EVOLUTION, Issue 9 2010
Parris T. Humphrey
Vector-borne microbes necessarily co-occur with their hosts and vectors, but the degree to which they share common evolutionary or biogeographic histories remains unexplored. We examine the congruity of the evolutionary and biogeographic histories of the bacterium and vector of the Lyme disease system, the most prevalent vector-borne disease in North America. In the eastern and midwestern US, Ixodes scapularis ticks are the primary vectors of Borrelia burgdorferi, the bacterium that causes Lyme disease. Our phylogeographic and demographic analyses of the 16S mitochondrial rDNA suggest that northern I. scapularis populations originated from very few migrants from the southeastern US that expanded rapidly in the Northeast and subsequently in the Midwest after the recession of the Pleistocene ice sheets. Despite this historical gene flow, current tick migration is restricted even between proximal sites within regions. In contrast, B. burgdorferi suffers no barriers to gene flow within the northeastern and midwestern regions but shows clear interregional migration barriers. Despite the intimate association of B. burgdorferi and I. scapularis, the population structure, evolutionary history, and historical biogeography of the pathogen are all contrary to its arthropod vector. In the case of Lyme disease, movements of infected vertebrate hosts may play a larger role in the contemporary expansion and homogenization of the pathogen than the movement of tick vectors whose populations continue to bear the historical signature of climate-induced range shifts. [source]

DS/CDMA throughput of a multi-hop sensor network in a Rayleigh fading underwater acoustic channel

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 8 2007
Choong Hock Mar
Abstract Asynchronous half-duplex Direct-Sequence Code-Division Multiple-Access (DS/CDMA) is a suitable candidate for the MAC protocol design of underwater acoustic (UWA) sensor networks owing to its many attractive features. Our ad-hoc multi-hop network is infrastructureless in that it is without centralized base stations or power control. Hence, we develop an asynchronous distributed half-duplex control protocol to regulate between the transmitting and receiving phases of transmissions. Furthermore, multi-hop communications are very sensitive to the time variability of the received signal strength in the fading channel and the ambient noise dominated by snapping shrimp in harsh underwater environments, because a broken link in the multi-hop path is enough to disrupt communications and initiate new route searches. In our configuration, we use the Ad hoc On-demand Distance Vector (AODV) routing protocol optimized for UWA networks. Empirical studies show that we can model the channel as a slow-varying frequency non-selective Rayleigh fading channel. We theoretically analyze the throughput of our configuration by considering three salient features: the ability of the receiver to demodulate the data, the effect of our control protocol and the effect of disconnections on the generation of routing packets. The throughput under various operating conditions is then examined. It is observed that at optimal node separation, the throughput is improved by a factor of 10. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Immune response to leishmania: paradox rather than paradigm

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2007
Parul Tripathi
Abstract The leishmaniases are a group of diseases caused by protozoan parasites of the genus Leishmania. Various Leishmania species can cause human infection, producing a spectrum of clinical manifestations. It is estimated that 350 million people are at risk, with a global yearly incidence of 1,1.5 million for cutaneous and 500 000 for visceral leishmaniasis (VL). VL is a major cause of morbidity and mortality in East Africa and the Indian subcontinent. Coinfection with HIV enhances the risk of the disease. The only control measure currently available in India is case detection and treatment with antimonial drugs, which are expensive, not always available and cannot be self-administered. Newer drugs like oral miltefosine have not become widely available. Vector and reservoir control is difficult due to the elusive nature of the vector and the diversity of the animal reservoir. A detailed knowledge of immune response to the parasite would help in designing prophylactic and therapeutic strategies against this infection. [source]

Over expression of a Cytochrome P450 (CYP6P9) in a Major African Malaria Vector, Anopheles Funestus, Resistant to Pyrethroids

INSECT MOLECULAR BIOLOGY, Issue 1 2008
D. A. Amenya
Abstract Anopheles funestus Giles is one of the major African malaria vectors. It has previously been implicated in a major outbreak of malaria in KwaZulu/Natal, South Africa, during the period 1996 to 2000. The re-emergence of this vector was associated with monooxygenase-based resistance to pyrethroid insecticides. We have identified a gene from the monooxygenase CYP6 family, CYP6P9, which is over expressed in a pyrethroid resistant strain originating from Mozambique. Quantitative Real-Time PCR shows that this gene is highly over expressed in the egg and adult stages of the resistant strain relative to the susceptible strain but the larval stages showed almost no difference in expression between strains. This gene is genetically linked to a major locus associated with pyrethroid resistance in this A. funestus population. [source]

