• Food Science of Animal Resources
• /
• v.30 no.2
• /
• pp.328-335
• /
• 2010

The aim of our study was to develop a new starter culture for fermented milk. Polymerase chain reaction screening of 103 acid-producing isolates from Kimchi identified 72 Lactobacillus strains. The ability of the strains to inhibit the growth of the food-borne human pathogens (Escherichia coli, Salmonella Enteritidis, Staphylococcus aureus) was measured, using a conventional paper disk method. Among the 72 strains, strain LHC52 displayed potent antagonistic activity. Use of 16S rDNA sequencing and the API 50CHL system identified the strain as Lactobacillus plantarum and it was designated L. plantarum LHC52. Biochemical analyses revealed especially high antibacterial activity against E. coli. Yogurt produced using L. plantarum LHC52 did not show different microbiological and physicochemical properties compared to conventionally-prepared yogurt, implicating L. plantarum LHC52 as a useful, potently antibacterial starter culture for yogurt preparation.

• Journal of Microbiology and Biotechnology
• /
• v.21 no.6
• /
• pp.574-581
• /
• 2011

A Gram-positive bacterium was isolated from the saline soils of Jangpura (U.P.), India, and showed high-level of radiation-resistant property and survived upto 12.5 kGy dose of gamma radiation. The 16S rDNA sequence of this strain was examined, identified as Bacillus sp. strain HKG 112, and was submitted to the NCBI GenBank (Accession No. GQ925432). The mechanism of radiation resistance and gene level expression were examined by proteomic analysis of whole-cell extract. Two proteins, 38 kDa and 86.5 kDa excised from SDS-PAGE, which showed more significant changes after radiation exposure, were identified by MALDI-TOF as being flagellin and S-layer protein, respectively. Twenty selected 2-DE protein spots from the crude extracts of Bacillus sp. HKG 112, excised from 2- DE, were identified by liquid chromatography mass spectrometry (LC-MS) out of which 16 spots showed significant changes after radiation exposure and might be responsible for the radiation resistance property. Our results suggest that the different responses of some genes under radiation for the expression of radiation-dependent proteins could contribute to a physiological advantage and would be a significant initial step towards a fullsystem understanding of the radiation stress protection mechanisms of bacteria in different environments.

• Korean Journal of Veterinary Research
• /
• v.54 no.2
• /
• pp.91-99
• /
• 2014

An antimicrobial susceptibility test was conducted to compare the resistance rates among Campylobacter spp. isolates from dogs (n = 50) raised under diverse conditions and humans (n = 50). More than 60% of Campylobacter (C.) jejuni from dogs and humans showed resistance to nalidixic acid, enrofloxacin and ciprofloxacin. C. jejuni isolates from humans showed higher resistance to tetracycline (83.3%) and ampicillin (91.3%) than those from dogs. None of the C. jejuni or Campylobacter coli isolates from humans or dogs were resistant to erythromycin. Overall, 85% of Campylobacter spp. isolates showed a multidrug resistant phenotype. Nucleotide sequencing analysis of the gryA gene showed that 100% of $NA^R/CIP^R$ C. jejuni isolates from dogs and humans had the Thr-$86^{th}$-Ile mutation, which is associated with fluoroquinolone resistance. flaA PCR restriction fragment length polymorphism (RFLP) typing to differentiate the isolates below the species level revealed 12 different clusters out of 73 strains. The human isolates belonged to eight different RFLP clusters, while five clusters contained dog and human isolates.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.4
• /
• pp.437-447
• /
• 2012

