Study of Age of Seedlings at Transplanting on Growth Dynamics and Yield of Rice under Alternating Flooding and Suspension of Irrigation of Water Management

Age of seedlings at transplanting is considered for influencing grain yield in water scarce rice production systems, primarily by laying the foundation for determining the number of panicles at harvest. This experiment investigated plant growth, yield and yield components of rice when transplanted at varying ages under alternating flooding and suspending irrigation in water management for saving water.  In a greenhouse study, nine ages of seedlings starting from 4 to 12 days were transplanted in pots and the performance of each age was compared with a direct-seeded crop in a completely randomized design with five replicates. Soil moisture content (SMC) in the 0-15, 15-25 and 25-50 cm soil layers were monitored. SMC reached near the lowest level of readily available water (RAW), but never reached below RAW during the first suspension of irrigation in all the treatments. However, SMC reached PWP in the 15-25 cm soil layer at the second period of suspension of irrigation.The number of tillers, leaf area per hill, plant height and above ground non-grain biomass did not differ between direct-seeded rice (DSR) and transplanted rice (TPR) with 4-12-day old seedlings. Maximum tillering occurred between 5 and 6 weeks after establishment in all age groups of seedlings. However, root depth, total root length, root dry weight and shoot to root ratio were significantly greater in DSR than TPR.  Age of seedlings at transplanting had a significant effect on number of productive tillers per hill, filled grains per panicle, panicle length, 1000-grain weight, grain yield and panicle setting rate. However, harvest index was not significantly affected. Establishment of rice by direct seeding and transplanting up to 12 days did not differ in handling the transplanting shock and resuming normal growth phase rapidly. And also, there was no difference in the tillering potential and the growth dynamics of seedlings of all ages used, but 9-day old seedlings had higher yield under alternating flooding and suspending irrigation compared to other ages of seedling and water management

Management of Selected Insect Pests with Pest-attractive Plants in Organic Tangerine Farming Systems in Northern Thailand

Tangerine is a cash crop in Thailand which is heavily vulnerable to insect pests. Heavy use of pesticides has severely affected environment and people’s health. This study was conducted to assess the biological pest management potential using pest attractive plant species to reduce the use of highly toxic pesticides and to improve the quality of the product and environment health. Sixteen suspected weed species were allowed to grow with tangerine and tested their pest attractiveness for four key insect pests for 12 weeks. From this study, three weeds [viz. goat weed (Ageratum conyzoides), Siam weed (Chromolaena odorata), and buffalo grass (Paspalum conjugatum)] were identified for further studies and tested together with cowpea (Vigna unguiculata), rice (Oryza sativa) and chilly pepper (Capsicum frutescens) based on farmers’ information in an organically grown tangerine farm. All plant species tested attracted citrus leafminers and citrus whiteflies as tangerine pests, and among the natural enemies, ladybird beetle and weaver ants. Asian citrus psyllids were attracted on buffalo grass, rice and chilly peppers, while black citrus aphids were attracted on Siam weed and chilly peppers only. The two natural enemies namely, green lacewings and tropical orb weaver spiders were attracted by Siam weed, buffalo grass and rice, which together with chilly peppers attracted tropical orb weaver.  The Asian citrus psyllids and citrus whitefly damage on tangerine associated with chilly peppers was minor-moderate, minor with Siam weed, buffalo grass and rice, but not observed on tangerine associated with goat weed and cowpea. Black citrus aphid damage was minor on tangerine associated with all plants, except cowpea.  Citrus leafminer damage was between minor-moderate in tangerine associated with Siam weed and cowpea, and above moderate-heavy with rest of the plant species. These results show that pest attraction varies with plant species and by selecting plant species in a mixed stand with cowpea and chilly peppers and by leaving these weeds can help managed tangerine pests and minimize use of toxic pesticides.Â

Production and fractionation of antioxidant peptides from soy protein isolate using sequential membrane ultrafiltration and nanofiltration