Non-surgical periodontal treatment with a new ultrasonic device (VectorÔ-ultrasonic system) or hand instruments

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2004
A prospective, controlled clinical study
Abstract Objectives: The aim of this prospective, randomized, controlled clinical study was to compare the effectiveness of a newly developed ultrasonic device to that of scaling and root planing for non-surgical periodontal treatment. Material and Methods: Thirty-eight patients with moderate to advanced chronic periodontal disease were treated according to an "one-stage procedure" with either a newly developed ultrasonic device (VUS) (VectorÔ-ultrasonic system) or scaling and root planing (SRP) using hand instruments. Clinical assessments by plaque index (PlI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL) were made prior to and at 6 months after treatment. Differences in clinical parameters were analyzed using the Wilcoxon signed ranks test and Mann and Whitney U -test. Results: No differences in any of the investigated parameters were observed at baseline between the two groups. The mean value of BOP decreased in the VUS group from 32% at baseline to 20% after 6 months (p<0.001) and in the SRP group from 30% at baseline to 18% after 6 months (p<0.001). The results have shown that at moderately deep sites (initial PD 4,5 mm) mean CAL changed in the test group from 4.6±1.2 to 4.2±1.6 mm (p< 0.001) and in the control group from 4.8±1.3 to 4.4±1.5 mm (p<0.001). At deep sites (inital PD>6 mm) mean CAL changed in the test group from 8.5±1.9 to 7.9±2.4 mm (p<0.001) and in the control group from 7.9±1.6 to 7.2±2.2 mm (p<0.001). No statistically significant differences in any of the investigated parameters were found between the two groups. Conclusion: Non-surgical periodontal therapy with the tested ultrasonic device may lead to clinical improvements comparable to those obtained with conventional hand instruments. [source]

Structural Properties of Inertia Matrix and Gravity Vector of Dynamics of Rigid Manipulators

JOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 11 2002
ba Ignacy
In this paper, with the use of Euler-Lagrange formalism, it has been proven which joint variables can influence entries of the inertia matrix and the gravity vector of dynamics of a manipulator relative to the kinematic structure of the manipulator. Some formulas, alternative to well-known ones, are presented that allow us to compute the inertia matrix and the gravity vector without using a trace operator. These formulas are computationally inexpensive and provide an inspiration for interesting interpretations. Complexity indices are defined that are able to evaluate the complexity of dynamics of manipulators based on their kinematics. A key role of the accumulated pseudoinertia matrix of the manipulator has been shown. © 2002 Wiley Periodicals, Inc. [source]

Molecular Characterization and Potential Insect Vector of a Phytoplasma Associated with Garden Beet Witches' Broom in Yazd, Iran

JOURNAL OF PHYTOPATHOLOGY, Issue 4 2007
A. Mirzaie
Abstract In 2002, garden beet witches' broom (GBWB) phytoplasma was detected for the first time in garden beet plants (Beta vulgaris L. ssp. esculenta) in Yazd, Iran. Nested polymerase chain reaction (PCR) and restriction fragment length polymorphic (RFLP) analysis of PCR-amplified phytoplasma 16S rDNA were employed for the detection and identification of the phytoplasma associated with garden beet. A phytoplasma belonging to subgroup 16SrII-E, in the peanut witches' broom group (16SrII), was detected in infected plants. Asymptomatic plant samples and the negative control yielded no amplification. The result of analysis of the nucleotide sequence of a 1428 bp fragment of 16S rDNA gene from GBWB phytoplasma (GenBank accession number DQ302722) was basically consistent with the classification based on RFLP analysis, in which GBWB phytoplasma clustered with phytoplasmas of the 16SrII-E subgroup. A search for a natural phytoplasma vector was conducted in Yazd in 2004, in an area where garden beet crops had been affected since 2002. The associated phytoplasma was detected in one leafhopper species, Orosius albicinctus, commonly present in this region. The leafhopper O. albicinctus was used in transmission tests to determine its vector status for the phytoplasma associated with GBWB. Two of eight plants that had been fed on by O. albicinctus, showed mild symptoms of GBWB including stunting and reddening of midveins. A phytoplasma was detected in the two symptomatic test plants by PCR using universal primers and it was identified by RFLP as the GBWB phytoplasma. This finding suggests O. albicinctus is a vector of the GBWB phytoplasma. [source]

