Evaluation of the random amplified polymorphic DNA (RAPD) assay for the detection of DNA damage and mutations

Phytotoxicity and genotoxicity study of reactive red 141 dye on mung bean (Vigna radiata (L.) Wilczek) seedlings

BACKGROUND

Reactive Red (RR) 141 dye is widely used in various industrial applications, but its environmental impact remains a growing concern. In this study, the phytotoxic and genotoxic effects of RR 141 dye on mung bean seedlings (Vigna radiata (L.) Wilczek) were investigated, serving as a model for potential harm to plant systems.

METHODS AND RESULTS

Short-term (14 days) and long-term (60 days) experiments in paddy soil pot culture exposed mung bean seedlings to RR 141 dye. The dye delayed germination and hindered growth, significantly reducing germination percentage and seedling vigor index (SVI) at concentrations of 50 and 100 ml/L. In short-term exposure, plumule and radical lengths dose-dependently decreased, while long-term exposure affected plant length and grain weight, leaving pod-related parameters unaffected. To evaluate genotoxicity, high annealing temperature-random amplified polymorphic DNA (HAT-RAPD) analysis was employed with five RAPD primers having 58-75% GC content. It detected polymorphic band patterns, generating 116 bands (433 to 2857 bp) in plant leaves exposed to the dye. Polymorphisms indicated the appearance/disappearance of DNA bands in both concentrations, with decreased genomic template stability (GTS) values suggesting DNA damage and mutation.

CONCLUSION

These findings demonstrate that RR 141 dye has a significant impact on genomic template stability (GTS) and exhibits phytotoxic and genotoxic responses in mung bean seedlings. This research underscores the potential of RR 141 dye to act as a harmful agent within plant model systems, highlighting the need for further assessment of its environmental implications.

Evaluation of Apical and Molecular Effects of Algae Pseudokirchneriella subcapitata to Cerium Oxide Nanoparticles

Cerium oxide engineered nanoparticles (nCeO₂) are widely used in various applications and are, also, increasingly being detected in different environmental matrixes. However, their impacts on the aquatic environment remain poorly quantified. Hence, there is a need to investigate their effects on non-target aquatic organisms. Here, we evaluated the cytotoxic and genotoxic effects of <25 nm uncoated-nCeO₂ on algae Pseudokirchneriella subcapitata. Apical (growth and chlorophyll a (Chl a) content) and genotoxic effects were investigated at 62.5-1000 µg/L after 72 and 168 h. Results demonstrated that nCeO₂ induced significant growth inhibition after 72 h and promotion post 96-168 h. Conversely, nCeO₂ induced enhanced Chl a content post 72 h, but no significant changes were observed between nCeO₂-exposed and control samples after 168 h. Hence, the results indicate P. subcapitata photosynthetic system recovery ability to nCeO₂ effects under chronic-exposure conditions. RAPD-PCR profiles showed the appearance and/or disappearance of normal bands relative to controls; indicative of DNA damage and/or DNA mutation. Unlike cell recovery observed post 96 h, DNA damage persisted over 168 h. Thus, sub-lethal nCeO₂-induced toxicological effects may pose a more serious threat to algae than at present anticipated.

In situ detection of the genotoxic potential as one of the lines of evidence in the weight-of-evidence approach-the Joint Danube Survey 4 Case Study

Environmental studies which aim to assess the ecological impact of chemical and other types of pollution should employ a complex weight-of-evidence approach with multiple lines of evidence (LoEs). This study focused on in situ genotoxicological methods such as the comet and micronucleus assays and randomly amplified polymorphic DNA analysis as one of the multiple LoEs (LoE3) on the fish species Alburnus alburnus (bleak) as a bioindicator. The study was carried out within the Joint Danube Survey 4 (JDS4) at nine sites in the Danube River Basin in the Republic of Serbia. Out of nine sampling sites, two were situated at the Tisa, Sava, and Velika Morava rivers, and three sites were at the Danube River. The three additionally employed LoEs were: SumTUwater calculated based on the monitoring data in the database of the Serbian Environmental Protection Agency (SEPA) (LoE1); in vitro analyses of JDS4 water extracts employing genotoxicological methods (LoE2); assessment of the ecological status/potential by SEPA and indication of the ecological status for the sites performed within the JDS4 (LoE4). The analyzed biomarker responses in the bleak were integrated into the unique integrated biomarker response index which was used to rank the sites. The highest pollution pressure was recorded at JDS4 39 and JDS4 36, while the lowest was at JDS4 35. The impact of pollution was confirmed at three sites, JDS4 33, 40, and 41, by all four LoEs. At other sampling sites, a difference was observed regarding the pollution depending on the employed LoEs. This indicates the importance of implementing a comprehensive weight-of-evidence approach to ensure the impact of pollution is not overlooked when using only one LoE as is often the case in environmental studies.

Molecular Evaluation of the Impact of Nd:YAG Laser and Static Magnetic Field on Genomic DNA of Some Bacterial Isolates using RAPD-PCR

Antimicrobial therapy is frequently associated with the emergence of resistant bacteria with a high rate of morbidity and mortality worldwide. The present study was aimed at investigating the impact of a neodymium-doped yttrium aluminum (Nd:YAG) laser, and a static magnetic field (SMF) on cellular growth and DNA alteration in some clinical bacterial isolates. Samples from cutaneous wounds were collected by sterile cotton swabs from three elderly women admitted to Tikrit Teaching Hospital, Tikrit City, Iraq. Isolation and identification of Streptococcus agalactiae, Staphylococcus aureus, and Pseudomonas aeruginosa were carried out using cultural characteristics, microscopy, and biochemical tests. Three broth cultures were prepared for each of the test isolates. The first broth culture served as untreated control, the second was exposed to an Nd:YAG laser and the third was exposed to SMF. Colony counting was done on all the samples. DNA was extracted from the test bacteria and used to perform the RAPD-PCR assay. In contrast to the untreated control, the results showed that Nd:YAG laser radiation was more effective than SMF at inhibiting the cellular growth of the test isolates. Also, the radiation caused DNA alteration, which was established by decreased microbial growth, as well as the development of new bands and the loss of original bands. According to the findings of this study, the Nd:YAG laser is a promising technique for influencing the healing of infected cutaneous wounds. RAPD-PCR is also a useful biomarker assay for assessing the biological impact of laser radiation and SMF on bacteria.

The Butterfly Effect: Mild Soil Pollution with Heavy Metals Elicits Major Biological Consequences in Cobalt-Sensitized Broad Bean Model Plants

Among the heavy metals (HMs), only cobalt induces a polymorphic response in Vicia faba plants, manifesting as chlorophyll morphoses and a ‘break-through’ effect resulting in the elevated accumulation of other HMs, which makes Co-pretreated broad bean plants an attractive model for investigating soil pollution by HMs. In this study, Co-sensitized V. faba plants were used to evaluate the long-term effect of residual industrial pollution by examining biochemical (H₂O₂, ascorbic acid, malondialdehyde, free proline, flavonoid, polyphenols, chlorophylls, carotenoids, superoxide dismutase) and molecular (conserved DNA-derived polymorphism and transcript-derived polymorphic fragments) markers after long-term exposure. HM-polluted soil induced a significantly higher frequency of chlorophyll morphoses and lower levels of nonenzymatic antioxidants in Co-pretreated V. faba plants. Both molecular markers effectively differentiated plants from polluted and control soils into distinct clusters, showing that HMs in mildly polluted soil are capable of inducing changes in DNA coding regions. These findings illustrate that strong background abiotic stressors (pretreatment with Co) can aid investigations of mild stressors (slight levels of soil pollution) by complementing each other in antioxidant content reduction and induction of DNA changes.

