The use of double lumen catheters as a means of hemodialysis access is commonly accompanied with the use of gentamicin as an antibiotic lock. Other antibiotics and anticoagulants are often added to increase the efficacy of gentamicin in order to reduce catheter-related infection and to prevent biofilm formation. This review aimed to evaluate the following: 1) the use of gentamicin in eliminating catheter-related infection and reducing biofilm formation in hemodialysis catheters, 2) the efficacy of additional antibiotics in combination with gentamicin, and 3) the effect of additional anticoagulants to complement the efficacy of gentamicin as the main prophylactic antibiotic lock. We sorted through data from 242 PubMed and ScienceDirect studies, which were then short-listed to 33 studies. Next, they were grouped, extracted, and analyzed qualitatively to fulfil the objectives of this review. Consequently, the use of a gentamicin-lock solution was shown to reduce the incidence of bacteremia; however, it was not strong enough to inhibit the growth of infectious microbes and formation of biofilms. Several bacteria, such as Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Klebsiella pneumoniae, have been reported as infectious agents. Combination with other antibiotics also provided no effect in reducing bacterial growth and biofilm formation in catheters. Furthermore, the additional anticoagulants (trisodium citrate and EDTA) were reported to be effective in enhancing the efficacy of gentamicin in avoiding catheter-related infection, bacterial growth, and biofilm formation; thus, the use of gentamicin can be rationalized.

The consumption of fresh vegetables has been related to recurrent outbreaks of foodborne diseases (FBD) worldwide. Therefore, the development of effective alternative technologies is necessary to improve the safety of these products. This study aimed to isolate and identify epiphytic lactic acid bacteria (LAB) from fresh fruits and leafy vegetables and characterize their antagonistic capacity due to their ability to produce bacteriocins or antibacterial compounds. For this, 92 LAB isolates from fruits and leafy vegetables were screened for antagonistic activity. Two strains with the highest and broadest antagonistic activities were selected for further characterization; one from cantaloupe melon (strain CM175) and one from cilantro leaves (strain C15). The cell-free supernatants (CFS) of CM175 and C15 were found to exhibit antagonistic activity against FBD-causing pathogens. The CM175 and C15 strains were identified as Pediococcus pentosaceus and Lactobacillus graminis, respectively. Notably, the P. pentosaceus CM175 CFS stopped the growth of Salmonella Typhimurium, Salmonella Saintpaul, Staphylococcus aureus, and Listeria monocytogenes, and delayed Escherichia coli O157:H7 growth. Moreover, L. graminis C15 CFS delayed the growth of all indicator pathogens, but did not completely stop it. Organic acids and bacteriocin-like molecules were determined to be possibly exerting the observed antagonistic activity of the identified LAB strains. Thus, application of the antagonistic compounds produced by Pediococcus pentosaceus and Lactobacillus graminis could be a novel and ecological strategy in developing antimicrobial biopreservatives for the food industry and mitigating FBD by reducing the biological contamination in fruit and vegetable orchards, mainly via their potential in controlling both gram-negative and gram-positive pathogenic bacteria.

The purpose of this study was to investigate the melanogenesis inhibiting activity of the ethanol extract from Polygonum amphibium L. Firstly, the n-hexane (Hx), chloroform ($CHCl_3$), ethyl acetate (EA), n-butanol (BuOH), and water (Water) fractions were isolated from the P. amphibium L. ethanol extract. The efficacy of melanogenesis was found to significantly decrease via the EA and BuOH fractions when compared to the control in B16F10 cells. EA particularly showed the lowest melanin content in B16F10 cells when compared to all the other extracts. Concentration-dependent inhibition of melanin synthesis was also observed in the EA fraction at concentrations below $50{\mu}g/ml$, which did not exhibit cytotoxicity in B16F10 cells. Notably, the expression of three key proteins (tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2), which are involved in melanogenesis, were significantly decreased via the EA fraction. EA also inhibited body pigmentation in vivo in a zebrafish model. Overall, we demonstrated melanogenesis suppression using the EA fraction from P. amphibium L., which could be a potential candidate for an antimelanogenesis agent.

