Micropropagation of \u3cem\u3ePopulus trichocarpa\u3c/em\u3e ‘Nisqually-1’ and genetic engineering \u3cem\u3ePopulus\u3c/em\u3e with CaMV35s-AtWBC19, CaMV35s-AgNt84 and -60CaMV35s-GUS genes

In Chapter one, we described development of a highly efficient micropropagation protocol from greenhouse-grown shoot tips of ‘Nisqually-1’. The optimal micropropagation protocol involves growing in vitro shoots in plant growth regulator free Murashige and Skoog (MS) basal medium supplemented with 3% sucrose, 0.3% Gelrite and 5–10 g∙L-1 of activated charcoal. Plants grown on this medium were significantly longer, and contained significantly higher concentrations of chlorophyll. In chapter II, we transferred the plant-originated Arabidopsis Atwbc19 gene encoding an ATP binding cassette transporter which confers resistance to aminoglycoside antibiotics. Transgenic plants were confirmed by polymerase chain reaction (PCR) with Atwbc19- specific primer pair. The expression was confirmed by the reverse transcription PCR. Transgenic plants were tested for aminoglycoside antibiotic resistance. The level of resistance conferred by CaMV35S-Atwbc19 is similar to that conferred by nptII gene. Therefore, plant-ubiquitous Atwbc19 gene can serve an alternative gene as a plant transformation selective marker gene to current bacterial antibiotic-resistance marker genes and alleviate the potential risk for horizontal transfer of bacterial resistance genes in transgenic plants. In Chapter III, we transformed a Populus clone with the enhancer trapping vector, pD991. All 250 transgenic lines were screened and 71 of them (28%) showed positive staining. They showed various patterns of the reporter gene expression, including expression in one tissue and simultaneously in two more tissues. These results confirmed the previously reports that enhancer trap lines can be produced in Populus, and these enhancer trap lines can be used for future gene cloning and studying gene expression in Populus. In Chapter IV, we transformed with the heavy metal binding protein agNt84 gene. Seven putative transgenic lines were confirmed by PCR with the agNt84 specific primers and two lines shoot tips of transgenic- and non-transgenic plants grown on cadmium (Cd) -containing rooting media to evaluate of Cd resistance. 33% of shoot tips from one line and 44% of those from another transgenic line survived on medium containing 250 mM Cd, respectively, but only 22% of the non-transgenic shoot tips survived on rooting medium with 150 mM Cd at week 8. Also, the Cd analysis by ICP-OES indicated that the transgenic plants which were grown on 100 mM Cd medium accumulated about 45% more Cd in the tissue than non-transgenic plants

Downregulation of a CYP74 Rubber Particle Protein Increases Natural Rubber Production in \u3ci\u3eParthenium argentatum\u3c/i\u3e

We report functional genomics studies of a CYP74 rubber particle protein from Parthenium argentatum, commonly called guayule. Previously identified as an allene oxide synthase (AOS), this CYP74 constitutes the most abundant protein found in guayule rubber particles. Transgenic guayule lines with AOS gene expression down-regulated by RNAi (AOSi) exhibited strong phenotypes that included agricultural traits conducive to enhancing rubber yield. AOSi lines had higher leaf and stem biomass, thicker stembark tissues, increased stem branching and improved net photosynthetic rate. Importantly, the rubber content was significantly increased in AOSi lines compared to the wild-type (WT), vector control and AOS overexpressing (AOSoe) lines, when grown in controlled environments both in tissue-culture media and in greenhouse/growth chambers. Rubber particles from AOSi plants consistently had less AOS particle-associated protein, and lower activity (for conversion of 13-HPOT to allene oxide). Yet plants with downregulated AOS showed higher rubber transferase enzyme activity. The increase in biomass in AOSi lines was associated with not only increases in the rate of photosynthesis and non-photochemical quenching (NPQ), in the cold, but also in the content of the phytohormone SA, along with a decrease in JA, GAs, and ABA. The increase in biosynthetic activity and rubber content could further result from the negative regulation of AOS expression by high levels of salicylic acid in AOSi lines and when introduced exogenously. It is apparent that AOS in guayule plays a pivotal role in rubber production and plant growth

Performance of Volcano-Like Laser Textured Cutting Tools: An Experimental and Simulative Investigation

