• Parasites, Hosts and Diseases
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• v.48 no.2
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• pp.105-111
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• 2010

To understand the situation of water contamination with Cryptosporidium spp. and Giardia spp. in the northern region of Portugal, we have established a long-term program aimed at pinpointing the sources of surface water and environmental contamination, working with the water-supply industry. Here, we describe the results obtained with raw water samples collected in rivers of the 5 hydrographical basins. A total of 283 samples were analyzed using the Method 1623 EPA, USA. Genetic characterization was performed by PCR and sequencing of genes 18S rRNA of Cryptosporidium spp. and $\beta$-giardin of Giardia spp. Infectious stages of the protozoa were detected in 72.8% (206 of 283) of the water samples, with 15.2% (43 of 283) positive for Giardia duodenalis cysts, 9.5% (27 of 283) positive for Cryptosporidium spp. oocysts, and 48.1% (136 of 283) samples positive for both parasites. The most common zoonotic species found were G. duodenalis assemblages A-I, A-II, B, and E genotypes, and Cryptosporidium parvum, Cryptosporidium andersoni, Cryptosporidium hominis, and Cryptosporidium muris. These results suggest that cryptosporidiosis and giardiasis are important public health issues in northern Portugal. To the authors' knowledge, this is the first report evaluating the concentration of environmental stages of Cryptosporidium and Giardia in raw water samples in the northern region of Portugal.

• The Plant Pathology Journal
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• v.31 no.3
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• pp.203-211
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• 2015

Maize is the dominant cereal crop produced in the US. One of the main fungal pathogens of maize is Fusarium verticillioides, the causative agent of ear and stalk rots. Significantly, the fungus produces a group of mycotoxins - fumonisins - on infested kernels, which have been linked to various illnesses in humans and animals. Nonetheless, durable resistance against F. verticillioides in maize is not currently available. In Texas, over 2.1 million acres of maize are vulnerable to fumonisin contamination, but understanding of the distribution of toxigenic F. verticillioides in maize-producing areas is currently lacking. Our goal was to investigate the genetic variability of F. verticillioides in Texas with an emphasis on fumonisin trait and geographical distribution. A total of 164 F. verticillioides cultures were isolated from 65 maize-producing counties. DNA from each isolate was extracted and analyzed by PCR for the presence of FUM1- a key fumonisin biosynthesis gene - and mating type genes. Results showed that all isolates are in fact F. verticillioides capable of producing fumonisins with a 1:1 mating-type gene ratio in the population. To further study the genetic diversity of the population, isolates were analyzed using RAPD fingerprinting. Polymorphic markers were identified and the analysis showed no clear correlation between the RAPD profile of the isolates and their corresponding geographical origin. Our data suggest the toxigenic F. verticillioides population in Texas is widely distributed wherever maize is grown. We also hypothesize that the population is fluid, with active movement and genetic recombination occurring in the field.

• Journal of Microbiology and Biotechnology
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• v.31 no.10
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• pp.1455-1464
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• 2021

Trehalose is a non-reducing disaccharide in increasing demand for applications in food, nutraceutical, and pharmaceutical industries. Single-step trehalose production by trehalose synthase (TreS) using maltose as a starting material is a promising alternative process for industrial application due to its simplicity and cost advantage. Pseudomonas monteilii TBRC 1196 was identified using the developed screening method as a potent strain for TreS production. The TreS gene from P. monteilii TBRC 1196 was first cloned and expressed in Escherichia coli. Purified recombinant trehalose synthase (PmTreS) had a molecular weight of 76 kDa and showed optimal pH and temperature at 9.0 and 40℃, respectively. The enzyme exhibited >90% residual activity under mesophilic condition under a broad pH range of 7-10 for 6 h. Maximum trehalose yield by PmTreS was 68.1% with low yield of glucose (4%) as a byproduct under optimal conditions, equivalent to productivity of 4.5 g/l/h using enzyme loading of 2 mg/g substrate and high concentration maltose solution (100 g/l) in a lab-scale bioreactor. The enzyme represents a potent biocatalyst for energy-saving trehalose production with potential for inhibiting microbial contamination by alkaline condition.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1307-1314
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• 2022

