Browsing by Author "S. Hassan, Osama"

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Identification of Chromosomal Regions and Genetic Contributions of Genes Controlling Yield and Other Agronomic Traits in Durum Wheat Grown under Different Egyptian Environmental Conditions
(World Journal of Agricultural Sciences, 2007) A. Diab, Ayman; H. Fahmy, Ashraf; S. Hassan, Osama; M. Nachit, M.; A. Momtaz, Osama
A better understanding of the genetics of complex traits, such as yield, may be achieved by using molecular tools. Molecular markers provide a rapid approach to breeding for desired agronomic traits. To use them, it is necessary to determine the linkage between quantitative trait loci (QTLs) and such markers. This study was conducted to estimate the number and effect of alleles and the chromosomal locations of QTLs responsible for yield and some agronomic traits in durum wheat. A recombinant inbred population derived from a cross between two durum (Triticum turgidum L. var durum) parents Jennah Khetifa and Chaml was characterized for molecular markers and traits measured in different Egyptian environments. The environmental and genotypic effects on the measured traits were determined. Single point analysis (using Qgene) and conposite interval mapping (using QTL cartographer) were used to identify …
Influence of Nitrogen Source for the Improvement of Shoots and Roots on in vitro Strawberry (Fragaria ananassa DUCH)
(Agricultural Chemistry &Environmental Protection Society, 2014) S. Hassan, Osama; El-Sharabasy, Sherif; M. Aziz, Marina
Quantification of the gene expression of bell peppers (Capsicum annuum) ripening gene (s) using real-time PCR
(Academic Journals (Kenya), 2014) S. Hassan, Osama; Badie, Fatma; Safwat, Gehan
Fruits can be divided into two groups according to the regulatory mechanisms underlying their ripening process. The two ripening processes are climacteric and non-climacteric process; bell peppers are part of the non-climacteric plant groups. Bell peppers are members of the Solanacaea family. The Solanacaea family is best known for its fruits around the world. Today’s main focus is targeted to fruit ripening, in an attempt to increase the fruit’s shelf life. Many genes have been linked to the maturation of the fruit such as in Arabidopsis, the genes found were elongation factor-1α (LeEF-1A), expansin protein (leEXP1) and ripening inhibitor (RIN). This research focused on discovering similar genes that may play an important role in the ripening of peppers. Real-time PCR was performed on the cDNA of the green bell pepper fruit during its stage of development in order to detect and identify the expression pattern of the gene. Through the comparison of the gene expression found in bell pepper and the pods of Arabidopsis as model to dicotyledonous plant, some variations have been detected.
Real Time quantitative PCR Analysis of Transgenic Maize Plants Produced by Agrobacterium-mediated Transformation and Particle Bombardment
(Journal of Applied Sciences Research, 2008) K., Shireen; Shireen; S. Hassan, Osama
In transgenic plants, transgene copy number can greatly influence the expression level and genetic stability of the target gene. Thus, making estimation of transgene copy number and determination of the expression levels an important area of genetically modified crop research. The analysis of transgenic plants can be as important as the transformation process itself. After producing the primary transformants, it is very important to decide which plants contain the transgene and in how many copies[7]. While multiple copies are useful for over-expression experiments, single or low copy transformation events are preferred for most applications because they are stable over several generation of subsequent breeding[24]. The analysis of transgene integration has been recently relied on PCR-based methods, which require only small amounts of plant material and are easily automated for high-throughput quantita tion . Conventional PCR is commonly used for screening large numbers of putative transformants for transgenic sequences[23] and as an alternative to marker selection for segregation analysis[18]. However, conventional PCR analysis is plagued by false positives from contamination because a band with the size of the desired product is counted as signal, regardless of the intensity. Transgene copy number has traditionally been estimated by Southern analysis, although recently other methods, including comparative genomic hybridization, fluorescence in situ hybridization, multiplex amplifiable probe hybridization and microarray have been applied to copy number estimation. Unfortunately, all of these methods are laborious and time-consuming, require considerable amount of DNA from fresh or frozen samples and often involve the use of hazardous radioisotopes[34]. Real time PCR (ABI Prism 7700 Sequence Detection System) has been recently established as a rapid and sensitive technique for precise quantitation[13]. With real-time PCR as a quantification tool, it is possible to rapidly analyze large numbers of putative transformants from high-throughput transformation procedures[7]. Real-time PCR was initially used in plant research as a highly specific and sensitive detection
Role of Trehalose during Recovery from Drought Stress in Micropropagated Banana (Musa spp.) Transplants.