Antioxidants are molecules capable of stabilizing and preventing oxidation. Certain peptides, protein hydrolysates, have shown antioxidant capacities, which are obtained once liberated from the native protein structure. Soy protein isolates (SPI) were enzymatically hydrolyzed by pepsin and pancreatin mixtures. The soy protein hydrolysates (SPH) were fractionated with sequential ultrafiltration (UF) and nanofiltration (NF) membrane steps. Heat pre-treatment of SPI at 95 degrees celsius (C) for 5 min prior to enzymatic hydrolysis was investigated for its effect on peptide distribution and antioxidant capacity. SPH were subjected to UF with a 10 kDa molecular weight cut off (MWCO) polysulfone membrane. UF permeate fractions (lower molecular weight than 10 kDa) were fractionated by NF with a thin film composite membrane (2.5 kDa MWCO) at pH 4 and 8. Similar peptide content and antioxidant capacity (α=0.05) were obtained in control and pre-heated SPH when comparing the respective UF and NF permeate and retentate fractions produced. FCR antioxidant capacities of the SPH fractions were significantly lower than their ORAC antioxidant capacities, and the distribution among the UF and NF fractions was generally different. Most UF and NF fractions displayed higher antioxidant capacities when compared to the crude SPI hydrolysates, showing the importance of molecular weight on antioxidant capacity of peptides. The permeate fractions produced by NF at pH 8 displayed the highest antioxidant capacity, expressed in terms of Trolox equivalents (TE) per total solids (TS): 5562 μmol TE/g TS for control SPH, and 5187 μmol TE/g TS for pre-heated SPH. Due to the improvement in antioxidant capacity of peptides by NF at pH 8, the potential for NF as a viable industrial fractionation process was demonstrated. Principal component analysis (PCA) of fluorescence excitation-emission matrix (EEM) data for UF and NF peptide fractions, followed by multi-linear regression analysis, was assessed for its potential to monitor and identify the contributions to ORAC and FCR, two in vitro antioxidant capacity assays, of SPH during membrane fractionation. Two statistically significant principal components (PCs) were obtained for UF and NF peptide fractions. Multi-linear regression models (MLRM) were developed to estimate their fluorescence and PCA-captured ORAC (ORAC-FPCA) and FCR (FCR-FPCA) antioxidant capacities. The ORAC-FPCA and FCR-FPCA antioxidant capacities for NF samples displayed strong, linear relationships at different pH conditions (R-squared>0.99). Such relationships are believed to reflect the individual and relative combined contributions of tryptophan and tyrosine residues present in the SPH fractions to ORAC and FCR antioxidant capacities. Therefore, the proposed method provides a tool for the assessment of fundamental parameters of antioxidant capacities captured by ORAC and FCR assays

Purification of artichoke polyphenols by using membrane filtration and polymeric resins

The present study aimed at evaluating the potential of an integrated process based on the use of membrane technology and adsorbent resins for the recovery, concentration and purification of phenolic compounds from artichoke wastewaters. In particular, artichoke wastewaters coming from the blanching step were pre-treated by ultrafiltration (UF) in order to remove suspended solids and macromolecular compounds. The UF permeate was submitted to a nanofiltration (NF) process producing a concentrated fraction enriched in phenolic and sugar compounds. Three different macroporous resins were tested through adsorption/desorption methods to produce purified phenolic fractions with high antioxidant activity. Samples produced in UF, NF and adsorption desorption tests were assayed for phenolic composition (chlorogenic acid and apigenin 7-O-glucoside), sugar composition (fructose, glucose and sucrose) and antioxidant activity. Among the three different tested resins, the S 7968 offered the best performance in terms of adsorption/desorption ratio for chlorogenic acid, with a total adsorption/desorption yield (TADY) of 63.39%; for the apigenin 7-O-glucoside the S 7968 and the S 2328 resins showed a TADY in the range 68.31-78.45%. (c) 2015 Elsevier B.V. All rights reserved.Authors acknowledge the Vicerrectorado de Investigacion of the "Universitat Politecnica de Valencia" for the financial support (project 1965) from the call "Proyectos de Nuevas Lineas de Investigacion Mul-tidisciplinares (PAID05-11)".Conidi, C.; Rodríguez López, AD.; Garcia-Castello, EM.; Cassano, A. (2015). Purification of artichoke polyphenols by using membrane filtration and polymeric resins. Separation and Purification Technology. 144(1):153-161. https://doi.org/10.1016/j.seppur.2015.02.025S153161144