Use of the Rotation Vector in Brownian Dynamics Simulation of Transient Electro-Optical Properties

MACROMOLECULAR THEORY AND SIMULATIONS, Issue 1 2009
Tom Richard Evensen
Abstract We have recently developed a new singularity-free algorithm for Brownian dynamics simulation of free rotational diffusion. The algorithm is rigorously derived from kinetic theory and makes use of the Cartesian components of the rotation vector as the generalized coordinates describing angular orientation. Here, we report on the application of this new algorithm in Brownian dynamics simulations of transient electro-optical properties. This work serves two main purposes. Firstly, it demonstrates the integrity of the new algorithm for BD-simulations of the most common transient electro-optic experiments. Secondly, it provides new insight into the performance of the new algorithm compared to algorithms that make use of the Euler angles. We study the transient electrically induced birefringence in dilute solutions of rigid particles with anisotropic polarization tensor in response to external electric field pulses. The use of both one single electric pulse and two electric pulses with opposite polarity are being analyzed. We document that the new singularity-free algorithm performs flawlessly. We find that, for these types of systems, the new singularity-free algorithm, in general, outperforms similar algorithms based on the Euler angles. In a wider perspective, the most important aspect of this work is that it serves as an important reference for future development of efficient BD-algorithms for studies of more complex systems. These systems include polymers consisting of rigid segments with single-segment translational,rotational coupling, segment,segment fluid-dynamic interactions and holonomic constraints. [source]

Brownian Dynamics Simulations of Rotational Diffusion Using the Cartesian Components of the Rotation Vector as Generalized Coordinates

MACROMOLECULAR THEORY AND SIMULATIONS, Issue 7-8 2008
Tom Richard Evensen
Abstract Here, we report on the first Brownian dynamics (BD) simulations of rotational diffusion using the Cartesian components of the rotation vector as the generalized coordinates. The model system employed in this study consists of freely rotating and non-interacting rigid particles with arbitrary surface topography. The numerical BD algorithm contains no singularities and yields numerical results that are in full agreement with known theoretical results. Because of the absence of singularities, this new algorithm is several orders of magnitude more efficient than a simple BD algorithm employing the Euler angles as the generalized coordinates. The general theory for using generalized coordinates in studies of more complex systems involving both translation, rotation, and fluid dynamic interactions is well known. Consequently, the benefits reported here can readily be extended to such systems. Important examples are segmented polymer chains, with and without holonomic constraints, and liquid crystals. [source]

Vector valued Fourier analysis on unimodular groups

MATHEMATISCHE NACHRICHTEN, Issue 8 2006
Hun Hee Lee
Abstract The notion of Fourier type and cotype of linear maps between operator spaces with respect to certain unimodular (possibly nonabelian and noncompact) group is defined here. We develop analogous theory compared to Fourier types with respect to locally compact abelian groups of operators between Banach spaces. We consider the Heisenberg group as an example of nonabelian and noncompact groups and prove that Fourier type and cotype with respect to the Heisenberg group implies Fourier type with respect to classical abelian groups. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Southeast Asian Slavery and Slave -Gathering Warfare as a Vector for Cultural Transmission: The Case of Burma and Thailand

THE HISTORIAN, Issue 3 2009
Bryce Beemer
First page of article [source]

