Asmaa Samir Attia El-shershaby
@nrc.sci.eg
national research centre
RESEARCH INTERESTS
Genetics and molecular biology, plant biotechnology
Scopus Publications
Scopus Publications
Mohamed N. F. Shaheen, Elmahdy Mohamed Elmahdy, Neveen M. Rizk, Sayeda M. Abdo, Nahla A. Hussein, Asmaa Elshershaby, Yasser E. Shahein, Mariam E. Fawzy, Mohamed Azab El-Liethy, Mohamed A. Marouf,et al.
Springer Science and Business Media LLC
Nahla A. Hussein, Asmaa S. El-Shershaby, Shaimaa Abdel-Moez, Amr E. El-Hakim, and Yasser E. Shahein
Springer Science and Business Media LLC
Abstract Background Members belonging to the tick genus Hyalomma function as a multi-host reservoir for several pathogens and important parasites infesting large animals, such as camels, goats, cattle and sheep. In Egypt, there is a high risk of pathogen transmission as camels and cattle are imported from Sudan and Ethiopia and shipped to slaughterhouses and animal markets located in populated areas. Hyalomma dromedarii ticks are semi-desert vectors and, similar to other members of the genus Hyalomma, characterized by long-term feeding. During this process, different physiological, biochemical and immunological interactions occur within both the feeding ticks and their hosts. These biological changes affect the different tick developmental phases. The aim of this study was to explore the transcriptome of mixed messenger RNAs (mRNAs) collected from H. dromedarii eggs, larvae, nymphs and fed and unfed adults, using the Gateway cDNA library prepared in pCMV sport6.1 vector Methods The clones were sequenced and searched for potential secreted, membrane-associated or transmembrane (SMaT) sequences. The identified SMaT sequences were compared to the National Center for Biotechnology Information (NCBI) non-redundant protein sequence database using Blastx. Annotation and functional classification were achieved by comparison to sequences in the UniProtKB/Swiss-Prot and VectorBase databases and to the publicly available annotated proteomes of six hard tick species (H. asiaticum, Rhipicephalus sanguineus sensu lato, Dermacentor silvarum, Rhipicephalus microplus, Ixodes scapularis and Haemaphysalis longicornis) in addition to the published H. dromedarii sialotranscriptome. For the common sequences, we predicted the physicochemical properties, secondary structures and antigenicity of the fragments similar to matched sequences in the UniProtKB/Swiss-Prot database using three different methods. Results The quality-trimmed sequences from the cDNA library revealed 319 SMaT transcripts among 1248 sequenced clones. Annotation of the SMaT sequences using the UniProtKB/Swiss-Prot database revealed only 232 non-redundant sequences with at least one match. According to the UniProtKB/Swiss-Prot and Vectorbase databases, the SMaT sequences were either secreted (extracellular) (29 sequences) or cellular (transmembrane and membrane-associated) (203 sequences). These were classified into 10 functional classes: biogenesis (49 sequences), defense (9 sequences), development (36 sequences), signal transduction (28 sequences), transport (15 sequences), protein modification (33 sequences), homeostasis (6 sequences), metabolism (45 sequences) and miscellaneous/uncharacterized (11 sequences). A total of 60 sequences were shared between H. dromedarii SMaT, the sialotransciptome and six other hard tick species. The peptide fragments of these sequences that aligned to proteins from the UniProtKB/Swiss-Prot database were predicted to be promising epitopes and mapped to 10 functional classes at different ratios. Conclusions Our immuno-informatics analysis identified 60 sequences common among hard tick species and encoded by H. dromedarii salivary glands. These annotated SMaT sequences of H. dromedarii will pave the way for the identification and discovery of novel potential protective antigens that are either secreted, membrane-associated or transmembrane. Graphical abstract
Sahar Ahmed, Waleed Abdelgaber Nemr, Asmaa El-Shershaby, Ehab Ali Mohamed Fouad, Mohamed Abd El-Fatah Mahmoud, Fatima Liaqat, Viskam Wijewardana, and Hermann Unger
Springer Science and Business Media LLC
AbstractPasteurella multocida is affecting a multitude of animals and severely affects livestock production. Existing vaccines are mostly chemically inactivated and do not lead to wide protection. Irradiated vaccines are enjoying a renaissance and the concept of “replication defficient but metabolically active” vaccines was recently evaluated in several vaccine trials. P. multocida was isolated from the nasal swab, blood, and lung swab samples from infected rabbits. Gamma irradiation of P. multocida for inhibition of replication was evaluated at an optimized irradiation dose of 10 Kgy established. Four groups of rabbits were (mock) vaccinated with a commercial P. multocida vaccine and three irradiated formulations as liquid, lyophilized formulations with added Trehalose and lyophilized-Trehalose with an “activation” culturing the irradiated bacteria for 24 in broth. Evaluation of humoral immune response by ELISA showed that all three irradiated vaccines produced an effective, protective, and continued IgG serum level after vaccination and bacterial challenge. The IFN-γ expression is maintained at a normal level, within each individual group however, the lyophilized trehalose irradiated vaccine showed peak mean of IFN-γ titer at one week after booster dose (day 21) which was statistically significant. Cumulatively, the results of this study show that gamma-irradiated P. multocida vaccines are safe and protect rabbits against disease. Moreover, Rabbits’ immunization with the three irradiated formulations avoided adverse side effects as compared to commercial polyvalent vaccine, the body weight gain for the irradiated vaccine groups indicates less stress compared to the commercial polyvalent vaccine.
