Nowdays in Vietnam, Fuji-One and Monitor are organophosphorus pesticides widely used in agriculture. In order to investigate chromosomal mutagenic effects of Fuji-One and Monitor, we have carried out this study in mice. 4 group of mice were analyzed: Negative control group: 16 male mice were non-exposed to pesticides. Positive control group: 15 male mice were injected into the peritoneum with cyclophosphamide, which is a kind of mutagen. Fuji-One group: 5 male mice were injected into the peritoneum with Monitor. Analyzing of frequencies of chromosomal aberration in bone marrow cells and testicular cells of mice, we found that: (1) Monitor can cause chromosomal mutagenic effects in the bone marrow cells. (2) Fuji-One can cause chromosomal structural and numerical aberration. (3) The rate of chromosomal aberration in Fuji-One group was lower than those in positive control group but they were higher than those in monitor group
Mutagenesis ; Chromosomal Instability

We identified two genes related to fungicide resistance in Fusarium fujikuroi through random mutagenesis. Targeted gene deletions showed that survival factor 1 deletion resulted in higher sensitivity to fungicides, while deletion of the gene encoding F-box/WD-repeat protein increased resistance, suggesting that the genes affect fungicide resistance in different ways.
Fusarium* ; Gene Deletion ; Mutagenesis

The purpose of this study was to investigate the cytotoxicity and mutagenicity of denture ase resins. According to manufacturer's instructions, resin specimens were made. Group 1: heat-polymerizing acrylic resin (Luciton 199(R)). Group 2: heat-polymerizing acrylic resin containing polyhedraloligosilsesquioxane(POSS esin). Group 3: auto-polymerizing acrylic resin (Repair Acrylic(R)). Group 4: direct relining auto-polymerizing acrylic resin (Tokuso Rebase(R)). Fresh specimens, 24 hrs. and 72 hrs. soaked specimens in distilled water were made. Responses with metabolic assay and mutagenesis assay to eluates from resin specimens were measured. Cultures with medium alone provided controls. Cytotoxicity was assessed with agar overlay test. The results were as follows: 1. Group 4 showed higher cytotoxicity than Group 1, Group 2 and Group 3 in fresh, 24-and 72-hour immersion cases (p<.05). Group 3 showed higher cytotoxicity than Group 2 in fresh cases and showed higher cytotoxicity than Group 1 and Group 2 in 24-and 72-hour immersion cases (p<.05). Group 1 and Group 2 showed no significant difference. 2. All acrylic denture base resins showed significant increase of cell activity as immersion time increased (p<.05). 3. Auto-polymerizing acrylic denture base resins showed higher cytotoxicity than heat-polymerizing acrylic denture base resins (p<.05). 4. All acrylic denture base resins showed lower mutagenicity than controls (p<.05).
Agar ; Denture Bases* ; Dentures* ; Immersion ; Mutagenesis ; Water

Docosahexaenoic acid (DHA) has many unique physiological functions such as promoting the development of brain and retina in infants. Therefore, it is widely applied to food, pharmacy, breeding and other industries. To obtain engineered strains of Aurantiochytrium limacinum SR21 suitable for industrial application with increased lipid and DHA production, we designed a simple, fast, accurate and high-throughput screening method based on Nile red staining of oil droplets. First, ultraviolet C (UVC) mutagenesis was used to generate a random mutant library of A. limacinum. Second, screening conditions were optimized including staining conditions of Nile red and the sorting criterion. Thereby, three putative high-lipid mutants (D03432, D05106 and D01521) were selected from the mutant library containing 3 648 mutated clones. The three mutants grew faster and produced higher amounts of lipids and DHA compared to wild type (WT). In 100 mL cultures, the lipid content of D03432 and D05106 mutants reached 64.74% and 63.13% of dry cell weight respectively, whereas the wild strain exhibited only 43.19%. DHA yield in these two mutants were even 2.26-fold and 2.37-fold higher than that of the wild strain. Experiment with 5 L fermentor further confirmed that D03432 and D05106 mutants had better performance than the wild strain on DHA yield (45.51% and 66.46% more than that of the wild strain, respectively), and demonstrated their high potential for industrial application. This work not only generated several high-DHA content mutants with high potential for industrial use, but also provided vital guidance for high-throughput screening of lipid hyper-accumulating mutants in other oil-producing microorganisms.
Bioreactors ; Docosahexaenoic Acids ; Mutagenesis ; Staining and Labeling ; Stramenopiles

Leaf water potential of peanut subjected to drought stress is positively related to the oil content of peanut kernels. The aim of this study was to directly screen the high oil mutants of peanut and create the new peanut varieties using hydroxyproline as water potential regulator. In vitro mutagenesis was carried out with the embryonic leaflets of peanut variety Huayu 20 as explants and pingyangmycin as a mutagen added into the somatic embryo formation medium. The formed somatic embryos were successively transferred to somatic embryo germination and selection medium containing 6 mmol/L hydroxyproline (at -2.079 MPa water potential ) to induce regeneration and directionally screen high oil content mutants. After that, these plantlets were grafted and transplanted to the experimental field and 132 high oil mutants with oil content over 55% were obtained from the offspring of regenerated plants. Finally, among them, the oil contents of 27 lines were higher than 58% and of 2 lines were higher than 60%. A new peanut variety Yuhua 9 with high yield and oil content was bred from the regenerated plant progenies combining the pedigree breeding method. The yield was 14.0% higher than that of the control cultivar in the testing new peanut varieties of Liaoning province, and also it has passed the national registration of non-major crop varieties. Yuhua 9 with an oil content of 61.05%, which was 11.55 percentage points higher than that of the parent Huayu 20, was the peanut cultivar with the highest oil content in the world. The result showed that it was an effective way for directional breeding of high oil peanut varieties by means of the three-step technique including in vitro mutagenesis, directional screening by reducing water potential in medium and pedigree selection of regenerated plant progenies.
Arachis ; Droughts ; Germination ; Mutagenesis ; Plant Breeding