Evaluation of the genotoxic and antigenotoxic effects of exopolysaccharide pullulan in human lymphocytes in vitro

Pullulan is a biocompatible and water-soluble exo-polysaccharide produced by primary strains of the fungus Aureobasidium pullulans. It is frequently used in the pharmaceutical and food industries. In this study, possible cytotoxic effect of pullulan was assessed using the MTT assay in the human breast cancer (MCF-7) cell line. Micronucleus (MN), micronucleus-FISH (MN-FISH), random amplified polymorphic DNA (RAPD-PCR), and comet assays were used to investigate genotoxic and antigenotoxic effects of pullulan against mitomycin C (MMC) (at MN assay) and hydrogen peroxide (at comet assay) in human lymphocytes. Antigenotoxicity was determined using two different applications: 1 h pretreatment and simultaneous treatment. In the MTT assay, pullulan significantly reduced the cell viability at 15.6-2000 μg/mL compared to the control. No significant alterations in MN rates were found in human lymphocytes treated with different concentrations of pullulan compared to the control. In contrast, co-treatment of pullulan and MMC decreased the frequency of MN in almost all the treatment concentrations and durations compared to the MMC. No significant change was observed in the frequency of the centromere-positive C + or negative C- MNi compared to the positive control. In comet assay, pullulan did not affect comet tail intensity compared to the negative control. On the contrary, pullulan in combination with H₂O₂ significantly decreased tail intensity at almost all the concentrations compared to the positive control. The changes occurring in RAPD-PCR profiles following pullulan treatments included an increase or decrease in band intensity and gain or loss of bands. These results indicate that exopolysaccharide Pullulan is not genotoxic; moreover, it possesses a protective effect against MMC and H₂O₂ induced genotoxicity. In breast cancer cells, pullulan induced cytotoxic/anti-proliferative effect.

Molecular identification and evaluation of gamma irradiation effect on modulating heavy metals tolerance in some of novel endophytic fungal strains

Heavy metal (HM) pollution is a worldwide environmental issue. Given the urgent need to develop more powerful approaches for effective phytoremediation of HMs, isolation of novel endophytic strains from hyperaccumulator plants having potent HM tolerance is the main objective in this research. Moreover, the recovered strains were characterized and subjected to radiation mutagenesis to enhance their tolerance to HMs. Among 105 isolates, Alternaria alternata AUMC14431 was identified as the most effective Cd⁺² tolerant strain having high recorded tolerance index (TI) (76.24%); in addition, the recorded minimum inhibitory concentration (MIC) was 300 ppm. Meanwhile, Chaetomium globosum AUMC14432 was identified as the most effective Pb⁺² and Ni⁺² tolerant strain having high recorded TI (97.46 and 93.34%, respectively); in addition, the evaluated MICs were 250 and 200 ppm, respectively. UV and gamma irradiation of the tested strains enhanced their Cd⁺² and Pb⁺² tolerance significantly (P ≤ 0.05). Meanwhile, irradiation had a negative impact on Ni⁺² tolerance of C. globosum. The mutation incidence at the molecular level arising from exposure to irradiation was investigated. Genomic DNA of both the wild and mutated endophytic strains were isolated followed by random amplified polymorphic DNA (RAPD-PCR) analysis, using two short primers. A remarkable difference in DNA gel pattern between the wild type and mutated strains was observed. In conclusion, the novel isolated and irradiated endophytic strains, A. alternata S5 and C. globosum El26, having high efficiency in Cd⁺² and Pb⁺² tolerance, respectively, are considered to be prospective and powerful bioremediation candidates for potential application in microbially assisted phytoremediation.

Cytotoxicity and genotoxicity of coated-gold nanoparticles on freshwater algae Pseudokirchneriella subcapitata

Gold engineered nanoparticles (nAu) are increasingly detected in ecosystems, and this raises the need to establish their potential effects on aquatic organisms. Herein, cytotoxic and genotoxic effects of branched polyethylenimine (BPEI)- and citrate (cit)-coated nAu (5, 20, and 40 nm) on algae Pseudokirchneriella subcapitata were evaluated. The apical biological endpoints: growth inhibition and chlorophyll a (Chl a) content were investigated at 62.5-1000 µg/L over 168 h. In addition, the apurinic/apyrimidinic (AP) sites, randomly amplified polymorphic deoxyribonucleic acid (RAPD) profiles, and genomic template stability (GTS) were assessed to determine the genotoxic effects of nAu. The results show algal growth inhibition at 5 nm BPEI-nAu up to 96 h, and thereafter cell recovery except at the highest concentration of 1000 µg/L. Insignificant growth reduction for cit-nAu (all sizes), as well as 20 and 40 nm BPEI-nAu, was observed over 96 h, but growth promotion was apparent at all exposures thereafter except for 40 nm BPEI-nAu at 250 µg/L. A decrease in Chl a content following exposure to 5 nm BPEI-nAu at 1000 µg/L corresponded to significant algal growth reduction. In genotoxicity studies, a significant increase in AP sites content was observed relative to the control - an indication of nAu ability to induce genotoxic effects irrespective of their size and coating type. For 5 nm- and 20 nm-sized nAu for both coating types and exposure concentrations no differences in AP sites content were observed after 72 and 168 h. However, a significant reduction in AP sites was observed following algae exposure to 40 nm-sized nAu (irrespective of coating type and exposure concentration) at 168 h compared to 72 h. Thus, AP sites results at 40 nm-size suggest likely DNA damage recovery over a longer exposure period. The findings on AP sites content showed a good correlation with an increase in genome template stability and growth promotion observed after 168 h. In addition, RAPD profiles demonstrated that nAu can induce DNA damage and/or DNA mutation to P. subcapitata as evidenced by the appearance and/or disappearance of normal bands compared to the controls. Therefore, genotoxicity results revealed significant toxicity of nAu to algae at the molecular level although no apparent effects were detectable at the morphological level. Overall, findings herein indicate that long-term exposure of P. subcapitata to low concentrations of nAu may cause undesirable sub-lethal ecological effects.

Biosynthesis of gold nanoparticles for the treatment of osteoarthritis alone or in combination with Diacerein® in a rat model

Gold (Au) compounds were used as an effective therapeutic agent for various inflammatory diseases; however, the use of Au compounds becomes limited because of its association with several side effects. Hence, gold nanoparticles (AuNPs) were developed as a new option for the medical proposes. However, the safety evaluation of gold nanoparticles (AuNPs) in osteoarthritis (OA) treatment remains vague. This study aimed to biosynthesize, characterize and evaluate the therapeutic effects of biosynthesized AuNPs and/or Diacerein^® (DIA) in experimental OA. OA was induced by a single injection of monosodium iodoacetate (3 mg/joint) in the intra-articular knee of female rats. Normal rats (N-rats) and OA-rats were treated orally for 5 weeks as follow: untreated N-rats; untreated OA-rats; N-rats received DIA (50 mg/kg b.w); N-rats received AuNPs (30 μg/kg b.w.); N-rats received AuNPs plus DIA; OA-rats received DIA; OA-rats received AuNPs, and OA-rats received AuNPs plus DIA. Blood, knee cartilage, liver and kidney samples were collected for biochemical and histological analysis. The synthesized AuNPs were nearly spherical with average size of 20 nm and zeta potential of 33 mV. AuNPs and DIA induced a significant improvement in serum inflammatory cytokines, biochemical parameters, estrogen level, hepatic and renal oxidative markers, hepatic DNA fragmentation, genomic template stability and cartilage joint histology of OA-rats. AuNPs were more effective than DIA and the combined treatment was more effective than the single treatment. It could be concluded that AuNPs are promising for the treatment of OA alone or in combination with DIA.

