DNA repair processes in germ cells demonstrated in ejaculated sperms of rabbits treated with methyl methane sulfonate

Male rabbits were treated with a single i.v. injection of 22.5 mg/kg methyl methane sulfonate (MMS). 0–24 h later [³H]-thymidine was injected in both testicles. Incorporation of the isotope in germ cell DNA was demonstrated in ejaculated sperms. In controls labeled sperms were demonstrated first on day 40–43. These cells were in the preleptotene spermatocyte phase at the time of [³H]-thymidine injection. In rabbits treated with MMS significant radioactivity occurred in sperms collected from day 19 onwards. These cells were in late spermatocyte and early spermatid phase of maturation when [³H]-thymidine was injected. Incorporation of thymidine in these cell populations is interpreted as an expression of unscheduled DNA synthesis, a repair process initiated after chemical damage of germ cell DNA by MMS. The usefulness of the rabbit test system within the framework of conventional mutagenicity screening tests is discussed.     

Induction of unscheduled DNA synthesis by chemical mutagens in testicular cells of the mouse in vitro

Testicular cells of male mice were isolated, and the incorporation of tritium labeled thymidine into the DNA of the cells was estimated after exposure to various chemical mutagens. The normal semiconservative DNA synthesis was suppressed by the addition of hydroxyurea. Thirteen compounds were tested. Unscheduled DNA synthesis (UDS) was stimulated by ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS), N-methyl-N-nitro-N-nitrosoguanidine (MNNG) and triaziquone, and, to a lesser extent, by 4-nitroquinoline 1-oxide (4-NQO), mitomycin C, ICR-191 and nitrogen mustard (HN-2). No thymidine incorporation could be estimated after incubation of the cells with 9 aminoacridine, hydroxyurethane, -naphthylamine, 2-acetylaminofluorene (AAF) nor with N-hydroxy-2-acetylaminofluorene (N-OH-AAF).Parts of these investigations were presented in the poster session at the sixth annual meeting of the EEMS in Gernrode, Democratic Republic of Germany 1976     

Modulation of chemical carcinogen-induced unscheduled DNA synthesis by dehydroepiandrosterone (DHEA) in the primary rat hepatocytes

Modulation of unscheduled DNA synthesis by dehydroepiandrosterone (DHEA) after exposure to various chemical carcinogens was investigated in the primary rat hepatocytes. Unscheduled DNA synthesis was induced by treatment of such direct acting carcinogens as methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) or procarcinogens including benzo(a)pyrene (BaP) and 7,12-dimethylbenz(a)anthracene (DMBA). Unscheduled DNA synthesis was determined by measuring [methyl-3H]thymidine radioactivity incorporated into nuclear DNA of hepatocytes treated with carcinogens in the presence or absence of DHEA. Hydroxyurea (5x10(-3) M) was added to growth medium to selectively suppress normal replication. DHEA at concentrations ranging from 1x10(-6) M to 5x10(-4) M did not significantly inhibit unscheduled DNA synthesis induced by either MMS (1x10(-4) M) or EMS (1x10(-2) M). In contrast, DHEA significantly inhibited unscheduled DNA synthesis induced by BaP (6.5x10(-5) M) and DMBA (2x10(-5) M). DHEA-induced hepatotoxicity in rats was examined using lactate dehydrogenase (LDH) release as an indicator of cytotoxicity. DHEA exhibit no significant increase in LDH release compared with the solvent control at 18 h. These data suggest that nontoxic concentration of DHEA does not affect the DNA excision repair process, but it probably influence the enzymatic system responsible for the metabolic activation of procarcinogens and thereby decreases the amount of the effective DNA adducts formed by the ultimate reactive carcinogenic species.     

Role of glutathione modulation in acrylonitrile-induced gastric DNA damage in rats

