug.

F.33. Prevention of CIA Though Antigen Independent Matured and Semi-Matured DC: In Vivo Induction of T Reg Markers

F.33. Prevention of CIA Though Antigen Independent Matured and Semi-Matured DC: In Vivo Induction of T Reg Markers

In Vivo Induction of Cytokine mRNA and Protein in Mice by the Radioprotectant Steroid 5-Androstenediol.

Abstract We previously showed 5-androstenediol (5-AED) injected sc enhanced survival in mice exposed to whole-body gamma-irradiation, ameliorated radiation-induced neutropenia in mice, dogs, and monkeys, and induced increases in bone marrow GM-CFC in irradiated mice. Radiation-induced decreases in platelets, natural killer cells, red blood cells, and monocytes were also blunted by the steroid. Administration of 5-AED caused functional activation of circulating granulocytes (phagocytic ability), monocytes (oxidative burst), and natural killer cells (surface CD11b expression). To test our hypothesis that 5-AED acts via initiation of a cytokine cascade in hematopoietic tissue, we performed real time quantitative PCR on spleen samples taken from mice and correlated the results with serum ELISA. PCR was performed for mRNAs of GM-CSF, IL-6, IL-10, IL-12, and IFNg. Spleens and serum were taken at 3 time points: 4 h after 5-AED or vehicle (PEG-400) injection, and 4 or 24 h after irradiation (7.5 Gy whole-body gamma) or sham-irradiation. Each group contained 5 mice. Results were analyzed by 2-way ANOVA for PCR results 4 and 24 h after irradiation, and by a t-test 4 h after injection. Radiation alone induced increases in mRNAs for all cytokines at both 4 and 24 h, except for IFNg, which was not elevated at 4 h. 5-AED alone did not induce a significant increase for any cytokine, but the increases bordered on significance for IL-12 at 4 h after irradiation or sham-irradiation (28 h after injection, p = 0.07), and for GM-CSF 24 h after irradiation or sham-irradiation (48 h after injection, p = 0.08). There was a significant positive interaction between radiation and 5-AED for IL-6, 4 h after irradiation (p = 0.006). The interaction effect bordered on significance for IL-12 4 h after irradiation (p = 0.07) and for GM-CSF 24 h after irradiation (p = 0.10). ELISA for serum cytokine protein was measured for G-CSF, IL-6, IL-10, and IL-12. Results were analyzed by the Mann-Whitney test for exact p-values. IL-6 was not detected in serum. G-CSF was detected 4 and 24 h after irradiation or sham-irradiation only in 5-AED-treated mice. IL-10 and IL-12 were detected only 24 h after irradiation, and the values in 5-AED-treated mice were significantly higher than those in vehicle-treated mice (p = 0.02). The results support our hypothesis that the previously observed increases in numbers of circulating innate immune cells and platelets, and functional activation of granulocytes, monocytes, and NK cells, result from a cytokine cascade induced by 5-AED.

In vivo induction of endothelial apoptosis leads to vessel thrombosis and endothelial denudation: a clue to the understanding of the mechanisms of thrombotic plaque erosion.

The mechanisms of thrombosis on plaque erosion are poorly understood. We examined the potential role of endothelial apoptosis in endothelial erosion and vessel thrombosis. Segments of New Zealand White rabbit femoral arteries were temporarily isolated in vivo. One artery was incubated with staurosporin for 30 minutes, whereas the contralateral artery was incubated with saline and served as control. Three days later, thrombosis was evaluated angiographically and histologically. TUNEL score in the endothelial layer was significantly increased in staurosporin-treated arteries compared with controls (2.43+/-0.30 versus 0.93+/-0.44, respectively; P=0.001). Large areas of endothelial denudation were detectable in staurosporin-treated vessels, whereas endothelium integrity was almost preserved in the saline group. Vessel thrombosis occurred in 58% of staurosporin-treated arteries (7 of 12) but in only 8% of saline-treated segments (P<0.01). Immunoreactivities for tissue factor, platelets, and fibrin were detectable within the thrombus. Addition of ZVAD-fmk (0.1 mmol/L) significantly reduced the occurrence of thrombosis (1 of 7 arteries or 14%, P=0.04). These results were confirmed in balloon-injured atheromatous arteries. In vivo induction of endothelial apoptosis leads to both vessel thrombosis and endothelial denudation. Endothelial apoptosis may be a critical step in the transition from a stable endothelialized plaque to plaque erosion and thrombosis.