Penconazole-resistant and cabendazim-resistant mutants of Venturiu inaequalis were developed by chemical (MNNG) mutagenesis. Protoplasts of these mutants were isolated and fused using polyethylene glycol as the fusogen. Fusants were classified into parental, non-parental and recombinant types. The recombinants were resistant to penconazole and carbendazim. The double resistant strains were stable and exhibited pathogenicity on fungicide-sprayed and unsprayed apple twigs.
Humans ; Mutagenesis ; Parents ; Polyethylene Glycols ; Protoplasts ; Virulence

Creatinine levels in biological fluids are important indicators for the clinical evaluation of renal function. Creatinase (CRE, EC3.5.3.3) is one of the key enzymes in the enzymatic measurement of creatinine concentration, and it is also the rate-limiting enzyme in the whole enzymatic cascade system. The poor catalytic activity of CRE severely limits its clinical and industrial applications. To address this issue, a semi-rational design is applied to increase the activity of a creatinase from Alcaligenes sp. KS-85 (Al-CRE). By high-throughput screen of saturation mutagenesis libraries on the selected hotspot mutations, multiple variant enzymes with increased activity are obtained. The five-point best variant enzyme (I304L/F395V/K351V/Y63S/Q88A) were further obtained by recombine the improved mutations sites that to showed a 2.18-fold increased specific activity. Additionally, structure analysis is conducted to understand the mechanism of the activity change. This study paves the way for a better practical application of creatinase and may help further understand its catalytic mechanism.
Creatinine ; Mutagenesis, Site-Directed ; Ureohydrolases/genetics* ; Catalysis

With the progess in studying gene structure and function of foot and mouth disease virus (FMDV), FMDV can express exogenous genes in different sites. Through transforming and modifying FMDV can achieve different application purposes such as improving virus titer, introducing tag, improving immune responses, and reducing pathogenicity. From the perspective of FMDV receiving inserted exogenous gene, this paper mainly describes the latest relevant developments of FMDV's expression to exogenous gene.
Foot-and-Mouth Disease Virus ; genetics ; Genetic Engineering ; Mutagenesis, Insertional

Saturation mutagenesis was performed on a single position in the voltage-sensing domain (VSD) of a genetically encoded voltage indicator (GEVI). The VSD consists of four transmembrane helixes designated S1-S4. The V220 position located near the plasma membrane/extracellular interface had previously been shown to affect the voltage range of the optical signal. Introduction of polar amino acids at this position reduced the voltage-dependent optical signal of the GEVI. Negatively charged amino acids slightly reduced the optical signal by 33 percent while positively charge amino acids at this position reduced the optical signal by 80%. Surprisingly, the range of V220D was similar to that of V220K with shifted optical responses towards negative potentials. In contrast, the V220E mutant mirrored the responses of the V220R mutation suggesting that the length of the side chain plays in role in determining the voltage range of the GEVI. Charged mutations at the 219 position all behaved similarly slightly shifting the optical response to more negative potentials. Charged mutations to the 221 position behaved erratically suggesting interactions with the plasma membrane and/or other amino acids in the VSD. Introduction of bulky amino acids at the V220 position increased the range of the optical response to include hyperpolarizing signals. Combining The V220W mutant with the R217Q mutation resulted in a probe that reduced the depolarizing signal and enhanced the hyperpolarizing signal which may lead to GEVIs that only report neuronal inhibition.
Amino Acids ; Cell Membrane ; Fluorescence ; Mutagenesis ; Neurons ; Plasma

Pichia pastoris is one of the most convenient and widely used heterologous protein expression systems. To further improve its ability to express heterologous proteins, we developed a high-throughput P. pastoris screening method based on droplet microfluidic and demonstrated the method by screening and obtaining mutants with enhanced xylanase expression and secretion abilities. We used PCR (Polymerase Chain Reaction) amplification to obtain a fusion fragment of xylanase xyn5 gene and green fluorescent protein gfp gene, and cloned this fragment into pPIC9K, the expression vector of Pichia pastoris, to construct the plasmid pPIC9K-xyn5-gfp that recombined the DNA fragments of xylanase and green fluorescent protein. After this plasmid entered P. pastoris GS115 by electroporation, the P. pastoris SG strain that could express xylanase and green fluorescent protein was obtained. The above-said strains were then mutagenized by atmospheric room temperature plasma and subsequently encapsulated to form single-cell droplets. After 24-hour cultivation of the droplets, microfluidic screening was carried out to obtain the mutant strain with high xylanase expression for further construction and screening of the next mutagenesis library. After five rounds of droplet microfluidic screening, a highly productive strain P. pastoris SG-m5 was obtained. The activity of the expressed xylanase was 149.17 U/mg, 300% higher than that of those expressed by the original strain SG. This strain's ability to secrete heterologous protein was 160% higher than that of the original strain. With a screening throughput of 100 000 strains per hour, the high-throughput P. pastoris screening system based on single-cell droplet microfluidic developed by the present study screens a library with million strains in only 10 hours and consumes only 100 μL of fluorescent reagent, thus reducing the reagent cost by millions of times compared with the traditional microplate screening and more importantly, providing a novel method to obtain P. pastoris with high abilities to express and secret heterologous proteins by efficient and low-cost screening.
Microfluidics ; Mutagenesis ; Pichia ; Plasmids ; Polymerase Chain Reaction ; Recombinant Proteins