Smartphone-based imaging colorimetric assay for monitoring the quality of curcumin in turmeric powder.

This research developed a colorimetric assay for semi-quantitative curcumin detection. The screening test was performed using a ferric chloride to form a brownish color which was further used to evaluate the amount of curcumin in the turmeric powder samples. The quantitative assay was performed based on the color intensity of the curcumin target using a smartphone digital image colorimetry with a developed lightbox constructed with a white light-emitting diodes (LED) light source as the measurement device. Images in red, green, and blue (RGB) color were processed to obtain relevant colors from the image and the color values were used to analyze curcumin concentrations. The intensity of the ΔB was correlated to the concentration of curcumin with high sensitivity. The method showed a linear range between 0.25 and 5 mg L-1 with the LOD and LOQ of 0.12 and 0.41 mg L-1, respectively. Sample analysis was carried out in turmeric powders. Curcumin in turmeric powder samples was simply extracted using acetonitrile followed by dilution 100 times for sample preparation. The accuracy was tested by spiking 0.25, 1.00, and 4.00 mg L-1 of standard curcumin into the turmeric sample solution. The average percentage recoveries were acceptable in all samples (90-104%). The method was validated by comparing the results obtained from the proposed method and high-performance liquid chromatography (HPLC). There was no statistically significant difference between the two methods (P = 0.05).

Characterization of Short Chain Fatty Acids Produced by Selected Potential Probiotic Lactobacillus Strains.

Short-chain fatty acids (SCFAs), particularly butyrate, have received considerable attention with regard to their anti-cancer efficacy in delaying or preventing colorectal cancer. Several studies have reported that certain probiotic strains could produce SCFAs; however, different strains yielded different amounts of SCFAs. This study explored the ability to produce SCFAs of the following probiotic strains: Lacticaseibacillus paracasei SD1, Lacticaseibacillus rhamnosus SD4, Lacticaseibacillus rhamnosus SD11, and Lacticaseibacillus rhamnosus GG. L. paracasei SD1 and L. rhamnosus SD11 exhibited high butyrate production, particularly when the strains were combined. The functions of the SCFAs were further characterized; the SCFAs exerted a positive anti-cancer effect in the colon via various actions, including inhibiting the growth of the pathogens related to colon cancer, such as Fusobacterium nucleatum and Porphyromonas gingivalis; suppressing the growth of cancer cells; and stimulating the production of the anti-inflammatory cytokine IL-10 and antimicrobial peptides, especially human ß-defensin-2. In addition, the SCFAs suppressed pathogen-stimulated pro-inflammatory cytokines, especially IL-8. The results of this study indicated that selected probiotic strains, particularly L. paracasei SD1 in combination with L. rhamnosus SD11, may serve as good natural sources of bio-butyrate, which may be used as biotherapy for preventing or delaying the progression of colon cancer.

Semiquantitative dot-blot immunogold assay for specific detection of white spot syndrome virus.

A dot-blot immunogold assay (DBIA) was developed to detect white spot syndrome virus (WSSV) using the polyclonal antibody VP26 (anti-VP26). The anti-VP26 was immobilized on gold nanoparticles (Ab-AuNPs), and a nitrocellulose membrane was used as a detection pad. When the target WSSV bound to the Ab-AuNPs a reddish dot appeared on the surface of the membrane used within 2-5 Min, which could be seen with the naked eye. The test was able to detect WSSV at concentrations as low as 105 copies µL-1 of WSSV. The DBIA developed had good specificity, and the colloidal gold probe can be applied within 2-3 days when stored at 4 °C. For real sample analysis, the DBIA was applied to samples of seawater used for shrimp cultivation without sample preparation. The results indicate that sample 1 showed a positive result, whereas samples 2 and 3 produced negative results. Then, samples 2 and 3 were spiked with WSSV for method validation. To confirm the performance of the DBIA developed, polymerase chain reaction (PCR) was conducted and the PCR results were the same as those found by the DBIA. Therefore, the DBIA developed could be applied for WSSV detection in real water samples.