Delivery of an Adenoviral Vector to the Crushed Recurrent Laryngeal Nerve,

THE LARYNGOSCOPE, Issue 6 2003
Adam Rubin MD
Abstract Objectives Objectives were to create a model of recurrent laryngeal nerve injury for testing the efficacy of potential therapeutic viral gene therapy vectors and to demonstrate that remote injection of a viral vector does not cause significant additional neuronal injury. Study Design Animal model. Methods Rats were randomly assigned to three groups of 10 animals each. In group I, the recurrent laryngeal nerve was crushed. In group II, the nerve was crushed and then injected with an adenoviral vector containing no transgene. In group III, the nerve was identified but was not crushed. Rats were killed at 1 week, and their larynges and brainstems were cryosectioned in 15-,m sections. Laryngeal cryosections were processed for acetylcholine histochemical analysis (motor endplates) followed by neurofilament immunoperoxidase (nerve fibers). Percentage of nerve,endplate contact was determined and compared between groups. Fluorescent in situ hybridization was performed on brainstem sections from rats in group II to confirm the presence of virus. Results No significant difference in percentage of nerve,endplate contact exists between the two crushed-nerve groups (groups I and II) (P = .88). The difference between both crushed-nerve groups and the group with noncrushed nerves (group III) was highly significant (P <.0001). The presence of virus was confirmed in group II rats. Conclusions Crush provides a significant measurable injury to the recurrent laryngeal nerve and may be used as a model to explore therapeutic interventions for nerve injury. The remote injection of viral vector did not cause significant additional neuronal injury. Remote delivery of viral vectors to the central nervous system holds promise in the treatment of recurrent laryngeal nerve injury and central nervous system diseases. [source]

Cationic Liposome Conjugation to Recombinant Adenoviral Vector Reduces Viral Antigenicity

CANCER SCIENCE, Issue 4 2000
Atsushi Natsume
Adenoviral (Ad) vectors are commonly used in gene therapy trials because of their efficiency in gene transfer. However, their use is limited by immune responses that reduce transgene expression and decrease the efficacy of repeated vector administration. In this study, we demonstrated that conjugation of Ad vector with our novel cationic liposomes could reduce viral antigenicity in vivo. Mice subcutaneously injected with liposome-conjugated Ad vector showed a 6.5-fold reduction of anti-Ad antibodies with neutralizing activity, compared to those with unconjugated Ad vector. Interestingly, we also found that the conjugated vector is less susceptible to inactivation by neutralizing antibodies in vitro and in vivo. Our results suggest that liposome conjugation reduces viral antigenicity, shields vectors from neutralizing antibody, and may allow repeated Ad vector administration. [source]

Larvicidal Effects of Fungal Meroterpenoids in the Control of Aedes aegypti L., the Main Vector of Dengue and Yellow Fever

CHEMISTRY & BIODIVERSITY, Issue 2 2008
Regina Geris
Abstract The mosquito Aedes aegypti is an increasing problem of public health, being the vector responsible for dengue and Yellow Fever in tropical and subtropical regions. The aim of this work was to determine the potential larvicidal activity of a series of meroterpenoids, compounds 1,7, previously obtained fungal secondary metabolites from Penicillium sp., against the third-instar larvae of A. aegypti. The lethal concentrations (LC50 and LC90) of 1,7 were evaluated 24,h after exposure. Dehydroaustin (4) was the most active meroterpenoid in the series, with an LC50 value of 2.9,ppm, making it an attractive natural insecticide. [source]

On Floating-Point Normal Vectors

COMPUTER GRAPHICS FORUM, Issue 4 2010
Quirin Meyer
Abstract In this paper we analyze normal vector representations. We derive the error of the most widely used representation, namely 3D floating-point normal vectors. Based on this analysis, we show that, in theory, the discretization error inherent to single precision floating-point normals can be achieved by 250.2 uniformly distributed normals, addressable by 51 bits. We review common sphere parameterizations and show that octahedron normal vectors perform best: they are fast and stable to compute, have a controllable error, and require only 1 bit more than the theoretical optimal discretization with the same error. [source]

An Adaptive Method for Indirect Illumination Using Light Vectors

COMPUTER GRAPHICS FORUM, Issue 3 2001
Xavier Serpaggi
In computer graphics, several phenomema need to be taken into account when it comes to the field of photo-realism. One of the most relevant is obviously the notion of global, and more precisely indirect, illumination. In "classical" ray-tracing if you are not under the light, then you are in a shadow. A great amount of work has been carried out which proposes ray-tracing based solutions to take into account the fact that "there is a certain amount of light in shadows". All of these methods carry the same weaknesses: high computation time and a lot of parameters you need to manage to get something out of the method. This paper proposes a generic computation method of indirect illumination based on Monte Carlo sampling and on the sequential analysis theory, which is faster and more automatic than classical methods. [source]

Structural Health Monitoring via Measured Ritz Vectors Utilizing Artificial Neural Networks

COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 4 2006
Heung-Fai Lam
Unlike most other pattern recognition methods, an artificial neural network (ANN) technique is employed as a tool for systematically identifying the damage pattern corresponding to an observed feature. An important aspect of using an ANN is its design but this is usually skipped in the literature on ANN-based SHM. The design of an ANN has significant effects on both the training and performance of the ANN. As the multi-layer perceptron ANN model is adopted in this work, ANN design refers to the selection of the number of hidden layers and the number of neurons in each hidden layer. A design method based on a Bayesian probabilistic approach for model selection is proposed. The combination of the pattern recognition method and the Bayesian ANN design method forms a practical SHM methodology. A truss model is employed to demonstrate the proposed methodology. [source]

Vectors and Beyond: Geometric Algebra and its Philosophical Significance

DIALECTICA, Issue 4 2009
Peter Simons
First page of article [source]

A Tale of Two Vectors

DIALECTICA, Issue 4 2009
Marc Lange
Why (according to classical physics) do forces compose according to the parallelogram of forces? This question has been controversial; it is one episode in a longstanding, fundamental dispute regarding which facts are not to be explained dynamically. If the parallelogram law is explained statically, then the laws of statics are separate from and (in an important sense) "transcend" the laws of dynamics. Alternatively, if the parallelogram law is explained dynamically, then statical laws become mere corollaries to the dynamical laws. I shall attempt to trace the history of this controversy in order to identify what it would be for one or the other of these rival views to be correct. I shall argue that various familiar accounts of natural law (Lewis's Best System Account, laws as contingent relations among universals, and scientific essentialism) not only make it difficult to see what the point of this dispute could have been, but also improperly foreclose some serious scientific options. I will sketch an alternative account of laws (including what their necessity amounts to and what it would be for certain laws to "transcend" others) that helps us to understand what this dispute was all about. [source]

Dynamics of a Transgene Expression in Acute Rat Brain Slices Transfected with Adenoviral Vectors

EXPERIMENTAL PHYSIOLOGY, Issue 4 2003
C. E. L. Stokes
We present a quantitative account of the expression dynamics of a transgene (enhanced green fluorescent protein, EGFP) in acute brain slices transfected with an adenoviral vector (AVV) under control of the human cytomegalovirus (HCMV) promoter. Micromolar concentrations of EGFP could be detected in brainstem and hippocampal slices as early as 7 h after in vitro transfection with a viral titre of 4.4 × 109 plaque-forming units (pfu) ml,1. Although initially EGFP appeared mainly in glia, it could be detected in neurones with longer incubation times of 10-12 h. However, fluorescence was never detected within some populations of neurones, such as hippocampal pyramidal cells, or within the hypoglossal motor nucleus. The density of cells expressing EGFP peaked at 10 h and then decreased, possibly suggesting that high concentrations of EGFP are toxic. The age of the animal significantly affected the speed of EGFP accumulation: after 10 h of incubation in 30-day-old rats only 4.88 ± 0.51 cells/10 000 ,m2 were fluorescent compared to 7.28 ± 0.39 cells/10 000 ,m2 in 12-day-old rats (P < 0.05). HCMV promoter-driven transgene expression depended on the activity of protein kinase A, and was depressed with a cAMP/protein kinase A antagonist (20 ,M Rp-cAMPS; P < 0.0005). This indicates that expression of HCMV-driven constructs is likely to be skewed towards cellular populations where cAMP-dependent signalling pathways are active. We conclude that acute transfection of brain slices with AVVs within hours causes EGFP expression in micromolar concentrations and that such transfected cells may remain viable for use in physiological experiments. [source]

Novel Magnetic Hydroxyapatite Nanoparticles as Non-Viral Vectors for the Glial Cell Line-Derived Neurotrophic Factor Gene

ADVANCED FUNCTIONAL MATERIALS, Issue 1 2010
Hsi-Chin Wu
Abstract Nanoparticles (NPs) of synthetic hydroxyapatite (Hap) and natural bone mineral (NBM) are rendered magnetic by treatment with iron ions using a wet-chemical process. The magnetic NPs (mNPs), which are about 300,nm in diameter, display superparamagnetic properties in a superconducting quantum interference device, with a saturation magnetization of about 30,emu g,1. X-ray diffraction and transmission electron microscopy reveal that the magnetic properties of the NPs are the result of the hetero-epitaxial growth of magnetite on the Hap and NBM crystallites. The mNPs display a high binding affinity for plasmid DNA in contrast to magnetite NPs which do not bind the plasmid well. The mHap and mNBM NPs result in substantial increases in the transfection of rat marrow-derived mesenchymal stem cells with the gene for glial cell line-derived neurotrophic factor (GDNF), with magnetofection compared to transfection in the absence of a magnet. The amount of GDNF recovered in the medium approaches therapeutic levels despite the small amount of plasmid delivered by the NPs. [source]

