Acceptor dependent catalytic properties of GH57 4-α-glucanotransferase from Pyrococcus sp. ST04.

The 4-α-glucanotransferase (4-α-GTase or amylomaltase) is an essential enzyme in maltodextrin metabolism. Generally, most bacterial 4-α-GTase is classified into glycoside hydrolase (GH) family 77. However, hyperthermophiles have unique 4-α-GTases belonging to GH family 57. These enzymes are the main amylolytic protein in hyperthermophiles, but their mode of action in maltooligosaccharide utilization is poorly understood. In the present study, we investigated the catalytic properties of 4-α-GTase from the hyperthermophile Pyrococcus sp. ST04 (PSGT) in the presence of maltooligosaccharides of various lengths. Unlike 4-α-GTases in GH family 77, GH family 57 PSGT produced maltotriose in the early stage of reaction and preferred maltose and maltotriose over glucose as the acceptor. The kinetic analysis showed that maltotriose had the lowest KM value, which increased amylose degradation activity by 18.3-fold. Structural models of PSGT based on molecular dynamic simulation revealed two aromatic amino acids interacting with the substrate at the +2 and +3 binding sites, and the mutational study demonstrated they play a critical role in maltotriose binding. These results clarify the mode of action in carbohydrate utilization and explain acceptor binding mechanism of GH57 family 4-α-GTases in hyperthermophilic archaea.

Production of Cinnamaldehyde through Whole-Cell Bioconversion from trans-Cinnamic Acid Using Engineered Corynebacterium glutamicum.

Cinnamaldehyde (CAD) has various applications in foods and pharmaceuticals and has gained prominence as a potent nematicide in agricultural research owing to its nematicidal activity. However, conventional methods of CAD production, including extraction from plants or organic chemical synthesis, are environmentally hazardous and limit its utilization for downstream applications. Here, we engineered Corynebacterium glutamicum as a whole-cell biocatalyst for the efficient bioconversion of trans-cinnamic acid (t-CA) into CAD. An expression module of Mycobacterium phlei carboxylic acid reductase was constructed for the conversion of t-CA to CAD. Additionally, the putative dehydrogenase-related genes (dkgA, adhC, and cg1176) responsible for the conversion of CAD to cinnamyl alcohol were deleted from the engineered C. glutamicum strain to prevent the loss of CAD. Furthermore, as the conversion is NADPH-dependent, we investigated the conversion efficiency by exchanging the putative promoter region for the zwf gene, which encodes glucose-6-phosphate dehydrogenase, with a strong promoter to increase the NADPH pool. Finally, a bioconversion platform using C. glutamicum as a whole-cell biocatalyst was developed by deleting the vdh gene, which is involved in the reverse conversion of CAD to t-CA. Taken together, a 100% conversion yield of 1.1 g/L CAD from 1.2 g/L t-CA was obtained within 30 min.

Production of trans-cinnamic acid by whole-cell bioconversion from L-phenylalanine in engineered Corynebacterium glutamicum.

BACKGROUND: trans-cinnamic acid (t-CA) is a phenylpropanoid with a broad spectrum of biological activities including antioxidant and antibacterial activities, and it also has high potential in food and cosmetic applications. Although significant progress has been made in the production of t-CA using microorganisms, its relatively low product titers still need to be improved. In this study, we engineered Corynebacterium glutamicum as a whole-cell catalyst for the bioconversion of L-phenylalanine (L-Phe) into t-CA and developed a repeated bioconversion process. RESULTS: An expression module based on a phenylalanine ammonia lyase-encoding gene from Streptomyces maritimus (SmPAL), which mediates the conversion of L-Phe into t-CA, was constructed in C. glutamicum. Using the strong promoter PH36 and ribosome binding site (RBS) (in front of gene 10 of the T7 phage), and a high-copy number plasmid, SmPAL could be expressed to levels as high as 39.1% of the total proteins in C. glutamicum. Next, to improve t-CA production at an industrial scale, reaction conditions including temperature and pH were optimized; t-CA production reached up to 6.7 mM/h in a bioreactor under optimal conditions (50 °C and pH 8.5, using NaOH as base solution). Finally, a recycling system was developed by coupling membrane filtration with the bioreactor, and the engineered C. glutamicum successfully produced 13.7 mM of t-CA (24.3 g) from 18.2 mM of L-Phe (36 g) and thus with a yield of 75% (0.75 mol/mol) through repetitive supplementation. CONCLUSIONS: We developed a highly efficient bioconversion process using C. glutamicum as a biocatalyst and a micromembrane-based cell recycling system. To the best of our knowledge, this is the first report on t-CA production in C. glutamicum, and this robust platform will contribute to the development of an industrially relevant platform for the production of t-CA using microorganisms.