Butylated hydroxytoluene and Butylated hydroxyanisole induced cyto-genotoxicity in root cells of Allium cepa L

This study aims to evaluate the effects of preservatives on somatic cells of Allium cepa. For the evaluation of cytotoxicity, root meristems of A. cepa were treated with 1000, 1500, 2000, 2500 ppm concentration for 5, 10, 15 days. The root tips showed concentration dependent growth retardation in all the used concentrations, as well as root texture, also has been changed mitotic index, total protein content decreased and frequency of chromosomal aberrations increased after 5 days treatment. Additionally, the RAPD-PCR method was applied to evaluate genotoxicity and found the highest concentration (2500 ppm) was comparatively more distant to the control group. Results concluded that BHT and BHA showed positive results and cytotoxic.

Cancer Cell Detection on the Surface of Top-Gated Monolayer Graphene via Raman Spectroscopy

A label-free biosensor is described based on the Raman spectroscopic signatures of monolayer graphene, which are modified in the compartment of cancer cells because of electron-phonon coupling in monolayer graphene. Specifically, the Raman spectra of electrostatically gated monolayer graphene on SiO₂/Si substrates, in the voltage range from 0 to 5 V, were studied in the absence and the presence of cancer cells. Density functional theory simulations afforded a correlation between cancer cells and the observed Raman spectra, through the regulation of the intensities of the G and 2D Raman vibrational modes with applied voltage. The C-H and N-H bonds of phenylalanine enabled the detection of this biosensing activity. Significantly, this detection can be carried out even in the absence of cancer cell-culturing steps.

The use of molecular markers in the verification of fish and seafood authenticity and the detection of adulteration

The verification of authenticity and detection of food mislabeling are elements that have been of high importance for centuries. During the last few decades there has been an increasing consumer demand for the verification of food identity and the implementation of stricter controls around these matters. Fish and seafood are among the most easily adulterated foodstuffs mainly due to the significant alterations of the species' morphological characteristics that occur during the different types of processing, which render the visual identification of the animals impossible. Even simple processes, such as filleting remove very important morphological elements and suffice to prevent the visual identification of species in marketed products. Novel techniques have therefore been developed that allow identification of species, the differentiation between species and also the differentiation of individuals that belong to the same species but grow in different populations and regions. Molecular markers have been used during the last few decades to fulfill this purpose and several improvements have been implemented rendering their use applicable to a commercial scale. The reliability, accuracy, reproducibility, and time-and cost-effectiveness of these techniques allowed them to be established as routine methods in the industry and research institutes. This review article aims at presenting the most important molecular markers used for the authentication of fish and seafood. The most important techniques are described, and the results of numerous studies are outlined and discussed, allowing interested parties to easily access and compare information about several techniques and fish/seafood species.

Questioning the radiation limits of life: Ignicoccus hospitalis between replication and VBNC

Radiation of ionizing or non-ionizing nature has harmful effects on cellular components like DNA as radiation can compromise its proper integrity. To cope with damages caused by external stimuli including radiation, within living cells, several fast and efficient repair mechanisms have evolved. Previous studies addressing organismic radiation tolerance have shown that radiotolerance is a predominant property among extremophilic microorganisms including (hyper-) thermophilic archaea. The analysis of the ionizing radiation tolerance of the chemolithoautotrophic, obligate anaerobic, hyperthermophilic Crenarchaeon Ignicoccus hospitalis showed a D₁₀-value of 4.7 kGy, fourfold exceeding the doses previously determined for other extremophilic archaea. The genome integrity of I. hospitalis after γ-ray exposure in relation to its survival was visualized by RAPD and qPCR. Furthermore, the discrimination between reproduction, and ongoing metabolic activity was possible for the first time indicating that a potential viable but non-culturable (VBNC) state may also account for I. hospitalis.

ERIC-PCR technique applied to monitoring and quantification of DNA damage during water disinfection process

In this work, we propose a novel application of ERIC-PCR technique to study DNA damage after ultraviolet radiation (UV) and peracetic acid (PAA) treatment for water disinfection purpose. The efficacy of both treatments on E. coli suspension was evaluated by two approaches: through monitoring of inactivation by conventional culture technique, and by analyzing DNA damage with ERIC-PCR. All the experiments were carried out in a batch reactor, using three intensities of UV-C radiation (10.5, 4.2 and 2.1 mW/cm2) and different PAA concentrations (4 to 16 ppm). Both treatments produced bacterial inactivation in a dose-response fashion. Based on the results of bacterial count we obtained an index of inactivation (INACI). For each sample, DNA extraction was performed and evaluated by ERIC-PCR. Qualitative modifications were observed in ERIC-PCR band patterns for all the UV-C radiation intensities used, but no changes were detected at any of the PAA concentrations. The banding pattern modifications observed are consequence of the interruption of Taq polymerase enzyme amplification-activity, caused by the presence of alterations on the DNA structure (dimer and hydrates formation). Furthermore, an index was proposed to measure DNA damage (DNADI) regarding the changes in the relative optical density values of the amplification products. A linear correlation was obtained with a high correspondence between the inactivation index (INACI) and the DNA damage index (DNADI), that was expressed as DNADI = 0.05881×INACI. This approach proves that ERIC-PCR is a feasible and valuable tool for detecting and quantifying DNA damage and it may provide a useful strategy for bacterial identification, tracking changes in DNA and providing reliable and reproducible data.

DNA fingerprinting and assessment of some physiological changes in Al-induced Bryophyllum daigremontianum clones

Aluminum (Al) is one of the most important stress factors that reduce plant productivity in acidic soils. Present work thereby analyzed Al-induced genomic alterations in Bryophyllum daigremontianum clones using RAPD and ISSR markers, and investigated responding changes in photosynthetic pigment (chlorophyll a, b, a/b, total chlorophyll and carotenoid) contents and total soluble protein amounts in plant leaves. The main reason for the use of bulbiferous spurs originated clone plants was to increase reliability and acceptability of RAPD and ISSR techniques in DNA fingerprinting. Raised 40 clone plants were divided into five separate groups each with eight individuals and each experimental group was watered with 0 (control), 0 (acid control), 50, 100 and 200 µM AlCl₃-containing Hoagland solutions on alternate days for two and a half months. All plant soils except control group were sprayed with 0.2% sulfuric acid following watering days and this contributed acidic characteristic (pH 4.8) to soil structure. Increase in Al concentrations were accompanied by an increase in total soluble protein amounts, a decrease in photosynthetic pigment contents, and with appearance, disappearance and intensity changes at RAPD and ISSR band profiles. Out of tested RAPD1-25 and ISSR1-15 primers, RAPD8, RAPD9, ISSR2 and ISSR7 primers produced reproducible band profiles that were distinguishable between treatment and control groups. Findings showed that RAPD and ISSR fingerprints have been useful biomarkers for investigation of plant genotoxicity, especially in clone plants. Moreover, if these fingerprints are integrated with other physiological parameters they could become more powerful tools in ecotoxicology.

Survival, DNA, and Ultrastructural Integrity of a Cryptoendolithic Antarctic Fungus in Mars and Lunar Rock Analogs Exposed Outside the International Space Station

The search for life beyond Earth involves investigation into the responses of model organisms to the deleterious effects of space. In the frame of the BIOlogy and Mars Experiment, as part of the European Space Agency (ESA) space mission EXPOSE-R2 in low Earth orbit (LEO), dried colonies of the Antarctic cryptoendolithic black fungus Cryomyces antarcticus CCFEE 515 were grown on martian and lunar analog regolith pellets, and exposed for 16 months to LEO space and simulated Mars-like conditions on the International Space Station. The results demonstrate that C. antarcticus was able to tolerate the combined stress of different extraterrestrial substrates, space, and simulated Mars-like conditions in terms of survival, DNA, and ultrastructural stability. Results offer insights into the habitability of Mars for future exploration missions on Mars. Implications for the detection of biosignatures in extraterrestrial conditions and planetary protection are discussed.

