Radiation induced mutagen sensitivity and chlorophyll mutation frequency on sesame seeds

Aim: Effect of gamma irradiation on genomic disorder in sesame are scanty. The present study was undertaken to evaluate the mutagenic effects of gamma rays on different parameters in two popular cultivars of sesame, Roma and Tilottama. Methodology: Seeds of these two cultivars were irradiated with five doses of gamma rays: (250, 300, 350, 400, and 450 Gy) at BARC, Trombay and were sown (along with the un-irradiated control) during March 2015 in a split plot design with 3 replications keeping row to row and plant to plant distance at 30 cm and 10 cm, respectively to determine mutagen sensitivity with regard to pollen fertility (%), germination (%) and seedling height (cm), root-shoot length (cm), plant survival (%) at maturity in M1 generation. To study mutability, four to five capsules from each M1 plants in all the treatments were collected separately to give rise the M2 generation. Individual plant progeny rows were sown in M2 during March 2016. ID50 was determined by probit analysis for germination, shoot-root length and plant survival. Since the dose requirement for pollen fertility is very high, ID30 was calculated instead of ID50 value. Results: It was observed that with increasing doses of gamma rays, the response of all characters decreased significantly and followed a linear relationship in both varieties. The root system was more profound to gamma rays than the shoot. Chlorophyll mutations showed independent response to different doses of gamma rays as they occurred in random. The mutability of genotype Roma induced with different doses of gamma rays was higher than that of Tilottama. Interpretation: Due to saturation in the mutational actions, response of characters decreased with increase in gamma ray doses but magnitudes of effect differed between genotypes. The cultivar Tilottama was found to be more sensitive than Roma.

Synthesis and Characterization of Novel Hydrazone Based Anti-mutagenic and Antioxidative Agents.

The present study was designed to produce novel hydrazine and evaluate their biological properties including antioxidant, antityrosinase and antimutagenic. 4-allyloxybenzoyl hydrazine (1) reacts with 5-acetyl-1,3-dimethyl barbituric acid (2) and 2-Isonitrosoacetophenone (3) in the presence of acetic acid as a catalyst to produce the hydrazone derivatives 4 and 5 in high yields respectively. The new hydrazone derivatives 4 and 5 have been fully characterized by using multinuclear NMR (1H, 13C) spectroscopy and elemental analysis. The compounds 4 and 5 were studied for their antioxidant and tyrosinase enzyme inhibition activity. In addition the mutagenic and antimutagenic activities were evaluated by Ames Salmonella/ microsome mutagenicity test. The results showed that both of compounds exhibited significant antioxidative and antimutagenic activity and compound 5 has shown moderate tyrosinase inhibition activity. This study suggested that these compounds could be considered as novel bioactive agents in pharmaceutical area.

Altered DNA repair, oxidative stress and antioxidant status in coronary artery disease.

Coronary artery disease (CAD) is a multifactorial disease caused by the interplay of environmental risk factors with multiple predisposing genes. The present study was undertaken to evaluate the role of DNA repair efficiency and oxidative stress and antioxidant status in CAD patients. Malonaldehyde (MDA), which is an indicator of oxidative stress, and mean break per cell (b/c) values, which is an indicator of decreased DNA repair efficiency, were found to be significantly increased in patients compared to normal controls (P<0.05) whereas ascorbic acid and GSH were found to be lower among patients than the control group. It has been found that elevated oxidative stress decreased antioxidant level and decreased DNA repair efficiency can contribute to the development of CAD. This study also showed that high MDA, low ascorbic acid and GSH were significantly associated with high b/c value.

Enhancement of wanlongmycin production by nitrogen ion beam implantation / Mejora de la producción de wanlongmycin por implantación de haces iónicos de nitrógeno

In an attempt to obtain an industrial strain with higher yield of wanlongmycin, the wild strain Streptomyces griseovariabilis GAAS2507 was mutated by a novel mutagen, nitrogen ion beam with energy of 20 kilo electron volts (KeV) and dose ranging from 7.80 x 10(14) to 2.86 x 10(15) ions/cm². One mutant strain WN939 was obtained. Its yield of wanlongmycin reached 271.24 µg/mL, which was 82.10 percent higher than that of the wild strain. The mutant strain WN939 was relatively stable for the production of wanlongmycin through six successive transfers of cultures and a repeat fermentation in a 30 L fermentor. In addition, the mutant strains were investigated and divided into five types by their colony phenotypes and production of wanlongmycin. Among them, three types mutant strains exhibited positive mutation, while the other two types mutant strains exhibited negative mutation.