Enhanced production of neoagarobiose from agar with Corynebacterium glutamicum producing exo-type and endo-type ß-agarases.

Neoagarobiose (NA2) derived from agar marine biomass is a rare reagent that acts as an anti-melanogenesis reagent and moisturizer. Here, for the economical manufacturing of NA2, we developed the co-secretory production system of endo-type ß-agarases (DagA) and exo-type ß-agarases (EXB3) in Corynebacterium glutamicum. For this purpose, we first developed a secretory system of DagA via Tat pathway. To improve the secretion efficiency, we coexpressed two Tat pathway components (TatA and TatC), and to improve the purity of secreted DagA in the culture supernatant, two endogenous protein genes (Cg2052 and Cg1514) were removed. Using the engineered strain (C. glutamicum SP002), we confirmed that DagA as high as 1.53 g l-1 was successfully produced in the culture media with high purity (72.7% in the supernatant protein fraction). Next, we constructed the expression system (pHCP-CgR-DagA-EXB3) for the simultaneous secretion of EXB3 via Sec-pathway together with DagA, and it was clearly confirmed that DagA and EXB3 were successfully secreted as high as 54% and 24.5%, respectively. Finally, using culture medium containing DagA and EXB3, we successfully demonstrated the conversion of high-concentration agar (40 g l-1 ) into NA2 via a two-stage hydrolysis process.

Recent advances in engineering Corynebacterium glutamicum for utilization of hemicellulosic biomass.

Corynebacterium glutamicum has been mainly used for industrial production of amino acids, and in recent years, it has also been successfully engineered to broaden its range of substrate and product profiles. In particular, C. glutamicum has been engineered to use non-natural sugar substrates (mainly pentoses) derived from hemicellulosic feedstock, which is the second abundant component of lignocellulosic biomass. Engineering of the host in this context can greatly contribute to the development of an economic and sustainable bioprocess. The present review focuses on the recent progress in engineering C. glutamicum towards efficient utilization of pentose sugars derived in hemicellulose and for direct utilization of hemicellulose. In addition, use of C. glutamicum as a biocatalyst for bioconversion of low-value sugars derived from hemicellulose to high-value product has been reviewed.

Engineering of Corynebacterium glutamicum for Consolidated Conversion of Hemicellulosic Biomass into Xylonic Acid.

Xylonic acid is a promising platform chemical with various applications in the fields of food, pharmaceuticals, and agriculture. However, in the current process, xylonic acid is mainly produced by the conversion of xylose, whose preparation requires substantial cost and time. Here, Corynebacterium glutamicum is engineered for the consolidated bioconversion of hemicellulosic biomass (xylan) into xylonic acid in a single cultivation. First, for the efficient conversion of xylose to xylonic acid, xylose dehydrogenase (Xdh) and xylonolactonase (XylC) from Caulobacter crescentus are evaluated together with a previously optimized xylose transporter module (XylE of Escherichia coli), and cells expressing xdh and xylE genes with an optimized expression system can produce xylonic acid from xylose with 100% conversion yield. Next, to directly process xylan as a substrate, an engineered xylan-degrading module is introduced, in which two xylan-degrading enzymes (endoxylanase and xylosidase) are secreted into the culture medium. The engineered C. glutamicum successfully produce 6.23 g L-1 of xylonic acid from 20 g L-1 of xylan. This is the first report on xylonic acid production in C. glutamicum and this robust system will contribute to development of an industrially relevant platform for production of xylonic acid from raw biomass.