A Class of Cationic Triblock Amphiphilic Oligopeptides as Efficient Gene-Delivery Vectors,

ADVANCED MATERIALS, Issue 1 2009
Wei Yang Seow
A new class of triblock oligopeptides, containing arginine for DNA binding, histidine for intracellular buffering, and hydrophobic residues for enhanced cellular uptake has been designed, with each block offering unique functionalities essential for efficient gene delivery. Together, these materials demonstrate strong DNA binding ability, low cytotoxicity, and significantly higher in vivo gene-transfection efficiency compared to the PEI standard. [source]

Climate change and vector-borne viral diseases potentially transmitted by transfusion

ISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue 1 2009
M. Rios
Vector-borne diseases occur when infectious agents (virus, protozoa, bacteria, or helminthes) are transmitted to their hosts by a carrier organism. Climate conditions and their changes play a role in the inter-relationship between these agents, the vectors and the host (or hosts). This review is focused on arthropod-borne viruses (Arboviruses). These viruses are transmitted between susceptible vertebrate hosts by blood-feeding arthropods, and may be transmitted by blood transfusion, tissue and organ transplantation and breast feeding. The lifecycle of arboviruses is influenced by changes in temperature, rainfall, humidity, length of day, average daily solar radiation and/or storm patterns, as well as changes in the frequency of rare events such as floods or droughts. A plethora of studies have suggested that climate changes, particularly temperature changes, are likely to be induced by increase in the amount of greenhouse gases, such as methane, carbon dioxide (CO2) and chlorofluorocarbons, which deplete ozone in the atmosphere leading to an increase in ultraviolet radiation. Current models predict that ambient temperature will increase by 3,5°C on average with a doubling in CO2 concentration in the atmosphere. Vectors, pathogens and hosts each survive and reproduce within a range of optimal climatic conditions: temperature and precipitation being most important, while sea level elevation, wind and daylight duration are also important. Climate changes may affect important determinants of vector-borne disease transmission including (i) vector survival and reproduction, (ii) the vector's biting rate, and (iii) the pathogen's incubation rate within the vector organism. Droughts can increase the dissemination of arboviral diseases in urban areas by allowing a boost in the population of mosquitoes in foul water concentrated in catch basins where they breed. Furthermore, eggs can be vertically infected with arboviruses and heat waves speed up the maturation of the mosquitoes and of the viruses within mosquitoes. Droughts also cause a decline in mosquito predators like frogs, darning needles and dragonflies. In addition, birds congregate around shrinking water sites, enhancing circulation of viruses among birds and mosquitoes. In conclusion, the seriousness of some of the recent epidemics like West Nile virus and Dengue appear to has been influenced by climate change. As most of the arboviral infections are asymptomatic in humans, there is an increased opportunity for blood, organ and tissue donations by infected individuals during the viraemic period, resulting in an increased risk of transmission of arboviruses. [source]

Construction and Application of Efficient Ac-Ds Transposon Tagging Vectors in Rice

JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 11 2009
Shaohong Qu
Abstract Transposons are effective mutagens alternative to T-DNA for the generation of insertional mutants in many plant species including those whose transformation is inefficient. The current strategies of transposon tagging are usually slow and labor-intensive and yield low frequency of tagged lines. We have constructed a series of transposon tagging vectors based on three approaches: (i) AcTPase controlled by glucocorticoid binding domain/VP16 acidic activation domain/Gal4 DNA-binding domain (GVG) chemical-inducible expression system; (ii) deletion of AcTPase via Cre- lox site-specific recombination that was initially triggered by Ds excision; and (iii) suppression of early transposition events in transformed rice callus through a dual-functional hygromycin resistance gene in a novel Ds element (HPT-Ds). We tested these vectors in transgenic rice and characterized the transposition events. Our results showed that these vectors are useful resources for functional genomics of rice and other crop plants. The vectors are freely available for the community. [source]

