Selecting Temperature for Screening Heat Tolerance in ‘Tavee 60’ Chili Seedlings

ABSTRACT Crop yield has been affected by unfavorable growth conditions. This study aimed to find temperature for screening heat-tolerate chili pepper (Capsicum annuum) mutated by gamma radiation. Two-month-old seedlings were grown in the growth chamber at four temperature treatments as 27 (control), 34, 36 and 40 oC for 7 days. Leaf temperature (LT), non-photochemical quenching (qN), photochemical efficiency of PSII (Fv/Fm) and electron transport rate (ETR) were determined. The results showed that leaf temperature of control plants was lower than other treatments. The qN tended to increase according to the higher temperature treatments. Fv/Fm ratio and ETR of seedlings under 40 oC treatment were lower than the others.  In addition, under 40 oC, seedlings displayed the injury symptom after 4 days and died after 7 days. These levels of injury symptoms lead to the new qualitative parameter for future work called ‘injury index’. In conclusion, the seedlings at 40 oC treatment were different from the control based on Fv/Fm. In order to get the new improved cultivar, the temperature at 40 oC and Fv/Fm were selected for the future heat-tolerant screening of chili pepper seedlings mutated by gamma irradiation

Antioxidant enzyme activity in salt tolerant selected clones of stylo 184 (Stylosanthes guianensis CIAT 184), an important forage legume

In vitro shoots from five selected clones-one sensitive (T1) and four salt tolerant (T2, T3, T4 and T5)-of Stylosanthes guianensis CIAT 184 were multiplied in Murashige and Skoog medium with 0, 0.5 and 1% (weight per volume) NaCl for 1 wk followed by transfer to a recovery medium for a further week. Their relative fresh weight (RFW) and antioxidative enzymes-superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX)-were measured after 7 d on the salt medium and again after another 7 d on a recovery medium (without additional NaCl). Exposure to NaCl reduced the growth of all clones at some stage. For the four clones selected as salt tolerant, the reduction in growth was evident after 7 d (up to 45%) on the NaCl media, however, for the clone selected as salt sensitive this reduction (50%) only occurred after 7 d on the recovery medium. Shoots of clones T2, T3 and T5, however, increased their growth on the recovery medium and this was associated with an increase in POX activity (from 0.5% NaCl medium for T2 and 1% NaCl medium for T3 and T5). The SOD activity of these clones was higher than the salt sensitive clone but decreased at 1% NaCl when shoots had been on the recovery medium for 7 d. In T4, the RFW increased to equal that of the control at 0.5% NaCl after recovery while the SOD activity was reduced and the POX activity was stable after both salt treatment and recovery. The NaCl treatments had no effect on the CAT activity for any of the clones. The lowest SOD activity was found in T1 while the tolerant clone, T5, showed the highest CAT and POX activity, providing the ability to distinguish between clones

Antioxidant enzyme activity in salt tolerant selected clones of stylo 184 (Stylosanthes guianensis CIAT 184), an important forage legume

In vitro shoots from five selected clones-one sensitive (T1) and four salt tolerant (T2, T3, T4 and T5)-of Stylosanthes guianensis CIAT 184 were multiplied in Murashige and Skoog medium with 0, 0.5 and 1% (weight per volume) NaCl for 1 wk followed by transfer to a recovery medium for a further week. Their relative fresh weight (RFW) and antioxidative enzymes-superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX)-were measured after 7 d on the salt medium and again after another 7 d on a recovery medium (without additional NaCl). Exposure to NaCl reduced the growth of all clones at some stage. For the four clones selected as salt tolerant, the reduction in growth was evident after 7 d (up to 45%) on the NaCl media, however, for the clone selected as salt sensitive this reduction (50%) only occurred after 7 d on the recovery medium. Shoots of clones T2, T3 and T5, however, increased their growth on the recovery medium and this was associated with an increase in POX activity (from 0.5% NaCl medium for T2 and 1% NaCl medium for T3 and T5). The SOD activity of these clones was higher than the salt sensitive clone but decreased at 1% NaCl when shoots had been on the recovery medium for 7 d. In T4, the RFW increased to equal that of the control at 0.5% NaCl after recovery while the SOD activity was reduced and the POX activity was stable after both salt treatment and recovery. The NaCl treatments had no effect on the CAT activity for any of the clones. The lowest SOD activity was found in T1 while the tolerant clone, T5, showed the highest CAT and POX activity, providing the ability to distinguish between clones

Variation and long term regenerative capacity of two important tropical forage legumes: Cavalcade (Centrosema pascuorum cv. Cavalcade) and Stylo 184 (Stylosanthes guianensis CIAT184) in vitro