Natural and beneficial associations between plants and bacteria have demonstrated potential commercial application for several agricultural crops. The sunflower has acquired increasing importance in Brazilian agribusiness owing to its agronomic characteristics such as the tolerance to edaphoclimatic variations, resistance to pests and diseases, and adaptation to the implements commonly used for maize and soybean, as well as the versatility of the products and by-products obtained from its cultivation. A study of the cultivable bacteria associated with two sunflower cultivars, using classical microbiological methods, successfully obtained isolates from different plant tissues (roots, stems, florets, and rhizosphere). Out of 57 plant-growth-promoting isolates obtained, 45 were identified at the genus level and phylogenetically positioned based on 16S rRNA gene sequencing: 42 Bacillus (B. subtilis, B. cereus, B. thuringiensis, B. pumilus, B. megaterium, and Bacillus sp.) and 3 Methylobacterium komagatae. Random amplified polymorphic DNA (RAPD) analysis showed a broad diversity among the Bacillus isolates, which clustered into 2 groups with 75% similarity and 13 subgroups with 85% similarity, suggesting that the genetic distance correlated with the source of isolation. The isolates were also analyzed for certain growth-promoting activities. Auxin synthesis was widely distributed among the isolates, with values ranging from 93.34 to 1653.37 ${\mu}M$ auxin per ${\mu}g$ of protein. The phosphate solubilization index ranged from 1.25 to 3.89, and siderophore index varied from 1.15 to 5.25. From a total of 57 isolates, 3 showed an ability to biologically fix atmospheric nitrogen, and 7 showed antagonism against the pathogen Sclerotinia sclerotiorum. The results of biochemical characterization allowed identification of potential candidates for the development of biofertilizers targeted to the sunflower crop.

• Ocean and Polar Research
• /
• v.32 no.3
• /
• pp.247-254
• /
• 2010

Single cell PCR analysis and light and scanning electron microscopic techniques were utilized to identify free living bivalve larvae in the coastal waters of Tae-an, on the west coast of Korea. Through DNA sequencing, venerid clam larvae were isolated and identified as Ruditapes philippinarum (99% similarity) and Meretrix lusoria (99%). Under microscopic observation, the D-veliger stage of R. philippinarum exhibited symmetrical shoulder angles and an elliptical ventral form. In contrast, M. lusoria displayed asymmetrical shoulder angles and a round ventral form in the umbonal stage. Size of the R. philippinarum larvae was $156{\pm}22{\mu}m$ in length, $126{\pm}12{\mu}m$ in height, $92{\pm}14{\mu}m$ in width with a length: height ratio of 1.23. Meretrix lusoria was $202{\pm}44{\mu}m$ in length, $161{\pm}35{\mu}m$ in height, $96{\pm}38{\mu}m$ in width with a length: height ratio of 1.25. Experimental results indicate that morphological and molecular characteristics provide evidence for the larval identification of these two venerid clam larvae species in nature.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.5
• /
• pp.862-870
• /
• 2010

Cyperus rotundus L. is a perennial herb that was found to be dominating an area in northeast Brazil previously contaminated with petroleum. In order to increase our knowledge of microorganism-plant interactions in phytoremediation, the bacterial community present in the rhizosphere and roots of C. rotundus was evaluated by culture-dependent and molecular approaches. PCR-DGGE analysis based on the 16S rRNA gene showed that the bacterial community in bulk soil, rhizosphere, and root samples had a high degree of similarity. A complex population of alkane-utilizing bacteria and a variable nitrogen-fixing population were observed via PCR-DGGE analysis of alkB and nifH genes, respectively. In addition, two clone libraries were generated from alkB fragments obtained by PCR of bulk and rhizosphere soil DNA samples. Statistical analyses of these libraries showed that the compositions of their respective populations were different in terms of alkB gene sequences. Using culturedependent techniques, 209 bacterial strains were isolated from the rhizosphere and rhizoplane/roots of C. rotundus. Dot-blot analysis showed that 17 strains contained both alkB and nifH gene sequences. Partial 16S rRNA gene sequencing revealed that these strains are affiliated with the genera Bosea, Cupriavidus, Enterobacter, Gordonia, Mycoplana, Pandoraea, Pseudomonas, Rhizobium, and Rhodococcus. These isolates can be considered to have great potential for the phytoremediation of soil with C. rotundus in this tropical soil area.

