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Pedogenetic features of the soils could be a proxy for revealing the landform surface processes. Our work first analyzed the particle size distributions and lithological discontinuities (LDs) of the soils in the midstream of the Zoushui River, central Taiwan. The results showed that the parental materials of the soils derive from mixed sediments of the Zoushui River and its tributaries, and the LDs of some soils suggested multi-depositional events with homogeneous lithology. Then, we proposed a soil chronosequence of Inceptisols, Ultisols, and Oxisols, over the Pleistocene timescale. There was a very well-defined semilogarithmic relationship between weighted profile development index (WPDI) values and soil age with correlation coefficients (r) greater than 0.9. The age of the soils did not certainly agree with the interglacials of the main marine isotope stage (MIS). However, the soils started to develop only after being aggraded by relatively warm and humid periods or by extreme rain events in cool and dry periods. Irrespective of whether the soils had started to develop, tectonic downcutting, providing clear altitudinal separation of the terrace treads, could inevitably happen later (or almost synchronologically) to ensure stabilities of the tread surfaces. [ABSTRACT FROM AUTHOR]

Under intensive and high-density aquaculture conditions, the cultured eels are easily infected by a variety of virulent Aeromonas species, which leads to high mortality rates and economic losses. In this study, a visual closed-tube loop-mediated isothermal amplification (LAMP) assay was developed for targeting aerolysin gene of Aeromonas species affecting cultured eels. Firstly, two pairs of outer and inner primers were designed against a conserved region of the aer gene from different Aeromonas species. Secondly, the weakly buffered aer-LAMP assay was optimized under various Mg2+ concentrations, different amplification times and amplification temperatures followed by the visual evaluation of phenol red dye and SYTO-9. Thirdly, the detection limit of the aer-LAMP assay showed 16.8 copy/μl which was simultaneously evaluated by the color changes from red to yellow and the real-time fluorescence amplification curves. The specificity of the aer-LAMP assay showed no cross-reaction with other related species. In addition, 30 Aeromonas strains and 40 clinical tissues from eels were used to further validate the effectiveness of the aer-LAMP assay. All the results showed that the aer-LAMP assay provided a rapid, simple, and reliable method for detecting Aeromonas harboring the aerolysin gene, which would be helpful for the prevention and control of Aeromonas infection in cultured eels. [ABSTRACT FROM AUTHOR]

Food-borne diseases induced by Staphylococcus aureus contamination seriously affect human health and food safety. Therefore, a closed-tube loop-mediated isothermal amplification (LAMP) assay for the visual detection of S. aureus was developed in this study. Firstly, two pairs of outer and inner primers were designed targeting on a conserved fragment of gyrB gene in different S. aureus strains. Secondly, the weakly buffered gyrB-LAMP assays were optimized under various pH values and other conditions, followed by the visual evaluation of five pH-sensitive indicators, and the cresol-red was chosen as the best dye for the best visual performance. Thirdly, the cresol-red-based LAMP assay showed good sensitivity with the detection limit of 5.4 copies/μL for purified DNAs, and good specificity with no cross-reaction with other related species. The specificity of the amplified products was further confirmed by XbaI restriction enzyme digestion analysis. Finally, the cresol-red-based LAMP assay was validated by the clinical-dried fish samples inoculated with known numbers of S. aureus and further validated by 20 blind samples. To our knowledge, this is the first report of a closed-tube LAMP assay based on pH-sensitive indicators for the visual detection of the food-borne S. aureus by the gyrB gene. [ABSTRACT FROM AUTHOR]

The hypsometric curve and hypsometric integral (HI) of drainage basins are common tectonic geomorphologic indices. Generally, the hypsometric curve is convex and the HI is high in areas of strong rock uplift. However, previous research indicates that an inverse correlation exists between the HI and rock uplift in the mountain-piedmont junction in California. It has also been proposed that the basin HI in the range front area has scale dependence, which increases the difficulty of inferring tectonic uplift. We therefore examined the effects of tectonic uplift and basin scale on basin HI in the southern Coastal Range of eastern Taiwan. The results showed that basin size could affect the HI. First-order Strahler basins are smaller and have higher HIs, whereas second- and third-order basins are larger and have lower HIs, indicating some form of scale dependence. The coefficient of logarithmic regression between mean area and mean HI of every subbasin was calculated to determine the scale dependence index (SDI). The lower the SDI, the higher the scale dependence. The SDI was utilized to distinguish basins' topographic tendencies between range interior and range front. We also applied the igneous-area ratio to define spatial tendencies of basins' lithology distributions. The lower the igneous-area ratio, the greater the spatial tendency toward range front will be. Basins in the middle of the south Coastal Range tended to approach a range interior steady state, with higher SDIs and a positive correlation between HI and rock uplift rate. Basins in the north and south of the south Coastal Range tended to be at a range front nonsteady state, with lower SDIs and a negative correlation between HI and rock uplift rate. The correlations may be applicable to estimate the rock uplift rate. [ABSTRACT FROM AUTHOR]