Duplex polymerase chain reaction method for detection of unapproved genetically modified tomato (Solanum lycopersicon L.) with cucumber mosaic virus (CMV) satellite RNA gene

The complete sequence of the cucumber mosaic virus (CMV) satellite RNA (satRNA) gene that was controlled by the cauliflower mosaic virus (CaMV) 35S promoter (P-35S) and the Agrobacterium nopaline synthase terminator (T-nos) was first identified in an unapproved genetically modified (GM) tomato (Solanum lycopersicum L.), and a duplex polymerase chain reaction (PCR) method was developed based on the CMV satRNA nucleotide sequence. To detect the unapproved GM tomato, the metallocarboxypeptidase inhibitor (Mcpi) gene was selected as an endogenous reference gene for tomato and was validated using 13 different crops. The primer pair PTD-F/R was designed to amplify the junction sequences between the 35S promoter and CMV satRNA gene introduced in the unapproved GM tomato, and its specificity was also validated using several different GM events. The detection limit of the duplex PCR method is approximately 1 copy. Using the duplex PCR method, 35 processed tomato foods and 13 tomato seeds were analyzed. Of these samples, 2 GM tomato seeds were identified using the duplex PCR method. The results indicate that this duplex PCR method could be useful for detecting the unapproved GM tomato.     

Identification of novel IgE-binding soybean allergens using serological analysis of a recombinant cDNA expression library (SEREX)

New immunoglobulin E (IgE)-binding proteins from soybean (Glycine max L.) were identified using serological analysis of a recombinant cDNA expression library (SEREX) derived from soybean seeds and an enzyme-linked immunosorbent assay (ELISA). A soybean cDNA expression library was synthesized using the lambda ZAP express phage vector system and screened using sera of soybean-sensitive patients with atopic dermatitis (AD). A total of 3 new IgE-binding soybean proteins were identified as enolase, triosephosphate isomerase (TPI), and malate dehydrogenase (MDH). Full-length cDNAs were cloned into the expression vector pET15b, and expressed in Escherichia coli BL21 (DE3). The recombinant proteins were purified using affinity chromatography, followed by ELISA, with the sera of AD patients, resulting in positive reactions. The cDNA sequences were submitted to the GenBank Nucleotide Sequence Database with the accession numbers AY496909 (enolase), AY631048 (TPI), and AY496910 (MDH).     

Rapid on-site detection of shrimp allergen tropomyosin using a novel ultrafast PCR system

Food Science and Biotechnology - Shrimp is seafood that can commonly trigger allergic reactions. In this study, the ultrafast real-time PCR assay with portable device was developed to detect a...     

Prevalence and Characteristics of Phenicol-Oxazolidinone Resistance Genes in Enterococcus Faecalis and Enterococcus Faecium Isolated from Food-Producing Animals and Meat in Korea

The use of phenicol antibiotics in animals has increased. In recent years, it has been reported that the transferable gene mediates phenicol-oxazolidinone resistance. This study analyzed the prevalence and characteristics of phenicol-oxazolidinone resistance genes in Enterococcus faecalis and Enterococcus faecium isolated from food-producing animals and meat in Korea in 2018. Furthermore, for the first time, we reported the genome sequence of E. faecalis strain, which possesses the phenicol-oxazolidinone resistance gene on both the chromosome and plasmid. Among the 327 isolates, optrA, poxtA, and fexA genes were found in 15 (4.6%), 8 (2.5%), and 17 isolates (5.2%), respectively. Twenty E. faecalis strains carrying resistance genes belonged to eight sequence types (STs), and transferability was found in 17 isolates. The genome sequences revealed that resistant genes were present in the chromosome or plasmid, or both. In strains EFS17 and EFS108, optrA was located downstream of the ermA and ant(9)-1 genes. The strains EFS36 and EFS108 harboring poxtA-encoding plasmid cocarried fexA and cfr(D). These islands also contained IS1216E or the transposon Tn554, enabling the horizontal transfer of the phenicol-oxazolidinone resistance with other antimicrobial-resistant genes. Our results suggest that it is necessary to promote the prudent use of antibiotics through continuous monitoring and reevaluation.     

Screening of Strains with fibrinolytic activity and angiotensin-converting enzyme inhibitory activity from doenjang

As a first step to develop a doenjang possessing functional properties, microbial strains possessing proteolytic activity, fibrinolytic activity, and angiotensin-converting enzyme (ACE) inhibitory activity were screened and isolated from Korean traditional doenjang. First, total 264 isolates showing proteolytic activity were isolated from 14 different doenjang samples. Among them, 4 strains producing both of fibrinolytic activity and ACE inhibitor into the culture medium were selected. The levels of ACE inhibitory effect of G19, G26, P16, and P25 strains were about 82.5, 78.5, 74.5, and 75.6% of inhibition ratio in soybean powder broth, respectively. All isolates were identified as Bacillus amyloliquefaciens based on SDS-PAGE profiles of whole cell proteins and 16S rRNA gene sequence analysis. The result implied that the selected Bacillus strains could be used for the development of doenjang possessing functional properties as potential starter.     

Regulatory policy on genetically modified breeding stack in key countries and the current status in Korea

With an increasing interest and demand for biotechnology crops in agriculture worldwide, genetically modified (GM) breeding stacks produced by conventional breeding of previously approved GM single events remain popular for farmers in GM crop cultivation countries. However, regulations on stacks vary in each country. Currently, Korea requires approval for all breeding stacks intended for cultivation. To determine whether the stack is subject to a full safety assessment as a new GM crop, molecular characterization, protein expression, composition analysis, and agronomic characterization data are required. Korea’s regulatory policy on stacks has not adopted the high-covers-low concept; therefore, subcombinations of already approved higher combination events are subject to breeding stack review if any subcombination was purposefully bred for cultivation use. This review will help promote the efficient management of GM breeding stacks in Korea in the future.

     

Distribution of lactic acid bacteria in garlic (Allium sativum) and green onion (Allium fistulosum) using SDS-PAGE whole cell protein pattern comparison and 16S rRNA gene sequence analysis

Distributions of lactic acid bacteria (LAB) in garlic and green onion samples as kimchi sub-ingredients were analyzed by comparing the SDS-PAGE whole cell protein patterns and 16S rRNA gene sequence analysis. In total, 245 LAB were isolated from 10 garlic samples and differentiated into 7 groups by comparing SDS-PAGE whole cell protein patterns. The groups were identified as Leuconostoc, Weissella, and Lactobacillus through the 16S rRNA gene sequence analysis. A total of 115 LAB were isolated from 7 green onion samples, differentiated into 6 groups, and identified as Weissella, Leuconostoc, and Lactococcus. Leuconostoc was the most dominated LAB in garlic and Weissella was the most dominated LAB in green onion. The LAB identified in this study was found as dominant microorganisms in kimchi. This result suggests the possible contribution of LAB in garlic and green onion to the bacterial microflora of kimchi, especially during early stage of fermentation.     

Simultaneous detection of fruit allergen-coding genes in tomato,apple, peach and kiwi through multiplex PCR

Food Science and Biotechnology - Fruit allergies have become more common in recent years, and are now a serious health problem. In this study, a multiplex PCR assay was used to detect potential...