Analysis of Factors Associated with the Severity of Acute Pancreatitis according to Etiology.

BACKGROUND: The objective of this study was to determine the factors associated with severity of acute pancreatitis (AP) according to two major etiologies: alcohol and gallstones. METHODS: We reviewed the medical records of consecutive patients who were admitted with AP between January 2003 and January 2013. A total of 905 patients with AP (660 alcohol-induced, 245 gallstone-induced) were enrolled. Among them, severe AP (SAP) occurred in 72 patients (53 alcohol-induced, 19 gallstone-induced). Contributing factors between patients with and without SAP were analyzed according to the etiology. RESULTS: Multivariate analysis demonstrated that current smoking, pancreatic necrosis, and bacteremia were associated with AP severity in both alcohol- and gallstone-induced AP. Pancreatic fluid collection was significantly associated with alcohol-induced SAP (p = 0.04), whereas dyslipidemia was significantly associated with gallstone-induced SAP (p = 0.01). Body mass index was significantly correlated with the Bedside Index of Severity in Acute Pancreatitis score in both alcohol- and gallstone-induced AP (p = 0.03 and 0.01, resp.). CONCLUSIONS: Current smoking, pancreatic necrosis, and bacteremia can aggravate the clinical course of AP. Pancreatic fluid collection and dyslipidemia were associated with AP severity according to the different etiologies. Obesity may also be associated with AP severity in both etiologies.

Comparative evaluation of microbial diversity and metabolite profiles in doenjang, a fermented soybean paste, during the two different industrial manufacturing processes.

Two different doenjang manufacturing processes, the industrial process (IP) and the modified industrial process (mIP) with specific microbial assortments, were subjected to metabolite profiling using liquid chromatography-mass spectrometry (LC-MS) and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). The multivariate analyses indicated that both primary and secondary metabolites exhibited distinct patterns according to the fermentation processes (IP and mIP). Microbial community analysis for doenjang using denaturing gradient gel electrophoresis (DGGE), exhibited that both bacteria and fungi contributed proportionally for each step in the process viz., soybean, steaming, drying, meju fermentation, cooling, brining, and aging. Further, correlation analysis indicated that Aspergillus population was linked to sugar metabolism, Bacillus spp. with that of fatty acids, whereas Tetragenococcus and Zygosaccharomyces were found associated with amino acids. These results suggest that the components and quality of doenjang are critically influenced by the microbial assortments in each process.

Factor analysis of recurrent biliary events in long-term follow up of gallstone pancreatitis.

OBJECTIVE: Recurrent attacks after acute gallstone pancreatitis (GSP) are substantial problems, together with associated morbidity and mortality. The recommended therapies for recurrent attacks are cholecystectomy and endoscopic sphincterotomy (EST). This study aimed to evaluate the long-term results of cholecystectomy and EST after clinical improvement of GSP. METHODS: A consecutive series of patients who were admitted with GSP from January 2003 to December 2014 were analyzed. Patients were categorized into three treatment subgroups: cholecystectomy (n = 53), EST (n = 51) and conservative care (n = 67). RESULTS: A total of 171 patients were enrolled. The mean follow-up period was 58 months (range 6-125 months). The pancreatitis-induced in-hospital mortality rate was 1.5%. The cholecystectomy and EST groups had a significantly lower frequency of recurrent pancreatitis than the conservative care group (P < 0.01). For recurrent pancreatitis, there was no significant difference between the cholecystectomy with and without EST subgroups. With respect to total recurrent biliary events, the cholecystectomy group was superior to the EST only group (P < 0.01). In patients receiving definitive treatment (cholecystectomy with or without EST), the presence of common bile duct (CBD) stone was an independent risk factor for recurrent biliary events (P < 0.01). CONCLUSIONS: In the long-term follow up of GSP, cholecystectomy can offer better protection against recurrent biliary events than EST only. The presence of CBD stones at time of definitive therapy might be a risk factor for recurrent biliary events.

