Prediction of Soluble-Solid Content in Citrus Fruit Using Visible-Near-Infrared Hyperspectral Imaging Based on Effective-Wavelength Selection Algorithm.

Citrus fruits were sorted based on external qualities, such as size, weight, and color, and internal qualities, such as soluble solid content (SSC), acidity, and firmness. Visible and near-infrared (VNIR) hyperspectral imaging techniques were used as rapid and nondestructive techniques for determining the internal quality of fruits. The applicability of the VNIR hyperspectral imaging technique for predicting the SSC in citrus fruits was evaluated in this study. A VNIR hyperspectral imaging system with a wavelength range of 400-1000 nm and 100 W light source was used to acquire hyperspectral images from citrus fruits in two orientations (i.e., stem and calyx ends). The SSC prediction model was developed using partial least-squares regression (PLSR). Spectrum preprocessing, effective wavelength selection through competitive adaptive reweighted sampling (CARS), and outlier detection were used to improve the model performance. The performance of each model was evaluated using the coefficient of determination (R2) and root mean square error (RMSE). In the present study, the PLSR model was developed using only a citrus cultivar. The SSC prediction CARS-PLSR model with outliers removed exhibited R2 and RMSE values of approximatively 0.75 and 0.56 °Brix, respectively. The results of this study are expected to be useful in similar fields such as agricultural and food post-harvest management, as well as in the development of an online system for determining the SSC of citrus fruits.

Development of Multiple UAV Collaborative Driving Systems for Improving Field Phenotyping.

Unmanned aerial vehicle-based remote sensing technology has recently been widely applied to crop monitoring due to the rapid development of unmanned aerial vehicles, and these technologies have considerable potential in smart agriculture applications. Field phenotyping using remote sensing is mostly performed using unmanned aerial vehicles equipped with RGB cameras or multispectral cameras. For accurate field phenotyping for precision agriculture, images taken from multiple perspectives need to be simultaneously collected, and phenotypic measurement errors may occur due to the movement of the drone and plants during flight. In this study, to minimize measurement error and improve the digital surface model, we proposed a collaborative driving system that allows multiple UAVs to simultaneously acquire images from different viewpoints. An integrated navigation system based on MAVSDK is configured for the attitude control and position control of unmanned aerial vehicles. Based on the leader-follower-based swarm driving algorithm and a long-range wireless network system, the follower drone cooperates with the leader drone to maintain a constant speed, direction, and image overlap ratio, and to maintain a rank to improve their phenotyping. A collision avoidance algorithm was developed because different UAVs can collide due to external disturbance (wind) when driving in groups while maintaining a rank. To verify and optimize the flight algorithm developed in this study in a virtual environment, a GAZEBO-based simulation environment was established. Based on the algorithm that has been verified and optimized in the previous simulation environment, some unmanned aerial vehicles were flown in the same flight path in a real field, and the simulation and the real field were compared. As a result of the comparative experiment, the simulated flight accuracy (RMSE) was 0.36 m and the actual field flight accuracy was 0.46 m, showing flight accuracy like that of a commercial program.

Real-time monitoring of water quality of stream water using sulfur-oxidizing bacteria as bio-indicator.

In aquatic ecosystems, real-time water-quality (WQ) biomonitoring has become the most effective technology for monitoring toxic events by using living organisms as a biosensor. In this study, an online WQ monitoring system using sulfur oxidizing bacteria (SOB) was tested to monitor WQ changes in real-time in natural stream water. The WQ monitoring system consisted of three SOB reactors (one continuous and two semi-continuous mode reactors). The SOB system did not detect any toxicity in relatively-unpolluted, natural stream water when operated for more than six months. When diluted swine wastewater (50:1) was added to the influent of the reactors, the system detected toxic conditions in both the continuous and semi-continuous operational modes, showing 90% inhibition of SOB activity within 1 h of operation. The addition of 30 mg/L NO2--N or 2 mg/L of Cr6+ to the influents of SOB reactors resulted in the complete inhibition of the SOB activity within 1-2 h. The results demonstrated the successful application of an SOB bioassay as an online toxicity monitoring system for detecting pollutants from stream or river waters.

Simultaneous determination of 3-O-acetyloleanolic acid and oleanolic acid in rat plasma using liquid chromatography coupled to tandem mass spectrometry.

3-O-Acetyloleanolic acid (OAA) is a triterpenoid compound, and exerts an apoptosis in cancer cell lines, an inhibition of both atopic and allergic contact dermatitis in murine model, and a suppression of inflammatory bone loss in mice. OAA can be converted into oleanolic acid (OA) by hydrolysis in vivo, and OA exhibits several pharmacological effects as well. A liquid chromatographic method using tandem mass spectrometry (MS/MS) was developed for the simultaneous determination of OAA and OA in rat plasma. After liquid-liquid extraction with ethylacetate, both substances were chromatographed on a reversed phase column with a mobile phase of 0.1% formic acid aqueous solution and acetonitrile (1:9, v/v). The accuracy and precision of the assay were in accordance with FDA regulations for the validation of bioanalytical methods. This analytical method was successfully applied to monitor plasma concentrations of both substances over time following an intravenous administration of OAA in rats.