• Molecules and Cells
• /
• v.40 no.8
• /
• pp.587-597
• /
• 2017

MicroRNAs (miRNAs) are essential small RNA molecules that regulate the expression of target mRNAs in plants and animals. Here, we aimed to identify miRNAs and their putative targets in Hibiscus syriacus, the national flower of South Korea. We employed high-throughput sequencing of small RNAs obtained from four different tissues (i.e., leaf, root, flower, and ovary) and identified 33 conserved and 30 novel miRNA families, many of which showed differential tissuespecific expressions. In addition, we computationally predicted novel targets of miRNAs and validated some of them using 5' rapid amplification of cDNA ends analysis. One of the validated novel targets of miR477 was a terpene synthase, the primary gene involved in the formation of disease-resistant terpene metabolites such as sterols and phytoalexins. In addition, a predicted target of conserved miRNAs, miR396, is SHORT VEGETATIVE PHASE, which is involved in flower initiation and is duplicated in H. syriacus. Collectively, this study provides the first reliable draft of the H. syriacus miRNA transcriptome that should constitute a basis for understanding the biological roles of miRNAs in H. syriacus.

• Animal Bioscience
• /
• v.36 no.11
• /
• pp.1727-1737
• /
• 2023

Objective: The poultry industry is a primary source of animal protein worldwide. The gut microbiota of poultry birds, such as chickens and ducks, is critical in maintaining their health, growth, and productivity. This study aimed to identify longitudinal changes in the gut microbiota of laying hens from birth to the pre-laying stage. Methods: From a total of 80 Hy-Line Brown laying hens, birds were selected based on weight at equal intervals to collect feces (n = 20 per growth) and ileal contents (n = 10 per growth) for each growth stage (days 10, 21, 58, and 101). The V4 regions of the 16S rRNA gene were amplified after extracting DNA from feces and ileal contents. Amplicon sequencing was performed using Illumina, followed by analysis. Results: Microbial diversity increased with growth stages, regardless of sampling sites. Microbial community analysis indicated that Firmicutes, Proteobacteria, and Bacteroidetes were the dominant phyla in the feces and ileal. The abundance of Lactobacillus was highest on day 10, and that of Escherichia-shigella was higher on day 21 than those at the other stages at the genus level (for the feces and ileal contents; p<0.05). Furthermore, Turicibacter was the most abundant genus after changing feed (for the feces and ileal contents; p<0.05). The fecal Ruminococcus torques and ileal Lysinibacillus were negatively correlated with the body weights of chickens (p<0.05). Conclusion: The gut microbiota of laying hens changes during the four growth stages, and interactions between microbiota and feed may be present. Our findings provide valuable data for understanding the gut microbiota of laying hens at various growth stages and future applied studies.

• Journal of Animal Science and Technology
• /
• v.51 no.4
• /
• pp.289-294
• /
• 2009

Inositol 1,4,5-triphosphate receptor type 1 (IP3R1) is a $Ca^{2+}$ release channel that responds to the second messenger IP3 and that modulates diverse cellular functions such as contraction/excitation, secretion, gene expression and cellular growth. We discovered single nucleotide polymorphisms (SNPs) within IP3R1 gene and analyzed associations between gene polymorphisms and carcass traits in Korean cattle (Hanwoo) in order to develop novel DNA markers at genomic level. Three SNPs were detected at the position of g.1428617A>G, g.1418843C>T and g.1414377C>T with 24 unrelated Hanwoo samples by direct sequencing of the PCR products. We found that genotype of g.1414377C>T SNP was associated with live weight (P<0.05) and carcass weight (P<0.01) using the general linear model of SAS package. These results suggest that polymorphism of IP3R1 gene was associated with weight-related traits in Hanwoo.

• Journal of Animal Science and Technology
• /
• v.53 no.1
• /
• pp.7-13
• /
• 2011

The aim of this study was to identify the polymorphism on exostosin-1 (EXT1) gene and to associate with economic traits in Hanwoo (Korean cattle). We sequenced for detection of single nucleotide polymorphism (SNP) with 24 unrelated individuals and identified four SNPs (T272196A, C272359T, G290964A and A302092G). Relationship between the genotypes of 583 Hanwoo individuals by PCR-RFLP and economic traits were analyzed by general linear model. In EXT1 gene, there were four SNPs associated with economic traits such as eye muscle area breeding value, marbling score breeding value, backfat and thickness breeding value (p<0.05 to p<0.01). In conclusion, this study indicates an important role of EXT1 gene in determining the meat quality or economic characteristics in Hanwoo.