Biotransformation of ginsenosides by microorganisms alters the absorption and bioavailability of ginseng as a medicinal herb. In this study, we isolated two kinds of fermenting microorganisms from Eoyukjang, which is a traditional Korean fermented food made from soybean. Next, we identified and detected their ability to convert major ginsenosides to compound K. The two microorganisms, referred to as R2-6 and R2-15, had 100% similarity with Lactobacillus plantarum subsp. plantarum ATCC $14917^T$ and Lactobacillus rhamnosus JCM $1136^T$, respectively. The optimal pH and growth temperature of the isolates were determined to be pH 6-7 and $30^{\circ}C$. After fermentation for 30 days, the major ginsenosides in the mountain-cultivated ginseng were transformed to the highly bioactive ginsenoside, compound K, in the final product.

The effect of microencapsulation on previously isolated Lactobacillus delbrueckii 94/L4 as starter culture for yogurt, and Lactobacillus casei 97/L3 as a probiotic candidate was investigated. Preliminary results showed that L. delbrueckii 94/L4 exhibited tolerance to bile, unlike L. casei 97/L3. Freeze drying significantly (p < 0.05) reduced the viability of both isolates by log 0.71-2.70. Although microencapsulation preserved the viability of L. casei 97/L3 cells exposed to simulated gastrointestinal tract conditions for 120 min, it did not impart significant (p < 0.05) protection against loss of viability during the first 30 min of exposure. Conversely, microencapsulated L. delbrueckii 94/L4 with the addition of Streptococcus thermophilus 24/S1 as starter culture was successfully incorporated into milk to form yogurt, yielding a significantly (p < 0.05) improved product quality.

Bacterial lysates have become a common ingredient for natural health care. Lactic acid bacteria (LAB) could serve as potential candidates for lysate production: the lactic acids produced by LAB have been utilized for their moisturizing, antimicrobial, and rejuvenating effects, while other substances provide topical benefits and health effects for the skin. Our study aimed to obtain lysate from a LAB S. macedonicus MBF 10-2 through an optimized fermentation using the Response Surface Methodology. Strain MBF10-2 was cultivated in a 2L fermenter tank in de Man Rogosa and Sharpe (MRS) medium and in plant-based peptone modified MRS, i.e. Soy-peptone and Vegitone. The duration and the medium composition (dextrose and soy peptone or proteose peptone) were adjusted to obtain an optimum production of cell lysate. Central Composite Design was employed for Design Expert 7.0.0 by adjusting 3 factors: dextrose (1%, 1.5%, 2%, 2.5%, 3%), soy or proteose peptone (0.5%, 0.75%, 1%, 1.25% and 1.5%), and duration of fermentation (8, 10, 12 14, and 16 h for MRS-Soy peptone and 15, 17, 19, 21, and 23 h for MRS Vegitone). Bacteriocin-Like Inhibitor Substance activity of lysate and pH were used as indicators. The optimum condition for lysate production using MRS Soy Peptone and Vegitone are as follows: dextrose concentration 2.5%, plant-based peptone 1.25%, while optimum fermentation duration were 11.18 h (MRS Soy Peptone) and 17 h (MRS Vegitone) with a starter concentration of 10% at $OD_{600nm}$ $0.2{\pm}0.05$. However, the standard MRS medium produced better quality lysate compared to MRS plant-based peptones.

In Korea, traditional doenjang is manufactured using the conventional method at home and by small-scale enterprises. Because this age-old process depends on natural inoculation of various microorganisms, it is difficult to reproduce or maintain consistency in the final product quality across batches. Moreover, doenjang occasionally prepared by this method raises safety concerns related to aflatoxin, biogenic amine, and Bacillus cereus contamination. To develop starters that can be conveniently used at home or in small industry settings for the manufacturing of safe and flavor-improved doenjang, autochthonous microbe starters were developed in dried forms as ready-to-use starters. Each starter powder prepared by heat- or freeze-drying methods remained stable even after 24-week storage. These ready- to-use starter powders were successfully applied to lab-scale fermentation for the production of safe and flavor-improved doenjang. We believe that these ready-to-use starter powders will benefit small-scale enterprises in the manufacturing of doenjang of good reproducible quality.