Application of a Label-Free Immunosensor for White Spot Syndrome Virus (WSSV) in Shrimp Cultivation Water.

White spot syndrome virus (WSSV) is a major pathogen affecting the shrimp industry worldwide. In a preliminary study, WSSV binding protein (WBP) was specifically bound to the VP26 protein of WSSV. Therefore, we have developed the label-free affinity immunosensor using the WBP together with anti-GST-VP26 for quantitative detection of WSSV in shrimp pond water. When the biological molecules were immobilized on a gold electrode to form a self-assembled monolayer, it was then used to detect WSSV using a flow injection system with optimized conditions. Binding between the different copies of WSSV and the immobilized biological molecules was detected by an impedance change (ΔZ″) in real time. The sensitivity of the developed immunosensor was in the linear range of 1.6 × 10(1)-1.6 × 10(6) copies/µl. The system was highly sensitive for the analysis of WSSV as shown by the lack of impedance change when using yellow head virus (YHV). The developed immunosensor could be reused up to 37 times (relative standard deviation (RSD), 3.24 %) with a good reproducibility of residual activity (80-110 %). The immunosensor was simple to operate, reliable, reproducible, and could be applied for the detection and quantification of WSSV in water during shrimp cultivation.

Development of an immuno-based colorimetric assay for white spot syndrome virus.

White spot syndrome virus (WSSV) is a major cause of infectious disease in cultured shrimp. A fast and reliable method for detecting and monitoring the amount of WSSV during farming would be extremely useful. This work describes a sandwich immunoassay that uses anti-GST-VP26, a WSSV-binding protein (WBP), and modified streptavidin magnesphere paramagnetic particles (SMPPs) to develop the technique. The WBP was immobilized on SMPPs and later bound to different copies of WSSV. The binding was detected using anti-GST-VP26 conjugated to alkaline phosphatase. This enzymatic reaction successfully changed the test solution to a concentration-dependent yellow color that was measured at 405 nm. The sensitivity of this method was between 1.6 × 10(4) and 1.6 × 10(7) copies µL(-1) of WSSV. In this study, the color for detection and semiquantitative analysis is easily observed and measured and can lead to the development of a test kit for screening WSSV during shrimp farming.

Validity evaluation of in-house preparation kit, vaginal pH paper test combined amine tube test, for the simple diagnosis of bacterial vaginosis.

OBJECTIVE: Determine the positive in-house preparation kit for suggested bacterial vaginosis (BV) for both elevated vaginal pH > 4.5 and positive amine test, as well as evaluate for validity of sensitivity, specificity, positive predictive value, and negative predictive value against Chandeying criteria for confirmed BV. MATERIAL AND METHOD: A cross-sectional study among the women who presented with an abnormal vaginal discharge (AVD) or asymptomatic annual cervical cytology screening was done. Each vaginal discharge was divided into two parts of investigation. The first part included the clinical criteria of confirmed BV, based on at least three out of five indicators, the vaginal pH > 4.5, homogeneous and thin discharge (milky discharge), positive sniff/amine test, clue cell > 20% of total vaginal epithelial cells, and scanty or absence lactobacilli. The second part included the in-house preparation kit of suggestive BV relied on elevated vaginal pH > 4.5 and positive amine tube test. RESULTS: Twenty-six women were enrolled. Of the complaint of AVD/asymptomatic had 2/10 of confirmed BV (12 cases), and 1/13 of confirmed non-BV (14 cases). The in-house preparation kit, compared with the clinical criteria, had sensitivity of 91%, specificity of 71%, positive predictive value of 73%, and negative predictive value of 90%. There were false negative of 1/12 cases (8.3%), and false positive of 4/14 cases (28.5%). CONCLUSION: The in-house preparation kit favorably compared with the clinical criteria and has the advantage of being simple, rapid, and easily performed in resource poor setting. Further development on sensitivity and specificity of the test is suggested.