Dual-priming oligonucleotide-based multiplex PCR using tissue samples from the rapid urease test kit for the detection of Helicobacter pylori in bleeding peptic ulcers.

BACKGROUND: In patients with peptic ulcer bleeding (PUB), diagnostic tests for Helicobacter pylori (H. pylori) infection have low sensitivity. The aim of our study was to investigate the diagnostic yield of dual-priming oligonucleotide-based multiplex (DPO)-PCR using tissue samples from the rapid urease test (RUT, CLO(®)test) kit in patients with PUB. METHODS: We prospectively enrolled patients with PUB. During second-look endoscopy, gastric biopsy specimens for histology and RUT were obtained from a total of 170 patients. DPO-PCR tests were performed on tissue samples obtained from the CLO(®)test kit. If testing for H. pylori was negative, endoscopy with re-biopsy was performed 8 weeks after the bleeding episode. RESULTS: H. pylori-associated bleeding was confirmed in 64.1% (109/170) of the patients. At the bleeding episode, the diagnostic sensitivities of RUT, histology, and DPO-PCR test were 47.7% (52/109), 71.6% (78/109) and 97.2% (106/109), respectively (p<0.01). The specificity of the DPO-PCR test was 91.8% (56/61). The positive predictive value (PPV) of the DPO-PCR test was 95.5% (106/111), and its negative predictive value (NPV) was 94.9% (56/59). CONCLUSIONS: In patients with PUB, the DPO-PCR test could be a useful diagnostic tool for H. pylori infection. Particularly given a negative RUT result, subsequent DPO-PCR testing of tissue samples from the CLO(®)test kit could be of considerable benefit.

Clinical characteristics of Helicobacter pylori-negative drug-negative peptic ulcer bleeding.

AIM: To investigate the clinical characteristics and outcomes of idiopathic Helicobacter pylori (H. pylori)-negative and drug-negative] peptic ulcer bleeding (PUB). METHODS: A consecutive series of patients who experienced PUB between 2006 and 2012 was retrospectively analyzed. A total of 232 patients were enrolled in this study. The patients were divided into four groups according to the etiologies of PUB: idiopathic, H. pylori-associated, drug-induced and combined (H. pylori-associated and drug-induced) types. We compared the clinical characteristics and outcomes between the groups. When the silver stain or rapid urease tests were H. pylori-negative, we obtained an additional biopsy specimen by endoscopic re-examination and performed an H. pylori antibody test 6-8 wk after the initial endoscopic examination. For a diagnosis of idiopathic PUB, a negative result of an H. pylori antibody test was confirmed. In all cases, re-bleeding was confirmed by endoscopic examination. For the risk assessment, the Blatchford and the Rockall scores were calculated for all patients. RESULTS: For PUB, the frequency of H. pylori infection was 59.5% (138/232), whereas the frequency of idiopathic cases was 8.6% (20/232). When idiopathic PUB was compared to H. pylori-associated PUB, the idiopathic PUB group showed a higher rate of re-bleeding after initial hemostasis during the hospital stay (30% vs 7.4%, P = 0.02). When idiopathic PUB was compared to drug-induced PUB, the patients in the idiopathic PUB group showed a higher rate of re-bleeding after initial hemostasis upon admission (30% vs 2.7%, P < 0.01). When drug-induced PUB was compared to H. pylori-associated PUB, the patients in the drug-induced PUB were older (68.49 ± 14.76 years vs 47.83 ± 15.15 years, P < 0.01) and showed a higher proportion of gastric ulcer (77% vs 49%, P < 0.01). However, the Blatchford and the Rockall scores were not significantly different between the two groups. Among the patients who experienced drug-induced PUB, no significant differences were found with respect to clinical characteristics, irrespective of H. pylori infection. CONCLUSION: Idiopathic PUB has unique clinical characteristics such as re-bleeding after initial hemostasis upon admission. Therefore, these patients need to undergo close surveillance upon admission.