Sahar Ahmed, Mohamed Abd El-Fatah Mahmoud, Waleed Abdelgaber Nemr, Eman Hussein Abdel-Rahman, Asmaa El-Shershaby, Ehab Ali Fouad, Fatima Liaqat, and Viskam Wijewardana
Springer Science and Business Media LLC
Ashraf A. Tabll, Yasser E. Shahein, Mohamed M. Omran, Nahla A. Hussein, Asmaa El-Shershaby, Ana Petrovic, Marija Glasnovic, Robert Smolic, and Martina Smolic
SAGE Publications
Due to their high specificity and scalability, Monoclonal IgY antibodies have emerged as a valuable alternative to traditional polyclonal IgY antibodies. This abstract provides an overview of the production and purification methods of monoclonal IgY antibodies, highlights their advantages over polyclonal IgY antibodies, and discusses their recent applications. Monoclonal recombinant IgY antibodies, in contrast to polyclonal IgY antibodies, offer several benefits. such as derived from a single B-cell clone, monoclonal antibodies exhibit superior specificity, ensuring consistent and reliable results. Furthermore, it explores the suitability of monoclonal IgY antibodies for low- and middle-income countries, considering their cost-effectiveness and accessibility. We also discussed future directions and challenges in using polyclonal IgY and monoclonal IgY antibodies. In conclusion, monoclonal IgY antibodies offer substantial advantages over polyclonal IgY antibodies regarding specificity, scalability, and consistent performance. Their recent applications in diagnostics, therapeutics, and research highlight their versatility.
Asmaa El-Shershaby, Nahla Hussein, Esraa Ali, Amr El-Hakim, Ashraf Tabll, Mohamed Shaheen, Ibrahim Ali, Mahmoud Elshall, and Yasser Shahein
Informa UK Limited
Several diagnostic measures have been employed to precisely detect the SARS-CoV-2 viral infection using viral antigens, nucleic acids, and other serological approaches. The sensitivity and specificity of the serological tests remain a challenging need. Here, we describe the detection of human anti-SARS-CoV-2 IgG and IgM antibodies qualitatively through two optimized in-house ELISA and lateral flow immunoassay. Both approaches are based on the prokaryotic expression of 50 kDa SARS-CoV-2 recombinant nucleocapsid protein. This SARS-CoV-2rN-6×His was used either to coat ELISA plates or to be conjugated to gold nanoparticles followed by colorimetric detection of bound human IgG or IgM. In the LFA, we show the optimization of nanoparticle size, protein-binding capacity, membrane treatment, and finally testing the potential capacity of using either the optimized ELISA or LFA in detecting antibodies raised against viral infection. Assessment of both methods was carried out using human sera-positive and negative SARS-CoV-2 antibodies. The ELISA and LFA tests showed 86%, 96.5% sensitivity, 92%, 93.75% specificity, 97%, 98.2% PPV, and 64%, 88.2% NPV, respectively. In conclusion, both approaches were able to successfully detect human antibodies against SARS-CoV-2 nucleocapsid protein. The importance of both protocols cannot be overstated in the detection and diagnosis of viral infections, especially in developing countries.
Nahla A. Hussein, Esraa A.A. Ali, Amr E. El-Hakim, Ashraf A. Tabll, Asmaa El-Shershaby, Azza Salamony, Mohamed N.F. Shaheen, Ibrahim Ali, Mahmoud Elshall, and Yasser E. Shahein
IOS Press
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. METHODS: We show the expression of the 30 kDa recombinant SARS-CoV-2 RBD-6×His in four different E. coli strains (at 28∘C using 0.25mM IPTG) including the expression strain E. coli BL21 (DE3) Rosetta Gami. SARS-CoV-2 rRBD-6×His protein was purified, refolded, and used as an antigen coat to assess antibody response in human sera against SARS-CoV-2 infection. RESULTS: The assessment was carried out using a total of 155 human sero-positive and negative SARS-CoV-2 antibodies. The ELISA showed 69.5% sensitivity, 88% specificity, 78.5% agreement, a positive predictive value (PPV) of 92.3%, and a negative predictive value of 56.5%. Moreover, the optical density (OD) values of positive samples significantly correlated with the commercial kit titers. CONCLUSIONS: Specific human antibodies against SARS-CoV-2 spike protein were detected by rapid in-house ELISA in sera of human COVID-19-infected patients. The availability of this in-house ELISA protocol would be valuable for various diagnostic and epidemiological applications, particularly in developing countries. Future studies are planned for the use of the generated SARS-CoV-2 rRBD-6×His protein in vaccine development and other diagnostic applications.
