ORCID Profile
0000-0003-1452-5126
Current Organisation
Taylor's University
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Publisher: Proceedings of the National Academy of Sciences
Date: 04-08-2009
Abstract: Toxoplasma gondii , as an obligate intracellular and promiscuous pathogen of mammalian cells, utilizes host sugars for energy and to generate glycoconjugates that are important to its survival and virulence. Here, we report that T. gondii glucose transporter (TgGT1) is proficient in transporting mannose, galactose, and fructose besides glucose, and serves as a major hexose transporter at its plasma membrane. Toxoplasma harbors 3 additional putative sugar transporters (TgST1–3), of which TgST2 is expressed at its surface, whereas TgST1 and TgST3 are intracellular. Surprisingly, TgGT1 and TgST2 are nonessential to the parasite as their ablations inflict only a 30% or no defect in its intracellular growth, respectively. Indeed, Toxoplasma can also tolerate the deletion of both genes while incurring no further growth phenotype. Unlike Δ tgst2 , the modest impairment in Δ tggt1 and Δ tggt1 /Δ tgst2 mutants is because of a minor delay in their intracellular replication, which is a direct consequence of the abolished import of glucose. The Δ tggt1 displays an attenuated motility in defined minimal media that is rescued by glutamine. TgGT1-complemented parasites show an entirely restored growth, motility, and sugar import. The lack of exogenous glucose in Δ tggt1 culture fails to accentuate its intrinsic growth defect and prompts it to procure glutamine to sustain its metabolism. Unexpectedly, in vivo virulence of Δ tggt1 in mice remains unaffected. Taken together, our data demonstrate that glucose is nonessential for T. gondii tachyzoites, underscore glutamine is a complement substrate, and provide a basis for understanding the adaptation of T. gondii to erse host cells.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2021
Publisher: MDPI AG
Date: 26-07-2022
DOI: 10.3390/ELECTRONICS11152324
Abstract: The popularity of wireless sensor networks for establishing different communication systems is increasing daily. A wireless network consists of sensors prone to various security threats. These sensor nodes make a wireless network vulnerable to denial-of-service attacks. One of them is a wormhole attack that uses a low latency link between two malicious sensor nodes and affects the routing paths of the entire network. This attack is brutal as it is resistant to many cryptographic schemes and hard to observe within the network. This paper provides a comprehensive review of the literature on the subject of the detection and mitigation of wormhole attacks in wireless sensor networks. The existing surveys are also explored to find gaps in the literature. Several existing schemes based on different methods are also evaluated critically in terms of throughput, detection rate, low energy consumption, packet delivery ratio, and end-to-end delay. As artificial intelligence and machine learning have massive potential for the efficient management of sensor networks, this paper provides AI- and ML-based schemes as optimal solutions for the identified state-of-the-art problems in wormhole attack detection. As per the author’s knowledge, this is the first in-depth review of AI- and ML-based techniques in wireless sensor networks for wormhole attack detection. Finally, our paper explored the open research challenges for detecting and mitigating wormhole attacks in wireless networks.
Publisher: Wiley
Date: 17-12-2010
DOI: 10.1096/FJ.10-173278
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.CHOM.2015.07.008
Abstract: The expression of gluconeogenic enzymes is typically repressed when glucose is available. The protozoan parasite Toxoplasma gondii utilizes host glucose to sustain high rates of intracellular replication. However, despite their preferential utilization of glucose, intracellular parasites constitutively express two isoforms of the gluconeogenic enzyme fructose 1,6-bisphosphatase (TgFBP1 and TgFBP2). The rationale for constitutive expression of FBPases in T. gondii remains unclear. We find that conditional knockdown of TgFBP2 results in complete loss of intracellular growth in vitro under glucose-replete conditions and loss of acute virulence in mice. TgFBP2 deficiency was rescued by expression of catalytically active FBPase and was associated with altered glycolytic and mitochondrial TCA cycle fluxes, as well as dysregulation of glycolipid, amylopectin, and fatty acid biosynthesis. Futile cycling between gluconeogenic and glycolytic enzymes may constitute a regulatory mechanism that allows T. gondii to rapidly adapt to changes in nutrient availability in different host cells.
Publisher: MDPI AG
Date: 02-12-2022
DOI: 10.3390/PATHOGENS11121464
Abstract: Background: Toxoplasma gondii and Neospora caninum are major protozoan parasites of worldwide distribution and significance in veterinary medicine and, for T. gondii, in public health. Cats and dogs, as final hosts for T. gondii and N. caninum, respectively, have a key function in environmental contamination with oocysts and, thus, in parasite transmission. Very little is known about the prevalence of T. gondii infections in dogs and cats in Egypt, and even less about the prevalence of N. caninum in the same hosts. Methods: In the current study, 223 serum s les of both dogs (n = 172) and cats (n = 51) were investigated for specific antibodies to T. gondii and N. caninum using commercially available ELISAs. A risk factor analysis was conducted to identify factors associated with seropositivity. Results & discussion: Exposure to T. gondii was reported in 23.3% of the dogs and in 9.8% of the cats, respectively. In addition, N. caninum-specific antibodies were recorded in 5.8% of dogs and in 3.4% of cats. A mixed infection was found in two dogs (1.2%) and in one cat (2%). Antibodies to T. gondii in dogs were significantly more frequent in dogs aged 3 years or more and in male German Shepherds. As this breed is often used as watchdogs and was the most s led breed in Alexandria governorate, the purpose “watchdog” (compared to “stray” or “companion”), the male sex, and the governorate “Alexandria” also had a significantly higher seroprevalence for T. gondii. No factors associated with antibodies to N. caninum could be identified in dogs, and no significant factors were determined in cats for either T. gondii or N. caninum infection. Our study substantially adds to the knowledge of T. gondii infection in dogs and cats and presents data on N. caninum infection in cats for the first and in dogs in Egypt for the second time.
No related grants have been discovered for Nishith Gupta.