Current status and clinical impact of pediatric endoscopy in Korea.

BACKGROUND/AIMS: In pediatrics, endoscopic examination has become a common procedure for evaluation of gastrointestinal presentations. However, there are limited data on pediatric endoscopy in Korea. The aim of this study was to analyze the current status and clinical impacts of endoscopic examination in children and adolescents. METHODS: We retrospectively reviewed the medical records of outpatients who visited the tertiary hospital. Patients under 18 years of age who underwent endoscopy were included. Endoscopic findings were classified as specific and normal based on gross findings. Specific endoscopic findings were reflux esophagitis, peptic ulcers, and Mallory-Weiss tear. Other findings included acute gastritis classified according to the updated Sydney system. RESULTS: In 722 of 330,350 patients (0.2%), endoscopic examination (554 esophagogastroduodenoscopies [EGDs], 121 colonos-copies, 47 sigmoidoscopies) was performed between January 2008 and January 2013. In EGD, abdominal pain was the most frequent presentation (64.1%). The most common diagnosis was gastritis (53.2%), followed by reflux esophagitis. The frequency of peptic ulcer disease was 12.8%. Frequent symptoms leading to colonoscopic examination were abdominal pain, diarrhea, and hematochezia. In colonoscopy, a negative result was more likely in children younger than 7 years old. After the procedure, the diagnostic yield of EGD and colonoscopy was 88.1% and 45.8%, respectively, and the rate of change in management was 67.1%. CONCLUSIONS: In pediatrics, endoscopic examination was useful for the choice of therapeutic strategy and it would be a standard method for evaluation of gastrointestinal presentation.

Primary and secondary metabolite profiling of doenjang, a fermented soybean paste during industrial processing.

In this study, a comprehensive metabolite profile analysis of doenjang, a fermented soybean paste, at various steps of its industrial 5-step production process was conducted, by combining gas and liquid chromatography-mass spectrometry techniques with multivariate analysis. From the partial least squares discriminant analysis of primary and secondary metabolites, the patterns were clearly distinguishable between the various processing steps (step 1: steaming, step 2: drying, step 3: meju fermentation, step 4: brining, step 5: doenjang aging). Of the primary metabolites, most of the monosaccharides, amino acids, and fatty acids increased in steps 3-5. Isoflavone and soyasaponin derivatives were major secondary metabolites identified during the processing of doenjang. Isoflavone glycosides gradually decreased after step 1, while isoflavone aglycones distinctly increased in steps 4-5. Soyasaponins generally decreased during processing after step 2. Increased isoflavone aglycones, such as daidzein, glycitein, and genistein, were observed in steps 4-5 showed the strongest positive correlation with doenjang's antioxidant potential and total phenolic content.

Bioinformatic and biochemical analysis of a novel maltose-forming α-amylase of the GH57 family in the hyperthermophilic archaeon Thermococcus sp. CL1.

