TalaaT Ahmed | University of Texas at San Antonio (original) (raw)

Papers by TalaaT Ahmed

Research paper thumbnail of Phylogenetic analyses of peanut resistance gene candidates and screening of different genotypes for polymorphic markers

Saudi Journal of Biological Sciences, 2010

The nucleotide-binding-site-leucine-rich-repeat (NBS-LRR)-encoding gene family has attracted much... more The nucleotide-binding-site-leucine-rich-repeat (NBS-LRR)-encoding gene family has attracted much research interest because approximately 75% of the plant disease resistance genes that have been cloned to date are from this gene family. Here, we describe a collection of peanut NBS-LRR resistance gene candidates (RGCs) isolated from peanut (Arachis) species by mining Gene Bank data base. NBS-LRR sequences assembled into TIR-NBS-LRR (75.4%) and non-TIR-NBS-LRR (24.6%) subfamilies. Total of 20 distinct clades were identified and showed a high level of sequence divergence within TIR-NBS and non-TIR-NBS subfamilies. Thirty-four primer pairs were designed from these RGC sequences and used for screening different genotypes belonging to wild and cultivated peanuts. Therefore, peanut RGC identified in this study will provide useful tools for developing DNA markers and cloning the genes for resistance to different pathogens in peanut.

Research paper thumbnail of Thermolysis of 3-phenyl-5-arylamino-1,2,4-oxadiazole and thiadiazole derivatives

Heteroatom Chemistry, 1997

Thermal reactions of 3-phenyl-5-arylamino-1,2,4-oxadiazoles I and II were investigated. Neat heat... more Thermal reactions of 3-phenyl-5-arylamino-1,2,4-oxadiazoles I and II were investigated. Neat heating at ca. 250ЊC for 6 hours

Research paper thumbnail of Groundwater quality model with applications to various aquifers

Environmental Earth Sciences, 2009

A finite element model was developed in order to solve for both regional groundwater flow and con... more A finite element model was developed in order to solve for both regional groundwater flow and conservative solute transport in porous medium. The model was applied to a 55-sq-km groundwater basin in the Ruehen region of Germany using a network of 1450 elements and 780 nodes. This model was used in simulating a contaminant plume clone through injection. Similarly, the model was applied to a 4750-sq-km portion in the eastern Nile Delta aquifer in Egypt. The model was applied to this portion of the delta using a network of 543 elements and 310 nodes with the main objective of simulating the problem of salt water intrusion.

Research paper thumbnail of An Integrated High-density Linkage Map of Soybean with RFLP, SSR, STS, and AFLP Markers Using A Single F2 Population

Dna Research, 2008

Soybean [Glycine max (L.) Merrill] is the most important leguminous crop in the world due to its ... more Soybean [Glycine max (L.) Merrill] is the most important leguminous crop in the world due to its high contents of high-quality protein and oil for human and animal consumption as well as for industrial uses. An accurate and saturated genetic linkage map of soybean is an essential tool for studies on modern soybean genomics. In order to update the linkage map of a F 2 population derived from a cross between Misuzudaizu and Moshidou Gong 503 and to make it more informative and useful to the soybean genome research community, a total of 318 AFLP, 121 SSR, 108 RFLP, and 126 STS markers were newly developed and integrated into the framework of the previously described linkage map. The updated genetic map is composed of 509 RFLP, 318 SSR, 318 AFLP, 97 AFLP-derived STS, 29 BAC-end or ESTderived STS, 1 RAPD, and five morphological markers, covering a map distance of 3080 cM (Kosambi function) in 20 linkage groups (LGs). To our knowledge, this is presently the densest linkage map developed from a single F 2 population in soybean. The average intermarker distance was reduced to 2.41 from 5.78 cM in the earlier version of the linkage map. Most SSR and RFLP markers were relatively evenly distributed among different LGs in contrast to the moderately clustered AFLP markers. The number of gaps of more than 25 cM was reduced to 6 from 19 in the earlier version of the linkage map. The coverage of the linkage map was extended since 17 markers were mapped beyond the distal ends of the previous linkage map. In particular, 17 markers were tagged in a 5.7 cM interval between CE47M5a and Satt100 on LG C2, where several important QTLs were clustered. This newly updated soybean linkage map will enable to streamline positional cloning of agronomically important trait locus genes, and promote the development of physical maps, genome sequencing, and other genomic research activities.

