29 research outputs found
Construction and Quality Analysis of Transgenic Rehmannia glutinosa Containing TMV and CMV Coat Protein
No full textPlant viruses, especially tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV) are serious threats to Rehmannia glutinosa which is a “top grade” herb in China. In the present study, TMV- and CMV-resistant Rehmannia glutinosa Libosch. plants were constructed by transforming the protein (CP) genes of TMV and CMV into Rehmannia glutinosa via a modified procedure of Agrobacterium tumefaciens-mediated transformation. Integration and expression of TMV CP and CMV CP transgenes in 2 lines, LBA-1 and LBA-2, were confirmed by PCR, Southern blot and RT-PCR. Both LBA-1 and LBA-2 were resistant to infection of homologous TMV and CMV strains. The quality of transgenic Rehmanniae Radix was evaluated based on fingerprint analysis and components quantitative analysis comparing with control root tubes. These results showed that chemical composition of transgenic Rehmanniae Radix were similar to non-transgenic ones, which demonstrated that the medical quality and biosafety of transgenic Rehmanniae Radix were equivalent to non-transgenic material when consumed as traditional Chinese medicinal (TCM)
Induction of systemic resistance against tobacco mosaic virus by Ningnanmycin in tobacco
No full textNingnanmycin (NNM) is an antiviral agent firstly isolated from Strepcomces noursei var.xichangensisn. Studies have shown that NNM promotes PAL POD and SOD activity and possesses antiviral activity against tobacco mosaic virus (TMV). In this study, our results demonstrated that NNM inhibited the polymerization process of TMV coat protein (TMV-CP) in vitro and promoted the systemic accumulation of pathogenesis-related proteins (PRs), which are the markers of systemic acquired resistance (SAR). An non-expressor, pathogenesis-related genes I (NPR1) that regulates SAR and induces systemic resistance (ISR), increased. In addition, the Jaz3 expression increase showed that NNM also induced ISR. Based on the results of this work and earlier reports, it is suggesting that NNM induces tobacco systemic resistance against TMV via activating multiple plant defense signaling pathways. (C) 2014 Elsevier Inc. All rights reserved
Author´s Correction: The multiplicity of infection of a plant virus varies during colonization of its eukaryotic host
No full text1 Pág.Volume 83, no. 15, p. 7487–7494, 2009. Page 7491: The multiplicity of infection (MOI) estimated for Tobacco mosaic virus (TMV), which appears as m in Table 3, has a calculation error. Estimates of m were obtained using a simple model that assumed that the probability of infection of each cell by each of two TMV genotypes in the inoculum was independent and binomially distributed according to their respective frequencies, p and q=1-p, in the inoculum, with mvirus genotypes, on average, infecting a cell; m was an estimate of the MOI.
The calculation error was that frequencies of cells infected by each TMV genotype, and of double-infected cells, were calculated over the total number of leaf cells (i.e., considering noninfected cells). The rationale for this calculation was that the number of available uninfected cells contacting infected ones decreases as infection progresses, which we tried to take into account. The correct calculation should have considered only infected cells. Thus, Table 3 should appear as shown below.Peer reviewe
Biocatalytically induced surface modification of the tobacco mosaic virus and the bacteriophage M13
No full textEngineered viruses are finding an increasing number of applications in basic, translational research and materials science. Genetic and chemical engineering of capsids represents a key point for tailoring the properties of viral particles, but the synthetic efforts and limits accompanying these processes still hinder their usability. Here, a single-step highly selective biocatalytic functionalization approach is described, providing a general platform for virus-acrylate hybrid particles. The tobacco mosaic virus (TMV) and the bacteriophage M13 have been successfully modified via laccase induced free radical formation on the tyrosine residues through single electron oxidation as the initiating step and the free radicals subsequently react with acrylate-based monomers. This new approach can be extended to other biomolecular assemblies with surface exposed tyrosine residues, when the introduction of new functionalities is desired.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.BT/Biocatalysi
Effect of Senescence on Lesion Formation and the Level of Induced Resistance in Samsun NN Plants Infected with TMV. I. Experiment with Changing Photoperiod
No full textInokulacija duhana samsuna NN virusom mozaika duhana izaziva hipersenzitivnu reakciju, tako da na listovima nastaju mnogobrojne lokalne nekrotične lezije. Poslije toga biljka postiže stanje otpornosti protiv superinfekcije s istim virusom. Ta specifična otpornost očituje se u redukciji veličine nekrotičnih lezija, koje se pojave na listovima poslije superinfekcije.
Stupanj specifične otpornosti ovisi o mnogim različitim faktorima, među ostalim i o starosti inficirane biljke ili čak pojedinih listova. Stariji su listovi obično otporniji. U ovoj studiji autor je pokazao kako je utjecao na prirodni proces starenja uzgajajući biljke pod nepovoljnim uvjetima kratkoga dana. Pokazalo se da su te biljke pod utjecajem kratke foto-periode dostizale poslije inokulacije virusom mozaika duhana mnogo veći stupanj inducirane otpornosti.