173 Challenges in Preventing, Eradicating, and Controlling Invasive Seaweeds: The Southern California Invasion of Caulerpa Taxifolia as a Model

JOURNAL OF PHYCOLOGY, Issue 2003
S. L. Williams
Invasions of marine communities by seaweeds are increasing globally. Vectors for introductions are primarily aquaculture and the aquarium trade. Attention to these vectors has been minimal, and few, if any, regulations exist to prevent seaweed introductions. Challenges in preventing, eradicating, and controlling invasive seaweeds will be discussed using the invasion of Caulerpa taxifolia in southern California as a model. [source]

Optimization of RT,PCR for the Detection of Bean leaf roll virus in Plant Hosts and Insect Vectors

JOURNAL OF PHYTOPATHOLOGY, Issue 2 2005
V. Ortiz
Abstract The detection of luteoviruses by reverse transcription polymerase chain reaction (RT,PCR) depends on the adequate quality and quantity of extracted viral nucleic acids. We have optimized the detection of Bean leaf roll virus (BLRV) using selective precipitation by LiCl of viral RNA from a small quantity of infected plant tissues and insect vectors. The optimal template for PCR was 15 ,l of RT reaction mixture. BLRV was detected in different plant hosts and aphid vectors and Aphis fabae, previously considered to be a non-vector of BLRV, was found to acquire the virus from infected plants. [source]

Disease Vectors and International Transport

JOURNAL OF TRAVEL MEDICINE, Issue 4 2003
Norman Gratz
No abstract is available for this article. [source]

Appendix B: Correlations Among Vectors of Factor Scores for Seven Random Samples of 5-Year-olds

MONOGRAPHS OF THE SOCIETY FOR RESEARCH IN CHILD DEVELOPMENT, Issue 1 2003
Daniel Hart
No abstract is available for this article. [source]

Conferring cadmium resistance to mature tobacco plants through metal-adsorbing particles of tomato mosaic virus vector

PLANT BIOTECHNOLOGY JOURNAL, Issue 3 2006
Yoshinori Shingu
Summary Tomato mosaic virus vectors were designed that produced, by a translational readthrough, a fusion protein consisting of coat protein and metal-binding peptide, as a result of which particles were expected to present the metal-binding peptides on their surface. When inoculated in plants, they were expected to replicate and form a metal-adsorbing artificial sink in the cytoplasm, so as to reduce metal toxicity. Vectors were constructed harbouring sequences encoding various lengths of polyhistidine as a metal-binding peptide. One of the vectors, TLRT6His, which contains a 6 × histidine sequence, moved systemically in tobacco plants, and its particles were shown to retain cadmium ions by an in vitro assay. When a toxic amount of cadmium was applied, the toxic effect was much reduced in TLRT6His-inoculated tobacco plants, probably as a result of cadmium adsorption by TLRT6His particles in the cytosol. This shows the possible use of an artificial sink for metal tolerance and the advantage of employing a plant viral vector for phytoremediation. [source]

Lentiviral vectors for treating and modeling human CNS disorders

THE JOURNAL OF GENE MEDICINE, Issue 9 2004
Mimoun Azzouz
Abstract Vectors based on lentiviruses efficiently deliver genes into many different types of primary neurons from a broad range of species including man and the resulting gene expression is long term. These vectors are opening up new approaches for the treatment of neurological diseases such as Parkinson's disease (PD), Huntington's disease (HD), and motor neuron diseases (MNDs). Numerous animal studies have now been undertaken with these vectors and correction of disease models has been obtained. Lentiviral vectors also provide a new strategy for in vivo modeling of human diseases; for example, the lentiviral-mediated overexpression of mutated human ,-synuclein or huntingtin genes in basal ganglia induces neuronal pathology in animals resembling PD and HD in man. These vectors have been refined to a very high level and can be produced safely for the clinic. This review will describe the general features of lentiviral vectors with particular emphasis on vectors derived from the non-primate lentivirus, equine infectious anemia virus (EIAV). It will then describe some key examples of genetic correction and generation of genetic animal models of neurological diseases. The prospects for clinical application of lentiviral vectors for the treatment of PD and MNDs will also be outlined. Copyright © 2004 John Wiley & Sons, Ltd. [source]