Research paper thumbnail of Signature Recognition using Multi Scale Fourier Descriptor And Wavelet Transform

Computing Research Repository, 2010

Key words: signature recognition; Fourier Descriptor; Wavelet transform; personal verification

Research paper thumbnail of Identification of RFLP markers linked with heading date and its heterosis in hexaploid wheat

Euphytica, 2000

Recombinant inbred lines (RILs) from a cross between hexaploid wheat (T. aestivum cv. Chinese Spr... more Recombinant inbred lines (RILs) from a cross between hexaploid wheat (T. aestivum cv. Chinese Spring (CS) and T. spelta (Sp)) were used for RFLP analysis of heading date and heterosis. Fourteen RFLP markers linking with heading date were identified; two were localized on chromosome 1A, one on 2A, three on 2B, one on 2D, four on 5A, two on 7A and one unlinked but reported to be on group 2. All of these markers may be attributable to genes for earliness per se. However, the markers in the chromosomes of 1A and 7A are new to this study. RILs were crossed with (tim)-CS, the alloplasmic CS with T. timopheevi cytoplasm, and the heterosis from earlier-parent and mid-parents were calculated for the F1s to examine the heterotic effect toward earliness on heading date. Five and two RFLP markers were associated with heterosis from the earlier-parent and mid-parents, respectively. They were distributed on the chromosomes of homoeologous groups 1 and 2.

Research paper thumbnail of Contributory presentations/posters

Journal of Biosciences, 1999

Research paper thumbnail of Signature Recognition using Multi Scale Fourier Descriptor And Wavelet Transform

Key words: signature recognition; Fourier Descriptor; Wavelet transform; personal verification

Research paper thumbnail of Combined electro-photochemical oxidation for iron removal from ground water

Desalination and Water Treatment, 2011

Iron in water presents health hazard, its presence in water may cause taste and staining problems... more Iron in water presents health hazard, its presence in water may cause taste and staining problems. Currently applied water treatment techniques consist of a combination of different methods to achieve the elimination of harmful pollutants. The aim of this study is to investigate the efficiency of the photo-assisted electrochemical oxidation process for the removal of dissolved iron as a cheaper technology. This process could be used at room temperature and low pressure without the need for special equipment and complex operation. The photoelectrochemical cell used in this study was composed of carbon cathode, aluminum anode and high pressure mercury lamp. The effect of the irradiation time, initial concentration of iron, amount of electrolyte and current intensity on the removal efficiency of iron was investigated through series of batch runs in a photo-electrochemical reactor. Results indicated that higher iron removal was obtained at neutral pH of the solution, 20 min irradiation time, 125 ppm of NaCl as electrolyte and (0.25 A) current intensity. By this technique, the ferrous ion was oxidized and is precipitated easily as ferric ions.

Research paper thumbnail of Phylogenetic analyses of peanut resistance gene candidates and screening of different genotypes for polymorphic markers

Saudi Journal of Biological Sciences, 2010

The nucleotide-binding-site-leucine-rich-repeat (NBS-LRR)-encoding gene family has attracted much... more The nucleotide-binding-site-leucine-rich-repeat (NBS-LRR)-encoding gene family has attracted much research interest because approximately 75% of the plant disease resistance genes that have been cloned to date are from this gene family. Here, we describe a collection of peanut NBS-LRR resistance gene candidates (RGCs) isolated from peanut (Arachis) species by mining Gene Bank data base. NBS-LRR sequences assembled into TIR-NBS-LRR (75.4%) and non-TIR-NBS-LRR (24.6%) subfamilies. Total of 20 distinct clades were identified and showed a high level of sequence divergence within TIR-NBS and non-TIR-NBS subfamilies. Thirty-four primer pairs were designed from these RGC sequences and used for screening different genotypes belonging to wild and cultivated peanuts. Therefore, peanut RGC identified in this study will provide useful tools for developing DNA markers and cloning the genes for resistance to different pathogens in peanut.

Research paper thumbnail of Thermolysis of 3-phenyl-5-arylamino-1,2,4-oxadiazole and thiadiazole derivatives

Heteroatom Chemistry, 1997

Thermal reactions of 3-phenyl-5-arylamino-1,2,4-oxadiazoles I and II were investigated. Neat heat... more Thermal reactions of 3-phenyl-5-arylamino-1,2,4-oxadiazoles I and II were investigated. Neat heating at ca. 250ЊC for 6 hours

Research paper thumbnail of Groundwater quality model with applications to various aquifers

Environmental Earth Sciences, 2009

A finite element model was developed in order to solve for both regional groundwater flow and con... more A finite element model was developed in order to solve for both regional groundwater flow and conservative solute transport in porous medium. The model was applied to a 55-sq-km groundwater basin in the Ruehen region of Germany using a network of 1450 elements and 780 nodes. This model was used in simulating a contaminant plume clone through injection. Similarly, the model was applied to a 4750-sq-km portion in the eastern Nile Delta aquifer in Egypt. The model was applied to this portion of the delta using a network of 543 elements and 310 nodes with the main objective of simulating the problem of salt water intrusion.