 Acrylonitrile (VCN) or its reactive metabolites irreversibly interact with gastric DNA in vivo and cause DNA damage. The effect of glutathione (GSH) modulation on VCN-induced genotoxicity and unscheduled DNA repair synthesis (UDRS) in DNA of gastric mucosal tissues was investigated. VCN-induced UDRS was determined: in control rats, rats with depleted gastric GSH contents, and rats treated with sulfhydryl compounds. A single oral dose (23 mg/kg) of VCN induced a time-and dose-dependent increase in gastric UDRS and decrease in GSH levels. While maximal UDRS in gastric mucosa was observed 2 h following oral administration of 23 mg/kg VCN, maximal GSH depletion (50% of control) was detected 4 h following treatment. Increasing the VCN dose to 46 mg/kg caused a further decrease in gastric GSH level (27% of control), while UDRS was elevated. Inhibition of VCN oxidation by treatment of the animals with the cytochrome P450 inhibitor, SKF 525-A, prior to VCN administration caused 65% reduction in VCN-induced UDRS. Treatment of rats with the GSH depletor diethylmaleate (DEM) prior to VCN administration caused 167% increase in UDRS in gastric mucosal tissues. Treatment of the animals with the sulfhydryl compounds, cysteine and penicillamine, prior to VCN administration protected against VCN-induced UDRS. The results demonstrated an inverse and highly significant correlation between gastric GSH levels and VCN-induced UDRS (r=−0.873, P<0.0001). In conclusion, our study indicates that VCN bioactivation and the homeostasis of gastric GSH may play a major role in the initial processes underlying VCN-induced gastric carcinogenesis. Received: 24 January 1996/Accepted: 9 April 1996     

DDRT法筛选抗肿瘤海洋微生物

海洋微生物药物资源是近年来寻找新药的研究热点。本文先采用 MTT法对近千株的海洋放线菌、细菌、霉及极地和大洋细菌进行细胞毒活性的筛选。结果得到约有 10 %的放线菌、1株极地细菌及 2株霉具有细胞毒活性 ,共 4 9株。利用 DNA修复特性在 E.coli343/ 5 91和 E.coli343/ 6 36之间的差异性 ,采用DDRT法对初筛得到的具细胞毒性菌株进行 DNA损伤的筛选 ,得到 3株活性菌株 ,AK- 17是其中之一。裸小鼠试验结果提示其具有抗肿瘤作用。采用 FCM进行细胞周期的分析 ,表明经 AK- 17处理后 ,其可对 MGC-80 3肿瘤细胞在 G2 / M期产生轻微的阻滞作用 ,当处理时间增长后 ,部分细胞发生凋亡。     

3H‐labelled alkyl‐nucleotides, ‐nucleosides and ‐bases for the immunoanalytical quantification of DNA damage and repair

Analysis of the formation and repair of structurally modified DNA is of particular interest in the study of carcinogenesis, cancer therapy and aging. The quantification of specific DNA lesions by sensitive immunoanalytical methods requires radiotracers with high specific activity. We describe the synthesis of ³H‐labelled adenine‐, cytosine‐, guanine‐ and thymine‐alkyl derivatives by nucleophilic N‐ and O‐alkylation using alkyl halides and diazoalkanes: 3‐alkyl‐[8‐³H]adenine (Alkyl = Me, Et, n‐Bu); O⁶‐alkyl‐deoxy[1′,2′‐³H]guanosine (Alkyl = Me, Et, i‐Pro, n‐Bu); O⁶‐ethyl‐deoxyguanosine‐5′‐triphosphate ([2‐³H‐Ethyl]; [8‐³H]); O⁶‐alkyl‐9‐hydroxyhexyl‐[8‐³H] guanine (Alkyl=Me, Et); 7‐ethyl‐[8,5′‐³H]guanosine‐3′,5′‐cyclic‐phosphate; O²‐andO⁴‐alkyl‐[methyl, 1′,2′‐³H]thymidine (Alkyl=Me, Et); the conversion of ³H‐labelled thymidine to the corresponding 5‐methylcytidine; the synthesis of three different 8‐oxo‐guanine tracers; and the generation of thymidine glycol (5,6‐dihydroxy‐5,6‐dihydro‐[methyl‐³H]thymidine) from thymidine. All radiotracers were sucessfully employed in competitive radioimmunoassays for the quantification of defined DNA alkylation products in DNA repair analyses. Copyright © 2003 John Wiley & Sons, Ltd.     