Broj lezija nije dobar indeks za stupanj inducirane otpornosti. Ovdje izneseni rezultati pokazuju da modalne vrijednosti čestoće distribucijskih krivulja dijametara lezija daju dobar indeks za stupanj inducirane otpornosti. One su bolji indeks nego aritmetičke sredine jer upozoravaju također i na dinamiku rasta lezija.Inoculation of Samsun NN tobacco leaves with TMV results in a hypersensitive reaction so that local necrotic lesions appear. Afterwards the whole plant reaches a status of resistance to superinfection with the same virus. This specific resistance manifests itself in the reduction of the size of necrotic lesions arising on the leaf after superinfection.
The level of specific resistance depends on many different factors, among which on the age of the infected plant or even of particular leaves. Older leaves are usually more resistant. In the present study the author stimulated the natural process of senescence by raising the plants under unfavourable conditions of a short photoperiod. It was shown that the plants influenced by a short photoperiod developed, after TMV inoculation, a much higher level of induced resistance.
The number of lesions is not a good index of the level of induced resistance. The results show that a good index of the level of induced resistance can be provided by modal values of the frequency distribution curves of lesion diameters. They are a better index than the arithmetic means because they also give an idea on the dynamics of lesion growth
Plant virus particles with various shapes as potential adjuvants
No full textPlant viruses are biologically safe for mammals and can be successfully used as a carrier/platform to present foreign epitopes in the course of creating novel putative vaccines. However, there is mounting evidence that plant viruses, their virus-like and structurally modified particles may also have an immunopotentiating effect on antigens not bound with their surface covalently. Here, we present data on the adjuvant properties of plant viruses with various shapes (Tobacco mosaic virus, TMV; Potato virus X, PVX; Cauliflower mosaic virus, CaMV; Bean mild mosaic virus, BMMV) and structurally modified TMV spherical particles (SPs). We have analysed the effectiveness of immune response to individual model antigens (ovalbumin, OVA/hen egg lysozyme, HEL) and to OVA/HEL in compositions with plant viruses/SPs, and have shown that CaMV, TMV and SPs can effectively induce total IgG titers to model antigen. Some intriguing data were obtained when analysing the immune response to the plant viruses/SPs themselves. Strong immunity was induced to CaMV, BMMV and PVX, whereas TMV and SPs stimulated considerably lower self-IgG titers. Our results provide new insights into the immunopotentiating properties of plant viruses and can be useful in devising adjuvants based on plant viruses. © 2020, The Author(s)
The effect of a rapid molecular blood test on the use of antibiotics for nosocomial sepsis: a randomized clinical trial
No full textBackground: Appropriate use of antimicrobials is essential to improve outcomes in sepsis. The aim of this study was to determine whether the use of a rapid molecular blood test - SeptiFast (SF) reduces the antibiotic consumption through early de-escalation in patients with nosocomial sepsis compared with conventional blood cultures (BCs). Methods: This was a prospective, randomized, superiority, controlled trial conducted at Sao Paulo Heart Institute in the period October 2012-May 2016. Adult patients admitted to the hospital for at least 48 h with a diagnosis of nosocomial sepsis underwent microorganism identification by both SF test and BCs. Patients randomized into the intervention group received antibiotic therapy adjustment according to the results of SF. Patients randomized into the control group received standard antibiotic adjustment according to the results of BCs. The primary endpoint was antimicrobial consumption during the first 14 days after randomization. Results: A total of 200 patients were included (100 in each group). The intention to treat analysis found no significant differences in median antibiotic consumption. In the subgroup of patients with positive SF and blood cultures (19 and 25 respectively), we found a statistically significant reduction in the median antimicrobial consumption which was 1429 (1071-2000) days of therapy (DOT)/1000 patients-day in the intervention group and 1889 (1357-2563) DOT/1000 patients-day in the control group (p = 0.017), in the median time of antimicrobial de-escalation (8 versus 54 h - p < 0.001), in the duration of antimicrobial therapy (p = 0.039) and in anti-gram-positive antimicrobial costs (p = 0.002). Microorganism identification was possible in 24.5% of patients (45/184) by SF and 21.2% (39/184) by BC (p = 0.45). Conclusion: This randomized clinical trial showed that the use of a rapid molecular-based pathogen identification test does not reduce the median antibiotic consumption in nosocomial sepsis. However, in patients with positive microbiological tests, the use of SeptiFast reduced antimicrobial consumption through early de-escalation compared to conventional blood cultures. These results were driven by a reduction in the consumption of antimicrobials used for Gram-positive bacteria. Trial registration: The trial was registered at ClinicalTrials.gov (NCT 01450358) on 12th October 201
Femtosecond X-ray coherent diffraction of aligned amyloid fibrils on low background grapheme
