203 research outputs found
Tobacco drought stress responses reveal new targets for Solanaceae crop improvement
No full textThis article proposes components of a core metabolic response to drought stress in plants and shows that some major responses to drought stress at the metabolome and transcriptome levels are family specific
A Two-Terminal IC Temperature Transducer
No full textAbstract–A monolithic IC temperature transducer with an operating temperature range of- 125°C to +200”C has been designed, fabricated, and tested. The two-terminal device, which is fabricated using laser trimmed thin-film-on-silicon technology, is a calibrated temperature-dependent current source with an average output impedence of 10 Ma over the 3.5-V to 30-V range of input voltage. Overall absolute ac-curacies of +0.5 ° C from –75°C to + 150”C have been achieved on a scale of 1 pA/K under optimum operating conditions. I
QTL Mapping of Ineffective Nodulation and Nitrogen Utilization-Related Traits in the IC-1 Mutant of Cowpea
No full textThe objectives of this study were to improve the characterization of the fix? cowpea mutant IC-1 and map QTL associated with the ineffective nodulation phenotype.Made available in DSpace on 2018-05-05T00:58:15Z (GMT). No. of bitstreams: 1
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Previous issue date: 2018-05-0
Genetic analysis for biological nitrogen fixation (BNF) in cowpea.
No full textThis work aimed to estimate the genetic parameters of biological nitrogen fixation (BNF) in cowpea to guide the development of efficient cultivars in N2 fixation. Inoculation was performed with a mix of three Bradyrhizobium strains. Two soil inoculations were performed with 1mL of the inoculum, at sowing and at five days after seedlings emergence. Plants were harvested and evaluated at 40 days after sowing. The means and variances of parents F1 and F2 and the BCs IC-1 (inefficient) × BRS Marataoã (efficient) (cross 1) and IC-1 × BRS Pujante (efficient) (cross 2) were analyzed. Segregation analyses for efficient and non-efficient plants indicate that BNF is controlled by two genes with dominant-recessive epistatic effect. Narrow-sense heritability estimates for crosses 1 and 2 were, respectively, 90% and 78% for shoot dry matter (SDM); 78% and 58%, for number of nodules/plant (NN); 86% and 58%, for nodule fresh matter (NFM); and 85% and 71%, for accumulated nitrogen (AN). Gene number estimates for SDM, NN, NFM, AN ranged from two to nine by the Mather and Jinks? method, and from one to two, by the Lande?s method, in both crosses. SDM x NFM and NFM x AN had significant and positive correlations, while NN showed significant negative correlation with AN and SDM. BNF efficiency in cowpea can be easily achieved using autogamou
Enhanced Tissue-Specific Expression of the Herbicide Resistance bar Gene in Transgenic Cotton (Gossypium hirsutum L cv. Coker 310FR) Using the Arabidopsis rbcS ats1A Promoter
No full textA highly regenerating cotton (Gossypium hirsutum L.) cultivar, Coker 310FR, was used to generate transgenic plants expressing the herbicide resistance gene, bar, encoding phosphinothricin acetyltransferase (PAT), under the transcriptional control of the ribulose-1, 5-bisphosphate carboxylase (Rubisco) small subunit (rbcS) ats1A gene promoter from Arabidopsis thaliana. Expression levels of the rbcS ats1A-bar transgenes were compared to bar transgenes under the control of the high level constitutive promoter from the Cauliflower Mosaic Virus 35S gene containing a dual enhancer region (2xE CaMV 35S). Significantly higher levels of bar mRNA, PAT protein and enzymatic activity, and enhanced levels of resistance to the herbicide Basta were observed in transgenic plants expressing bar under the rbcS ats1A promoter compared to the 2xE CaMV 35S promoter. Transgenic plants containing 2xE CaMV 35S-bar transgenes tolerated the maximum herbicide (Basta) application up to 200 mg PPT whereas rbcS ats1A-bar transgenic plants were capable of detoxifying Basta up to 400 mg l-1 PPT. These findings indicate that the rbcS ats1A promoter may be useful for higher expression of transgenes in developing tissues of cotton for improving it further through genetic engineering
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Structural domains in NADPH: Protochlorophyllide oxidoreductases involved in catalysis and substrate binding. Final report
