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Molecular and immunogenic analysis of Jembrana disease virus Tat
Get PDFJembrana disease is an acute and severe disease of Bali cattle (Bos javanicus) endemic in Indonesia that is caused by a bovine lentivirus designated Jembrana disease virus (JDV). Previous studies have demonstrated that it is possible to induce a protective immunity against the disease by immunisation with a crude whole virus vaccine prepared from the tissues of infected cattle. This vaccine has been demonstrated to ameliorate the clinical signs of disease resulting from exposure to virus infection but a safer vaccine amenable to commercial production techniques is required.
JDV, like all lentiviruses, encodes a transcriptional trans-activator Tat protein that is encoded from one or both of two exons of the tat gene. Tat is particularly essential for virus replication and it was hypothesised that the induction of an immune response in cattle against JDV Tat may effect protection against virus infection. Investigations were therefore conducted on JDV Tat to provide basic information on the protein that would enable it to be further investigated as a potential immunogen for incorporation into vaccines for the control of Jembrana disease.
Analysis of tat transcripts obtained from tissues of cattle infected with three strains of JDV suggested that, during the acute clinical disease, Tat produced at this stage of the disease process was translated from the first coding exon only. Nucleotide variation in this exon, which would have translated into amino acid variations in the Tat protein, was evident especially between strains from geographically different regions of Indonesia. There was; however, conservation of the essential functional domains of cysteine-rich, core and basic regions, which suggested immunity to a single Tat protein might protect against infection by heterologous strains. Subsequent studies on Tat reported in the thesis therefore concentrated on the protein encoded by tat exon 1 of a single strain of JDV. The exon 1 of tat was cloned into the pGEX vector and recombinant Tat expressed in Escherichia coli. Methods for the purification of the expressed protein were developed. Immunogenicity of the recombinant protein was initially demonstrated by inoculation of the protein into a sheep which developed a high titred specific antibody response. Antibodies induced by this recombinant protein recognised native Tat proteins produced by three JDV strains in Bali cattle and provided a valuable reagent for the subsequent detection of Tat in vitro and in vivo.
Aspects of the antibody response to Tat were determined in cattle that had been infected naturally or experimentally with JDV, and compared with the levels of antibody to the immunodominant capsid protein. Tat antibodies were detected in 23 % of 128 Bali cattle from Jembrana disease-endemic areas of Indonesia; in all these cattle, evidence of previous virus infection had been demonstrated by detection of antibody to the JDV capsid protein by Western blot analysis. In cattle experimentally infected with JDV, low levels of serum antibody to Tat were detected by Western blot in the first month post-infection but the levels of antibody then decreased; levels of antibody to the JDV capsid protein increased over the 6-month observation period following infection. The detection of Tatantibody soon after the acute clinical disease suggested that this protein is secreted extracellularly during JDV infection in cattle. In contrast to the antibody response to Tat in JDV-infected cattle, an apparently greater antibody response to Tat was induced by injection of recombinant Tat in Bali cattle. The strong antibody response resulting from inoculation of the recombinant Tat and low levels of Tat antibody in animals that had been naturally or experimentally infected with virus suggested there might be a conformational difference in the recombinant and native Tat protein and that the native protein was a poor immunogen, or that the levels of Tat in infected cattle were too low to induce a strong antibody response. As an alternative means of inducing an immune response to JDV Tat, perhaps one associated with a greater cell-mediated rather than an antibody response, a candidate tat DNA vaccine was produced by insertion of tat exon 1 into a DNA vaccine vector. Transfection of this naked DNA plasmid into mammalian cells induced the expression of a functional Tat protein which maintained antigenicity. The results suggested this construct merits further animal studies attempting to induce a protective immune response against Jembrana disease in cattle. A method of assaying the trans-acting function of Tat was also developed which will have application for quality control procedures for large-scale production of tat DNA vaccine
Il-forma ortografika u t-tifsira semantika fl-għażla tal-lessiku Malti fl-oqsma tat-traduzzjoni u tat-terminoloġija
Get PDFDin l-analiżi turi kif is-Semitiku, ir-Rumanz u l-Ingliż li minnhom magħmul il-Malti
jippermettu dinamiżmu u flessibilità kbira fil-qasam tat-traduzzjoni kemm letterarja kif
ukoll nonletterarja. Il-forma ortografika u t-tifsira semantika tal-kliem Malti-Rumanz huma
ħafna drabi l-istess bħal dawk tal-kliem Malti-Ingliż u dan għax kemm l-Ingliż kif ukoll
