384 research outputs found

    An Investigation into Designing a Derivative Vehicle

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    There are growing concerns about global warming and growing carbon dioxide levels in the atmosphere. Transportation produces about 20% of the total CO2 emission. This study proposes to investigate is the fuelling system for a derivative car based on a natural gas fuelling system

    βC1 of chili leaf curl betasatellite is a pathogenicity determinant

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    <p/> <p>Background</p> <p>Cotton leaf curl disease in the Indian subcontinent is associated with several distinct begomoviruses that interact with a disease-specific DNA satellite named Cotton leaf curl Multan betasatellite (CLCuMB). However, we have recently reported that Chili leaf curl betasatellite (ChLCB) is also occasionally found associated with the disease in Pakistan. The question as to whether ChLCB contributes to the development of disease symptoms such as leaf curling and enations remain to be answered. We have previously shown that the expression of βC1 of CLCuMB develops all symptoms of cotton leaf curl disease in <it>Nicotiana benthamiana </it>when expressed from PVX vector.</p> <p>Findings</p> <p>The role of ChLCB in the induction of typical disease symptoms was studied by its expression from PVX vector in <it>N. benthamiana</it>. The expression of βC1 from PVX vector developed severe leaf curl symptoms and leaf-like enations that resemble the phenotype induced by βC1 of CLCuMB.</p> <p>Conclusions</p> <p>The results presented here show that the expression of βC1 of ChLCB from PVX vector exhibit phenotype typical of cotton leaf curl and therefore ChLCB may contribute to the disease symptoms.</p

    Reactions of Nicotiana species to inoculation with monopartite and bipartite begomoviruses

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    <p>Abstract</p> <p>Background</p> <p>Some <it>Nicotiana </it>species are widely used as experimental hosts for plant viruses. <it>Nicotiana </it>species differ in ploidy levels, chromosome numbers and have diverse geographical origins. Thus, these species are useful model systems to investigate virus-host interactions, co-evolution of pathogens and hosts and the effects of ploidy level on virus resistance/susceptibility.</p> <p>Results</p> <p>Here we have studied the responses of seven <it>Nicotiana </it>species to inoculation with <it>Cotton leaf curl Multan virus </it>(CLCuMV), a monopartite begomovirus, and <it>Tomato leaf curl New Delhi virus </it>(ToLCNDV), a bipartite begomovirus, both from the Indian subcontinent. All <it>Nicotiana </it>species supported the replication of both begomoviruses in inoculated leaves. However, only three <it>Nicotiana </it>species, namely <it>N. benthamiana</it>, <it>N. tabacum </it>and <it>N. sylvestris </it>showed symptoms when inoculated with ToLCNDV, while <it>N. benthamiana </it>was the only species that developed leaf curl symptoms when inoculated with CLCuMV. CLCuMV accumulated to detectable levels in <it>N. tabacum</it>, but plants remained asymptomatic. A previously identified mutation of RNA dependent RNA polymerase 1 was shown to be present only in <it>N. benthamiana</it>. The finding is in line with earlier results showing that the susceptibility of this species to a diverse range of plant viruses correlates with a defective RNA silencing-mediated host defense.</p> <p>Conclusions</p> <p>The results presented show that individual <it>Nicotiana </it>species respond differently to inoculation with begomoviruses. The inability of begomoviruses to systemically infect several <it>Nicotiana </it>species is likely due to inhibition of virus movement, rather than replication, and thus provides a novel model to study virus-host interactions in resistant/susceptible hosts.</p

    Silencing of the AV2 gene by antisense RNA protects transgenic plants against a bipartite begomovirus

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    Whitefly-transmitted geminiviruses (genus Begomovirus) are phytopathogens that cause heavy losses to crops worldwide. Efforts to engineer resistance against these viruses are focused mainly on silencing of complementary-sense virus genes involved in virus replication. Here we have targeted a virion-sense gene (AV2) to develop resistance against Tomato leaf curl New Delhi virus, a bipartite begomovirus prevalent throughout the Indian subcontinent. We show that tobacco plants transformed with an antisense construct targeting this gene are resistant to the virus. Following challenged with the virus, transgenic plants remained symptomless, although viral DNA could be detected in some plants by PCR. This is the first report of transgenic resistance against a bipartite begomovirus obtained by targeting a virion-sense gene. The relatively conserved nature of the gene suggests that the technology may be useful to develop broad-spectrum resistance which is required because of the fact that plants are often infected with multiple begomoviruses in the field