In vivo induction of virulence and antibiotic resistance transfer in Enterococcus faecalis mediated by the sex pheromone-sensing system of pCF10.

Enterococcus faecalis has become one of the most notable nosocomial pathogens in the last decade. Aggregation substance (AS) on the sex pheromone plasmids of E. faecalis has been implicated as a virulence factor in several model systems. We investigated the AS-encoding plasmid pCF10 for its ability to increase virulence in a rabbit endocarditis model. Cells containing pCF10 increased the virulence in the model significantly, as assessed by an increase in aortic valve vegetation size. The results confirmed in vivo induction of the normally tightly controlled AS. In addition to the expression of AS when E. faecalis cells were in contact with plasma, plasmid transfer of the tetracycline resistance-carrying plasmid was also activated in vitro and in vivo. In vivo, plasmid transfer reached remarkable frequencies of 8 x 10(-2) to 9 x 10(-2). These values are comparable to the highest frequencies ever observed in vitro. Cells harboring pCF10 had a significant survival advantage over plasmid-free cells indicated by pCF10 present in two-thirds of the recipient population. Plasma induction was dependent on the presence of the plasmid-encoded PrgZ protein, indicating the requirement of the pheromone-sensing system in the induction process. The data suggested that the mechanism of in vivo induction may involve interference of plasma with the normal function of the pheromone peptide and its inhibitor.

Opponent Activities of Shh and BMP Signaling during Floor Plate Induction In Vivo

We performed in vivo experiments in chick embryos that examined whether application of an exogenous source of Shh protein mimics the ability of the notochord to induce ectopic floor plate cells in the neural tube. Shh cannot act alone to induce a floor plate. However, coapplication of Shh and chordin, a BMP antagonist normally coexpressed with Shh in the notochord, results in a marked switch from dorsal to ventral cell fate, including a dramatic and widespread induction of floor plate cells. These data provide in vivo evidence that notochord-derived BMP antagonists may normally generate a permissive environment for the Shh-mediated induction of floor plate. Further experiments performed to address the source of BMPs that are inhibited by the action of chordin suggest that they derive specifically from the surface ectoderm and dorsal-most neuroepithelium. These data indicate that, at neural groove stages, dorsally derived BMPs affect ventral-most regions of the neural plate, suggesting a novel long-range action of BMPs. Together, these studies suggest that the balance of dorsally derived signals and notochord-derived signals determines the extent of floor plate cell induction.

The DNA Damage Signal for Mdm2 Regulation, Trp53 Induction, and Sunburn Cell Formation In Vivo Originates from Actively Transcribed Genes

The stratum corneum and DNA repair do not completely protect keratinocytes from ultraviolet B. A third defense prevents cells with DNA photoproducts from becoming precancerous mutant cells: apoptosis of ultraviolet-damaged keratinocytes ("sunburn cells"). As signals for ultraviolet-induced apoptosis, some studies implicate DNA photoproducts in actively transcribed genes; other studies implicate non-nuclear signals. We traced and quantitated the in vivo DNA signal through several steps in the apoptosis-signaling pathway in haired mice. Homozygous inactivation of Xpa, Csb, or Xpc nucleotide excision repair genes directed the accumulation of DNA photoproducts to specific genome regions. Repair-defective Xpa-/- mice were 7-10-fold more sensitive to sunburn cell induction than wild-type mice, indicating that 86-90% of the ultraviolet B signal for keratinocyte apoptosis involved repairable photoproducts in DNA; the remainder involves unrepaired DNA lesions or nongenomic targets. Csb-/- mice, defective only in excising photoproducts from actively transcribed genes, were as sensitive as Xpa-/-, indicating that virtually all of the DNA signal originates from photoproducts in active genes. Conversely, Xpc-/- mice, defective in repairing the untranscribed majority of the genome, were as resistant to apoptosis as wild type. Sunburn cell formation requires the Trp53 tumor suppressor protein; 90-96% of the signal for its induction in vivo involved transcribed genes. Mdm2, which regulates the stability of Trp53 through degradation, was induced in vivo by low ultraviolet B doses but was suppressed at erythemal doses. DNA photoproducts in actively transcribed genes were involved in approximately 89% of the Mdm2 response.