it-Taljan għandhom fil-lessiku għadd ta’ għeruq komuni li etimoloġikament imorru lura
għal-Latin Medjevali. Ir-rwol tat-traduzzjoni hu li jwassal it-test sors b’mod awtentiku lillqarrej
tat-test mira u mhux li jippreserva l-element Semitiku fil-Malti. Għalhekk għandha
ssir distinzjoni bejn lingwa u traduzzjoni sabiex jiġi osservat id-determiniżmu lingwisitku
stabbilit mill-awtur tal-lingwa sors fl-għażla tal-lessiku li twassal għar-replika vera tat-test
oriġinali fil-lingwa mira tat-traduttur.peer-reviewe
Environmental salinity determines the specificity and need for tat-dependent secretion of the YwbN protein in bacillus subtilis
Get PDFTwin-arginine protein translocation (Tat) pathways are required for transport of folded proteins across bacterial, archaeal and chloroplast membranes. Recent studies indicate that Tat has evolved into a mainstream pathway for protein secretion in certain halophilic archaea, which thrive in highly saline environments. Here, we investigated the effects of environmental salinity on Tat-dependent protein secretion by the Gram-positive soil bacterium Bacillus subtilis, which encounters widely differing salt concentrations in its natural habitats. The results show that environmental salinity determines the specificity and need for Tat-dependent secretion of the Dyp-type peroxidase YwbN in B. subtilis. Under high salinity growth conditions, at least three Tat translocase subunits, namely TatAd, TatAy and TatCy, are involved in the secretion of YwbN. Yet, a significant level of Tat-independent YwbN secretion is also observed under these conditions. When B. subtilis is grown in medium with 1% NaCl or without NaCl, the secretion of YwbN depends strictly on the previously described “minimal Tat translocase” consisting of the TatAy and TatCy subunits. Notably, in medium without NaCl, both tatAyCy and ywbN mutants display significantly reduced exponential growth rates and severe cell lysis. This is due to a critical role of secreted YwbN in the acquisition of iron under these conditions. Taken together, our findings show that environmental conditions, such as salinity, can determine the specificity and need for the secretion of a bacterial Tat substrate
Twin arginine translocase (Tat) : structural and functional insight
Get PDFThe twin arginine tranlocation (Tat) pathway is responsible for the transport of folded protein across the membrane. In bacteria, this occurs at the cytoplasmic membrane. In Gram-negative bacteria, Tat forms a 3-component machinery named TatABC. The current hypothesised mechanism is compiled from the model organism Escherichia coli.
In Gram-positive bacteria the Tat machinery lack the TatB component and so raises the question on the validity of the mechanism assumed from the TatABC system. To date there is limited research available on the TatAC system with in Gram-postive bacteria. Recent characterisation has been focused on the Bacillus subtilis system, which contain two TatAC systems; the TatAdCd and TatAyCy.
This thesis focuses on the structural characterisation of the TatAC system of B. subtilis and their similarity to the TatABC system in E. coli. The TatAdCd complex was studies by electron microscopy (EM) to show structure similarity to the TatBC complex. Mutation within the N-terminus region of the TatAy protein showed functional involved in complex assembly. The TatAyCy was also analysed by EM show conserved round complexes similar to the TatAdCd and TatBC. The similarity in structure may suggest the Gram-negatives and the Gram-Positives share a similar mechanism of transport despite difference in the components
TAT
No full textHistograms representing the proportion of time a tag spent in 12 temperature bins define in 2C increments between 4C and 24C TAT histograms were returned by Argos satellites from SPOT5 tags produced by Wildlife Computers. TAT were collected in 6-hour sampling periods, and sampling periods were programmed to begin at 01:00, 07:00, 13:00, or 21:00 local time, so that the majority (>80%) of sampling of each TAT histogram fell within either daytime or nighttime. TAT histograms that were translated into units of depth using the hydrographic data and interpolation methods detailed in Joyce et al. (2016)
A structural investigation of bacterial twin-arginine translocation (tat) complexes by single-particle electron microscopy
Get PDFThe Twin arginine translocase (Tat) pathway was first characterised in chloroplast
thylakoid membranes in the late 1990s. It has since been identified in the plasma
membranes of both Gram-positive and Gram-negative bacteria. Substrates of this
transport system contain a critical twin-arginine motif within their cleavable Nterminal
signal sequence and the majority are large co-factor containing proteins.
There is now considerable evidence that Tat systems can transport such globular
proteins in a fully folded state. The minimal components required for transport in
E.coli are TatA, TatB and TatC; these three integral membrane proteins are thought
to form an active translocon. In Bacillus subtilis only TatA and TatC subunits are
present, with TatA acting in a bifunctional manner to replace TatB. Little structural
information is known about these multimeric integral membrane protein complexes
due to the inherent difficulty in purifying them and their compositional variability.