A new approach for exploiting microbial new strain resources for drug screening / 国际药学研究杂志

Generally absolute majority of wild-type microbial strains do not produce bioactive metabolites, resulting in large numbers of so-called 'useless strains' stocked or destroyed. These strains, however, would become a great source of bioactive meabolites if their secondary metabolism could be altered to produce diverse metabolites. We have therefore undertaken a research work on exploiting microbial new strain resources for drug screening by altering secondary metabolism of the 'useless strains' to discover bioactive metabolites. A considerable progress with expectant advantage desired has been made in the studies on marine-derived actinomycetic and fungal strains. This paper summarizes our research results including several new developments in brief.

Screening for bioactive mutants with antitumor activity from an actinomycetic wild-type strain without antitumor activity by antibiotic-resistant mutation technique and by coupled with chemical mutagen-induced mutation / 军事医学科学院院刊

Objective To obtain antibiotic-resistant mutants producing metabolites with antitumor activity from wild-type actinomycete strains without antitumor activity. Methods An actinomycete strain L35-1 was used as an initial strain for obtaining antibiotic-resistant mutants, which is a marine-derived wild-type strain without antitumor activity with an inhibition rate of 2.8% at the 1000 μg/ml of high sample concentration on K562 cells. The antibiotic-resistant mutants both from auto-mutagenesis and chemical mutagen-induced mutagenesis were selected by single colony isolation on antibiotic-containing plates according to the method for obtaining drug-resistant mutants in ribosome engineering. The antitumor activity was assayed by the MTT method using K562 cells for the mutants with aqueous acetone extracts of the whole broth of their fermentation.Results A total of 114 neomycin-resistant (ner) and 68 streptomycin-resistant (str) mutants, all from auto-mutagenesis, was obtained on drug-containing plates. Among them, the 7 ner and 3 str mutants appeared to be bioactive with an inhibition rate above 20% at the 100 μg/ml sample concentration on K562 cells. On the other hand, 41 str and 32 ner mutants from DES-induced mutagenesis and 46 ner mutants from NTG-induced mutagenesis were obtained by mutagen-induced mutation coupled with the single colony isolation on antibiotic-containing plates, among which, one str mutant from DES-induced mutagenesis and one ner mutant from NTG-induced mutagenesis were bioactive with an inhibition rate over 20% at the 100 μg/ml sample concentration on K562 cells. Conclusions The present result has revealed that the wild-type actinomycete strains without bioactivity might become a great source initial strains to obtain bioactive mutants by drug-resistant mutation technique.

Mutational analysis of virus specific amino acids in the fusion active domain of paramyxovirus fusion protein / 中华微生物学和免疫学杂志

Objective To identify the effects of virus specific amino acids in the fusion active domains of paramyxovirus fusion proteins on the specific membrane fusion. Methods Site-directed mutagenesis was used to obtain mutants in the identified fusion active domains of Newcastle disease virus (NDV) fusion protein (F) and human parainfluenza virus (hPIV) fusion protein (F). All the mutant F genes were co-expressed with their homol-ogous or heterogenous hemagglutinin-neuraminidase (HN) genes in eukaryocytes. The fusion functions of mutants were assayed by Giemsa staining and reporter gene method. The expression efficiencies of mutants were assayed by fluorescence-activated cell sorter (FACS). Results In the NDV F mutants, N150D-L152D had 46.31% fusion activity of wide type. The fusion activities of N257D-N258D-Q259E, G271D-N272D and Q279E-Q281E almost disappeared, and they had only 1.25%, 3.14% and 2.23% of fusion activities, respectively, compared with wide type. N296D-N297D had 97.68% fusion activity of wide type. In the hPIV F mutants, D143A-E145A had 32.63% fusion activity of wide type. The fusion activity of E223Q-K224A almost disappeared, and it had only 1.91% fusion activity of wide type. K263A-R265A, D268A-D270A and R475A-R476A had 14.63%, 19.52% and 28.95% of fusion activities respectively compared with wild type. The analysis of FACS indicated that proteins of NDV F N257D-N258D-Q259E, G271D-N272D, Q279E-Q281E and hPIV F E223Q-K224A were not expressed on the cell surface, while proteins of the rest mutants were expressed nearly as the same as the wide types. Con-clusion As to NDV F, the amino acids of N257, N258, Q259, G271, N272, Q279 and Q281 were significant to the specific membrane fusion, and N150 and L152 were also important, but N296 and N297 were not. For hPIV F, the amino acids of E223 and K224 were significant to the specific membrane fusion, and D143, E145, K263, 11265, D268, D270, R475 and R476 were also important.