In Vivo Induction of Hair Growth by Dermal Cells Isolated from Hair Follicles After Extended Organ Culture

Successful hair follicle organ culture has been established for some time, but hair growth in vitro is limited and generally terminates prematurely in comparison with in vivo. The reasons why growth stops in culture are as yet unknown. In this investigation, adult rat vibrissa follicles for which growth in culture is limited to about 10 d, were maintained in vitro for a minimum of 20 d after the hair shaft stopped growing. The pattern of fiber growth and long-term follicle pathology reflected the initial hair cycle stage at the time of isolation. Furthermore, there was evidence that a group of follicles put into culture when in late anagen were attempting to cycle in vitro. Microscopy showed that, in spite of widespread pathologic changes to the follicle epithelium, dermal cells in the follicle showed remarkable resilience. Their viability was confirmed when primary cell cultures were established from isolated dermal tissue. These cells labeled positively for alpha-smooth muscle actin, an established marker of hair follicle dermal cell phenotype in vitro. Moreover, isolated dermal tissue induced hair growth when implanted into inactivated hair follicles in vivo. These data confirm that the cessation in hair growth is not due to a loss of the inductive capacity in the dermal component. Long-term organ culture may provide opportunities to investigate factors that are expressed or lost during hair growth cessation. In addition it may be possible to develop this method further to obtain a reliable and predictable model of hair follicle cycling in vitro.

In Vitro andIn Vivo induction of bone formation using a recombinant adenoviral vector carrying the human BMP-2 gene.

It has been well established that bone morphogenetic protein-2 (BMP-2) can induce bone formation bothin vivo andin vitro, although high concentrations (up to milligrams) of BMP-2 have been required to achieve this effectin vivo. Further, clinical applications are usually limited to a single dose at the time of implantation. In an attempt to prolong the transforming effect of BMP-2 we used a recombinant adenoviral vector carrying the human BMP-2 gene (Adv-BMP2) to transduce marrow-derived mesenchymal stem cells (MSC) of skeletally mature male New Zealand white rabbits. The pluripotential MSC were incubated with Adv-BMP2 overnight followed by culture in growth medium for 1 week. Assays on tissue cultures demonstrated that these Adv-BMP2 transduced MSC produced BMP-2 protein, differentiated into an osteoprogenitor line, and induced bone formationin vitro. These MSC had increased alkaline phosphatase activity, increased expression of type I collagen, osteopontin, and osteocalcin mRNA, and induced matrix mineralization compared with both nontransduced cells and cells transduced with a control adenoviral construct. To analyze the osteogenic potentialin vivo, Adv-BMP2-transduced MSC were autologously implanted into the intertransverse process space between L5 and L6 of the donor rabbits. The production of new bone was demonstrated by radiographic examination 4 weeks later in areas implanted with cells transduced with Adv-BMP2, whereas no bone was evident at sites implanted with cells transduced with the control adenoviral construct. Histological examination further confirmed the presence of new bone formation. These accumulated data indicate that it is possible to successfully transduce mesenchymal stem cells with a recombinant adenoviral vector carrying the gene for BMP-2 such that these cells will produce BMP-2, differentiate into an osteoprogenitor line, and induce bone formation bothin vitro andin vivo. Moreover, incubation of the Adv-BMP2-transduced cells for an additional 7 days in culture before transplantation enhances the success rate in bone formation (three out of three) as compared with our previous report (one out of five, Calcif Tissue Int 63:357-360, 1998).