Design,synthesis, and evaluation of a series of novel phenylpropanoic acid derivatives agonists for the FFA1

Free fatty acid 1 (FFA1/GPR40) has attracted extensive attention as a novel target for the treatment of type 2 diabetes for its role in the enhancement of insulin secretion with glucose dependency. Aiming to develop novel potent FFA1 agonists, a new series of phenylpropionic acid derivatives were designed and synthesized on the basis of the modification of chemical cement of TAK‐875, AMG‐837, and LY2881835. Among them, most promising compounds 7 , 14 , and 15 were obtained with EC₅₀ values of 82, 79, and 88 nM, exhibiting a powerful agonistic activity compared to TAK‐875 (95.1 nM). During Oral glucose tolerance test in normal mice, compound 7 , 14 , and 15 had significant glucose‐lowering effect at the dose of 50 mg/kg. Furthermore, compound 15 (50 mg/kg) also significantly improved in glucose tolerance in type 2 diabetic mice. Herein, we reported the discovery and optimization of a series of potent FFA1 agonists. The discovery supported further exploration surrounding this scaffold.     

镉对LLC─P_1细胞增殖与DNA合成的影响及硒的保护效应

观察了镉（Ｃｄ）对猪肾近曲小管上皮细胞（ＬＬＣ－ＰＫ１）增殖和ＤＮＡ合成代谢的影响，及亚硒酸钠和硒代蛋氨酸的保护作用。结果表明，Ｃｄ对ＬＬＣ－ＰＫ１细胞增殖有明显的抑制作用；低浓度Ｃｄ（３μｍｏｌ／Ｌ）与细胞作用３小时，对ＤＮＡ合成有一定的促进作用；当Ｃｄ浓度达到１６μｍｏｌ／Ｌ时ＤＮＡ合成受到明显的抑制；Ｃｄ与细胞作用１２小时，对ＲＮＡ及蛋白质合成也具有明显的抑制作用。结果还显示，Ｎａ２ＳｅＯ３对Ｃｄ抑制的ＤＮＡ合成作用无任何保护作用，而Ｄ，Ｌ－ＳｅＭｅｔ在一定程度上能减轻Ｃｄ对ＬＬＣ－ＰＫ１细胞ＤＮＡ合成的抑制作用；Ｄ，Ｌ－ＳｅＭｅｔ提前或与Ｃｄ同时加入的两种给药方式，其保护作用没有明显差异。     

Evaluation of purified 4-deoxynivalenol (vomitoxin) for unscheduled DNA synthesis in the primary rat hepatocyte-DNA repair assay

Primary cultures of rat hepatocytes were used to determine unscheduled DNA synthesis (UDS) and cytotoxicity of purified 4-deoxynivalenol (vomitoxin), a trichothecene mycotoxin produced on cereal grains by fungi of the genus Fusarium. Nontoxic and toxic doses of deoxynivalenol, 0.1 to 1000 μg/ml, did not significantly increase UDS as measured by net grains per nucleus, net grains per nuclear area or percentage of cells incorporating 5, 6, 10 or 20 grains per nucleus. Evidence of cytotoxicity, manifested as a reduction in cell number in autoradiographs, pyknotic nuclei or vacuolated cytoplasm, was observed in hepatocytes treated with deoxynivalenol concentrations of 5 μg/ml and above. These findings suggest that the cellular toxicity of deoxynivalenol may not be mediated by a DNA-damaging event in cultured hepatocytes. An increased percentage of large-sized nuclei was also found to be associated with toxic doses of deoxynivalenol as well as 2-acetylaminofluorene used as the positive control.     

Distribution of the [3H]-label from low doses of radioactive ochratoxin a ingested by rats,and evidence for DNA single-strand breaks caused in liver and kidneys

The distribution of a single low dose of [³H]ochratoxin A (OTA) in different tissues of male Wistar rats, after administration by intubation, was investigated after 5 h, 24 h and 48 h. This dose corresponds to concentrations encountered in naturally contaminated feed (4 ppm). The distribution of [³H]-label varied with the time elapsed after administration; at 5 h the highest specific label was found in the stomach contents and in decreasing order in: intestinal contents, lung, liver, kidney, heart, fat, intestine, testes, and the lowest in muscles, spleen and brain. With exception of brain, fat, stomach and lung, all tissues showed maximum levels at 24 h, after which time the label decreased steadily, whereas in fat it increased.After a 12-week feeding experiment, with doses of 288.8 g/kg corresponding to an intake of 4 ppm in feed each 48 h, the DNA in liver and kidneys was investigated for damage. By the alkaline elution method combined with micro-spectrofluorimetric determinations of DNA, evidence for DNA single-strand breaks was obtained. These findings support reports on the carcinogenic action of OTA.     