Skin mechanics, intradermal delivery and biosensing with hollow metallic microneedles

Microneedles (MNs) have gained significant attention over the past decade in drug delivery and biosensing due to their minimally-invasive and less painful nature of use compared to intramuscular/subcutaneous injections, and significant biological benefits. Several fundamental processes enabling MN functionality have not been completely understood, including mechanical interaction between MNs and skin for targeted depth penetration; and precise quantification of fluid delivery in the skin. This thesis presents novel materials, and methodologies for evaluating MN interactions with skin, and investigates the performance of hollow MNs in both intradermal fluid drug delivery and biosensing. A micromechanical comparison between human skin and porcine skin was performed using to determine their mechanical behavior affecting MN insertions. Stratum corneum (SC) of human skin was significantly stiffer (117 ± 42 MPa) than porcine skin (81 ± 32 MPa), requiring higher force of MN insertion to rupture the SC in human skin (107 ± 17 mN) than porcine skin (96 ± 23 mN). An artificial mechanical skin model was developed layer-by-layer to simulate tough human skin (MN insertion force 162 ± 11 mN) and to study the dynamics of MN insertion. Key factors that affected MN insertions into skin, including velocity of impact and total energy delivered to the skin, were identified. ID fluid delivery by hollow MNs was assessed using a novel method involving the low-activity radiotracer technetium-99m pertechnetate (⁹⁹mTcO₄₋). Its delivery allowed accurate quantification of fluid delivered into the skin, back-flowed to the skin surface, and total fluid ejected from the syringes via ID devices with sub-nanoliter resolution. Hollow MNs performed more accurate ID injections than conventional needles (93% vs. 69-87% of fluid per 0.1 mL injection volume). A MN-optofluidic biosensing platform capable of eliminating blood sampling was developed with MNs that can access dermal interstitial fluid that contains numerous drugs at concentrations comparable to blood. The MN lumen was functionalized to collect, trap and detect drugs in 0.6 nL of sample. The optofluidic components provided specific high-sensitivity absorbance measurements for drug binding using enzyme-linked assays. Streptavidin-horseradish peroxidase (LoD = 60.2 nM) and vancomycin (LoD = 84 nM) binding validated this point of care system.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat

Molecular and Physical Regulation of Collective Cancer Invasion

Cellular plasticity is essential for healthy function during development and healing. However, it is the dysregulated plasticity of neoplastic cells that gives cancer its advantageous heterogeneity and resistance to therapy. Plasticity also endows cancer cells with the ability to mimic and aberrantly activate fundamental developmental processes such as collective cell migration (CCM) in the form of collective invasion, which initiates the metastatic cascade that is the primary cause for cancer-related deaths. Remarkably, the initiation of this process is strongly associated with changes in the extracellular matrix (ECM) environment of the tumor, which functions as both a physical barrier and dynamic signaling cue for cell migration. Namely, simultaneous increases in the density, stiffness, and alignment of Collagen I fibers in the tumor ECM mark a key transition. However, challenges associated with modeling this process limit our capacity for identifying new approaches that target these plastic cancer cells. In this dissertation, we develop ECM engineering and dynamic measurement techniques to enable study of the biophysical cell-cell and cell-matrix interactions that drive collective cancer cell invasion. We then use these newfound insights to develop a phenotypic screening model that successfully identifies a cytodifferentiation therapy of plastic Triple Negative Breast Cancer (TNBC) cells. In chapter I, we advance a matrix engineering approach to tune Collagen I fibrillar architecture independently of known modulators of collective cell behavior such as ECM density and stiffness. We find that tighter fibril networks are less degradable and adhesive, inducing cellular confinement that prompts a switch from single cell migration to CCM. Chapter II integrates multiple modalities of biophysical imaging with in silico modeling to dissect the underlying cell-cell and cell-matrix interactions of the two distinct CCM behaviors that emerge from single populations of cancer cells in confining matrices: collective rotational migration and collective invasive migration. We find that the predominant phenotype of invasive CCM relies on a combination of proteolytic-based matrix remodeling and physical remodeling while the less common rotational CCM relies solely on mechanical-based matrix remodeling. Contrary to the current paradigm, we also find that epithelial characteristics such as cadherin-based cell-cell junctions or establishment of a Laminin-rich basement membrane are non-essential for either CCM behavior. In chapter III, we conduct a phenotypic screen of TNBC cells within confining Collagen I matrices to identify cytodifferentiation therapies targeting CCM, a trait that is associated with enrichment for Cancer Stem Cells (CSCs). Phenotypic screening identified two structurally similar leads that abrogate collective invasion, induce CSC cytodifferentiation and Mesenchymal-to-Epithelial Transition, and increase sensitivity to traditional chemotherapies. Importantly, this cytodifferentiation response is not observed in 2D-treated cells or in non-confining 3D matrices, highlighting our simple 3D phenotypic screening assay as an improved method for identifying relevant cytodifferentiation therapies for TNBC. Taken together, we provide a bottom-up description of how understanding and designing cell-matrix interactions can give rise to physiologically relevant CCM behaviors that provide a novel paradigm for identifying therapeutics that target cancer plasticity