Shoots of Cavalcade (Centrosema pascuorum cv. Cavalcade) and Stylo 184 (Stylosanthes guianensis CIAT 184) from in vitro germinated seeds were cultured on Murashige and Skoog (MS) medium supplemented with 0 to 7 mg L-1 N 6-benzyladenine (BA) in combination with 0 to 0.5 mg L-1 napthalene acetic acid (NAA) for shoot induction and MS supplemented with 0 to 0.5 mg L-1 indolebutyric acid (IBA) for root induction. For Cavalcade, the medium containing 1 mg L-1 BA produced the best shoot multiplication with an excess of six shoots produced from a single shoot (over four weeks) with a mean height 2.0 ± 0.01 cm. Adventitious shoot regeneration was obtained directly from stem axes. For Stylo 184, the maximum shoot regeneration (29.5 ± 1.0 cm shoots/explant) and height (1.5 ± 0.1 cm) was achieved using 7 mg L-1 BA and 0.01 mg L-1 NAA. Direct and indirect shoot regeneration was obtained on the medium containing 1 mg L-1 BA and 0.01 mg L-1 NAA. The regeneration of shoots from callus of Stylo 184 varied between different genotypes and was high (2.6 to 5.8 shoots/explant) even after maintenance in culture of over three years. Both Cavalcade and Stylo 184 shoots were rooted on media supplemented with IBA (0 to 0.5 mg L-1) and readily transferred to soil (Stylo 184).Key words: Callus, forage legume, micropropagation, organogenesis, root induction

Fabrication of 3D Polycaprolactone Macrostructures by 3D Electrospinning

Building 3D electrospun macrostructures and monitoring the biological activities inside them are challenging. In this study, 3D fibrous polycaprolactone (PCL) macrostructures were successfully fabricated using in-house 3D electrospinning. The main factors supporting the 3D self-assembled nanofiber fabrication are the H 3PO 4 additives, flow rate, and initial distance. The effects of solution concentration, solvent, H 3PO 4 concentration, flow rate, initial distance, voltage, and nozzle speed on the 3D macrostructures were examined. The optimal conditions of 4 mL/h flow rate, 4 cm initial nozzle-collector distance, 14 kV voltage, and 1 mm/s nozzle speed provided a rapid buildup of cylinder macrostructures with 6 cm of diameter, reaching a final height of 16.18 ± 2.58 mm and a wall thickness of 3.98 ± 1.01 mm on one perimeter with uniform diameter across different sections (1.40 ± 1.10 μm average). Oxygen plasma treatment with 30-50 W for 5 min significantly improved the hydrophilicity of the PCL macrostructures, proving a suitable scaffold for in vitro cell cultures. Additionally, 3D images obtained by synchrotron radiation X-ray tomographic microscopy (SRXTM) presented cell penetration and cell growth within the scaffolds. This breakthrough in 3D electrospinning surpasses current scaffold fabrication limitations, opening new possibilities in various fields.</p

Simultaneous determination of neomycin sulfate and polymyxin B sulfate by capillary electrophoresis with indirect UV detection

A simple and rapid capillary electrophoresis method, with indirect UV detection, for the simultaneous determination of neomycin sulfate and polymyxin B sulfate in pharmaceutical formulations was developed. Critical parameters such as pH, buffer composition and concentration, voltage and injection time have been studied to evaluate, how they affect responses, such as resolution and migration times. Separation was performed on a fused silica capillary with 50 μm i.d. and 27 cm total length at an applied voltage of 6 kV with a 15 mM phosphate run buffer (pH 5.0) containing 40 mM N-(4-hydroxy-phenyl)acetamide and 50 mM tetradecylammonium bromide (TTAB). The detection wavelength was set at 280 nm. Quantitative analysis was validated by testing the reproducibility of the method, giving a relative standard deviation less than 0.4 and 2.4% for the repeatability of migration time and corrected peak area, respectively. Accuracy was tested by spiking eye–ear formulations with standards and the recoveries of neomycin sulfate and polymyxin B sulfate were found to be between 97.44–103.18% and 96.85–101.68%, respectively. Linearity of neomycin sulfate and polymyxin B sulfate were obtained in the ranges of 17–682 and 24–608 μg/mL, respectively, with r2 values above 0.999. The established TLC–densitometric method was applied to evaluate the proposed CE method, and comparable results were obtained by using CE with much shorter analysis time and a small quantity of solvents consumed. The developed method is also the first report on the simultaneous determination of neomycin sulfate and polymyxin B sulfate in pharmaceutical preparations by CE

New method for arbuscular mycorrhizal fungus spore separation using a microfluidic device based on manual temporary flow diversion.

Arbuscular mycorrhizal fungi are beneficial components often included in biofertilizers. Studies of the biology and utilization of these fungi are key to their successful use in the biofertilizer industry. The acquisition of isolated spores is a required step in these studies; however, spore quality control and spore separation are bottlenecks. Filtered and centrifuged spores have to be hand-picked under a microscope. The conventional procedure is skill-demanding, labor-intensive, and time-consuming. Here, we developed a microfluidic device to aid manual separation of spores from a filtered and centrifuged suspension. The device is a single spore streamer equipped with a manual temporary flow diversion (MTFD) mechanism to select single spores. Users can press a switch to generate MTFD when the spore arrives at the selection site. The targeted spore flows in a stream to the collection chamber via temporary cross flow. Using the device, spore purity, the percentage of spore numbers against the total number of particles counted in the collecting chamber reached 96.62% (median, n = 10) which is greater than the spore purity obtained from the conventional method (88.89% (median, n = 10))