Biosynthesis of indole-3-acetate (IAA) from L-tryptophan via indole-3-pyruvate pathway requires three enzymes including aminotransferase, indole-3-pyruvate decarboxylase, and indole-3-acetate dehydrogenase. To establish a bio-based production of IAA, the aspC, ipdC, and iad1 from Escherichia coli, Enterobacter cloacae, and Ustilago maydis, respectively, were expressed under control of the tac, ilvC, and sod promoters in C. glutamicum. Cells harboring ipdC produced tryptophol, indicating that the ipdC product is functional in this host. Analyses of SDS-PAGE and enzyme activity revealed that genes encoding AspC and Iad1 were efficiently expressed from the sod promoter, and their enzyme activities were 5.8 and 168.5 nmol/min/mg-protein, respectively. The final resulting strain expressing aspC, ipdC, and iad1 produced 2.3 g/l and 7.3 g/l of IAA from 10 g/l L-tryptophan, respectively, in flask cultures and a 5-L bioreactor.

삼림지역의 고목에서 분리한 Peniophora sp. JS17 균주는 사람 머리카락 유래 멜라닌을 탈색하는 세포 외 분비효소를 생산했다. JS17 균주는 laccase 및 manganese peroxidase 활성을 나타냈지만 lignin peroxidase 활성은 나타내지 않았다. 본 균주를 회분배양한 결과 멜라닌 탈색 활성은 laccase 활성으로부터 유래하는 것으로 확인되었다. Peniophora sp. JS17 균사체로부터 멜라닌 탈색 효소를 생산하기 위한 배지 조건을 조사하였다. 다양한 합성 배지 중에서 minimal medium (2% glucose, 0.2% malt extract, 0.1% $KH_2PO_4$, 0.4% $MgSO_4{\cdot}7H_2O$)이 가장 높은 laccase 활성을 나타내었다. Laccase 생산에 대한 배양 조건을 최적화하기 위하여 minimal medium의 조성 중에서 탄소원 및 질소원에 대한 영향을 조사하였다. 다양한 탄소원 및 질소원 중에서 각각 2% xylose 및 0.4% tryptone의 경우에 가장 높은 laccase 활성을 나타내었다. Ammonium sulfate 침전 및 Hitrap Q Sepharose column을 이용하여 정제한 효소는 SDS-PAGE에서 약 70 kDa의 분자량 부근에 2종류의 isozyme 형태로 존재 하였다. 멜라닌 탈색율은 HBT 및 syringaldehyde의 존재하에서 48시간 만에 각각 77% 및 55%를 나타내었고, mediator가 없는 조건에서는 9%의 멜라닌 탈색율을 나타내었다.

In this study, the extracellular metalloprotease from Serratia marcescens PPB-26 was purified to homogeneity via ethanol fractionation and DEAE-cellulose column chromatography. Thus, a 3.8-fold purification was achieved with a 20% yield and specific activity of 76.2 U/mg. The purified protease was a 50-kDa monomer whose optimum pH and temperature for activity were 7.5 and $30^{\circ}C$ respectively; however, it was found to remain active in the 5-9 pH range and up to $40^{\circ}C$ for 6 h. The protease had a half-life of 15 days at $4^{\circ}C$, an optimum reaction time of 10 min, and an optimum substrate (casein) concentration of 0.25%. Furthermore, the Michaelis constant ($K_m$) and reaction velocity ($V_{max}$) of the protease were calculated to be 0.28% and $111.11{\mu}moles/(min{\cdot}mg)^{-1}$, respectively. The protease was stable when subjected to metal ions (2 mM), showing increased activity with most (especially $CoCl_2$ and $MgSO_4$ (30.54% increase)). It was also stable when exposed to oxidizing agents, bleaching agents, and detergents (5% v/v for 60 min). It retained 93% of its activity in non-ionic detergents (Tween-20, Tween-80, and Triton X-100). Moreover, wash performance analysis in commercial detergents (Ariel and Tide) showed that not only was the protease capable of protein stain removal, but also reduced cleaning time by 80% when added to detergents. Thus, the Serratia marcescens PPB-26 metalloprotease appears to be a promising new candidate as a laundry additive in the detergent industry.

