Flow-Based Systems for Rapid and High-Precision Enzyme Kinetics Studies

Enzyme kinetics studies normally focus on the initial rate of enzymatic reaction. However, the manual operation of steps of the conventional enzyme kinetics method has some drawbacks. Errors can result from the imprecise time control and time necessary for manual changing the reaction cuvettes into and out of the detector. By using the automatic flow-based analytical systems, enzyme kinetics studies can be carried out at real-time initial rate avoiding the potential errors inherent in manual operation. Flow-based systems have been developed to provide rapid, low-volume, and high-precision analyses that effectively replace the many tedious and high volume requirements of conventional wet chemistry analyses. This article presents various arrangements of flow-based techniques and their potential use in future enzyme kinetics applications

Simple flow-injection system for the simultaneous determination of nitrite and nitrate in water samples

A novel spectrophotometric reaction system was developed for the determination of nitrite as well as nitrate in water samples, and was applied to a flow-injection analysis (FIA). The spectrophotometric flow-injection system coupled with a copperised cadmium reductor column was proposed. The detection was based on the nitrosation reaction between nitrite ion and phloroglucinol (1,3,5-trihydroxybenzene), a commercially available phenolic compound. Sample injected into a carrier stream was split into two streams at the Y-shaped connector. One of the streams merged directly and reacted with the reagent stream: nitrite ion in the samples was detected. The other stream was passed through the copperised cadmium reductor column, where the reduction of nitrate to nitrite occurred, and the sample zone was then mixed with the reagent stream and passed through the detector: the sum of nitrate and nitrite was detected. The optimised conditions allow a linear calibration range of 0.03-0.30 mug NO2--N ml(-1) and 0.10-1.00 mug NO3--N ml(-1). The detection limits for nitrite and nitrate, defined as three times the standard deviation of measured blanks are 2.9 ng NO2--N ml(-1) and 2.3 ng NO3--N ml(-1), respectively. Up to 20 samples can be analyzed per hour with a relative standard deviation of less than 1.5%. The proposed method could be applied successfully to the simultaneous determination of nitrite and nitrate in water samples.</p

Determination of trace amounts of bromide by flow injection/stopped-flow detection technique using kinetic-spectrophotometric method

A simple, sensitive and selective method for the determination of bromide in seawater by using a flow injection/stopped-flow detection technique was examined. The detection system was developed for a new kinetic-spectrophotometric determination of bromide in the presence of chloride matrix without any extraction and/or separation. The detection was based on the kinetic effect of bromide on the oxidation of methylene blue (MB) with hydrogen peroxide in a strongly acidic solution. Large amounts of chloride could enhance the sensitivity of the method as an activator. The decolorisation of the blue color of MB was used for the spectrophotometric determination of bromide at 746 nm. A stopped-flow approach was used to improve the sensitivity of the measurement and provide good linearity of the calibration over the range of 0-3.2 p,g ml(-1) of bromide. The relative standard deviation was 0.74% for the determination of 2.4 jig ml(-1) bromide (n=5). The detection limit (3 sigma) was 0.1 mu g ml(-1) with a sampling frequency of 12 h(-1). The influence of potential interfering ions was studied. The proposed method was applied to the determination of bromide in seawater samples and provided satisfactory results. </p

Flow injection spectrophotometry coupled with a crushed barium sulfate reactor column for the determination of sulfate ion in water samples

A new type of a reactor column, a crushed BaSO4 reactor column used for the flow injection spectrophotometric determination of sulfate ion using the exchange reaction of sulfate ion and barium-dimethylsulfonazo III is proposed. The column is very simple and economical. It can be continuously used for 8 h before washing with water for repeated usage of at least 1 month. The procedure is sensitive. Application to various water samples was demonstrated. </p

Dietary protein requirements for growth performance and effects on carcass composition of young Siamese spiny eel, Macrognathus siamensis (Günther, 1861)

The study on protein requirement of young Siamese spiny eel, Macrognathus siamensis (GÜnther, 1861) was conducted using six different protein level (35, 40, 45, 50, 55 and 60 % protein) with average gross energy of 450 kcal·100/g. The results demonstrated the maximum specific growth rate (SGR), % weight gain and daily weight gain were achieved at 55% protein while the fishes fed with 35% protein was the lowest. It was estimated by broken line regression that dietary protein level producing maximum growth was 46.50% protein. There was no significant difference (P>0.05) on survival rate amongst treatments. Protein efficiency ratio (PER) and apparent net protein retention (ANPR) were not significantly (P>0.05) affected by diet protein levels. No significant (P>0.05) effect of dietary protein levels was found on carcass moisture, crude protein, crude lipid and ash. However, carcass moisture, protein and ash were apparently increased in all fish groups after feeding trial, comparing to fish before the experiment

Consumer electronics devices for DNA genotyping based on loop-mediated isothermal amplification and array hybridisation