In this study, we sought to investigate the various characteristics of Salmonella spp. isolated from raw chicken meats available in Korean markets. The data collected, such as food source of isolation, sampling information, serotype, virulence, and genetic profile including sequence type, were registered in the database for further comparative analysis of the strains isolated from the traceback investigation samples. To characterize serotype, virulence and gene sequences, we examined 113 domestically distributed chicken meat samples for contamination with Salmonella spp. Phylogenetic analysis was conducted on 24 strains (21.2%) of Salmonella isolated from 113 commercially available chicken meats and by-products, using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Serotyping of the isolated Salmonella spp. revealed S. Enteritidis in 11 strains (45.8%), S. Virchow in 6 strains (25%), S. Montevideo in 2 strains (8.3%), S. Bsilla in 2 strains (8.3%), S. Bareilly in 1 strain (4.2%), S. Dessau in 1 strain (4.2%), and S. Albany in 1 strain (4.2%). The genetic correlation indicated that 24 isolated strains were classified into 18 clusters with a genetic similarity of 64.4-100% between them. Eleven isolated S. Enteritidis strains were classified into 9 genotypes with a sequence identity of 74.4%, whereas the most distantly related S. Virchow was divided into five genotypes with 85.9% identity. Here, the MLST analysis indicated that the major Sequence Type (ST) of the Salmonella spp. isolated from domestic chicken sold in Chungcheong Province belongs to the ST 11 and 16, which differs from the genotype of Salmonella isolated from imported chicken. The differential sequence characteristics can be a genetic marker for identifying causative bacteria for epidemiological investigations of food poisoning.

• Advances in environmental research
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• v.2 no.3
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• pp.245-260
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• 2013

Biosorption represents a technological innovation as well as a cost effective excellent remediation technology for cleaning up radionuclides from aqueous environment. In the present study, a bacteria strain FB12 with high adsorption rate of uranium ion was isolated from the vicinity of the nuclear power plant. It was tentatively identified as Bacillus sp.FB12 according to the 16S rDNA sequencing. Efforts were made to further improve the adsorption rate and genetic stability by UV irradiation and UV-LiCl cooperative mutagenesis. The improved strain named Bacillus sp.UV32 obtains excellent genetic stability and a high adsorption rate of 95.9%. The adsorption of uranium U (VI) by Bacillus sp.UV32 from aqueous solution was examined as a function of metal ion concentration, cell concentration, adsorption time, pH, temperature, and the presence of some foreign ions. The adsorption process of U (VI) was found to follow the pseudo-second-order kinetic equation. The adsorption isotherm study indicated that it preferably followed the Langmuir adsorption isotherm. The thermodynamic parameters values calculated clearly indicated that the adsorption process was feasible, spontaneous and endothermic in nature. These properties show that Bacillus sp.UV32 has potential application in the removal of uranium (VI) from the radioactive wastewater.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.578-587
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• 2015

Nuclear SSR (nSSR) and chloroplast SSR (cpSSR) markers were analyzed to assess the parameters of mating system in seed orchard, such as outcrossing rates, the number of potential pollen contributors, paternal contribution rates, degree of pollen contamination, and biparental inbreeding ($t_m-t_s$). In 2006, 2007, seeds were collected from the seed orchard of Pinus densiflora, established in 1977 at Anmyeon island. Estimates of outcrossing rates ranged from 94.9 to 100% (mean 98.9%) in 2006 and from 91.2 to 100% (mean 97.7%) in 2007 on the basis of the analysis of cpSSR haplotypes and from 90.3 to 100% (mean 95.9%) in 2006 and from 81.6 to 100% (mean 95.3%) in 2007 on the basis of the analysis of nSSR genotypes. By cross checking of both DNA markers, mean cumulative outcrossing rates of 100% and 98.9% were estimated in each year. Mean contamination rates were estimated as 48.9% and 42.4%, respectively. On the basis of cpSSR haplotype observed in each seed, paternal contribution rates (the number of pollen contributors) were estimated as 0.458 (mean 16.2) in 2006 and 0.512 (mean 14.8) in 2007. In conclusion, considering pretty high level of outcrossing rates observed in a seed orchard, there might be little to be influenced by inbreeding depression for genetic potential of the seeds induced by selfing. Estimates of the mating system parameters obtained from the two reproductive years were not statistically different, which revealed stable genetic quality of seeds produced in different years. Observed results from this study may provide useful information for the management and establishment of the seed orchard of the progressive generation.