No full text© 2018 The Author(s). Here we present a new approach to diffraction imaging of amyloid fibrils, combining a free-standing graphene support and single nanofocused X-ray pulses of femtosecond duration from an X-ray free-electron laser. Due to the very low background scattering from the graphene support and mutual alignment of filaments, diffraction from tobacco mosaic virus (TMV) filaments and amyloid protofibrils is obtained to 2.7 Å and 2.4 Å resolution in single diffraction patterns, respectively. Some TMV diffraction patterns exhibit asymmetry that indicates the presence of a limited number of axial rotations in the XFEL focus. Signal-to-noise levels from individual diffraction patterns are enhanced using computational alignment and merging, giving patterns that are superior to those obtainable from synchrotron radiation sources. We anticipate that our approach will be a starting point for further investigations into unsolved structures of filaments and other weakly scattering objects
Environmental sampling for legionella proliferation risk in three long-term care facilities in Vancouver, British Columbia
No full text
Background: Legionella is a pathogen that causes Legionnaires’ disease in high risk populations. The pathogen is known to exist in plumbing systems that do not have preventative factors in place to prevent its growth and proliferation. Legionella grows between 25˚C and 42˚C and is killed at 60˚C, yet long-term care facilities (LTCFs) reduce accessible hot water temperatures from 60˚C at the hot water tank to less than 49˚C at the taps in order to prevent scalding of their residents. Currently, prevention against scalding takes precedence as temperature at accessible taps is regulated within the Residential Care Regulation (RCR) of the Community Care and Assisted Living Act. It is thought that Legionella proliferation risk can be balanced with scalding in-part through the appropriate installation location of thermostatic mixing valves (TMVs). Methods: Three LTCFs in Vancouver, British Columbia were selected for environmental sampling for Legionella proliferation risk. At each LTCF the author recorded the type of hot water tank, temperature of water within the hot water tank, the presence of a TMV and temperature of pipes before and after the TMV. As well, the author recorded hot water temperatures after one minute and free available chlorine concentration ([FAC]) at numerous resident-accessible taps throughout each LTCF. Results: The hot water tank temperatures were set at 60.6˚C, 73.0˚C and 62.0˚C for LTCF #1, LTCF #2 and LTCF #3, respectively. All three LTCFs had installed a TMV within the boiler room immediately after the hot water tank. It was found that LTCF #1’s plumbing system water temperature was reduced from 60.6˚C (at the tank) to 48.9˚C after the TMV. LTCF #2’s plumbing system water temperature was reduced from 73.0˚C (at the tank) to 43.3˚C after the TMV. LTCF #3 was an older plumbing system that did not have thermometers within the boiler room to check the drop in temperature after the TMV. Water temperatures at taps were compared to a standard of 49°C and [FAC] levels at taps to a standard of 0.2 mg/L. The mean hot water temperature and mean [FAC] residual for all three LTCFs were 40.2˚C and 0.27 mg/L, respectively. For all three LTCFs, it was statistically significant that mean water temperatures were less than the comparison value of 49˚C (LTCF #1 p = 0.00000, LTCF #2 p = 0.00022, LTCF #3 p = 0.00110). It was also statistically significant that the mean [FAC] of all three LTCFs were greater than the comparison vale of 0.20 mg/L (LTCF #1 p = 0.00042, LTCF #2 p = 0.00000, LTCF #3 p = 0.00107). Conclusion: It was found that all three LTCFs had set preventive measures in place to protect their residents. Water was heated to at least 60˚C to prevent Legionella and lowered to less than 49˚C to prevent scalding. [FAC] residual was also adequate to prevent growth of Legionella. However, the location of the TMV in the boiler room was suspected to be a possible contributing factor to Legionella growth, especially if cold water temperatures were to reach 20˚C or above, as they could in warm summer months. Further research is needed to determine the significance of the TMV location and the presence of Legionella.
 
Evaluation of Plant-based Viral Vectors for West Nile Virus Antibody Expression Levels
No full textabstract: Plant viral vectors have previously been used to produce high expression levels of antibodies and other proteins of interest. By utilizing a transformed Agrobacterium with the vector containing the protein of interest for infiltration, viral vectors can easily reach the plant cells making it an effective form of transient protein expression. For this project two different plant viral vectors were compared; the geminiviral vector derived from Bean yellow dwarf virus (BeYDV) and the MagnICON vector system derived from Tobacco Mosaic Virus(TMV) and Potato Virus X(PVX). E16, an antibody against West Nile virus, has previously been expressed using both systems but expression levels between the systems were not directly compared. Agrobacterium tumefaciens EHA105 cells were transformed with both systems and expression levels of E16 were quantified using ELISAs. Results showed very low expression levels of E16 using the geminiviral vector indicating a need for further investigation into the clone used as previous studies reported much higher expression levels with the system