(RJPBCS RESEARCH JOURNAL PHARMACEUTICAL, BIOLOGICAL & CHEMICAL SCIENCES, 2017) A. Mahmoud, Rania; S. Hassan, Osama; Abou-Hashish, Ahmed; Amin, Ayman
Micropropagated banana (Musa spp.) plants are widely accepted by growers as valuable, pathogen-free stock materials. Water stress is believed to adversely affect growth and yield of banana plants, as banana plants requires water in sufficient quantity for their normal metabolic activities. Trehalose is one of the organic substances currently known to be involved in osmotic adjustment, a significant strategy for plant drought tolerance. The current study was aimed to assess the role of trehalose as a presoaking treatment at 0, 20, 60 or 100 mM in improving tolerance of banana plantlets under in vitro drought stress conditions and following transitional period required in preparation for planting in the field. The pretreatment of 20 mM trehalose enhanced growth of banana plantlets under in vitro drought stress conditions in terms of root system and fresh weight. Non of in vitro stressed un-pretreated plantlets succeeded to continue grow during recovery stage in the green house. Results showed markedly higher indicators of growth recovery in banana transplants previously supplied with 20 mM trehalose. This growth improvement was accompanied with enhancement of chemical composition in terms of increasing pigments and reducing total free amino acids contents to reach almost normal levels in addition to higher total phenols content and overall antioxidant activity even more than control plants. Sodium Dodicyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) analysis showed over expressed protein band of 32 kDa molecular weight in recovered transplants pretreated with the highest trehalose concentration (100 mM). Recovered transplants pretreated with trehalose at the lowest concentration (20 mM) showed balanced up regulation of both trehalose-6-phosphate synthase (TPS) and trehalase genes over control, while recovered transplants pretreated with trehalose at the highest concentration (100 mM) showed also over expression of TPS gene but down regulation of trehalase gene under control.
Universal and Specific 16S-23Sr RNA PCR Primers for Identification of Phytoplasma associated with sesame in Egypt.
(International Journal of Advanced Research in Biological Sciences, 2007) A.Youssef, Sahar; Sayed, Yasmin; S. Hassan, Osama; Safwat, Gehan; A. Shalaby, A.
Sesame (Sesamum indicum L.), family Pedaliaceae is one of the most ancient cultivated oilseed crops among the edible annual group in Egypt and all over the world. Phytoplasmas are pathogens of many plant species throughout the world including sesame causing a large variety of symptoms ranged from mild yellowing to death of infected plants. Symptomatic samples including green leaf-like floral organs, virescence, phyllody and proliferation were collected from infected sesame field in Giza Governorate. This research was undertaken to develop a diagnostic tool to identify phytoplasmas recently discovered infecting sesame in Egypt, and to classify them according to their phylogenetic group. Direct and nested PCR primers of 16S-23SrRNA gene, paired with phytoplasma universal primer followed by strain-specific PCR primers were used in this study. Spacer Region (SR) primers were employed for identification of Phytoplasma group associated with sesame symptoms. Results showed the presences of mixed infections of phytoplasma in the tested sesame samples which collected from the field with different type of Phytoplasma like symptoms. Results also indicated that polymerase chain reaction with primers from sequencing of 16S-32S rRNA and from SR opened new paths for research on phytoplasma identification and classification. Nested PCR has been applied to overcome problems related to sensitivity of phytoplasma detection, although this approach is more time consuming and subject to template. Unfortunately, nested-PCR also meets some difficulties: unspecific bands, false positives or negatives caused by DNA and contamination of single or nested PCR. Therefore, confirmation of PCR results by using different primer pair combinations (generic and group-specific) seems to be the way for correct phytoplasma identification in the examined sesame