Effect of Boron Toxicity on Oxidative Stress and Genotoxicity in Wheat (Triticum aestivum L.)

Boron (B) toxicity, which occurs in semi-arid and arid environments, can adversely affect the growth and yield of many plants. The aim of this study was to determine the effects of different concentrations of boric acid (3, 6, 9 and 12 mM) on growth, oxidative stress and genotoxicity parameters in root and shoot tissues of wheat seedlings. Our results indicate that B stress inhibits root and shoot growth of wheat in a concentration-dependent manner, and leads to increases in TBARS and H₂O₂ contents in shoot tissue. Moreover, our findings suggest that high concentrations of B may exert a genotoxic effect on wheat. To the best of our knowledge, this is the first report to evaluate the effect of B stress on genotoxicity in both root and shoot tissues of wheat.

Cellular Responses of the Lichen Circinaria gyrosa in Mars-Like Conditions

Lichens are extremely resistant organisms that colonize harsh climatic areas, some of them defined as "Mars-analog sites." There still remain many unsolved questions as to how lichens survive under such extreme conditions. Several studies have been performed to test the resistance of various lichen species under space and in simulated Mars-like conditions. The results led to the proposal that Circinaria gyrosa (Lecanoromycetes, Ascomycota) is one of the most durable astrobiological model lichens. However, although C. gyrosa has been exposed to Mars-like environmental conditions while in a latent state, it has not been exposed in its physiologically active mode. We hypothesize that the astrobiological test system "Circinaria gyrosa," could be able to be physiologically active and to survive under Mars-like conditions in a simulation chamber, based on previous studies performed at dessicated-dormant stage under simulated Mars-like conditions, that showed a complete recover of the PSII activity (Sánchez et al., 2012). Epifluorescence and confocal laser scanning microscopy (CLSM) showed that living algal cells were more abundant in samples exposed to niche conditions, which simulated the conditions in micro-fissures and micro-caves close to the surface that have limited scattered or time-dependent light exposure, than in samples exposed to full UV radiation. The medulla was not structurally affected, suggesting that the niche exposure conditions did not disturb the lichen thalli structure and morphology as revealed by field emission scanning electron microscopy (FESEM). In addition, changes in the lichen thalli chemical composition were determined by analytical pyrolysis. The chromatograms resulting from analytical pyrolysis at 500°C revealed that lichen samples exposed to niche conditions and full UV radiation consisted primarily of glycosidic compounds, lipids, and sterols, which are typical constituents of the cell walls. However, specific differences could be detected and used as markers of the UV-induced damage to the lichen membranes. Based on its viability responses after rehydration, our study shows that the test lichen survived the 30-day incubation in the Mars chamber particularly under niche conditions. However, the photobiont was not able to photosynthesize under the Mars-like conditions, which indicates that the surface of Mars is not a habitable place for C. gyrosa.

No induced mutagenesis in human lymphoblast cell line and bacterial systems upon their prolonged sub-culturing in irradiated food blended media

BACKGROUND

Profound apprehension towards safety of irradiated food has remained a major cause behind tardy acceptance of this technology although it has immense socio-economic potential. Generation of in-depth scientific evidence will help to refute these apprehensions. With this prospective, the present study was undertaken where safety of various irradiated (D_min up to 25 kGy) foods was evaluated through long-term exposure studies in models including human lymphoblast TK6 cell line (100 generations) and Escherichia coli MG1655 cells (exclusive sub-culturing in irradiated food medium for 3000 generations). Additionally, the Ames test, micronucleus test, comet assay, DNA sequencing and restriction profiling of phagemid DNA from E. coli cells sub-cultured in irradiated food medium were also performed.

RESULTS

No induced mutagenesis was observed in these cells during long-term sub-culturing in various irradiated food medium. Also no change was observed in profiles of comet, micronucleus, restriction digestion, random amplification of polymorphic DNA as well as DNA sequences. The latter also ruled out the possibility of any silent mutation.

CONCLUSION

Findings of the current study thus provided credible molecular evidence supporting the safety of irradiated foods. This would be helpful in confidence building among consumers, entrepreneurs, and strengthening the overall food irradiation program to achieve 'food safety' and 'security'. © 2017 Society of Chemical Industry.

Phenotypic, fermentation characterization, and resistance mechanism analysis of bacteriophage-resistant mutants of Lactobacillus delbrueckii ssp. bulgaricus isolated from traditional Chinese dairy products

Bacteriophage infection is a large factor in dairy industrial production failure on the basis of pure inoculation fermentation, and developing good commercial starter cultures from wild dairy products and improving the environmental vigor of starter cultures by enhancing their phage resistance are still the most effective solutions. Here we used a spontaneous isolation method to obtain bacteriophage-resistant mutants of Lactobacillus delbrueckii ssp. bulgaricus strains that are used in traditional Chinese fermented dairy products. We analyzed their phenotypes, fermentation characteristics, and resistance mechanisms. The results showed that bacteriophage-insensitive mutants (BIM) BIM8 and BIM12 had high bacteriophage resistance while exhibiting fermentation and coagulation attributes that were as satisfying as those of their respective parent strains KLDS1.1016 and KLDS1.1028. According to the attachment receptor detection, mutants BIM8 and BIM12 exhibited reduced absorption to bacteriophage phiLdb compared with their respective bacteriophage-sensitive parent strains because of changes to the polysaccharides or teichoic acids connected to their peptidoglycan layer. Additionally, genes, including HSDR, HSDM, and HSDS, encoding 3 subunits of a type I restriction-modification system were identified in their respective parent strains. We also discovered that HSDR and HSDM were highly conserved but that HSDS was variable because it is responsible for the DNA specificity of the complex. The late lysis that occurred only in strain KLDS1.1016 and not in strain KLDS1.1028 suggests that the former and its mutant BIM8 also may have an activatable restriction-modification mechanism. We conclude that the L. bulgaricus BIM8 and BIM12 mutants have great potential in the dairy industry as starter cultures, and their phage-resistance mechanism was effective mainly due to the adsorption interference and restriction-modification system.

Flavonoid constituents of Dobera glabra leaves: amelioration impact against CCl4-induced changes in the genetic materials in male rats

CONTEXT

Dobera glabra (Forssk.) Poir (Salvadoraceae) is a highly valued tree with diverse importance as special mineral sourced feed and a folkloric tool for forecasting droughts. However, there are no reports on its phytochemical and biological investigations.

OBJECTIVE

Phytochemical investigation of D. glabra leaves and its protective potential against CCl₄ inducing changes in the genetic materials.

MATERIALS AND METHODS

D. glabra extract, DGE (70% MeOH/H₂O), was applied to polyamide column chromatography, eluting with MeOH/H₂O of decreasing polarities, followed by preparative chromatographic tools, yielded seven compounds. Three DGE doses (50, 100 and 200 mg/kg bw/d) were administrated for 8 weeks intragastrically to male albino rats prior treated with CCl₄ (0.5 mL/kg/bw). The reactive oxygen species (ROS) levels, expression changes of glutamate transporters (GLAST, GLT-1 and SNAT3) mRNA, DNA fragmentation and glutathione peroxidase (GPx) activity were investigated in the liver tissues of these rats.

RESULTS

Isorhamnetin-3-O-β-glucopyranoside-7-O-α-rhamnopyranoside, isorhamnetin-3-O-α-rhamnopyranoside-7-O-β-glucopyranoside, kaempferol-3,7-di-O-α-rhamnopyranoside, isorhamnetin-3-O-β-glucopyranoside, kaempferol-3-O-β-glucopyranoside, isorhamnetin and kaempferol were identified. DGE (200 mg/kg bw) + CCl₄ exhibited the most significant reduction in ROS levels and DNA fragmentation with 251.3% and141% compared to 523.1% and 273.2% for CCl₄, respectively. Additionally, it increased significantly the mRNA expression of GLAST, GLT-1 and SNAT3 to 2.16-, 1.72- and 2.09-fold, respectively. Also, GPx activity was increased to 4.8 U/mg protein/min compared to CCl₄ (1.8 U/mg protein/min).