Maltose-forming α-amylase is a glycoside hydrolase family 57 (GH57) member that is unique because it displays dual hydrolysis activity toward α-1,4- and α-1,6-glycosidic linkages and only recognizes maltose. This enzyme was previously identified only in Pyrococcus sp. ST04 (PSMA); however, we recently found two homologs subgroups in Thermococcus species. One subgroup (subgroup A) showed relatively high amino acid sequence similarity to PSMA (>71%), while the other subgroup (subgroup B) showed lower homology with PSMA (<59%). To characterize the subgroup B maltose-forming α-amylase from Thermococcus species (TCMA), we cloned the CL1_0868 gene from Thermococcus sp. CL1 and then successfully expressed the gene in Escherichia coli. Although TCMA has a different oligomeric state relative to PSMA, TCMA showed similar substrate specificity. However, TCMA was shown to hydrolyze maltooligosaccharides more easily than PSMA. Also, TCMA displayed different optimum conditions depending on the glycosidic linkage of the substrate. TCMA had the highest activity at 85°C and at pH 5.0 for α-1,4-glycosidic linkage hydrolysis whereas it showed its maximal activity to cleave α-1,6-glycosidic linkages at 98°C and pH 6.0.

Is the AIMS65 score useful in predicting outcomes in peptic ulcer bleeding?

AIM: To evaluate the applicability of AIMS65 scores in predicting outcomes of peptic ulcer bleeding. METHODS: This was a retrospective study in a single center between January 2006 and December 2011. We enrolled 522 patients with upper gastrointestinal haemorrhage who visited the emergency room. High-risk patients were regarded as those who had re-bleeding within 30 d from the first endoscopy as well as those who died within 30 d of visiting the Emergency room. A total of 149 patients with peptic ulcer bleeding were analysed, and the AIMS65 score was used to retrospectively predict the high-risk patients. RESULTS: A total of 149 patients with peptic ulcer bleeding were analysed. The poor outcome group comprised 28 patients [male: 23 (82.1%) vs female: 5 (10.7%)] while the good outcome group included 121 patients [male: 93 (76.9%) vs female: 28 (23.1%)]. The mean age in each group was not significantly different. The mean serum albumin levels in the poor outcome group were slightly lower than those in the good outcome group (P = 0.072). For the prediction of poor outcome, the AIMS65 score had a sensitivity of 35.5% (95%CI: 27.0-44.8) and a specificity of 82.1% (95%CI: 63.1-93.9) at a score of 0. The AIMS65 score was insufficient for predicting outcomes in peptic ulcer bleeding (area under curve = 0.571; 95%CI: 0.49-0.65). CONCLUSION: The AIMS65 score may therefore not be suitable for predicting clinical outcomes in peptic ulcer bleeding. Low albumin levels may be a risk factor associated with high mortality in peptic ulcer bleeding.

Complete genome sequence of hyperthermophilic archaeon Thermococcus sp. ES1.

Thermococcus sp. strain ES1 is an anaerobic, hyperthermophilic archaeon from a hydrothermal vent that catabolizes sugars and peptides and produces H2S from S°, H2, acetate and CO2 as its primary metabolites. We present the complete genome sequence of this strain (1,957,742bp) with a focus on its substrate utilization and metabolite production capabilities. The sequence will contribute to the development of heterotrophic archaea for bioenergy production and biogeochemical modeling in hydrothermal environments.

Mass spectrometry-based metabolite profiling and bacterial diversity characterization of Korean traditional meju during fermentation.

The metabolite profile of meju during fermentation was analyzed using mass spectrometry techniques, including GC-MS and LC-MS, and the bacterial diversity was characterized. The relative proportions of bacterial strains indicated that lactic acid bacteria, such as Enterococcus faecium and Leuconostoc lactis, were the dominant species. In partial least-squares discriminate analysis (PLS-DA), the componential changes, which depended on fermentation, proceeded gradually in both the GC-MS and LC-MS data sets. During fermentation, lactic acid, amino acids, monosaccharides, sugar alcohols, and isoflavonoid aglycones (daidzein and genistein) increased, whereas citric acid, glucosides, and disaccharides decreased. MS-based metabolite profiling and bacterial diversity characterization of meju demonstrated the changes in metabolites according to the fermentation period and provided a better understanding of the correlation between metabolites and bacterial diversity.