• Journal of Food Hygiene and Safety
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• v.29 no.3
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• pp.228-233
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• 2014

This study was performed to examine antimicrobial resistance of Enterococcus spp. strains from retail raw meat and fish products purchased in 2012. 43 Enterococcus spp. strains were isolated from a total of 207 samples (beef, pork, chicken, fish) with contamination rate of 20.8%. The isolated strains were identified as E. faecalis (22 strains), E. gallinarum, E. hirae (5 strains), E. avium (4 strains), E. faecium (3 strains), E. duram, E. casseliflavus (2 strains). Susceptibility to 10 antibiotics was tested, and the highest resistance was observed to tetracycline. And antimicrobial resistance rates were presented below 20% with most of the other antimicrobial agents. The isolated Enterococci from chicken showed higher resistance also to ciprofloxacin and erythromycin, not only to tetracycline, compared to the isolated Enterococci from beef, pork and fish. Sixteen isolates (37.2%) were sensitive to all antibiotics. Four isolates (9.3%) were resistant to 3 or more antibiotics. Vancomycin-resistant enterococci (VRE) was not identified. According to the results of genetic similarity pattern analysis via PFGE and rep-PCR, Enterococci strains showed different patterns from these collected in 2011. This indicates that there is no genetic similarity among all the strains.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.25-25
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• 2018

The Fukushima Daiichi Nuclear Power Plant accident in March 2011 caused severe radioactive contamination in the surrounding environment. Since the accident, much attention has been paid to the biological and genetic consequences of organism inhabiting the contaminated area. The effect of radiation exposure on genetic mutation rates is little known, especially for low doses and in situ conditions. Evaluating DNA mutation by low levels of radiation dose is difficult due to the rare mutation event and lack of sequence information before the accident. In this study, correlations with air dose levels and somatic DNA mutation rates were evaluated using Next Generation Sequencer for the clonal plant, Phyllostachys edulis. This bamboo is known to spread an identical clone throughout Japan, and it has the advantage that we can compare genetic mutation rate among identical clone growing different air dose levels. We collected 94 samples of P. edulis from 14 sites with air dose rates from $0.04{\sim}7.80{\mu}Gy/h$. Their clonal identity was confirmed by analysis using 24 microsatellite markers, and then, sequences among samples were compared by MIG sequence. The sequence data were obtained from 2,718 loci. About ~200,000 bp sequence (80 bp X 2,718 loci) were obtained for each sample, and this corresponds to about 0.01% of the genome sequence of P. edulis. In these sequences, 442 loci showed polymorphism patterns including recent origin mutation, old mutation, and sequence errors. The number of mutations per sample ranged from 0 to 13, and did not correlate with air dose levels. This result indicated that DNA mutations have not accumulated in P. edulis living in the air doses levels less than $10{\mu}Gy/h$. Our study also suggests that mutation rates can be assessed by selecting an appropriate experimental approach and analyzing with next generation sequencer.

• Parasites, Hosts and Diseases
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• v.55 no.3
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• pp.239-246
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• 2017

Strains of Toxoplasma gondii in Brazil are highly genetically diverse compared to strains from North America and Europe. Dogs are epidemiologically important because they act as sentinels for T. gondii infections in humans and are good indicators of environmental contamination. The aim of this study was to isolate and genetically characterize T. gondii strains from tissues of naturally infected Brazilian dogs. For this study, 21 blood samples were collected from dogs at the Zoonosis Control Centers of $Ilh{\acute{e}}us$ and Itabuna cities, Bahia, Brazil. The sera were examined for T. gondii antibodies using the indirect hemagglutination test. Brains and hearts of seropositive dogs were bioassayed in mice to isolate and characterize T. gondii parasites by PCR-RFLP using 10 genetic markers (SAG1, newSAG2, SAG3, BTUB, c22-8, c29-2, GRA6, PK1, APICO, and L358). However, T. gondii was isolated from only 4 (57.1%) dogs, designated TgDgBr6, 13, 17, and 21. All strains were virulent, causing clinical changes (rough hair coat, lethargy, and abdominal distention) and the death of all mice within 8-20 days after inoculation. Genetic analysis of these 4 T. gondii isolates revealed 4 distinct genotypes with different clonal lineage combinations (types I, II, and III) and 2 atypical alleles. Using PCR-RFLP with several markers, this study contributes to evaluations of the genetic diversity of strains circulating in Brazil.

• Journal of Applied Biological Chemistry
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• v.44 no.4
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• pp.194-198
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• 2001

Contaminated sites are often abandoned for an extended period of time, thus organopollutants becoming sequestered. The information on the initial concentrations of the contaminants would be helpful for the economic bioremediation of the chemicals. The present study estimated the initial concentrations of atrazine and phenanthrene through multiple regression analyses using soil properties and the amount of chemicals available in situ. Percentage mineralized or extracted was best correlated with organic C or logarithm of organic C, and the $R^2$ values were 0.548 and 0.894 for atrazine and phenanthrene, respectively. Estimation of the initial concentration of the chemicals was then calculated from both the percentage mineralized or extracted and the amount of chemicals extracted or mineralized. Results showed that the estimation of the initial concentration of the chemical at the time of contamination is feasible.