DISCUSSION AND CONCLUSION

Flavonoid constituents, antioxidant effect and genotoxic protection activity of D. glabra were first reported. DGE may be valuable in the treatment and hindrance of hepatic oxidative stress and genotoxicity.

Assessment of Achyranthes aspera induced toxicity and molecular analysis of RAPD-PCR profiles of larval genomic DNA of Aedes aegypti L. (Diptera: Culicidae)

Current studies investigated the anti-mosquito potential of Achyranthes aspera against the dengue vector, Aedes aegypti. The stems and leaves of A. aspera were extracted in hexane and evaluated for their toxicity against early fourth instars of A. aegypti. The larvicidal efficacy of the extract was validated as per WHO protocol. The mortality counts were made after 24 h and LC values were calculated at different levels. The adverse impact of extracts was also explored on the larval genomic DNA. The larvae were exposed to extracts at LC₅₀ levels and the alterations in g-DNA was evaluated through RAPD-PCR technique using three random primers; MA-09, MA-12 and MA-26. Our investigations ascertained the larvicidal efficacy of both the leaf and stem extracts of A. aspera resulting in respective LC₅₀ values of 0.068 and 0.082 mg/mL. The extracts also caused variable genotoxic effects with significant changes in the RAPD profiles. The results showed appreciable modifications in larval g-DNA with loss of certain bands and gain of unique bands with 82.35% DNA polymorphism. These alterations suggest the probable DNA damage and mutations in the larval g-DNA caused by certain phytocomponents which could be the possible reason of larval mortality. Our studies evidenced the anti-mosquito potential of A. aspera extracts against A. aegypti causing appreciable larval mortality and significant changes in g-DNA. The A. aspera extracts are suggested as efficient and eco-friendly control agent against A. aegypti, yet further investigations are needed to identify the bioactive constituent and ascertain its effectiveness in the field conditions.

Cryptoendolithic Antarctic Black Fungus Cryomyces antarcticus Irradiated with Accelerated Helium Ions: Survival and Metabolic Activity, DNA and Ultrastructural Damage

Space represents an extremely harmful environment for life and survival of terrestrial organisms. In the last decades, a considerable deal of attention was paid to characterize the effects of spaceflight relevant radiation on various model organisms. The aim of this study was to test the survival capacity of the cryptoendolithic black fungus Cryomyces antarcticus CCFEE 515 to space relevant radiation, to outline its endurance to space conditions. In the frame of an international radiation campaign, dried fungal colonies were irradiated with accelerated Helium ion (150 MeV/n, LET 2.2 keV/μm), up to a final dose of 1,000 Gy, as one of the space-relevant ionizing radiation. Results showed that the fungus maintained high survival and metabolic activity with no detectable DNA and ultrastructural damage, even after the highest dose irradiation. These data give clues on the resistance of life toward space ionizing radiation in general and on the resistance and responses of eukaryotic cells in particular.

Genotoxicity evaluation of zinc oxide nanoparticles in Swiss mice after oral administration using chromosomal aberration, micronuclei, semen analysis, and RAPD profile

The expanded uses of zinc oxide nanoparticles (ZnO NPs) have grown rapidly in the field of nanotechnology. Thus, rising production of nanoparticles (NPs) increases the possible risks to the environment and occupationally exposed humans. Hence, it is indispensable to appraise the safety toxicity including genotoxicity for these NPs. In the present study, we have evaluated the genotoxic effect of ZnO NPs after oral administration to Swiss mice at dose levels of 300 and 2000 mg/kg body weight. These doses were administered for 2 days at 24 h apart. Chromosomal aberration (CA) and micronucleus tests were conducted following Organization for Economic Co-operation and Development guidelines. DNA damage was evaluated at 0, 24, 48, and 72 h posttreatment using a randomly amplified polymorphic DNA (RAPD) assay; additionally, semen analyses were also performed at 34.5 days post oral exposure. The reactive oxygen species (ROS), 8-oxo-2'-deoxyguanosine and CAs were increased ( p < 0.05) at the highest dosage (2000 mg/kg) of ZnO NPs compared to controls. Aberrant sperm morphology with reduced sperm count and motility were also present ( p < 0.05) in the high-dose group. Based on the RAPD assay, the genomic template stability within the high-dose group (<90%) was less than the controls (100%). The results suggested that ZnO NPs are mildly genotoxic in a dose-related manner and this toxicity were induced by generation of ROS.

Evaluation of the antimicrobial activities of ultrasonicated spinach leaf extracts using RAPD markers and electron microscopy

Spinach (Spinacia oleracea L.) leaves represent an important dietary source of nutrients, antioxidants and antimicrobials. As such, spinach leaves play an important role in health and have been used in the treatment of human diseases since ancient times. Here, the aims were to optimize the extraction methods for recovering antimicrobial substances of spinach leaves, determine the minimum inhibitory concentrations (MICs) of the antimicrobial substances against Escherichia coli and Staphylococcus aureus and, finally, evaluate the effects of spinach leaves' antimicrobials on bacterial DNA using central composite face-centered methods. The effect of the extracts on both Gram-positive and Gram-negative bacterial models was examined by scanning electron microscopy (SEM) and random amplification of polymorphic (bacterial) DNA (RAPD). The optimal extraction conditions were at 45 °C, ultrasound power of 44% and an extraction time of 23 min. The spinach extracts exhibited antimicrobial activities against both bacteria with MICs in the 60-100 mg/ml range. Interestingly, SEM showed that the treated bacterial cells appear damaged with a reduction in cell number. RAPD analysis of genomic DNA showed that the number and sizes of amplicons were decreased by treatments. Based on these results, it was inferred that spinach leaf extracts exert bactericidal activities by both inducing mutations in DNA and causing cell wall disruptions.

BIOMEX Experiment: Ultrastructural Alterations, Molecular Damage and Survival of the Fungus Cryomyces antarcticus after the Experiment Verification Tests

The search for traces of extinct or extant life in extraterrestrial environments is one of the main goals for astrobiologists; due to their ability to withstand stress producing conditions, extremophiles are perfect candidates for astrobiological studies. The BIOMEX project aims to test the ability of biomolecules and cell components to preserve their stability under space and Mars-like conditions, while at the same time investigating the survival capability of microorganisms. The experiment has been launched into space and is being exposed on the EXPOSE-R2 payload, outside of the International Space Station (ISS) over a time-span of 1.5 years. Along with a number of other extremophilic microorganisms, the Antarctic cryptoendolithic black fungus Cryomyces antarcticus CCFEE 515 has been included in the experiment. Before launch, dried colonies grown on Lunar and Martian regolith analogues were exposed to vacuum, irradiation and temperature cycles in ground based experiments (EVT1 and EVT2). Cultural and molecular tests revealed that the fungus survived on rock analogues under space and simulated Martian conditions, showing only slight ultra-structural and molecular damage.

Multigenerational effects and DNA alterations of QDs-Indolicidin on Daphnia magna

The complex QDs-Indolicidin (QDs-Ind) has been previously shown to be a good antimicrobial system with a low acute toxicity on Daphnia magna (D. magna). However, multigenerational effects caused by exposure to QDs-Ind and after subsequent recovery are still unknown. In this study, we performed multigenerational exposure tests and we evaluated individual fitness, population growth, DNA alteration, expression of Dhb (haemoglobin), Vtg (vitellogenin), CYP4 (cytochrome P450s CYP4 family), and CYP314 (cytochrome P450s mitochondrial family 314) genes on three generation of D. magna. Results showed that the total amount of eggs produced per female and total number of brood per female and body lengths were significantly decreased, Dhb, CYP4 were upregulated while Vtg was down-regulated except at reproduction days when it was slightly up-regulated under QDs-Ind exposure. Random Amplification of Polymorphic DNA (RAPD) method has proven to be useful to qualitative assess of DNA damage during generation and to underline modification in somatic or germinal cells. The results of the study suggest that effects of chronic exposure cannot be ignored.