Soil dehydrogenase in a land degradation-rehabilitation gradient: observations from a savanna site with a wet/dry seasonal cycle

Soil dehydrogenase activity is a good indicator of overall microbial activity in soil, and it can serve as a good indicator of soil condition. However, seasonal changes in soil moisture content may have an effect on soil dehydrogenase activity, making an accurate assessment of soil condition difficult. In this study, we attempted to determine the significance of soil dehydrogenase activity for assessing soil condition, and we attempted to find a way to account for the influence of soil moisture content on soil dehydrogenase activity. Soils were sampled in dry evergreen forest (original vegetation), bare ground (severely degraded) and Acacia plantation plots established on bare ground in 1986 and 1987 in Sakaerat, Thailand. Soil physico-chemical characteristics and dehydrogenase activity in the Acacia plantation soil had few differences from those in the evergreen forest soil. Soil dehydrogenase activity varied significantly between the bare ground and the forests regardless of the season (wet or dry), while the season did not produce a significant variation in soil dehydrogenase activity, as determined by repeated measures analysis of variance (p=0.077). The physico-chemical data provided the first principal component as a good measure of soil fertility. Values of soil dehydrogenase activity significantly cor- related to scores of the soil samples of the first principal component (R=0.787, p<0.001). We found that soil dehydrogenase activity is a useful indicator of the extent of soil degradation and the rehabilitative effects of reforestation in this part of Thailand.La actividad de la deshidrogenasa del suelo es un buen indicador de la actividad microbiana en el suelo en general, y que puede servir como un buen indicador del estado del suelo. Sin embargo, los cambios estacionales en el contenido de humedad del suelo pueden tener un efecto sobre la actividad de la deshidrogenasa del suelo, lo que hace difícil una evaluación precisa del estado del suelo. En este estudio, hemos tratado de determinar la importancia de la actividad deshidrogenasa del suelo para evaluar el estado de los suelos, y hemos tratado de encontrar una manera de dar cuenta de la influencia del contenido de humedad del suelo en la actividad deshidrogenasa del suelo. Los suelos fueron muestreados en el bosque seco siempre verde (vegetación original), suelo desnudo (muy degradado) y parcelas de plantación de Acacia establecidos en el suelo desnudo, en 1986 y 1987 en Sakaerat, Tailandia. Suelo características físico-químicas y la actividad deshidrogenasa en el suelo de plantación Acacia tenían pocas diferencias con los del suelo de los bosques de hoja perenne. Actividad de la deshidrogenasa del suelo varió significativamente entre el suelo desnudo y los bosques, independientemente de la temporada (húmedo o seco), mientras que la estación no produjo una variación significativa en la actividad de la deshidrogenasa del suelo, tal como se determina por análisis de medidas repetidas de la varianza (p = 0,077). Los datos físico-químicos siempre que el primer componente principal como una buena medida de la fertilidad del suelo. Los valores de actividad de la deshidrogenasa del suelo correlacionado significativamente con las puntuaciones de las muestras de suelo de la primera componente principal (R = 0,787, p <0,001). Se encontró que la actividad deshidrogenasa del suelo es un indicador útil del grado de degradación del suelo y los efectos de rehabilitación de reforestación en esta parte de Tailandia