Expression of stress regulator and virulence genes of Cronobacter sakazakii strain Yrt2a as a response to acid stress

Food Science and Biotechnology - This research aimed to evaluate the effect of acid stress on the expression of stress regulator (grxB and rpoS) and virulence (ompA, hfq, and cpa) genes of...     

Stability and growth characteristics of GFPuv-labeled Cronobacter sakazakii isolated from foods

Stability of ultraviolet green fluorescent protein (GFPuv)-labeled Cronobacter sakazakii and C. muytjensii isolated from foods and the effects of the plasmid GFPuv (pGFPuv) on growth were analyzed. PCR analysis and microscopic observation showed that C. sakazakii and C. muytjensii isolates took up the plasmid into cells and expressed the GFPuv gene. All Cronobacter transformants maintained this plasmid after frozen storage and 2 consecutive subcultures. The C. sakazakii FWHd16 transformant was the most stable, while the C. muytjensii FWHd11 transformant was the least stable. All transformants showed nearly identical growth curves during lag, log and stationary phases, compared to wild type parental isolates. The maximum bacterial growth rates (μ_max) of the transformants and parents were similar, indicating that the presence of pGFPuv in transformants did not affect cell growth. Stable GFPuv-labeled Cronobacter has potential for use in tracking bacterial behavior during food handling and drying.     

Marine-derived bioactive materials for neuroprotection

A sensitive and specific liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the determination of 56 residual pesticides from commercial crops. For a validation of the method, the recoveries, linearities, limits of detection (LOD), and limits of quantitation (LOQ) of the 56 pesticides were investigated. The linearities, LOD, and mean recoveries of the pesticides ranged 0.9686–0.9999, 0.00–11.54 μg/kg, and 65–82%, respectively. This method was evaluated by its application to monitor 345 agricultural products collected from 9 provinces in Korea 2011. Fifteen pesticides were detected from 39 samples and 2 or more residual pesticides were found in 7 samples. However, none of the compounds were observed above the corresponding maximum residue level. The results reflect that the detected pesticide residues were in a safe range and that residual pesticides in the agricultural products in Korea were properly controlled.     

Expression of rpoS,ompA and hfq genes of Cronobacter sakazakii strain Yrt2a during stress and viable but nonculturable state

Food Science and Biotechnology - Cronobacter spp. in powdered infant formula has been etiologically linked to meningitis and necrotizing enterocolitis in certain groups of infants. This study aimed...     

Biological activities and health benefit effects of natural pigments derived from marine algae

The importance of marine algae as sources of functional ingredients has been well recognized due to their valuable health beneficial effects. Therefore, isolation and investigation of novel ingredients with biological activities from marine algae have attracted a great deal of attention. Among functional ingredients identified from marine algae, natural pigments (NPs) have received particular attention. These NPs exhibit various beneficial biological activities such as antioxidant, anticancer, anti-inflammatory, anti-obesity, anti-angiogenic and neuroprotective activities. This contribution focuses on biological activities of marine algae-derived NPs and emphasizing their potential applications in foods as well as pharmaceuticals areas.