Survival, DNA Integrity, and Ultrastructural Damage in Antarctic Cryptoendolithic Eukaryotic Microorganisms Exposed to Ionizing Radiation

Life dispersal between planets, planetary protection, and the search for biosignatures are main topics in astrobiology. Under the umbrella of the STARLIFE project, three Antarctic endolithic microorganisms, the melanized fungus Cryomyces antarcticus CCFEE 515, a hyaline strain of Umbilicaria sp. (CCFEE 6113, lichenized fungus), and a Stichococcus sp. strain (C45A, green alga), were exposed to high doses of space-relevant gamma radiation (⁶⁰Co), up to 117.07 kGy. After irradiation survival, DNA integrity and ultrastructural damage were tested. The first was assessed by clonogenic test; viability and dose responses were reasonably described by the linear-quadratic formalism. DNA integrity was evaluated by PCR, and ultrastructural damage was observed by transmission electron microscopy. The most resistant among the tested organisms was C. antarcticus both in terms of colony formation and DNA preservation. Besides, results clearly demonstrate that DNA was well detectable in all the tested organisms even when microorganisms were dead. This high resistance provides support for the use of DNA as a possible biosignature during the next exploration campaigns. Implication in planetary protection and contamination during long-term space travel are put forward. Key Words: Biosignatures-Ionizing radiation-DNA integrity-Eukaryotic microorganisms-Fingerprinting-Mars exploration. Astrobiology 17, 126-135.

Inducing mutations through γ-irradiation in seeds of Mucuna pruriens for developing high L-DOPA-yielding genotypes

PURPOSE

To develop elite genotypes in Mucuna pruriens (L.) DC with high L-DOPA (L-3, 4 dihydroxyphenylalanine) yields, with non-itching characteristics and better adaptability by applying γ-irradiation. Molecular and chemical analysis was performed for screening based on specific characteristics desired for developing suitable genotypes.

MATERIALS AND METHODS

Developed, mutant populations were analyzed for L-DOPA % in seeds through TLC (thin layer chromatography), and the results obtained were validated with the HPLC (High performance liquid chromatography). The DNA (Deoxyribonucleic acid) was isolated from the leaf at the initial stage and used for DNA polymorphism. RNA (Ribonucleic acid) was isolated from the leaf during maturity and used for expression analysis.

RESULTS

The selected mutant T-I-7 showed 5.7% L-DOPA content compared to 3.18% of parent CIM-Ajar. The total polymorphism obtained was 57% with the molecular marker analysis. The gene expression analysis showed higher fold change expression of the dopadecarboxylase gene (DDC) in control compared to selected mutants (T-I-7, T-II-23, T-IV-9, T-VI-1).

CONCLUSION

DNA polymorphism was used for the screening of mutants for efficient screening at an early stage. TLC was found suitable for the large-scale comparative chemical analysis of L-DOPA. The expression profile of DDC clearly demonstrated the higher yields of L-DOPA in selected mutants developed by γ-irradiation in the seeds of the control.

The Survival and Resistance of Halobacterium salinarum NRC-1, Halococcus hamelinensis, and Halococcus morrhuae to Simulated Outer Space Solar Radiation

Solar radiation is among the most prominent stress factors organisms face during space travel and possibly on other planets. Our analysis of three different halophilic archaea, namely Halobacterium salinarum NRC-1, Halococcus morrhuae, and Halococcus hamelinensis, which were exposed to simulated solar radiation in either dried or liquid state, showed tremendous differences in tolerance and survivability. We found that Hcc. hamelinensis is not able to withstand high fluences of simulated solar radiation compared to the other tested organisms. These results can be correlated to significant differences in genomic integrity following exposure, as visualized by random amplified polymorphic DNA (RAPD)-PCR. In contrast to the other two tested strains, Hcc. hamelinensis accumulates compatible solutes such as trehalose for osmoprotection. The addition of 100 mM trehalose to the growth medium of Hcc. hamelinensis improved its survivability following exposure. Exposure of cells in liquid at different temperatures suggests that Hbt. salinarum NRC-1 is actively repairing cellular and DNA damage during exposure, whereas Hcc. morrhuae exhibits no difference in survival. For Hcc. morrhuae, the high resistance against simulated solar radiation may be explained with the formation of cell clusters. Our experiments showed that these clusters shield cells on the inside against simulated solar radiation, which results in better survival rates at higher fluences when compared to Hbt. salinarum NRC-1 and Hcc. hamelinensis. Overall, this study shows that some halophilic archaea are highly resistant to simulated solar radiation and that they are of high astrobiological significance.

KEY WORDS

Halophiles-Solar radiation-Stress resistance-Survival.

RETRACTED: Glyphosate herbicide induces genotoxic effect and physiological disturbances in Bulinus truncatus snails

Herbicides are being used in agriculture for controlling noxious weed. Glyphosate is a herbicide that is widely applied to cereal crops in Egypt and is used in controlling a very broad spectrum of weeds. The present study was designed to investigate the response of the snail Bulinus truncatus as a bioindicator for physiological and molecular aspects of B. truncatus snails after exposure to sublethal concentrations of glyphosate for two weeks. In treating snails, glucose concentration (GL) in the haemolymph as well as lactate (LT) in soft tissues of treated snails increased, while glycogen (GN), pyruvate (PV), total protein (TP), nucleic acids (DNA and RNA) levels in snail's tissues decreased. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR), thioredoxin reductase (TrxR), glycogen phosphorylase (GP), glucose-6-phosphatase (G-6-Pase), succinic dehydrogenase (SDH) and lactic dehydrogenase (LDH) enzymes in homogenate of snail's tissues were reduced in response to the treatment with the herbicide, while lipid peroxide (LP), sorbitol dehydrogenase (SDH) and transaminases (GOT and GPT) activity increased (P < 0.001). The changes in the number, position and intensity of DNA bands induced by glyphosate herbicide may be attributed to the fact that the herbicide can induce genotoxicity through DNA damage. Thus, the present result indicated that the genotoxicity products at low concentration and for long time treatment showed the hazard of herbicide addiction on man's life.

Zebrafish genome instability after exposure to model genotoxicants

Sublethal exposure to environmental genotoxicants may impact genome integrity in affected organisms. It is therefore necessary to develop tools to measure the extent and longevity of genotoxicant-induced DNA damage, and choose appropriate model organisms for biomonitoring. To this end, markers of DNA damage were measured in zebrafish larvae and adults following exposure to model genotoxicants (benzo[a]pyrene and ethyl methanesulfonate). Specifically, we assessed primary DNA damage and the existence of potentially persistent genomic alterations through application of the comet assay, quantitative random amplified polymorphic DNA (qRAPD) and amplified fragment length polymorphism (AFLP) assays. Furthermore, expression of genes involved in DNA repair, oxidative stress response and xenobiotic metabolism was evaluated as well. Additionally, the AFLP method was applied to adult specimens 1 year after larval exposure to the genotoxicants to evaluate the longevity of the observed DNA alterations. Large numbers of DNA alterations were detected in larval DNA using the comet assay, qRAPD and AFLP, demonstrating that zebrafish larvae are a sensitive model for revealing genotoxic effects. Furthermore, some of these genomic alterations persisted into adulthood, indicating the formation of stable genomic modifications. qRAPD and AFLP methods proved to be highly sensitive to genotoxic effects, even in cases when the comet assay indicated a lack of significant damage. These results thus support the use of zebrafish larvae as a sensitive model for monitoring the impact of genotoxic insult and give evidence of the longevity of genomic modifications induced by genotoxic agents.