Research paper thumbnail of An Integrated High-density Linkage Map of Soybean with RFLP, SSR, STS, and AFLP Markers Using A Single F2 Population

Dna Research, 2008

Soybean [Glycine max (L.) Merrill] is the most important leguminous crop in the world due to its ... more Soybean [Glycine max (L.) Merrill] is the most important leguminous crop in the world due to its high contents of high-quality protein and oil for human and animal consumption as well as for industrial uses. An accurate and saturated genetic linkage map of soybean is an essential tool for studies on modern soybean genomics. In order to update the linkage map of a F 2 population derived from a cross between Misuzudaizu and Moshidou Gong 503 and to make it more informative and useful to the soybean genome research community, a total of 318 AFLP, 121 SSR, 108 RFLP, and 126 STS markers were newly developed and integrated into the framework of the previously described linkage map. The updated genetic map is composed of 509 RFLP, 318 SSR, 318 AFLP, 97 AFLP-derived STS, 29 BAC-end or ESTderived STS, 1 RAPD, and five morphological markers, covering a map distance of 3080 cM (Kosambi function) in 20 linkage groups (LGs). To our knowledge, this is presently the densest linkage map developed from a single F 2 population in soybean. The average intermarker distance was reduced to 2.41 from 5.78 cM in the earlier version of the linkage map. Most SSR and RFLP markers were relatively evenly distributed among different LGs in contrast to the moderately clustered AFLP markers. The number of gaps of more than 25 cM was reduced to 6 from 19 in the earlier version of the linkage map. The coverage of the linkage map was extended since 17 markers were mapped beyond the distal ends of the previous linkage map. In particular, 17 markers were tagged in a 5.7 cM interval between CE47M5a and Satt100 on LG C2, where several important QTLs were clustered. This newly updated soybean linkage map will enable to streamline positional cloning of agronomically important trait locus genes, and promote the development of physical maps, genome sequencing, and other genomic research activities.

Research paper thumbnail of Signature Recognition using Multi Scale Fourier Descriptor And Wavelet Transform

Computing Research Repository, 2010

Key words: signature recognition; Fourier Descriptor; Wavelet transform; personal verification

Research paper thumbnail of Identification of RFLP markers linked with heading date and its heterosis in hexaploid wheat

Euphytica, 2000

Recombinant inbred lines (RILs) from a cross between hexaploid wheat (T. aestivum cv. Chinese Spr... more Recombinant inbred lines (RILs) from a cross between hexaploid wheat (T. aestivum cv. Chinese Spring (CS) and T. spelta (Sp)) were used for RFLP analysis of heading date and heterosis. Fourteen RFLP markers linking with heading date were identified; two were localized on chromosome 1A, one on 2A, three on 2B, one on 2D, four on 5A, two on 7A and one unlinked but reported to be on group 2. All of these markers may be attributable to genes for earliness per se. However, the markers in the chromosomes of 1A and 7A are new to this study. RILs were crossed with (tim)-CS, the alloplasmic CS with T. timopheevi cytoplasm, and the heterosis from earlier-parent and mid-parents were calculated for the F1s to examine the heterotic effect toward earliness on heading date. Five and two RFLP markers were associated with heterosis from the earlier-parent and mid-parents, respectively. They were distributed on the chromosomes of homoeologous groups 1 and 2.

Research paper thumbnail of Contributory presentations/posters

Journal of Biosciences, 1999

Research paper thumbnail of Signature Recognition using Multi Scale Fourier Descriptor And Wavelet Transform

Key words: signature recognition; Fourier Descriptor; Wavelet transform; personal verification

Research paper thumbnail of Combined electro-photochemical oxidation for iron removal from ground water

Desalination and Water Treatment, 2011

Iron in water presents health hazard, its presence in water may cause taste and staining problems... more Iron in water presents health hazard, its presence in water may cause taste and staining problems. Currently applied water treatment techniques consist of a combination of different methods to achieve the elimination of harmful pollutants. The aim of this study is to investigate the efficiency of the photo-assisted electrochemical oxidation process for the removal of dissolved iron as a cheaper technology. This process could be used at room temperature and low pressure without the need for special equipment and complex operation. The photoelectrochemical cell used in this study was composed of carbon cathode, aluminum anode and high pressure mercury lamp. The effect of the irradiation time, initial concentration of iron, amount of electrolyte and current intensity on the removal efficiency of iron was investigated through series of batch runs in a photo-electrochemical reactor. Results indicated that higher iron removal was obtained at neutral pH of the solution, 20 min irradiation time, 125 ppm of NaCl as electrolyte and (0.25 A) current intensity. By this technique, the ferrous ion was oxidized and is precipitated easily as ferric ions.