Design,synthesis and evaluation of DNA nano-cubes as a core material protected by the alginate coating for oral administration of anti-diabetic drug

Poor control towards glycemic levels among diabetic patients may lead to severe micro/macro-vascular and neuropathic complexities. Proper functioning of alpha-beta cells of pancreases is required to attain long term glycemic control among type 2 diabetics. The recent developments to manage diabetes are focused on controlling the insulin-glucagon secretions from the pancreases. DPP-4 inhibitors class of drugs after elevating GLP-1/GIP (incretins) levels in the blood, not only raise the insulin levels but also suppress the glucagon level. Vildagliptin (VI) is a potent DPP-4 inhibitor with least adverse events compared to other DPP-4 inhibitors. We encapsulated VI into 3D nanocube that gets bind to the DNA due to secondary amine in its chemical structure. DNA-nanocube being negatively charged was incubated with the PLL to attain positive surface. Ultimately VI loaded nanocubes were coated with the negatively charged Na-alginate via electrostatic attraction method to get stable spherical nanospheres for oral delivery of VI. Nanospheres were evaluated physically through native PAGE analysis, DSC, TGA, dissolution testing, XRD and FTIR. We attained uniformed and spherical nanospheres with stable topology, nanoscale size precision (40–150 nm in diameter), Entrapment efficiency (up to 90%), prolonged drug release (13 ± 4 h) at basic pH, and superior oral antidiabetic effects with improved GLP1 and glycemic levels. The formulated nanospheres attained size uniformity and better therapeutic outcomes in terms of reduced adverse events and better control of glycemic levels than previously reported methods with decreased dosage frequency tested in Db/Db mice.     

Suppression of apoptosis and induction of DNA synthesis in vitro by the phthalate plasticizers monoethylhexylphthalate (MEHP) and diisononylphthalate (DINP): a comparison of rat and human hepatocytes in vitro

Diethylhexylphthalate (DEHP) and diisononylphthalate (DINP) are plasticizers with many important commercial, industrial and medical applications. However, both DEHP and DINP are rodent peroxisome proliferators (PPs), a class of compounds that cause rodent liver tumours associated with peroxisome proliferation, induction of hepatic DNA synthesis and the suppression of apoptosis. Despite these effects in the rodent, humans appear to be nonresponsive to the adverse effects of PPs. Previously, we have shown that the fibrate hypolipidaemic peroxisome proliferator, nafenopin, induced DNA synthesis and suppressed apoptosis in rat but not in human hepatocytes. In this work, we have examined species differences in the response of rat and human hepatocytes to DEHP and DINP in vitro. In rat hepatocytes in vitro, both DINP and MEHP (a principle metabolite of DEHP and the proximal peroxisome proliferator) caused a concentration-dependent induction of DNA synthesis and suppression of both spontaneous and transforming growth factor β1 (TGFβ1)-induced apoptosis. Similarly, both MEHP and DINP caused a concentration-dependent induction of peroxisomal β-oxidation although the response to DINP was less robust. In contrast to the pleiotropic response noted in rat hepatocytes, neither DINP nor MEHP caused an induction of β-oxidation, stimulation of DNA synthesis and suppression of apoptosis in human hepatocytes cultured from three separate donors. These data provide evidence for species differences in the hepatic response to the phthalates DEHP and DINP, confirming that human hepatocytes appear to be refractory to the hepatocarcinogenic effects of PPs first noted in rodents. Received: 16 August 1999 / Accepted: 21 September 1999     

Neverland regulates embryonic moltings through the regulation of ecdysteroid synthesis in the water flea Daphnia magna,and may thus act as a target for chemical disruption of molting