MWCNT uptake in Allium cepa root cells induces cytotoxic and genotoxic responses and results in DNA hyper-methylation

Advances in nanotechnology have led to the large-scale production of nanoparticles, which, in turn, increases the chances of environmental exposure. While humans (consumers/workers) are primarily at risk of being exposed to the adverse effect of nanoparticles, the effect on plants and other components of the environment cannot be ignored. The present work investigates the cytotoxic, genotoxic, and epigenetic (DNA methylation) effect of MWCNT on the plant system- Allium cepa. MWCNT uptake in root cells significantly altered cellular morphology. Membrane integrity and mitochondrial function were also compromised. The nanotubes induced significant DNA damage, micronucleus formation and chromosome aberration. DNA laddering assay revealed the formation of internucleosomal fragments, which is indicative of apoptotic cell death. This finding was confirmed by an accumulation of cells in the sub-G0 phase of the cell cycle. An increase in CpG methylation was observed using the isoschizomers MspI/HpaII. HPLC analysis of DNA samples revealed a significant increase in the levels of 5-methyl-deoxy-cytidine (5mdC). These results confirm the cyto-genotoxic effect of MWCNT in the plant system and simultaneously highlight the importance of this epigenetic study in nanoparticle toxicity.

Effect of malachite green toxicity on non target soil organisms

Although malachite green (MG), is banned in Europe and US for its carcinogenic and teratogenic effect, the dye being cheap, is persistently used in various countries for fish farming, silk, dye, leather and textile industries. Current research, however, fails to elucidate adequate knowledge concerning the effects of MG in our ecosystem. In the present investigation, for the first time, an attempt has been made to study the effects of MG on soil biota by testing Bacillus subtilis, Azotobacter chroococcum, Saccharomyces cerevisiae, Penicillium roqueforti, Eisenia fetida and seeds of three crop plants of different families. Various tests were conducted for determining cytotoxicity, genotoxicity, acute toxicity, morphological and germination effect. Our data confirmed MG toxicity on fungi and bacteria (gram positive and gram negative organisms) showing elevated level of ROS. Genotoxicity caused in the microorganisms was detected by DNA polymorphism and fragmentation. Also, scanning electron microscopy data suggests that the inhibitory effect of MG to these beneficial microbes in the ecosystem might be due to pore formation in the cell and its eventual disruption. Filter paper and artificial soil test conducted on earthworms demonstrated a LC 50 of 2.6 mg cm(-2) and 1.45 mg kg(-1) respectively with severe morphological damage. However, seed germination of Mung bean, Wheat and Mustard was found to be unaffected in presence of MG up to 100 mL(-1) concentration. Thus, understanding MG toxicity in non target soil organisms and emphasis on its toxicological effects would potentially explicate its role as an environmental contaminant.

Determination of genotoxic effects of fipronil in Vicia faba using random amplified polymorphic DNA analysis

This study was undertaken to appreciate genotoxic potential of fipronil herbicides in the roots of Vicia faba seedlings. Fipronil was clearly dose dependent on root growth inhibitors, total soluble protein, and random amplified polymorphic DNA (RAPD) assays. Increase in concentration of fipronil resulted in decreased amount of root length and increased level of protein. For the RAPD analyses, 15 RAPD primers were found to produce unique polymorphic band patterns and were subsequently used to produce a total of 110 bands of 45–1250 bp. Each primer generated 4–11 RAPD bands across 15 primers. The changes occurring in RAPD profiles following fipronil treatment included variation becoming evident as disappearance and/or appearance of DNA bands compared with the normal seedlings. These results indicated that genomic template stability was significantly affected at the above fipronil concentration. This study further confirmed that the RAPD assays are useful in determining potential genotoxicity of fipronil.

Utility of RAPD marker for genetic diversity analysis in gamma rays and ethyl methane sulphonate (EMS)-treated Jatropha curcas plants

The presence of important chemical and physical properties in Jatropha curcas makes it a valuable raw material for numerous industrial applications, including the production of biofuel. Hence, the researcher's interest is diversified to develop more and better varieties with outstanding agronomic characteristics using conventional breeding. Among these, mutation breeding is one of the best approaches to bring genetic changes in plant species. The aim of this study is to evaluate the diversity and genetic relationship among J. curcas mutants, which were obtained from different doses of gamma rays (control, 5 Kr, 10 Kr, 15 Kr, 20 Kr and 25 Kr) and EMS (1%, 2%, 3% and 4%), using RAPD marker. Among the 21 random primers, 20 produced polymorphic bands. The primers, OPM-14 and OPAW-13, produced a minimum number of bands (3) each across the ten mutants, while the primer OPF-13 produced the maximum number of bands (10), followed by the primers OPU-13, OPAM-06, OPAW-09 and OPD-05, which produced 9 bands each. The number of amplicons varied from 3 to 10, with an average of 7 bands, out of which 4.57 were polymorphic. The percentage of polymorphism ranged from 0.00 to 100 with an average of 57%. In the present study, RAPD markers were found most polymorphic, with an average polymorphism information content (PIC) value of 0.347, effective multiplex ratio (EMR) of 35.14, marker index (MI) of 14.19, resolution power (Rp) of 11.19, effective marker index (EMI) of 8.21 and genotype index (GI) of 0.36, indicating that random primers are useful in studies of genetic characterization in J. curcas mutant plants. In a dendrogram constructed based on Jaccard's similarity coefficients, the mutants were grouped into three main clusters viz., (a) control, 10 Kr, 15 Kr, 20 Kr, 2% EMS, and 3% EMS, (b) 5 Kr and 1% EMS, and (c) 25 Kr and 4% EMS mutants. Based on the attributes of the random primers and polymorphism studied, it is concluded that RAPD analysis offers a useful molecular marker for the identification of the mutants in gamma rays and EMS treated plants.

Assessment of arsenic-induced DNA damage in goldfish by a polymerase chain reaction-based technique using random amplified polymorphic DNA markers

Arsenic is a groundwater contaminant of global concern. It is a potent human carcinogen, and its marked genotoxic effects have been reported in several human and animal studies. The present work investigates the applicability of the random amplified polymorphic DNA (RAPD) assay to study the DNA-damaging effects of arsenic at low-level exposure in goldfish Carassius auratus. Four experimental groups of fish, A, B, C and D, were exposed to 0, 10, 50, and 1,000 µg L(-1) of arsenic, respectively, in aquaria water for 15 consecutive days. Genomic DNA extraction was followed by RAPD-polymerase chain reaction amplification for each fish separately. One arbitrary decamer primer (PUZ-19) of 33 primers used appeared as the most informative and was capable of exhibiting marked alterations in RAPD profiles between arsenic-exposed and unexposed (control) samples. Different sets of 11 loci were amplified in various experimental groups with four clear polymorphic bands by the primer PUZ-19. The X and XIII amplification loci, which were prominent in the unexposed group, failed to appear in the arsenic-exposed groups. In contrast, the I and XI RAPD bands appeared as new amplification loci in all of the exposed groups. Such alterations in genomic DNA, however, did not exhibit a clear dose-dependent tendency. The RAPD assay, because of its efficacy to unmask alterations in genomic DNA induced by arsenic at low exposure level of 10 µg L(-1), appears to be a sensitive and potential tool for detecting arsenic genotoxicity.