No full textUntil recently little direct information was available about specific structural determinants within the light-dependent NADPH: protochlorophyllide oxidoreductases (PORs) required for substrate and cofactor binding, catalytic activity, and thylakoid membrane localization. Based on our previous DOE-funded studies, during the past year we brought to fruition a number of ongoing experiments, initiated several new avenues of investigations, and overall have made considerable progress towards establishing the basic structural parameters governing POR function. Our studies to date have defined residues and domains involved in substrate and cofactor binding and catalysis, and elaborated on the mechanism for membrane localization of POR in developing plastids. Our results and their significance, as well as our work in progress, are detailed
ÃÂNADPH: Protochlorophyllide Oxidoreductase-Structure, Catalytic Function, and Role in Prolamellar Body Formation and Morphogenesis
No full textThe biosynthesis of chlorophyll is a critical biochemical step in the development of photosynthetic vascular plants and green algae. From photosynthetic bacteria (cyanobacteria) to algae, non-vascular plants, gymnosperms and vascular plants, mechanisms have evolved for protochlorophyllide reduction a key step in chlorophyll synthesis. Protochlorophyllide reduction is carried out by both a light-dependent (POR) and light-independent (LIPOR) mechanisms. NADPH: protochlorophyllide oxidoreductase (EC 1.3.1.33, abbreviated POR) catalyzes the light-dependent reduction of protochlorophyllide (PChlide) to chlorophyllide (Chlide). In contrast, a light-independent protochlorophyllide reductase (LIPOR) involves three plastid gene products (chlL, chlN, and chlB) and several nuclear factors. Our work focused on characterization of both the POR and LIPOR catalyzed processes
Magnetically Triggered Nanocomposite Membranes: A Versatile Platform for Triggered Drug Release
No full textAuthor Manuscript 2012 March 9.Drug delivery devices based on nanocomposite membranes containing thermoresponsive nanogels and superparamagnetic nanoparticles have been demonstrated to provide reversible, on−off drug release upon application (and removal) of an oscillating magnetic field. We show that the dose of drug delivered across the membrane can be tuned by engineering the phase transition temperature of the nanogel, the loading density of nanogels in the membrane, and the membrane thickness, allowing for on-state delivery of model drugs over at least 2 orders of magnitude (0.1−10 μg/h). The zero-order kinetics of drug release across the membranes permit drug doses from a specific device to be tuned according to the duration of the magnetic field. Drugs over a broad range of molecular weights (500−40000 Da) can be delivered by the same membrane device. Membrane-to-membrane and cycle-to-cycle reproducibility is demonstrated, suggesting the general utility of these membranes for drug delivery.Ruth L. Kirschstein National Research Service AwardNational Institutes of Health (U.S.) (Award F32GM096546
Identification of a Papain-like Cysteine Protease Functioning as an Avirulence Factor in Striga–Cowpea Interactions
No full textWhile most cowpea cultivars are susceptible to parasitism by the root parasitic weed Striga gesnerioides (Willd.) Vatke, cultivar B301 is resistant to all Striga races except for SG4z. Resistance to Striga parasitism is manifested by the elicitation of a hypersensitive response (HR) at the site of parasite attachment on the host root followed by rapid death of the attached parasite. We isolated a papain-like cysteine protease (PLCP) designated SGCP1 that is highly expressed in the haustoria of S. gesnerioides race SG3 at the time of parasite attachment to the host root. SGCP1 contains an apoplast-targeting signal peptide, a Cathepsin pro-peptide inhibitory domain, a papain family cysteine protease domain, and a granulin domain. Full-length SGCP1 and a variant lacking the signal peptide (SGCP∆SP) were expressed in the roots of composite B301 plants. Expression of SGCP1 and SGCP∆SP resulted in activation of host innate immune responses exemplified by increased frequency of HR and decreased levels of parasite cotyledon expansion (CE), indicative of successful host parasitism, in transgenic compared to wild-type B301 roots parasitized by SG4z. These data indicate that SGCP1 functions as an avirulence factor capable of activating host innate immunity and furthers our understanding of how compatible and incompatible host–parasite interactions are controlled
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