Exposure assessment of epidermal growth factor to various tissues in mice after intravenous and subcutaneous administration.

OBJECTIVES: This study was conducted to examine the tissue distribution of human recombinant epidermal growth factor (EGF) after multiple intravenous and subcutaneous injections in mice. METHODS: Male BALB/c mice were divided into (1) EGF 1 mg/kg intravenous dose, (2) EGF 5 mg/kg intravenous dose, (3) drug-free intravenous control, (4) EGF 1 mg/kg subcutaneous dose, (5) EGF 5 mg/kg subcutaneous dose and (6) drug-free subcutaneous control groups. EGF and drug-free dosing solutions were injected by intravenous and subcutaneous injections once a day for 3 days. EGF concentrations in serum and tissues of kidney, liver, lung, small intestine and tongue were determined by ELISA. KEY FINDINGS: As the intravenous and subcutaneous doses were increased from 1 to 5 mg/kg, serum Cmax and area under the concentration-time curve (AUC) values were increased dose-proportionally. In lung, tongue and small intestine, increases in AUC were dose-proportional after intravenous injections, but greater than dose-proportional after subcutaneous injections. The fold-increases in Cmax and AUC values were lowest in liver and highest in kidney. CONCLUSION: Based on Cmax and AUC data, the systemic exposure achieved by subcutaneous injections was comparable with that achieved by intravenous injections.

Development of an online sulfur-oxidizing bacteria biosensor for the monitoring of water toxicity.

A toxicity monitoring system based on the metabolic properties of sulfur-oxidizing bacteria (SOB) in continuous and fed-batch modes has been applied for the detection of nitrite (NO2 (-)-N). In this study, the effects of different concentrations of NO2 (-)-N (0.1 to 5 mg/L) on the SOB bioreactors were tested. We found that 5 mg/L NO2 (-)-N was very toxic to the SOB bioreactors in both continuous (R1) and fed-batch (R2) modes, showing complete inhibition of SOB activity within 2 h of operation. R1 and R2 were operated in different ways; however, the EC inhibition and recovery patterns were very similar. The EC rate increased with an increasing NO2 (-)-N concentration in both continuous and fed-batch modes. The addition of 5 mg/L NO2 (-)-N in continuous mode decreased the average EC rate by 14.38 ± 2.1 µS/cm/min; while in fed-batch mode, the EC rate decreased by 23 µS/cm/min. Although the toxicity monitoring system could detect 0.5-5 mg/L NO2 (-)-N, it could not detect 0.1 mg/L NO2 (-)-N in either continuous or fed-batch operation. Thus, the SOB biosensor method presented is useful to detect toxic agents such as NO2 (-)-N within a few minutes or hours.

Simultaneous determination of 7-O-succinyl macrolactin A and its active major metabolite, macrolactin A in dog plasma using high-performance liquid chromatography with UV detection.

We developed a method for the simultaneous quantification of 7-O-succinyl macrolactin A and its active metabolite, macrolactin A, in dog plasma. After protein precipitation with acetonitrile including flufenamic acid as an internal standard, 7-O-succinyl macrolactin A, macrolactin A, and flufenamic acid were chromatographed on a reverse-phase C18 analytical column. The mobile phase, consisting of 20 mM acetate buffer and acetonitrile, was eluted using a gradient program at 1 mL/min, and the UV absorbance was measured at 230 nm. The retention times of 7-O-succinyl macrolactin A, flufenamic acid, and macrolactin A were 3.4, 4.8, and 6.9 min, respectively. The coefficient of variation in the assay precision for both substances was less than 6%, and the accuracy ranged from 96 to 105%. This method was used to measure the concentrations of 7-O-succinyl macrolactin A and macrolactin A in dog plasma following an intravenous administration of a single dose (25 mg/kg) of 7-O-succinyl macrolactin A salt.

Assessment of chromium-contaminated groundwater using a thiosulfate-oxidizing bacteria (TOB) biosensor.

The effect of Cr(6+)-contaminated groundwater was assessed using thiosulfate-oxidizing bacteria (TOB). Electrical conductivity (EC), pH, and sulfate production were determined based on thiosulfate oxidation. Final pH values in the different test treatments of Cr(6+)-contaminated groundwater (50-1000 µg Cr(6+)L(-1)) ranged from 2.02 ± 0.09 to 7.76 ± 0.07 and EC ranged from 5.95 ± 0.03 to 3.63 ± 0.03 mS cm(-1). Inhibition of TOB due to Cr(6+) was between 16.7% and 100%, with higher levels of inhibition occurring at higher Cr(6+) concentrations. The median effective concentration (EC50) was 78.96 µg Cr(6+)L(-1). These data demonstrate that TOB can detect less than 100 µg L(-1) of Cr(6+) in the groundwater and can be used as an effective bioassay for toxicity assessment.

Semi-continuous detection of toxic hexavalent chromium using a sulfur-oxidizing bacteria biosensor.