Complexes formed by B. subtilis TatAd and TatAyCy and E. coli TatE were
investigated by single-particle EM analysis. An image processing protocol was
developed to analyse and separate out individual Tat complexes based on their size.
Using this method 3D electron density maps were generated of TatAd and TatE,
which appear as small, ring-shaped complexes. Unlike E. coli TatA complexes, that
have been shown to vary widely in size, those observed here appear small and
homogeneous. These data conflict with the widely accepted ‘size-fitting pore’ model
of Tat mediated translocation and rather support the alternative transient coalescent
model.
Additionally the first structural characterisation of a TatA-type mutant protein was
performed revealing a dramatic polymerisation phenotype and indicating a primary
role for the N-terminus in forming protein-protein interactions
TAT-pep-α1<sup>ins</sup> attenuated inflammatory pain.
No full text(A) Formalin injection into left hindpaws of mice enhanced pS380 in the ipsilateral dorsal horn of spinal cord. Effects of intrathecal MPEP (50 nmol), U-0126 (2 nmol), TAT-pep-α1ins, or TAT-Scram (200 pmol) on pS380 were also examined. *p = 0.017, #p = 0.007 versus contralateral sides (one-way ANOVA with post hoc Bonferroni test), n = 10. (B) Effects of formalin on α1ins ubiquitination. *p = 0.002, #p = 0.002 versus contralateral sides (one-way ANOVA with post hoc Bonferroni test), n = 6. (C) Effects of TAT-pep-α1ins and TAT-Scram on formalin-induced spontaneous pain. F(44, 396) = 1.652, p = 0.007 (repeated measures ANOVA). n = 10 mice/group. (D–E) The first-phase (0–10 min, D) and second-phase (15–60 min, E) behaviors in formalin tests were summarized. *p = 0.004 versus TAT-Scram–treated mice (one-way ANOVA with post hoc Bonferroni test). (F) GlyR-IPSCs in slices from formalin-injected mice were potentiated by TAT-pep-α1ins (144.9 ± 7.6% of baseline at 15–20 min postpeptide, t[15] = 6.495, p t test) but not by TAT-Scram (88.0 ± 6.5% of baseline at 15–20 min postpeptide, t[10] = 1.856, p = 0.093). The underlying data for this figure can be found in S1 Data. Error bars indicated SEM. ANOVA, Analysis of Variance; GlyR, glycine receptor; IP, immunoprecipitation; IPSC, inhibitory postsynaptic current; MPEP, 6-Methyl-2-(phenylethynyl) pyridine; pS380, phosphorylation at Ser380; TAT-pep-α1ins, TAT-fused α1ins-derived peptide; TAT-Scram, TAT-fused scrambled peptide; Ubi, ubiquitin.</p
Learners’ attitudes towards blended learning at Nguyen Tat Thanh University
No full text7 p.In many educational settings accross the world, including Viet Nam, blended learning has grown quickly due to evidence of its benefits over traditional classroom or online instruction alone. The study examined the attitudes of students at Nguyen Tat Thanh University toward the existing English blended learning course with the overall goal of enhancing the quality of language teaching and learning. A total of 367 students non-majoring in English language participated in the survey conducted at Nguyen Tat Thanh University in Ho Chi Minh City, Viet Nam. The 44-item survey was used to collect the data, and SPSS version 20.0 was used for statistical analysis. The results demonstrated that most students had very positive sentiments towards four factors: the course's overall quality, the quality of the instructors, the course material, and the supportive services. However, a few students expressed dissatisfaction with the technology system, as they frequently encounter technical issues when engaging in online learning outside of the classroom
PSYNDEX Tests Review für A-TAT - AGGRESSIONS-TAT
No full textThis is a PSYNDEX Tests Review of A-TAT - AGGRESSIONS-TAT. PSYNDEX Tests Reviews are written in German and describe and evaluate psychological and educational tests used in the German-speaking countries. PSYNDEX Tests is offered by the Leibniz Institute for Psychology as open access documentation.Das ist ein PSYNDEX Tests Review zu A-TAT - AGGRESSIONS-TAT. PSYNDEX Tests Reviews beschreiben und bewerten zentrale psychologische und pädagogische Testverfahren, die in den deutschsprachigen Ländern eingesetzt werden, nach einem standardisierten Raster. PSYNDEX Tests wird durch das Leibniz-Institut für Psychologie als Open Access Dokumentation angeboten.publishedVersio
TAT-NSF700 effect on BAL fluid characteristics following pulmonary challenge.
No full textTAT-NSF700 effect on BAL fluid characteristics following pulmonary challenge.</p
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