Publications by authors named "Amr E El-Hakim"

Article Synopsis
  • - The study focuses on Hyalomma dromedarii ticks, which are significant for transmitting pathogens to large animals in Egypt, especially as camels and cattle are imported from neighboring countries.
  • - Researchers analyzed the transcriptome of these ticks by examining mixed mRNAs from various life stages (eggs, larvae, nymphs, and both fed and unfed adults) to understand the biochemical interactions that take place during tick feeding.
  • - The results included a comparison of identified sequences with databases to identify potential protein functions and properties, setting the stage for further understanding of tick physiology and its implications for disease transmission in livestock.
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Ticks have harmful impacts on both human and animal health and cause considerable economic losses. Leucine aminopeptidase enzymes (LAP) play important roles during tick infestation to liberate vital amino acids necessary for growth. The aim of the current study is to identify, express and characterize the LAP from the hard tick Hyalomma dromedarii and elucidate its biochemical characteristics.

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Hepatocellular carcinoma and bacterial resistance are major health burdens nowadays. Thus, providing new therapies that overcome that resistance is of great interest, particularly those derived from nature rather than chemotherapeutics to avoid cytotoxicity on normal cells. Venomous animals are among the natural sources that assisted in the discovery of novel therapeutic regimens.

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Background: The recently emerged SARS-CoV-2 caused a global pandemic since the last two years. The urgent need to control the spread of the virus and rapid application of the suitable health measures raised the importance of available, rapid, and accurate diagnostic approaches.

Objective: The purpose of this study is to describe a rapid in-house optimized ELISA based on the expression of the receptor binding domain (RBD) of the SARS-CoV-2 spike protein in a prokaryotic system.

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Ticks are hematophageal ectoparasites that transport major pathogens around the world. Glutathione S-transferases (GST) are involved in resistance to acaricide and redox balancing during the life cycle of the tick. The inhibition of tick GST enzymes by certain phenolic compounds, such as phenolic acids and tannins, can be a promising approach to tick control.

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Article Synopsis
  • * The study focused on purifying antigens from camel hydatid cysts to accurately detect echinococcosis using the ELISA method, identifying two main protein bands of 130 kDa and 55 kDa.
  • * An attempt to create a conjugate using peroxidase from turnip roots showed inferior results compared to commercially available horseradish peroxidase (HRP), with the best conjugation achieved at a 10% glutaraldehyde concentration.
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Article Synopsis
  • - The study investigates the potential of a new source of peroxidase from sycamore latex (POL) for antibody conjugation, comparing its properties to the widely used horseradish peroxidase (HRP).
  • - Results indicate that POL conjugates show better recovery rates, higher thermal stability, and a wider pH range than HRP conjugates, along with a demonstrated ability to bind effectively to substrates in immunoassays.
  • - The findings suggest that POL is a promising alternative for use in immunodiagnostic kits due to its superior storage stability and enzymatic activity over time.
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A homodimeric l-amino acid oxidase enzyme (Cv-LAAOI) was isolated from the venom of Cerastes vipera (Egyptian Sand viper) using gel filtration followed by anion exchange chromatography. The molecular mass of Cv-LAAO is 120 kDa in its native form and 60 kDa in its monomeric form. The optimum enzyme activity was achieved on l-Leucine as a substrate in 50 mM buffer pH 7.

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A thermostable metallo-collagenase enzyme (150 kDa), recently identified in a newly isolated actinomycestes strain (Nocardiopsis dassonvillei NRC2aza), has been purified from natural source, characterized to have application in wound healing. A simple 3 step purification procedure gave an increase of purity by 6.23 fold with a specific activity of 387.

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A serine metallokeratinase enzyme (30 kDa) produced by a newly isolated Bacillus strain (Bacillus pumilus NRC21) cultivated under optimized conditions in medium containing chicken feather meal was purified and characterized in a set of biochemical assays. The purification was carried out using two successive chromatographic steps; cation exchange chromatography on CM-cellulose and gel filtration on sephadex G-100 columns. The purified enzyme showed a specific activity of 2000 units/mg protein against 170 units/mg protein for crude extract with 12 fold purification.

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Infestation of cattle by ticks of Rhipicephalus spp. results in severe veterinary and economical losses. Identification of novel proteins from tick salivary glands will enhance our understanding of several aspects of tick physiology and will aid in the development of anti-tick vaccines.

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The control of Rhipicephalus annulatus ticks in Egypt and other countries relies principally on the application of acaricides which have many drawbacks. Recently, cattle vaccination against ticks showed a potential unconventional approach to control ticks. As a target, salivary glands contain various proteins that may play specific roles during attachment, feeding and may modulate the immune system of the host.

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The middle capsid protein of rotavirus, VP6, constitutes approximately 51% of the virion by weight. The high degree of identity (>87-99%) in the primary amino acid sequences of VP6 proteins from mammalian rotaviruses suggests VP6-based vaccines could potentially provide heterotypic protection. For this reason, significant effort has been directed toward producing recombinant rotavirus VP6 vaccines.

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Article Synopsis
  • - A novel keratinolytic enzyme (32kDa) was isolated from a newly discovered Bacillus subtilis NRC3 strain, which was grown using chicken feather meal and then purified through cation exchange chromatography and gel filtration methods.
  • - The purified enzyme displayed significantly higher specific activity than the crude extract, achieving 31-fold purification, and was classified as a metallo-keratinase due to its response to various cations and inhibitors.
  • - The enzyme's optimal pH and temperature for activity were found to be around 7.5-8.0 and 40-50°C, respectively, while remaining stable across a wide range, suggesting its potential utility for environmentally friendly management of feather waste.
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In order to identify antigens that can help prevent camel tick infestations, three major glycoproteins (GLPs) about 97, 66 and 40 kDa in size were purified from adult and larval Egyptian ticks, Hyalomma (H.) dromedarii, using a single-step purification method with Con-A sepharose. The purified GLPs were evaluated as vaccines against camel tick infestation in rabbits.

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This study reported the purification and characterization of a cytotoxic, neurotoxin-like protein derived from the venom of the Egyptian cobra Naja haje haje, Elapidae family, and explored their mechanistic role in the cell death. The protein purification was performed through ion-exchange chromatography and gel-filtration chromatography and was characterized by SDS-PAGE, amino acid sequencing, and mass spectrum analysis. The antitumor activity of Naja haje venom (NHV) and its fractions (NHVI, NHV-Ia, NHV-Ib, NHV-Ic, NHV-II, NHV-III, and NHV-IV) were tested against different human cancer cell lines.

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Article Synopsis
  • Scientists studied a special type of tick called Rhipicephalus annulatus and found a new protein they named Ra-sHSPII by using antibodies from rabbits.
  • This protein can help protect other proteins from getting damaged by heat, acting like a shield.
  • The researchers found that Ra-sHSPII reacts well with different tick proteins, showing it might be useful for understanding how ticks survive and protect themselves.
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The present study was conducted to identify new target immunogenic molecules from the larval stage of the cattle tick, Boophilus annulatus (Acari: Ixodidae). Two specific larval glycoproteins (GLPs) were isolated by two-step affinity chromatography. The larval immunogens were first purified with CNBr-Sepharose coupled to rabbit anti-larval immunoglobulins, and the glycoproteins were then purified with Con-A Sepharose.

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