In the present study, we have studied the bioremediating capability of bacterial strain against six heavy metals. The strain was isolated from river Yamuna, New Delhi which is a very rich repository of bioremediating flora and fauna. The strain was found to be Gram positive as indicated by Gram staining. The strain was characterized using 16s rRNA gene sequencing and the BlastN result showed its close resemblance with the Cellulosimicrobium sp. As each treatment has its own toxicity eliciting expression of different factors, we observed varied growth characteristics of the bacterial isolate and its protein content in response to different heavy metals. The assessment of its bioremediation capability showed that the strain Cellulosimicrobium sp. has potential to consume or sequester the six heavy metals in this study in the following order iron > lead > zinc > cooper > nickel > cadmium. Thus, the strain Cellulosimicrobium sp. isolated in the present study can be a good model system to understand the molecular mechanism behind its bioremediating capabilities under multiple stress conditions.

In the present investigation, we attempted to design a protocol to develop a hybrid protein with better bioremediation capacity. Using in silico approaches, a Hybrid Open Reading Frame (Hybrid ORF) is developed targeting the genes of microorganisms known for degradation of organophosphates. Out of 21 genes identified through BLAST search, 8 structurally similar genes (opdA, opd, opaA, pte RO, pdeA, parC, mpd and phnE) involved in biodegradation were screened. Gene conservational analysis categorizes these organophosphates degrading 8 genes into 4 super families i.e., Metallo-dependent hydrolases, Lactamase B, MPP and TM_PBP2 superfamily. Hybrid protein structure was modeled using multi-template homology modeling (3S07_A; 99%, 1P9E_A; 98%, 2ZO9_B; 33%, 2DXL_A; 33%) by $Schr{\ddot{o}}dinger$ software suit version 10.4.018. Structural verification of protein models was done using Ramachandran plot, it was showing 96.0% residue in the favored region, which was verified using RAMPAGE. The phosphotriesterase protein was showing the highest structural similarity with hybrid protein having raw score 984. The 5 binding sites of hybrid protein were identified through binding site prediction. The docking study shows that hybrid protein potentially interacts with 10 different organophosphates. The study results indicate that the hybrid protein designed has the capability of degrading a wide range of organophosphate compounds.

Acute diarrhea is a global health problem that causes high morbidity and mortality in children. Notably, enteric pathogen co-infections have been suggested to play an important role in gastroenteritis. In this study, we analyzed 1150 stool specimens of patients who visited the pediatric ward of Dongguk University Hospital in Gyeongju province from January 2011 to December 2017. The average isolation rate of potential stool pathogens over 7 years was 37.3% (429/1150), and coinfections were observed in 51 patients (51/429; 11.9%). In the 51 co-infection cases, the most frequent type of co-infection was found to be that of virus-bacteria (33/51). The most frequently detected bacterial pathogen among the co-infected cases was Clostridium spp. (22/51), out of which Clostridium perfringens was found to be the main pathogen (16/22; 72.7%). Escherichia coli spp. were the second most common bacterial pathogens found in 12 cases (12/51; 23.5%), with 10 cases of E. coli EPEC. Furthermore, the most frequently implicated viral pathogen among the co-infected cases was norovirus (16/51), followed by rotavirus (12/51).

In this study, the effects of ammonium concentration ($117.5-1155.0mg-N{\cdot}l^{-1}$), nitrite concentration ($0-50.0mg-N{\cdot}l^{-1}$), and temperature ($15-35^{\circ}C$) on nitrification performance and its functional genes (amoA-arc, amoA-bac, hao) in an enriched consortium inoculated with humic acid were determined. Notably, the maximum nitrification rate value was observed at $315mg-N{\cdot}l^{-1}$ of ammonium, but the highest functional gene copy numbers were obtained at $630mg-N{\cdot}l^{-1}$ of ammonium. No inhibition of the nitrification rate and functional gene copy numbers was observed via the added nitrites. The optimum temperature for maximum nitrification performance was observed to be $30^{\circ}C$. The amoA-bac copy numbers were also greater than those of amoA-arc under all test conditions. Notably, amoA-arc copy numbers and nitrification efficiency showed a positive relationship in network analysis. These results indicate that ammonium-oxidizing archaea and bacteria play important roles in the nitrification process.