Low productivity of ribonucleotide reductase in Saccharomyces cerevisiae increases sensitivity to stannous chloride

Ribonucleotide reductase (RNR) of the yeast Saccharomyces cerevisiae is a tetrameric protein complex, consisting of two large and two small subunits. The small subunits Y2 and Y4 form a heterodimer and are encoded by yeast genes RNR2 and RNR4, respectively. Loss of Y4 in yeast mutant rnr4delta can be compensated for by up-regulated expression of Y2, and the formation of a small subunit Y2Y2 homodimer that allows for a partially functional RNR. However, rnr4delta mutants exhibit slower growth than wild-type (WT) cells and are sensitive to many mutagens, amongst them UVC and photo-activated mono- and bi-functional psoralens. Cells of the haploid rnr4delta mutant also show a 3- to 4-fold higher sensitivity to the oxidative stress-inducing chemical stannous chloride than those of the isogenic WT. Both strains acquired increased resistance to SnCl2 with age of culture, i.e., 24-h cultures were more sensitive than cells grown for 2, 3, 4, and 5 days in liquid culture. However, the sensitivity factor of three to four (WT/mutant) did not change significantly. Cultures of the rnr4delta mutant in stationary phase of growth always showed higher frequency of budding cells (budding index around 0.5) than those of the corresponding WT (budding index <0.1), pointing to a delay of mitosis/cytokinesis.

Site-Specific Mutagenesis in Human Cells by Bulky Exocyclic Amino-Substituted Guanine and Adenine Derivatives / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: 7-Bromomethylbenz[a]anthracene is a well- known mutagen and carcinogen. The aim of this study is to determine the mutagenic potency of its two major DNA adducts [N2-(benz[a]anthracen-7-ylmethyl)-2'-deoxyguanosine (b[a]a2G) and N6-(benz[a]anthracen-7- ylmethyl)-2'-deoxyadenosine (b[a]a6A)] and the simpler benzylated analogs [N2-benzyl-2'-deoxyguanosine (bn2G) and N6-benzyl-2'-deoxyadenosine (bn6A)] in Ad293 human cells and to compare to their mutagenicity in human cells and E. coli. MATERIALS AND METHODS: The shuttle vector pGP50 is capable of replicating in E. coli and human cells. Modified nucleotides were positioned in the plasmid pGP50 in a manner similar to pGP10 as described (8). Adenovirus transformed human embryonic kidney cells (line 293) were transfected with a shuttle vector containing an adduct. Two days later, the plasmids were recovered and treated with DpnI to remove unreplicated DNA. DH10B E. coli were transformed with the plasmids. Bacteria were cultured with the media containing X-gal, IPTG and ampicillin. Bacteria transformed by the plasmid with the adduct-induced mutation in the initiation codon of lacZ' form white colonies whereas bacteria transformed by the plasmid without mutation form blue colonies. RESULTS: In the human cell site-specific mutagenesis system, bn2G exhibited weak mutagenicity and bn6A was not mutagenic, although b[a]a2G or b[a]a6A produced 8% and 7% mutant colonies, respectively. At the site of the adduct, b[a]a2G induced the G--> T transversion mutation while b[a]a6A produced the A--> G transition mutation. CONCLUSION: These data indicate that bulkier b[a]a2G and b[a]a6A exhibit significantly greater mutagenicity in human cells than in E. coli.

ACRIDINE MUTAGEN ICR-170 INDUCED DEVELOPMENTAL SUPPRESSION OF OVARY AND VITELLINE GLAND IN FEMALE SCHISTOSOMA JAPONICUM / 中国寄生虫学与寄生虫病杂志

Mice of Kunming strain were infected with Schistosoma japonicum cercariae previously incubated with various concentrations of acridine mutagen ICR-170 for different time durations. At 6 weeks after infection, the mice were autopsied. The results showed that 24 out of 28(85. 7%) adult female worms had deformed or lacked ovaries and vitelline glands when the cercariae were treated with the agent at a concentration of 10?g/ml and incubated at 30. 5℃ for 30min. No apparnet changes were observed in the male worms inhabiting the mesenteric and portal veins with the females worms in their gynecophoral canals. The mutagenized female schistosomes obtained from the present experiment might be served as another form of attenuated worms for the induction of protective immunity.