[EN] Consumer electronic technologies offer practical performances to develop compact biosensing systems intended for the point-of-care testing of DNA biomarkers. Herein a discrimination method for detecting single nucleotide polymorphisms, based on isothermal amplification and on-chip hybridisation, was developed and integrated into user-friendly optical devices: e.g., USB digital microscope, flatbed scanner, smartphone and DVD drive. In order to adequately identify a single base change, loop-mediated isothermal amplification (LAMP) was employed, with high yields (8 orders) within 45 min. Subsequently, products were directly hybridised to the allele-specific probes attached to plastic chips in an array format. After colorimetric staining, four consumer electronic techniques were compared. Sensitive precise measurements were taken (high signal-to-noise ratios, 10-mu m image resolution, 99% scan-to-scan reproducibility). These features confirmed their potential as analytical tools, are a competitive alternative to fluorescence scanners, and incorporate additional advantages, such as user-friendly interface and connectivity for telemedicine needs. The analytical performances of the integrated platform (assay and reader) in the human samples were also excellent, with a low detection limit (100 genomic DNA copies), and reproducible (< 15%) and cheap assays (< 10 (sic)/test). The correct genotyping of a genetic biomarker (single-nucleotide polymorphism located in the GRIK4 gene) was achieved as the assigned genotypes agreed with those determined by using sequencing. The portability, favourable discriminating and read-out capabilities reveal that the implementation of mass-produced low-cost devices into minimal-specialised clinical laboratories is closer to becoming a reality.The authors acknowledge the financial support received from the Generalitat Valenciana, Spain (GVA-PROMETEOII/2014/040 Project and GRISOLIA/2014/024 Ph.D. grant) and the Spanish Ministry of Economy and Competitiveness, Spain (MINECO CTQ2016-75749-R project) by U. E. FEDER funds. The authors also thank J. Carrascosa for supporting the DVD reader measurements.Tortajada-Genaro, LA.; Yamanaka, ES.; Maquieira Catala, A. (2019). Consumer electronics devices for DNA genotyping based on loop-mediated isothermal amplification and array hybridisation. Talanta. 198:424-431. https://doi.org/10.1016/j.talanta.2019.01.124S42443119

The Asia‐Pacific Biodiversity Observation Network : 10‐year achievements and new strategies to 2030.

The Asia-Pacific Biodiversity Observation Network (APBON) was launched in 2009, in response to the establishment of the Biodiversity Observation Network under the Group on Earth Observations in 2008. APBON's mission is to increase exchange of knowledge and know-how between institutions and researchers concerning biodiversity science research in the Asia-Pacific (AP) region and thereby contribute to evidence-based decision-making and policy-making. Here we summarize APBON activities and achievements in its first 10 years. We review how APBON has developed networks, facilitated communication for sharing knowledge, and built capacity of researchers and stakeholders through workshops and publications as well as discuss the network plan. Key findings by APBON members include descriptions of species new to science, mapping tropical forest cover change, evaluating impacts of hydropower dams and climate change on fish species diversity in the Mekong, and mapping “Ecologically and Biologically Significant Areas” in the oceans. APBON has also contributed to data collection, sharing, analysis, and synthesis for regional and global biodiversity assessment. A highlight was contributing to the “Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services” regional report. New strategic plans target the development of national-level BONs and interdisciplinary research to address the data and knowledge gaps and increase data accessibility for users and for meeting societal demands. Strengthening networks in AP region and capacity building through APBON meetings will continue. By promoting monitoring and scientific research and facilitating the dialogue with scientists and policymakers, APBON will contribute to the implementation of conservation and sustainable use of biodiversity in the entire AP region.publishedVersio

Thryssocypris T.R.Roberts & Kottelat 1984

Key to species of &lt;i&gt;Thryssocypris&lt;/i&gt; &lt;p&gt; 1a. Origin of dorsal fin over or in front of origin of anal fin, 14&ndash;15 circumpeduncular scales........ &lt;i&gt;Thryssocypris smaragdinus&lt;/i&gt;&lt;/p&gt; &lt;p&gt;1b. Origin of dorsal fin behind origin of anal fin, 16&ndash;17 circumpeduncular scales...................................... 2&lt;/p&gt; &lt;p&gt; 2a. 37&ndash;40 lateral-line scales....................................................... &lt;i&gt;Thryssocypris wongrati&lt;/i&gt; sp. nov.&lt;/p&gt; &lt;p&gt;2b. 42&ndash;46 lateral-line scales................................................................................ 3&lt;/p&gt; &lt;p&gt; 3a. Black spot on caudal-fin base, hyaline caudal fin with black on proximal portion of medial caudal-fin rays............................................................................................. &lt;i&gt;Thryssocypris tonlesapensis&lt;/i&gt;&lt;/p&gt; &lt;p&gt; 3b. No dark spot on caudal-fin base, yellowish caudal fin without black on medial rays........... &lt;i&gt;Thryssocypris ornithostoma&lt;/i&gt;&lt;/p&gt;Published as part of &lt;i&gt;Grudpan, Chaiwut &amp; Grudpan, Jarungjit, 2012, Thryssocypris wongrati, a new anchovy-like cyprinid (Cypriniformes) from the Chao Phraya basin, Thailand, pp. 228-235 in Zootaxa 3586&lt;/i&gt; on page 23