    Infectious clones of Tomato leaf curl Palampur virus with a defective DNA B and their pseudo-recombination with Tomato leaf curl New Delhi virus

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    <p>Abstract</p> <p>Background</p> <p><it>Tomato leaf curl Palampur virus </it>(ToLCPMV) is a bipartite begomovirus which has been reported from India and Iran but infectious clones have not been obtained. We have previously shown the association of <it>Zucchini yellow mosaic virus </it>(ZYMV), a potyvirus, with severe leaf curl disease of muskmelon in Pakistan. However, the severity of symptoms in the field and yield losses led us to believe that some other agent, such as a begomovirus, could be associated with the disease.</p> <p>Results</p> <p>A bipartite begomovirus associated with a severe yellow leaf curl disease on muskmelon in Pakistan has been characterized. Analysis of the complete nucleotide sequence of the DNA A and DNA B components of the begomovirus showed that it has the highest DNA sequence identity with ToLCPMV. However, the gene encoding the nuclear shuttle protein (NSP) was truncated in comparison to previously characterised isolates. <it>Agrobacterium</it>-mediated inoculation of <it>Nicotiana benthamiana </it>with the ToLCPMV clones obtained here did not result in symptoms. However, inoculation of plants with the DNA A component of ToLCPMV and the DNA B component of <it>Tomato leaf curl New Delhi virus </it>(ToLCNDV) lead to systemic infection with leaf curl symptoms. This suggested that the lack of infectivity of the ToLCPMV clones was due to the defect in DNA B. The DNA B of ToLCPMV was able to move systemically when inoculated with DNA A of the either virus. Agro-infiltration of muskmelon with the DNA A and DNA B components of ToLCPMV did not lead to symptomatic infection whereas inoculation with the DNA A with the DNA B of ToLCNDV resulted in a hypersensitive response (HR) along the veins. Additionally, agro-infiltration of muskmelon with a construct for the expression of the NSP gene of ToLCNDV under the control of the cauliflower mosaic virus 35S promoter induced a HR, suggesting that this is the gene causing the HR.</p> <p>Conclusions</p> <p>Both ToLCPMV and ZYMV are associated with muskmelon leaf curl disease in Pakistan. However, the ToLCPMV variant identified in association with ZYMV has a defective NSP. The results suggest that a variant with a defective NSP may have been selected for in muskmelon, as this protein is an avirulence determinant in this species, and possibly that infection requires the synergistic interaction with ZYMV.</p

    RNA interference-based resistance against a legume mastrevirus

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    <p>Abstract</p> <p>Background</p> <p>RNA interference (RNAi) is a homology-dependant gene silencing mechanism and has been widely used to engineer resistance in plants against RNA viruses. However, its usefulness in delivering resistance against plant DNA viruses belonging to family <it>Geminiviridae </it>is still being debated. Although the RNAi approach has been shown, using a transient assay, to be useful in countering monocotyledonous plant-infecting geminiviruses of the genus <it>Mastrevirus</it>, it has yet to be investigated as a means of delivering resistance to dicot-infecting mastreviruses. <it>Chickpea chlorotic dwarf Pakistan virus </it>(CpCDPKV) is a legume-infecting mastrevirus that affects chickpea and other leguminous crops in Pakistan.</p> <p>Results</p> <p>Here a hairpin (hp)RNAi construct containing sequences encompassing part of replication-associated protein gene, intergenic region and part of the movement protein gene of CpCDPKV under the control of the <it>Cauliflower mosaic virus </it>35S promoter has been produced and stably transformed into <it>Nicotiana benthamiana</it>. Plants harboring the hairpin construct were challenged with CpCDPKV. All non-transgenic <it>N. benthamiana </it>plants developed symptoms of CpCDPKV infection within two weeks post-inoculation. In contrast, none of the inoculated transgenic plants showed symptoms of infection and no viral DNA could be detected by Southern hybridization. A real-time quantitative PCR analysis identified very low-level accumulation of viral DNA in the inoculated transgenic plants.</p> <p>Conclusions</p> <p>The results presented show that the RNAi-based resistance strategy is useful in protecting plants from a dicot-infecting mastrevirus. The very low levels of virus detected in plant tissue of transgenic plants distal to the inoculation site suggest that virus movement and/or viral replication was impaired leading to plants that showed no discernible signs of virus infection.</p