Toxicity testing is becoming a useful tool for environmental risk assessment. A biosensor based on the metabolic properties of sulfur-oxidizing bacteria (SOB) has been applied for the detection of toxic chemicals in water. The methodology exploits the ability of SOB to oxidize elemental sulfur to sulfuric acid under aerobic conditions. The reaction results in an increase in electrical conductivity (EC) and a decrease in pH. Five hours after Cr(6+) was added to the SOB biosensor operated in semi-continuous mode (1 min rapid feeding and 29 min batch reaction), a decrease in effluent EC and an increase in pH (from 2-3 to 6) were detected due to Cr(6+) toxicity to SOB. The SOB biosensor is simple; it can detect toxic levels of Cr(6+) on the order of minutes to hours, a useful time scale for early warning detection systems designed to protect the environment from further degradation.

Cholinesterase inhibitors from Cleistocalyx operculatus buds.

Five flavonoids, myricetin-3'-methylether 3-O-ß-D: -galactopyranoside (1), myricetin-3',5'-dimethylether 3-O-ß-D: -galactopyranoside (2), quercetin (3), kaempferol (4), and tamarixetin (5) were isolated from the buds of Cleistocalyx operculatus (Myrtaceae). The chemical structures of these compounds were determined on the basis of spectroscopic analyses, including 2D NMR. Their anti-Alzheimer effects were evaluated via acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity assays. All five compounds 1-5 showed potential inhibitory activities against AChE with IC(50) values of 19.9, 37.8, 25.9, 30.4 and 22.3 µM, respectively, while compounds 1, 3, 4 and 5 also possessed BChE inhibitory activity with IC(50) values of 152.5, 177.8, 62.5, and 160.6 µM, respectively.

Isolation and characterization of Acidithiobacillus caldus from a sulfur-oxidizing bacterial biosensor and its role in detection of toxic chemicals.

A novel toxicity detection methodology based on sulfur-oxidizing bacteria (SOB) has been developed for the rapid and reliable detection of toxic chemicals in water. The methodology exploits the ability of SOB to oxidize sulfur particles in the presence of oxygen to produce sulfuric acid. The reaction results in an increase in electrical conductivity (EC) and a decrease in pH. The assay is based on the inhibition of SOB in the presence of toxic chemicals by measuring changes in EC and pH. We found that SOB biosensor can detect toxic chemicals, such as heavy metals and CN-, in the 5-2000ppb range. One bacterium was isolated from an SOB biosensor and the 16S rRNA gene of the bacterial strain has 99% and 96% sequence similarity to Acidithiobacillus sp. ORCS6 and Acidithiobacillus caldus DSM 8584, respectively. The isolate was identified as A. caldus SMK. The SOB biosensor is ideally suited for monitoring toxic chemicals in water having the advantages of high sensitivity and quick detection.

Production of a novel cold-active lipase from Pichia lynferdii Y-7723.

Lipase (triacylglycerol acylhydrolases, E.C. 3.1.1.3) is one of the most important enzymes applied to a broad range of industrial application fields. Especially, lipases with abnormal functionality such as thermostability and alkaline, acidic, and cold activities gain special attention because of their applicability in the restricted reaction conditions. In this study, 16 yeast strains prescreened for lipase induction were investigated for their actual lipase production, and we found a novel cold-active lipase produced from Pichia lynferdii Y-7723. The activity of lipase Y-7723 was retained by 74 and 70% at 20 and 10 degrees C, respectively, as compared to the maximum value at 35 degrees C. On the basis of an optimization study, the optimal lipase productivity was obtained at 96 h of incubation with 3% oil substrate in a medium composed of sucrose as a carbon source at pH 7.0. Among carbon sources tested, sucrose showed almost twice as high of a lipase production (184%) as the control, while the cell growth was similar (105%). Yeast extract and ammonium salts were effective as individual nitrogen sources for lipase production. This study demonstrated that the cold activity of lipase Y-7723 at 10 degrees C was highest among the cold-active lipases reported so far.

Isolation and characterization of a novel thermostable alpha-amylase from Korean pine seeds.

Amylases have significant importance in broad industrial application including bio-ethanol production. Although amylases are widely distributed in microbes, plants and animals, it has been sought for new amylases from various sources with special industrial potential. In this study we firstly isolated and characterized a novel thermostable alpha-amylase from Korean pine seed. Enzyme was purified to homogeneity level with purification fold of 1286.1 using several techniques such as self-precipitation, (NH(4))(2)SO(4) fractionation, DEAE anion exchange and starch affinity chromatography. The purified alpha-amylase showed two bands in SDS-PAGE with molecular weight of 44 and 45 kDa. The apparent molecular weight of native enzyme was calculated to be 46.7 kDa. Internal peptide sequencing confirmed that the purified alpha-amylase was a novel enzyme. The optimum pH and temperature for enzyme activity were pH 4.5 and 65 degrees C, respectively. This enzyme was fully stable for 48h at 50 degrees C and retained 80% activity up to 96h. The K(m) and V(max) were 0.84 mg/ml and 3.71 micromol/min, respectively. On the basis of high thermal stability and a broad range of pH stability, the pine seed alpha-amylase showed a good prospect of industrial application.