Embryo development in arthropods is accompanied by a series of moltings. A cladoceran crustacean Daphnia magna molts three times before reaching first instar neonate during embryogenesis. Previous studies argued ecdysteroids might regulate D. magna embryogenesis. However, no direct evidence between innate ecdysteroids fluctuation and functions has been forthcoming. Recently, we identified genes involved in ecdysteroid synthesis called, neverland (neverland1 and neverland 2) and shade and in the ecdysteroid degradation (Cyp18a1). To understand the physiological roles of ecdysteroids in D. magna embryos, we performed expression and functional analyzes of those genes. Examining innate ecdysteroids titer during embryogenesis showed two surges of ecdysteroids titer at 41 and 61 h after oviposition. The first and second embryonic moltings occurred at each ecdysteroid surge. Expression of neverland1 and shade began to increase before the first peak in ecdysteroid. Knockdown of neverland1 or shade by RNAi technique caused defects in embryonic moltings and subsequent development. The ecdysteroids titer seemingly decreased in nvd1‐knowckdown embryos. Knockdown of Cyp18a1 resulted in early embryonic lethality before the first molting. Our in situ hybridization analysis revealed that nvd1 was prominently expressed in embryonic gut epithelium suggesting the site for an initial step of ecdysteroidgenesis, a conversion of cholesterol to 7‐dehydrocholesterol and possibly for ecdysone production. Taken together, de novo ecdysteroid synthesis by nvd1 in the gut epithelial cells stimulates molting, which is indispensable for D. magna embryo development. These findings identify neverland as a possible target for chemicals, including various pesticides that are known to disrupt molting, development and reproduction. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of combinations of Fusarium mycotoxins on the inhibition of macromolecular synthesis, malondialdehyde levels, DNA methylation and fragmentation, and viability in Caco-2 cells.

We studied the interactive effects of either binary or tertiary mixtures of Fusarium mycotoxins, deoxynivalenol (DON), zearalenone (ZEA), and fumonisin B1 (FB1) on the human intestinal cell line, Caco-2, using the endpoints including malonedialdehyde (MDA) production, inhibition of protein and DNA syntheses, DNA methylation, DNA fragmentation, and cell viability as measured by the neutral red (NR) test. The mixtures of mycotoxins reduce cellular viability in increasing order: [FB1+ZEA]<[FB1+DON]<[ZEA+DON]<[FB1+DON+ZEA] in NR test. Because FB1 antagonizes the effects of estrogenic Zearalenone, FB1 was assayed against estradiol. In NR assay, mixture of FB1 and estradiol and/or ZEA improves Caco-2 cells viability in contrast to individual effects. Mixtures of ZEA or FB1 and DON, display synergistic effects in lipid peroxidation. The ability of the toxins to inhibit DNA synthesis is 45%, 70%, and 43% for 10 microM of ZEA, DON, and FBI, respectively. Their binary mixtures (at 10 microM each), inhibit DNA synthesis by 35%, 62%, and 65%, far less than additive effects. Surprisingly, the tertiary mixture (10 microM each) only inhibits DNA synthesis by 25%. ZEA, DON, and FB1 induce DNA fragmentation individually. However, mixtures of these mycotoxins always damage DNA to a greater extent. Each individual mycotoxin (10 microM) raises the percentage of 5-methylcytosine (m5dC) in DNA from 4.5% to 9%, while the combination does not increase this rate any further. Altogether, the data indicate that mixtures of Fusarium toxins are able to induce lipid peroxidation, DNA damage, DNA fragmentation, DNA methylation, and cytotoxicity in Caco-2 cells, and suggest a potential promoter effect in human intestinal cells.     

The DNA repair host-mediated assay as a rapid and sensitive in vivo procedure for the determination of genotoxic factors present in various organs of mice

The DNA repair host-mediated assay, in which repairable DNA damage is determined in E. coli cells present in various organs of mice exposed to genotoxic agents, was further developed to broaden the range of organs under study and to simplify the procedure of assessing differential bacterial cell survival. A pair of derivatives of E. coli K-12 strain 343/113 was constructed which differed vastly in DNA repair capacity (uvr ⁺/rec ⁺ vs uvrB/recA), as a means of assessing DNA damaging effects; furthermore, the strains differed in their ability to ferment lactose ( Lac vs Lac ⁺), so that the individual survival of both strains could be determined on a single agar medium (containing neutral red as pH indicator), on which the strains had different colony colour morphology (red, Lac ⁺ vs white, Lac ^– colonies). Finally, the strains were made streptomycin-dependent, to prevent uncontrolled growth of the bacterial cells within the various organs and also to inhibit contamination of the survival agar medium by representatives of the normal intestinal microflora.The experimental procedure consisted of injecting mixtures of stationary cells of the two strains (ca. 3–5×10⁸ viable cells per mouse) both intravenously and orally into mice, either pretreated or subsequently treated with test chemicals. Ninety minutes after injection of the bacteria, the liver, spleen, lungs, kidneys, stomach, intestine, colon, and ca. 50 l blood, were removed, suspended in buffer, homogenized, and the survival of the two strains determined on neutral red agar supplemented with streptomycin.In preliminary experiments in which the mice were treated with intraperitoneal injections of mitomycin C (0–2.0 mg per kg body weight), a dose-dependent increase in DNA damaging activity was induced in bacterial cells present in all organs tested, the lowest effects being observed in kidneys and lungs, and the highest in liver and blood. These results need further confirmation in more extensive tests, but they do nevertheless clearly indicate the possible usefulness of the DNA repair host-mediated assay as a rapid biological dose monitor for obtaining information on the genotoxic activity in vivo of compounds for which long-term mutagenicity and carcinogenicity data are not yet available.     