Earlier studies by our group revealed that gallic acid in phytochemicals stimulated biofilm production in epiphytes, while caffeic acid in phytochemicals inhibited biofilm production in non-epiphytes. It is well documented that antimicrobial secretion by some epiphytic bacteria inhibits non-epiphytic bacterial growth on leaf surfaces. These selection criteria help plants choose their microbial inhabitants. Calcium and iron in phytochemicals also stimulate biofilm formation and thus, may be selection criteria adopted by plants with respect to their native epiphytic population. Furthermore, the processing of leaves during phytochemical extraction impacts the composition of the extract, and therefore its ability to affect bacterial biofilm formation. Computation of the Hurst exponent using biofilm thickness data obtained from the Ellipsometry of Brewster Angle Microscopic (BAM) images is an efficient tool for understanding the impact of phytochemicals on epiphytic and non-epiphytic populations when compared to fluorescent microscopy, scanning electron microscopy, and staining techniques. To the best of our knowledge, this is the first report that uses the Hurst exponent to elucidate the mechanism involved in plant microbe interaction.

Distribution of Salmonella enterica serovars and their associated virulence determinants is wide-spread among food animals, which are continuously implicated in periodic salmonellosis outbreaks globally. The aim of this study was to determine and evaluate the diversity of five Salmonella serovar virulence genes (invA, pefA, cdtB, spvC and iroN) isolated from food animals and humans. Using standard microbiological techniques, Salmonella spp. were isolated from the feces of humans and three major food animals. Virulence determinants of the isolates were assayed using PCR. Clonal relatedness of the dominant serovar was determined via pulsed-field gel electrophoresis (PFGE) using the restriction enzyme, Xbal. Seventy one Salmonella spp. were isolated and serotyped into 44 serovars. Non-typhoidal Salmonella (NTS; 68) accounted for majority (95.8%) of the Salmonella serovars. Isolates from chicken (34) accounted for 47.9% of all isolates, out of which S. Budapest (14) was predominant (34.8%). However, the dominant S. Budapest serovars showed no genetic relatedness. The invA gene located on SPI-1 was detected in all isolates. Furthermore, 94% of the isolates from sheep harbored the spvC genes. The iroN gene was present in 50%, 100%, 88%, and 91% of isolates from human, chicken, sheep, and cattle, respectively. The pefA gene was detected in 18 isolates from chicken and a single isolate from sheep. Notably, having diverse Salmonella serovars containing plasmid encoded virulence genes circulating the food chain is of public health significance; hence, surveillance is required.

Gastroenteritis with diarrhea is one of the most infectious diseases in the world following respiratory infections. Notably, diarrhea-causing viruses (DVs) cause more than 70% of such cases. In this study, 3,065 stool specimens from patients with diarrhea (median age, 1.1 years; range, 0.0-91.1 years), who were admitted to the DanKook University Hospital, were examined using multiplex reverse transcription PCR (mRT-PCR). The target viruses were astrovirus (AstV), enteric adenovirus (EAdV), group A rotavirus (RotV), norovirus GI (NoV-GI), and norovirus GII (NoV-GII). The mRT-PCR results were analyzed based on various factors such as seasonality, age, presence of co-infection, and analyzed trends. The detection rate of the DVs during the study period was found to be 30.8% (n = 943/3,065). When the detection rate was analyzed monthly, the DV detection rate was found to be highest between December to January. Of the detected DVs, NoV-GII was the most common, accounting for 45.5% of the detected viruses (n = 446/980). Notably, 86.5% (n = 848/980) of the pathogens were detected in individuals who were less than 5 years of age. During the study period, NoV-GII and RotV showed alternating trends. In addition, both the number and rate of co-infections increased.