In recent years, surface texturing in micro-scale has been attempted on the surface of cutting tools for multiple purposes, e.g., cutting force reduction, prolonging life-span, anti-adhesion, etc. With respect to machinability and performance, micro-groove texture (MGT) has dominated in this field compared to other textured patterns. In this study, a novel volcano-like texture (VLT) was fabricated on the rake face of cemented carbide inserts (WC-Co, YG6) by fiber laser. The following cutting experiment tested the flat, MGT and VLT tools in turning aluminum alloy 6061. The effects of coolant and cutting conditions were investigated. In addition, a validated FEM model was employed to explore the distribution of stress and temperature fields in the tool-chip interface. The initial forming process of adhesion layer on rake face was investigated as well. The results indicated that lower cutting force and less adhesion can be achieved by small scale VLT. This study not only introduced VLT on cutting tools but also revealed its comprehensive performance

Catalytic Asymmetric Formal Insertion of Aryldiazoalkanes into the C–H Bond of Aldehydes: Synthesis of Enantioenriched Acyclic α‑Tertiary Aryl Ketones

A novel, catalytic enantioselective route to synthesize a variety of α-tertiary aryl ketones via a boron Lewis acid promoted formal insertion of aryldiazoalkane into the C–H bond of both aromatic and aliphatic aldehydes is described. In the presence of chiral (<i>S</i>)-oxazaborolidinium ion catalyst <b>1</b>, the reaction proceeded in good yields (up to 94%) with excellent enantioselectivities (up to 99% ee)

The renal tubular damage marker urinary N-acetyl-\u3b2-d-glucosaminidase may be more closely associated with early detection of atherosclerosis than the glomerular damage marker albuminuria in patients with type 2 diabetes

Abstract Background To determine the association between urinary N -acetyl-\u3b2- d -glucosaminidase (NAG), a marker of renal tubulopathy, and carotid intima-media thickness (IMT) and plaques in patients with type 2 diabetes mellitus (T2D) and to compare the predictive value of NAG versus albuminuria, a marker of renal glomerulopathy. Methods A total of 343 participants were enrolled in this retrospective cross-sectional study. We recruited participants with T2D who were tested for blood glucose parameters, urinary NAG, and urinary albumin-to-creatinine ratio (ACR) and had been checked for carotid ultrasonography. Results We classified participants into a below-median urinary NAG group (Group I; n\ua0=\ua0172) or an above-median group (Group II; n\ua0=\ua0171). Mean, maximum, and mean of maximum carotid IMT and the proportion of patients with carotid plaques were significantly higher in Group II compared with Group I. In multiple linear regression analyses, high urinary NAG (Group II) was significantly associated with carotid IMT, independently of urinary ACR and other confounding factors. In terms of carotid plaques, both urinary NAG and ACR were significantly higher in participants with carotid plaques than in those without carotid plaques. After adjustment for confounding factors, both urinary NAG and ACR were significantly associated with the presence of carotid plaques. Conclusions Elevated urinary NAG, a marker of renal tubular damage, was related to increased carotid IMT and the presence of carotid plaques in patients with T2D. Urinary NAG may be a more sensitive biomarker than urinary albumin for early detection of atherosclerosis

Downregulation of a CYP74 Rubber Particle Protein Increases Natural Rubber Production in \u3ci\u3eParthenium argentatum\u3c/i\u3e

We report functional genomics studies of a CYP74 rubber particle protein from Parthenium argentatum, commonly called guayule. Previously identified as an allene oxide synthase (AOS), this CYP74 constitutes the most abundant protein found in guayule rubber particles. Transgenic guayule lines with AOS gene expression down-regulated by RNAi (AOSi) exhibited strong phenotypes that included agricultural traits conducive to enhancing rubber yield. AOSi lines had higher leaf and stem biomass, thicker stembark tissues, increased stem branching and improved net photosynthetic rate. Importantly, the rubber content was significantly increased in AOSi lines compared to the wild-type (WT), vector control and AOS overexpressing (AOSoe) lines, when grown in controlled environments both in tissue-culture media and in greenhouse/growth chambers. Rubber particles from AOSi plants consistently had less AOS particle-associated protein, and lower activity (for conversion of 13-HPOT to allene oxide). Yet plants with downregulated AOS showed higher rubber transferase enzyme activity. The increase in biomass in AOSi lines was associated with not only increases in the rate of photosynthesis and non-photochemical quenching (NPQ), in the cold, but also in the content of the phytohormone SA, along with a decrease in JA, GAs, and ABA. The increase in biosynthetic activity and rubber content could further result from the negative regulation of AOS expression by high levels of salicylic acid in AOSi lines and when introduced exogenously. It is apparent that AOS in guayule plays a pivotal role in rubber production and plant growth