Biotechnological production of arbutins (α- and ß-arbutins), skin-lightening agents, and their derivatives.

Arbutins (α- and ß-arbutins) are glycosylated hydroquinones that are commercially used in the cosmetic industry. These compounds have an inhibitory function against tyrosinase, a critical enzyme for generating pigments, which leads to the prevention of melanin formation, resulting in a whitening effect on the skin. Although ß-arbutin is found in various plants including bearberry, wheat, and pear, α-arbutin and other arbutin derivatives are synthesized by chemical and enzymatic methods. This article presents a mini-review of recent studies on the production of α-arbutin and other α- and ß-arbutin derivatives via enzymatic bioconversion methods. In addition, the structures of α- and ß-arbutin derivatives and their biological activities are discussed. The catalytic characteristics of various enzymes used in the biosynthesis of arbutin derivatives are also reviewed.

Incidence and clinical features of endoscopic ulcers developing after gastrectomy.

AIM: To determine the precise incidence and clinical features of endoscopic ulcers following gastrectomy. METHODS: A consecutive series of patients who underwent endoscopic examination following gastrectomy between 2005 and 2010 was retrospectively analyzed. A total of 78 patients with endoscopic ulcers and 759 without ulcers following gastrectomy were enrolled. We analyzed differences in patient age, sex, size of the lesions, method of operation, indications for gastric resection, and infection rates of Helicobacter pylori (H. pylori) between the nonulcer and ulcer groups. RESULTS: The incidence of endoscopic ulcers after gastrectomy was 9.3% and that of marginal ulcers was 8.6%. Ulcers were more common in patients with Billroth II anastomosis and pre-existing conditions for peptic ulcer disease (PUD). Infection rates of H. pyloridid not differ significantly between the two groups. The patients who underwent operations to treat PUD had lower initial levels of hemoglobin and higher rates of hospital admission. CONCLUSION: H. pylori was not an important factor in ulcerogenesis following gastrectomy. For patients who underwent surgery for PUD, clinical course of marginal ulcers was more severe.

Theranostic nanoparticles based on PEGylated hyaluronic acid for the diagnosis, therapy and monitoring of colon cancer.

Colon cancer is the second leading cause of cancer-related death in the United States. The considerable mortality from colon cancer is due to metastasis to other organs, mainly the liver. In the management of colon cancer, early detection and targeted therapy are crucial. In this study, we aimed to establish a versatile theranostic system for early tumor detection and targeted tumor therapy by using poly(ethylene glycol)-conjugated hyaluronic acid nanoparticles (P-HA-NPs) which can selectively accumulate in tumor tissue. For the diagnostic application, a near-infrared fluorescence (NIRF) imaging dye (Cy 5.5) was chemically conjugated onto the HA backbone of P-HA-NPs. After intravenous injection of Cy5.5-P-HA-NPs into the tumor-bearing mice, small-sized colon tumors as well as liver-implanted colon tumors were effectively visualized using the NIRF imaging technique. For targeted therapy, we physically encapsulated the anticancer drug, irinotecan (IRT), into the hydrophobic cores of P-HA-NPs. Owing to their notable tumor targeting capability, IRT-P-HA-NPs exhibited an excellent antitumor activity while showing a reduction in undesirable systemic toxicity. Importantly, we demonstrated the theranostic application using Cy5.5-P-HA-NPs and IRT-P-HA-NPs in orthotopic colon cancer models. Following the systemic administration of Cy5.5-P-HA-NPs, neoplasia was clearly visualized, and the tumor growth was effectively suppressed by intravenous injection of IRT-P-HA-NPs. It should be emphasized that the therapeutic responses could be simultaneously monitored by Cy5.5-P-HA-NPs. Our results suggest that P-HA-NPs can be used as a versatile theranostic system for the early detection, targeted therapy, and therapeutic monitoring of colon cancer.