In vivo induction of a high-avidity, high-frequency cytotoxic T-lymphocyte response is associated with antiviral protective immunity.

Many approaches are currently being developed to deliver exogenous antigen into the major histocompatibility complex class I-restricted antigen pathway, leading to in vivo priming of CD8(+) cytotoxic T cells. One attractive possibility consists of targeting the antigen to phagocytic or macropinocytic antigen-presenting cells. In this study, we demonstrate that strong CD8(+) class I-restricted cytotoxic responses are induced upon intraperitoneal immunization of mice with different peptides, characterized as CD8(+) T-cell epitopes, bound to 1-microm synthetic latex microspheres and injected in the absence of adjuvant. The cytotoxic response induced against a lymphocytic choriomeningitis virus (LCMV) peptide linked to these microspheres was compared to the cytotoxic T-lymphocyte (CTL) response obtained upon immunization with the nonreplicative porcine parvovirus-like particles (PPV:VLP) carrying the same peptide (PPV:VLP-LCMV) previously described (C. Sedlik, M. F. Saron, J. Sarraseca, I. Casal, and C. Leclerc, Proc. Natl. Acad. Sci. USA 94:7503-7508, 1997). We show that the induction of specific CTL activity by peptides bound to microspheres requires CD4(+) T-cell help in contrast to the CTL response obtained with the peptide delivered by viral pseudoparticles. Furthermore, PPV:VLP are 100-fold more efficient than microspheres in generating a strong CTL response characterized by a high frequency of specific T cells of high avidity. Moreover, PPV:VLP-LCMV are able to protect mice against a lethal LCMV challenge whereas microspheres carrying the LCMV epitope fail to confer such protection. This study demonstrates the crucial involvement of the frequency and avidity of CTLs in conferring antiviral protective immunity and highlights the importance of considering these parameters when developing new vaccine strategies.

In Vivo Antitumor Activity and Induction of Insulin-Like Growth Factor-1-Resistant Apoptosis by SC-ααδ9

In Vivo Antitumor Activity and Induction of Insulin-Like Growth Factor-1-Resistant Apoptosis by SC-ααδ9

Kinetics and In Vivo Induction of Genetic Variation of vlsE in Borrelia burgdorferi

Kinetics and In Vivo Induction of Genetic Variation of <i>vlsE</i> in <i>Borrelia burgdorferi</i>

Probing the mechanism of the carcinogenic activation of N-nitrosodiethanolamine with deuterium isotope effects: in vivo induction of DNA single-strand breaks and related in vitro assays.

A series of bioassays, including in vivo induction of DNA single-strand breaks (SSB) and cytotoxicity in cytochrome P450 2E1-transfected cells, were utilized with N-nitrosodiethanolamine (NDELA), its deuterated isotopomers (alpha-D4NDELA and beta-D4NDELA), N-nitroso-2-hydroxymorpholine (NHMOR), and two of its deuterated isotopomers (2-D-NHMOR and 5,5-D2-NHMOR) to probe the mechanism of carcinogenic activation of NDELA and the role of its metabolite NHMOR. DNA samples, taken from the livers of male Wistar rats 4 h after the administration of NDELA, exhibited dose-dependent DNA SSB levels over the range of 0.08-0.75 mmol/kg (body weight), with the greatest SSB level at the highest dose. Deuterium isotope effects on DNA SSB levels were inversely dependent on dose: alpha-D4NDELA, 3. 22-1.37; and beta-D4NDELA, 1.38-0.79. At the lowest dose of 0.15 mmol/kg (body weight), 5,5-D2-NHMOR gave an isotope effect for DNA SSB of 2.8 while that for 2-D-NHMOR was 0.7. NDELA and beta-D4NDELA were equally cytotoxic to human P450 2E1-transfected V79 Chinese hamster cells, while alpha-D4NDELA was not. Significant DNA SSB levels were observed in these cells for NDELA and beta-D4NDELA but not for alpha-D4NDELA. A kinetic deuterium isotope effect of 2.6 for Vmax/Km was observed for the horse liver alcohol dehydrogenase-mediated oxidation of beta-D4NDELA to NHMOR, while kH/kD for alpha-D4NDELA was 1.05. These data provide the first definitive evidence for the activation of NDELA by a pathway involving the scission of the alpha-CH bond and are consistent with P450 2E1-mediated alpha-hydroxylation of NDELA producing the corresponding reactive alpha-hydroxynitrosamine.