Asmaa El-shershaby, Sarah Ullrich, Stefan Simm, Klaus-Dieter Scharf, Enrico Schleiff, and Sotirios Fragkostefanakis
Elsevier BV
In all eukaryotes, the response to heat stress (HS) is dependent on the activity of HS transcription factors (Hsfs). Plants contain a large number of Hsfs, however, only members of the HsfA1 subfamily are considered as master regulators of stress response and thermotolerance. In Solanum lycopersicum, among the four HsfA1 members, only HsfA1a has been proposed to possess a master regulator function. We performed a comparative analysis of HsfA1a, HsfA1b, HsfA1c and HsfA1e at different levels of regulation and function. HsfA1a is constitutively expressed under control and stress conditions, while the other members are induced in specific tissues and stages of HS response. Despite that all members are localized in the nucleus when expressed in protoplasts, only HsfA1a shows a wide range of basal activity on several HS-induced genes. In contrast, HsfA1b, HsfA1c, and HsfA1e show only high activity for specific subsets of genes. Domain swapping mutants between HsfA1a and HsfA1c revealed that the variation in that transcriptional transactivation activity is due to differences in the DNA binding domain (DBD). Specifically, we identified a conserved arginine (R107) residue in the turn of β3 and β4 sheet in the C-terminus of the DBD of HsfA1a that is highly conserved in plant HsfA1 proteins, but is replaced by leucine and cysteine in tomato HsfA1c and HsfA1e, respectively. Although not directly involved in DNA interaction, R107 contributes to DNA binding and consequently the activity of HsfA1a. Thus, we demonstrate that this variation in DBD in part explains the functional diversification of tomato HsfA1 members.
Dominik Marko, Asmaa El-shershaby, Filomena Carriero, Stephan Summerer, Angelo Petrozza, Rina Iannacone, Enrico Schleiff, and Sotirios Fragkostefanakis
MDPI AG
The identification of heat stress (HS)-resilient germplasm is important to ensure food security under less favorable environmental conditions. For that, germplasm with an altered activity of factors regulating the HS response is an important genetic tool for crop improvement. Heat shock binding protein (HSBP) is one of the main negative regulators of HS response, acting as a repressor of the activity of HS transcription factors. We identified a TILLING allele of Solanum lycopersicum (tomato) HSBP1. We examined the effects of the mutation on the functionality of the protein in tomato protoplasts, and compared the thermotolerance capacity of lines carrying the wild-type and mutant alleles of HSBP1. The methionine-to-isoleucine mutation in the central heptad repeats of HSBP1 leads to a partial loss of protein function, thereby reducing the inhibitory effect on Hsf activity. Mutant seedlings show enhanced basal thermotolerance, while mature plants exhibit increased resilience in repeated HS treatments, as shown by several physiological parameters. Importantly, plants that are homozygous for the wild-type or mutant HSBP1 alleles showed no significant differences under non-stressed conditions. Altogether, these results indicate that the identified mutant HSBP1 allele can be used as a genetic tool in breeding, aiming to improve the thermotolerance of tomato varieties.
Sotirios Fragkostefanakis, Stefan Simm, Asmaa El-Shershaby, Yangjie Hu, Daniela Bublak, Anida Mesihovic, Katrin Darm, Shravan Kumar Mishra, Bettina Tschiersch, Klaus Theres,et al.
Wiley
Plants code for a multitude of heat stress transcription factors (Hsfs). Three of them act as central regulators of heat stress (HS) response in tomato (Solanum lycopersicum). HsfA1a regulates the initial response, and HsfA2 controls acquired thermotolerance. HsfB1 is a transcriptional repressor but can also act as co-activator of HsfA1a. Currently, the mode of action and the relevance of the dual function of HsfB1 remain elusive. We examined this in HsfB1 overexpression or suppression transgenic tomato lines. Proteome analysis revealed that HsfB1 overexpression stimulates the co-activator function of HsfB1 and consequently the accumulation of HS-related proteins under non-stress conditions. Plants with enhanced levels of HsfB1 show aberrant growth and development but enhanced thermotolerance. HsfB1 suppression has no significant effect prior to stress. Upon HS, HsfB1 suppression strongly enhances the induction of heat shock proteins due to the higher activity of other HS-induced Hsfs, resulting in increased thermotolerance compared with wild-type. Thereby, HsfB1 acts as co-activator of HsfA1a for several Hsps, but as a transcriptional repressor on other Hsfs, including HsfA1b and HsfA2. The dual function explains the activation of chaperones to enhance protection and regulate the balance between growth and stress response upon deviations from the homeostatic levels of HsfB1.