Test battery with the human cell line activation test,direct peptide reactivity assay and DEREK based on a 139 chemical data set for predicting skin sensitizing potential and potency of chemicals

To develop a testing strategy incorporating the human cell line activation test (h‐CLAT), direct peptide reactivity assay (DPRA) and DEREK, we created an expanded data set of 139 chemicals (102 sensitizers and 37 non‐sensitizers) by combining the existing data set of 101 chemicals through the collaborative projects of Japan Cosmetic Industry Association. Of the additional 38 chemicals, 15 chemicals with relatively low water solubility (log Kow > 3.5) were selected to clarify the limitation of testing strategies regarding the lipophilic chemicals. Predictivities of the h‐CLAT, DPRA and DEREK, and the combinations thereof were evaluated by comparison to results of the local lymph node assay. When evaluating 139 chemicals using combinations of three methods based on integrated testing strategy (ITS) concept (ITS‐based test battery) and a sequential testing strategy (STS) weighing the predictive performance of the h‐CLAT and DPRA, overall similar predictivities were found as before on the 101 chemical data set. An analysis of false negative chemicals suggested a major limitation of our strategies was the testing of low water‐soluble chemicals. When excluded the negative results for chemicals with log Kow > 3.5, the sensitivity and accuracy of ITS improved to 97% (91 of 94 chemicals) and 89% (114 of 128). Likewise, the sensitivity and accuracy of STS to 98% (92 of 94) and 85% (111 of 129). Moreover, the ITS and STS also showed good correlation with local lymph node assay on three potency classifications, yielding accuracies of 74% (ITS) and 73% (STS). Thus, the inclusion of log Kow in analysis could give both strategies a higher predictive performance. Copyright © 2015 John Wiley & Sons, Ltd.     

Perspectives for the use of biotechnology in green chemistry applied to biopolymers,fuels and organic synthesis: from concepts to a critical point of view

Since the eighteenth century, after the first industrial revolution, humans have been exploiting the planet's natural resources in an unsustainable manner. This has caused some irreversible impacts on the environment. Because of this, we are facing a change of philosophy within the scientific community about chemical and industrial processes. During the 1990s, the concepts of green chemistry began to solidify, while in parallel some major advances in biotechnology were achieved through developments of genomic sciences and genetic and metabolic engineering. This work will discuss some new insights into the use of biotechnology as an important tool in green chemistry, showing new applications to biopolymers, biofuels and as a new alternative to traditional organic synthesis, making chemical processes more sustainable and less damaging to the planet.     

New mild acid-labile protecting groups for the guanidino function of Nα-fluorenylmethoxycarbonyl-l-arginine in solid-phase peptide synthesis: 10, 11-dihydro-5H-dibenzo[a,d]. cyclohepten-5-yl, 2-methoxy-10, 11-dihydoro-5H-dibenzo[a,d]. cyclohepten-5-yl and 5H-dibenzo[a,d]. cyclohepten-5-yl groups

10, 11-Dihydro-5H-dibenzo[a, d]. cyclohepten-5-yl [5-dibenzosuberyl]. and 5H-dibenzo[a, d]. -cyclohepten-5-yl [5-dibenzosuberenyl]. groups have been found to be useful protecting groups for the guanidino function of arginine in solid-phase peptide synthesis on Fmoc chemistry. The arginine derivatives ( 4a, b, c ) derivatized with these groups were easily deprotected with mild acid (less than 30 min with 25% trifluoroacetic acid). Tryptophan-containing peptide sequences, two hexapeptides ( 6 ) and (8), were synthesized in good yield by mild acid treatment (50% trifluoroacetic acid in 1 h) of the peptide resins ( 5a, c-f and 7a, c, d ) assembled via 4a, b, c using benzotriazol-1 -yl-oxy-tris-(pyrrolidino)-phosphonium hexafluorophosphate-1-hydroxybenzotriazole mediated coupling.