    Empirical Evaluation of Pre-Trained Deep Learning Networks for Pneumonia Detection

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    Pneumonia is a significant global health issue, characterized by a substantial mortality risk, impacting a vast number of individuals on a global scale. The quick and precise identification of pneumonia is crucial for the optimal treatment and management of this condition. This research work aims to answer the pressing need for precise diagnostic methods by using two advanced deep learning models, namely VGG19 and ResNet50, for the purpose of pneumonia detection in chest X-ray pictures. Furthermore, the present area of research is on the use of deep learning methodologies in the domain of medical image analysis, namely in the identification of pneumonia cases via the examination of chest X-ray images. The study challenge pertains to the pressing need for accurate and automated pneumonia diagnosis to assist healthcare professionals in making timely and educated judgements. The VGG19 and ResNet50 models were trained and assessed using the comprehensive RSNA Pneumonia dataset. In order to enhance their performance in the classification of chest X-ray pictures as either normal or pneumonia-affected, the models underwent rigorous training and meticulous fine-tuning. Based on the results obtained from our investigation, it was seen that the VGG19 model exhibited a notable accuracy rate of 93\%, surpassing the ResNet50 model's accuracy of 84\%. Furthermore, it is worth noting that both models demonstrated a notable level of precision, recall, and f1-scores in the identification of normal and pneumonia patients. This indicates their potential for accurately classifying such instances. Furthermore, our research findings indicate that deep learning models, namely VGG19, have a high level of efficacy in reliably detecting pneumonia via the analysis of chest X-ray pictures. These models has the capacity to function as helpful tools for expediting and ensuring the precise identification of pneumonia by healthcare practitioners

    Selection of target sequences as well as sequence identity determine the outcome of RNAi approach for resistance against cotton leaf curl geminivirus complex

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    Cotton leaf curl disease is caused by a geminivirus complex that involves multiple distinct begomoviruses and a disease-specific DNA satellite, cotton leaf curl Multan betasatellite (CLCuMB), which is essential to induce disease symptoms. Here we have investigated the use of RNA interference (RNAi) for obtaining resistance against one of the viruses, Cotton leaf curl Multan virus (CLCuMV), associated with the disease. Three hairpin RNAi constructs were produced containing either complementary-sense genes essential for replication/pathogenicity or non-coding regulatory sequences of CLCuMV. In transient assays all three RNAi constructs significantly reduced the replication of the virus in inoculated tissues. However, only one of the constructs, that targeting the overlapping genes involved in virus replication and pathogenicity (the replication-associated protein (Rep), the transcriptional activator protein and the replication enhancer protein) was able to prevent systemic movement of the virus, although the other constructs significantly reduced the levels of virus in systemic tissues. In the presence of CLCuMB, however, a small number of plants co-inoculated with even the most efficient RNAi construct developed symptoms of virus infection, suggesting that the betasatellite may compromise resistance. Further analyses, using Rep gene sequences of distinct begomoviruses expressed from a PVX vector as the target, are consistent with the idea that the success of the RNAi approach depends on sequence identity to the target virus. The results show that selection of both the target sequence, as well as the levels of identity between the construct and target sequence, determine the outcome of RNAi-based resistance against geminivirus complexes

    Transient expression of βC1 protein differentially regulates host genes related to stress response, chloroplast and mitochondrial functions