Kinetics and in vivo induction of genetic variation of vlsE in Borrelia burgdorferi.

The Lyme disease agent, Borrelia burgdorferi, is able to persistently infect humans and animals for months or years in the presence of an active immune response. It is not known how the organisms survive immune attack in the mammalian host. vlsE, a gene localized near one end of linear plasmid lp28-1 and encoding a surface-exposed lipoprotein in B. burgdorferi B31, was shown recently to undergo extensive genetic and antigenic variation within 28 days of initial infection in C3H/HeN mice. In this study, we examined the kinetics of vlsE sequence variation in C3H/HeN mice at 4, 7, 14, 21, and 28 days and at 7 and 12 months postinfection. Sequence changes were detected by PCR amplification and sequence analysis as early as 4 days postinfection and accumulated progressively in both C3H/HeN and CB-17 severe combined immunodeficient (SCID) mice throughout the course of infection. The sequence changes were consistent with sequential recombination of segments from multiple silent vls cassette sites into the vlsE expression site. No vlsE sequence changes were detected in organisms cultured in vitro for up to 84 days. These results indicate that vlsE recombination is induced by a factor(s) present in the mammalian host, independent of adaptive immune responses. The possible inducing conditions appear to be present in various tissue sites because isolates from multiple tissues showed similar degrees of sequence variation. The rate of accumulation of predicted amino acid changes was higher in the immunologically intact C3H/HeN mice than in SCID mice, a finding consistent with immune selection of VlsE variants.

In Vivo Induction of Tyrosylprotein Sulfotransferase by Ethanol: Role of Increased Enzyme Synthesis

Tyrosine sulfation is a posttranslational modification involved in the synthesis, secretion, and biological activity of proteins and peptides. Our previous studies have demonstrated that the enzyme activity was induced by ethanol. In the present work, the induction was studied in detail. Initial experiments were conducted to examine the time course of tyrosylprotein sulfotransferase (TPST) induction in rats pair-fed liquid diets containing either ethanol or carbohydrate substitute (controls). Marked elevation of TPST activity (3-fold) was measured on day 10 in the liver and gastric mucosa of ethanol-fed rats. Ethanol-mediated enhancement was also noticed by Western-blot analysis with anti-TPST antibody in both the liver and gastric mucosa on days 5 and 10. We then determined the steady-state TPST protein turnover in ethanol-fed and control animals that were given 35S-methionine after 10 days of pair-feeding with liquid diet. The rates of TPST synthesis assessed by measuring initial rates of incorporation of 35S-methionine into TPST was increased in the liver and gastric mucosa of animals fed with ethanol. Monophasic exponential decay curves showed that TPST protein half-lives for liver (control: 34 hr, ethanol: 32 hr) and gastric mucosa (control: 52 hr, ethanol: 48 hr) did not differ between control and ethanol groups. Our overall results indicate that the in vivo induction of TPST by ethanol involves increased enzyme synthesis rather than decreased enzyme degradation.

In Vivo Induction of Tyrosylprotein Sulfotransferase by Ethanol

In Vivo Induction of Tyrosylprotein Sulfotransferase by Ethanol

In Vivo Induction of Sister Chromatid Exchanges (SCE) in a Tropical Fish, Etroplus suratensis (Bloch)

Sister chromatid exchange (SCE) test was applied to a tropical cultured fish, Etroplus suratensis by exposing to known mutagens. Intramuscular injections of methyl methane sulphonate (MMS) and cyclophosphamide (CP) for an exposure period of 96 h resulted in significant increase in the frequency of SCE in gill tissues. MMS induced dose dependent increase in SCE. The findings revealed that the test species in the present study may be used in mutagenicity assays for screening environmental pollutants.