The Cytogenetic Effects of Mutagens on Mouse Offspring / 대한정형외과학회잡지

When chemical agents penetrate the placenta, it is potentially hazardous to the embryo because the embryonic stage is known to be extremely sensitive to various toxic agents. It has been reported that exposure to some chemical agents during pregnancy resulted in the induction of malformation or cancer in the offspring of experimental animals (Larsen, 1947; Klein, 1952; DiPaolo, 1964; Druckrey et al. 1966; Mohr et al, 1966; DiPaolo and Elis, 1967; Spatz and Laqueus, 1967; Alexandrov, 1968; Fujii and Nishimura, 1969; Rice, 1969; Bulay and Wattenberg, 1970; Currie, 1970; Vesselinovitch et al, 1971; Swenberg et al, 1972; Nomura et al, 1973). Fraser and Fainstat (1954) and Kalter (1954) found that administration of cortisone to pregnant female mice induced the appearance of cleft palates in the offspring. The frequency with which this deformity appears was observed to depend on: I) the genotype of the treated animal (strain differences), 2) the dose of the chemical administered, 3) the time during the gestation period when the animal was treated. A single intraperitoneal injection of 5-fluorouracil at 10, 11, 12 or 13 days after copulation in mice also produced abnormalities to the feet, deft palate and deformities of the tail in a large proportion of fetuses (Dagg, 1960). Urethan has been considered to be a highly teratogenic and carcinogenic agent in experimental animals (Nishimura and Kuginuki, 1958: Nomura and Okamoto, 1972). However, they stated that accurate timing of urethan toxicity and accurate calculation of urethan dosage actually reaching the embryo make it possible to analyze the sensitivity of the developing mouse embryo to mortality, growth inhibition, malformation and neoplasm. Nomura and Okamoto (1972) reported that when pregnant mice were exposed to urethan on various days of gestation (day 5 to 19) by a single injection malformations and neoplasms were induced in their offspring. It is frequently implied that an abnormal phenotype is due to the aberration in the genotype, but it is not possible to prove the specitic causal relation. Though, the frequent association between a variety of chromosomal abnormalities solves the problem of how the genotypic and phenotypic are interreiated (Schultz, 1965). 5-bromodeoxyuridine (BUdR) and dimethylnitrosamine (DMN) induce chromosome aberrations in Chinese hamster cells cultured human lymphocytes and mouse cells in vivo (Somers and Hus, 1962; Kato, 1968; Matsuoka et al, 1979; Hahn and Kim, 1979). BUdR is a thymidine analog incorporated into only the DNA of proliferating cells and its mutagenic action is well understood (Freese, 1963). DMN is a potent carcinogen which induces tumors of the liver, lung, and kidney in rats (Magee and Bames, 1959). This agent has no teratogenic effect in rats when given in doses of different concentrations for different periods of time and by several routes of administeration during all stages of embryogeny (Alexandrov, 1967). The experiments reported in this study were undertaken to investigate the possibility that treatment of ICR inbred pregnant mice with BUdR and DMN might shows deformities or abnormalities in their offspring and also to determine whether chemical exposure during fetus will effect at 32 weeks after birth with second exposure to DMN by cytogenetical means. In this study, estrus ICR females were mated and 32 mice which had been diagnosed as pregnant were used. BUdR at the rate of 70, 100 and 150mg/kg of body weight was injected intraperitoneally at 6, 7, 8 days and 9, 11, 13 days of gestation, and DMN at the rate of 10, 20 and 30 mg/kg of body weight was injected at 8, 10, 12 days and 14, 15, 16 days of gestation, The offspring were examined macroscopicaily at time of birth for malformations. All animals were killed at 32 weeks of age and examined for liver abnormalities. The liver were cultured and treated with 1, 5 and 10 ug/ml of DMN for 18 hours. The frequencies of chromosome aberrations and sister chromatid exchanges (SCE) were analyzed. The results are summarized as follows: 1. The litter size was reduced on treated animals. 2. Among the 279 progeny from 36 BUdR treated mothers, malformations were seen in a total of 10 progeny and the group treated at the 9 to 13 gestation days stage had the most. 3. Of the 155 progeny from 24 mothers injected with DMN, none had any visible deformity. However. 37.5% of the group were found to have liver nodules after 32 weeks treated at the 8 to 12 gestation day stage. 4. Repetitive treatment with DMN of the liver culture of the previously BUdR and DMN treated progeny, showed increased chromosome aberrations and SCE frequencies. In conclusion since the exposure of the mother of BUdR and DMN during pregnancy leads to increased chromosomal abnormalities of the cultured liver cells of progeny when treated with DMN a second time, it is necessary to keep in mind that genetic damage may be occure to the progeny by exposing the mother during pregnancy.

Antimutagenic Effects of 17 Compounds / 第二军医大学学报

The inhibitory and antimutagenic effects of 17 compounds, cysteine (1), cinnamic acid (2), rutin (3), tannic acid (4), germanium dioxide (5), fluro uracil (6), sodium copper chlorophylline (7), B-sitosterol (8), vitamin C (9), coumarin (10), vitamin E (11), L-glutathione (oxidized form) (12), L-glutathione (reduced form) (13), sodium selenile (14), organic germanium (15), L-methioine (16) and proline (17) on the SOS response induced by N-methyl-N'-nitro-N-nitrosoguanidine, niethly muthanesulfonate, benzo (a)pyrine and UV were studied by using SOS chromotest. The results showed that compounds 1~15 revealed inhibitory effects, and compounds 2~8 and 10-11 revealed antimutagenic effects. It was demonstrated that cinnamic acid is the best antimutagen among 17 compounds. Cinnamic acid has not only inhibitory effect but also antimutagenic activity towards a wide variety of mutagens/carcinogens. The modes, specificity and end point of action of antimutagens are discussed.