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    <p>Abstract</p> <p>Background</p> <p>Geminiviruses are emerging plant pathogens that infect a wide variety of crops including cotton, cassava, vegetables, ornamental plants and cereals. The geminivirus disease complex consists of monopartite begomoviruses that require betasatellites for the expression of disease symptoms. These complexes are widespread throughout the Old World and cause economically important diseases on several crops. A single protein encoded by betasatellites, termed βC1, is a suppressor of gene silencing, inducer of disease symptoms and is possibly involved in virus movement. Studies of the interaction of βC1 with hosts can provide useful insight into virus-host interactions and aid in the development of novel control strategies. We have used the differential display technique to isolate host genes which are differentially regulated upon transient expression of the βC1 protein of chili leaf curl betasatellite (ChLCB) in <it>Nicotiana tabacum</it>.</p> <p>Results</p> <p>Through differential display analysis, eight genes were isolated from <it>Nicotiana tabacum</it>, at two and four days after infitration with βC1 of ChLCB, expressed under the control of the <it>Cauliflower mosaic virus </it>35S promoter. Cloning and sequence analysis of differentially amplified products suggested that these genes were involved in ATP synthesis, and acted as electron carriers for respiration and photosynthesis processes. These differentially expressed genes (DEGs) play an important role in plant growth and development, cell protection, defence processes, replication mechanisms and detoxification responses. Kegg orthology based annotation system analysis of these DEGs demonstrated that one of the genes, coding for polynucleotide nucleotidyl transferase, is involved in purine and pyrimidine metabolic pathways and is an RNA binding protein which is involved in RNA degradation.</p> <p>Conclusion</p> <p>βC1 differentially regulated genes are mostly involved in chloroplast and mitochondrial functions. βC1 also increases the expression of those genes which are involved in purine and pyrimidine metabolism. This information gives a new insight into the interaction of βC1 with the host and can be used to understand host-virus interactions in follow-up studies.</p

    Pepper leaf curl Lahore virus requires the DNA B component of Tomato leaf curl New Delhi virus to cause leaf curl symptoms

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    <p>Abstract</p> <p>Background</p> <p>Begomoviruses are whitefly-transmitted geminiviruses with genomes that consist of either two components (known as DNA A and DNA B) or a single component (homologous to the DNA A component of bipartite begomoviruses). Monopartite begomoviruses are often associated with a symptom-modulating DNA satellite (collectively known as betasatellites). Both bipartite and monopartite begomoviruses with associated satellites have previously been identified in chillies showing leaf curl symptoms in Pakistan.</p> <p>Results</p> <p><b>A </b>chilli plant (<it>Capsicum annum</it>) with chilli leaf curl disease symptoms was found to contain a begomovirus, a betasatellite and the DNA B component of <it>Tomato leaf curl New Delhi virus </it>(ToLCNDV). The begomovirus consisted of 2747 nucleotides and had the highest sequence identity (99%) <it>with Pepper leaf curl Lahore virus </it>(PepLCLV-[PK: Lah:04], acc. no. AM404179). <it>Agrobacterium</it>-mediated inoculation of the clone to <it>Nicotiana benthamiana</it>, induced very mild symptoms and low levels of viral DNA, detected in systemically infected leaves by PCR. No symptoms were induced in <it>Nicotiana tabacum </it>or chillies either in the presence or absence of a betasatellite. However, inoculation of PepLCLV with the DNA B component of ToLCNDV induced leaf curl symptoms in <it>N. benthamiana</it>, <it>N. tabacum </it>and chillies and viral DNA accumulated to higher levels in comparison to plants infected with just PepLCLV.</p> <p>Conclusions</p> <p>Based on our previous efforts aimed at understanding of diversity of begomoviruses associated with chillies, we propose that PepLCLV was recently mobilized into chillies upon its interaction with DNA B of ToLCNDV. Interestingly, the putative rep-binding iterons found on PepLCLV (GGGGAC) differ at two base positions from those of ToLCNDV (GGTGTC). This is the first experimental demonstration of the infectivity for a bipartite begomovirus causing chilli leaf curl disease in chillies from Pakistan and suggests that component capture is contributing to the emerging complexity of begomovirus diseases in the region.</p
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