DNA-Based Asymmetric Catalysis: Role of Ionic Solvents and Glymes

Recently, DNA has been evaluated as a chiral scaffold for metal complexes to construct so called 'DNA-based hybrid catalysts', a robust and inexpensive alternative to enzymes. The unique chiral structure of DNA allows the hybrid catalysts to catalyze various asymmetric synthesis reactions. However, most current studies used aqueous buffers as solvents for these asymmetric reactions, where substrates/products are typically suspended in the solutions. The mass transfer limitation usually requires a long reaction time. To overcome this hurdle and to advance DNA-based asymmetric catalysis, we evaluated a series of ionic liquids (ILs), inorganic salts, deep eutectic solvents (DES), glymes, glycols, acetonitrile and methanol as co-solvents/additives for the DNA-based asymmetric Michael addition. In general, these additives induce indistinguishable changes to the DNA B-form duplex conformation as suggested by circular dichroism (CD) spectroscopy, but impose a significant influence on the catalytic efficiency of the DNA-based hybrid catalyst. Conventional organic solvents (e.g. acetonitrile and methanol) led to poor product yields and/or low enantioselectivities. Most ILs and inorganic salts cause the deactivation of the hybrid catalyst except 0.2 M [BMIM][CF₃COO] (95.4% ee and 93% yield) and 0.2 M [BMIM]Cl (93.7% ee and 89% yield). Several other additives have also been found to improve the catalytic efficiency of the DNA-based hybrid catalyst (control reaction without additive gives >99% ee and 87% yield): 0.4 M glycerol (>99% ee and 96% yield at 5 °C or 96.2% ee and 83% yield at room temperature), 0.2 M choline chloride/glycerol (1:2) (92.4% ee and 90% yield at 5 °C or 94.0% ee and 88% yield at room temperature), and 0.5 M dipropylene glycol dimethyl ether (>99% ee and 87% yield at room temperature). The use of some co-solvents/additives allows the Michael addition to be performed at a higher temperature (e.g. room temperature vs 5 °C) and a shorter reaction time (24 h vs 3 days). In addition, we found that a brief pre-sonication (5 min) of DNA in MOPS buffer prior to the reaction could improve the performance of the DNA-based hybrid catalyst. We have also shown that this DNA-based catalysis method is suitable for a variety of different substrates and relatively large-scale reactions. In conclusion, a judicious selection of benign co-solvents/additives could improve the catalytic efficiency of DNA-based hybrid catalyst.

Detection of tannery effluents induced DNA damage in mung bean by use of random amplified polymorphic DNA markers

Common effluent treatment plant (CETP) is employed for treatment of tannery effluent. However, the performance of CETP for reducing the genotoxic substances from the raw effluent is not known. In this study, phytotoxic and genotoxic effects of tannery effluents were investigated in mung bean (Vigna radiata (L.) Wilczek). For this purpose, untreated and treated tannery effluents were collected from CETP Unnao (UP), India. Seeds of mung bean were grown in soil irrigated with various concentrations of tannery effluents (0, 25, 50, 75, and 100%) for 15 days. Inhibition of seed germination was 90% by 25% untreated effluent and 75% treated effluent, compared to the control. Plant growth was inhibited by 51% and 41% when irrigated with untreated and treated effluents at 25% concentration. RAPD technique was used to evaluate the genotoxic effect of tannery effluents (untreated and treated) irrigation on the mung bean. The RAPD profiles obtained showed that both untreated and treated were having genotoxic effects on mung bean plants. This was discernible with appearance/disappearance of bands in the treatments compared with control plants. A total of 87 RAPD bands were obtained using eight primers and 42 (48%) of these showed polymorphism. Irrigating plants with untreated effluent caused 12 new bands to appear and 18 to disappear. Treated effluent caused 8 new bands and the loss of 15 bands. The genetic distances shown on the dendrogram revealed that control plants and those irrigated with treated effluent were clustered in one group (joined at distance of 0.28), whereas those irrigated with untreated effluent were separated in another cluster at larger distance (joined at distance of 0.42). This indicates that treated effluent is less genotoxic than the untreated. Nei's genetic similarity indices calculated between the treatments and the control plants showed that the control and the plants irrigated with treated tannery effluent had a similarity index of 0.75, the control and plants irrigated with untreated 0.65, and between the treatments 0.68. We conclude that both untreated and treated effluents contain genotoxic substances that caused DNA damage to mung beans. CETP Unnao removes some, but not all, genotoxic substances from tannery effluent. Consequently, use of both untreated and treated wastewater for irrigation poses health hazard to human and the environment.

Genoprotectivity of methanol and ethanol extracted leaf sap of Trigonella foenum-graecum in Allium cepa root assay

Fenugreek (Trigonella foenum-graecum) of Fabacecae family is widely distributed throughout the world and used as an old medicinal plant and traditional food. The present study deals with the investigation of the anti-genotoxic potential of methanol (MTG) and ethanol (ETG) extracted leaf sap of fenugreek on Allium cepa root tip cells, which were treated with cadmium sulfate (CdSO(4)). Three types of treatments were applied. First, roots were treated with different concentrations of methanolic and ethanolic extracts (0.1%, 0.5% and 1%) separately for 3 h each, followed by CdSO(4) treatment (at 250 ppm, for 3 h). Second, roots were first treated with CdSO(4) followed by extracts treatment. Third, root tips were treated with CdSO(4) with extracts treatments at the same time. For controls, roots with CdSO(4) (250 ppm) and distilled water served as positive and negative control, respectively. The results showed that the methanol and ethanol extracts of fenugreek modulated the genotoxic and clastogenic aberrations, which were induced by CdSO(4). The protection activity of MTG (1%) was 50% in the first treatment, 70% in the second treatment and 82% in the third treatment and 61%, 68% and 88% of ETG (1%), respectively. DNA rearrangements were also observed by revealing new RAPD bands in the total DNS samples isolated from Allium roots after treatmenst.

Effect of pulsed light on structural and physiological properties of Listeria innocua and Escherichia coli

AIMS

The application of broad-spectrum intense light pulses is an innovative nonthermal technology for the decontamination of packaging materials, liquids or foodstuffs. The objective of this study was the fundamental investigation of the cellular impact of a pulsed light treatment on Listeria innocua and Escherichia coli.

METHODS AND RESULTS

Flow cytometry in combination with different fluorescent stains, conventional plate count technique and a viability assay were applied to investigate the effects of a pulsed light treatment on the physiological properties of L. innocua and E. coli. The results showed that loss of cultivability occurred at considerably lower fluences than the shutdown of cellular functions such as the depolarization of cell membranes, the loss of metabolic, esterase and pump activities or the occurrence of membrane damage. Therefore, a considerable proportion of cells appeared to have entered the viable but nonculturable (VBNC) state after the pulsed light treatment. A high percentage of L. innocua was able to maintain certain cellular vitality functions after storage overnight, whereas a further decrease in vitality was observed in case of E. coli. The loss of culturability was on the other hand directly accompanied by the formation of reactive oxygen species (ROS) and DNA damages, which were assessed by the ROS-sensitive probe DCFH-DA and RAPD-PCR, respectively.

CONCLUSIONS

A significant discrepancy between conventional plate counts and different viability staining parameters was observed, which shows that a pulsed light treatment does not cause an immediate shutdown of vitality functions even when the number of colony-forming units already decreased for more than 6 log10 sample(-1) . Oxidative stress with concomitant damage to the DNA molecule showed to be directly responsible for the loss of cultivability due to pulsed light rather than a direct rupture of cell membranes or inactivation of intracellular enzymes.

SIGNIFICANCE AND IMPACT OF THE STUDY

The presented results suggest an UV light-induced photochemical rather than a photothermal or photophysical inactivation of bacterial cells by pulsed light under the applied experimental conditions. Flow cytometry in combination with different viability stains proved to be a suitable technique to gain deeper insight into the cellular response of bacteria to inactivation processes like a pulsed light treatment.