Research Title: Epidemiology of multiple sclerosis in Arabs in Jordan: a comparative study between Jordanians and Palestinians

Author: Raida W. Khalil, Published Year: 1996

Journal of the Neurological Sciences, 135

Faculty: Science

Abstract: In a 2-year hospital-based study in Jordan 131 Arab multiple sclerosis patients were identified including 84 Palestinians and 36 Jordanians. Based on case ratio, multiple sclerosis was found to be twice as common among Palestinians than Jordanians. Other than the less marked female preponderance among Jordanian patients, the disease had the same clinical and paraclinical characteristics in both groups. It was more likely for Palestinian and Jordanian patients to originate from the northern parts of their countries, to be Rh negative and to be HLA-DR2 positive than their controls. Palestinians (patients and controls) did not show significant differences from Jordanians (patients and controls) in relation to their eye color, ABO and Rh blood groups distribution nor the HLA-DR or HLA-DQ (apart from HLA-DQ3) epitopes frequency, thus not offering any significant difference in the genetic-racial markers studies to explain the difference in the observed disease susceptibility. Previous studies demonstrated that 2 racially different populations sharing the same environment can have different risk of developing multiple sclerosis, but this study has shown that this can also be true for 2 racially similar populations sharing the same environment.

Keywords: Multiple sclerosis Epidemiology Comparative study Arabs Jordan

Research Title: Multiple sclerosis in Arabs in Jordan

Author: Raida W. Khalil, Published Year: 1995

Journal of the Neurological Sciences, 131

Faculty: Science

Abstract: In a 2-year hospital-based study (1992 and 1993), there were 131 multiple sclerosis patients attending 2 large referral hospitals in Jordan. Based on case ratios an overall rate of 32.1 (95% CI 19.7–55.2) was estimated. There were 126 Arabs of whom 84 were Palestinians and 36 indigenous Jordanians. Comparison of these subgroups, which had a similar age distribution revealed that the disease was twice as frequent in Palestinians (estimated (CI 2.8–90.8)) among Jordanians (estimated (CI 9.5–47.2)). Clinical presentation, pattern of disease, disability and HLA association were similar to that in the disease reported in Caucasians in the West. All investigations including neurophysiology and imaging were also very similar to Western reports.

Keywords: Multiple sclerosis Epidemiology HLA Arabs Jordan

Research Title: Randomly amplified polymorphic DNA (RAPD) analysis of some species of Aegilops.

Author: Sameer Masoud, Published Year: 2004

Dirasat, Agriculture Sciences , 31

Faculty: Science

Abstract: Randomly amplified polymorphic DNA (RAPD) analysis of some species of Aegilops.

Keywords: RAPD, Aegilops

Research Title: Genetic diversity in some Aegilops species in Jordan revealed using RAPD.

Author: Sameer Masoud, Published Year: 2004

Plant Genetic Resources Newsletter , 139

Faculty: Science

Abstract: Genetic diversity in some Aegilops species in Jordan revealed using RAPD.

Keywords: Aegilops species

Research Title: Performance of some Aegilops species under different water regimes (Research note)

Author: Sameer Masoud, Published Year: 2003

Dirasat, Agriculture Sciences , 30

Faculty: Science

Abstract: Performance of some Aegilops species under different water regimes (Research note)

Keywords: Aegilops species

Research Title: Specificity of different PCR primers for Verticillium dahliae isolated from olive trees in Jordan

Author: Sameer Masoud, Published Year: 2002

Mu’tah Lil-Buhuth wad-Dirasat , 17

Faculty: Science

Abstract: Three pairs of polymerase chain reaction (PCR) primers were compared to amplify characteristic DNA fingerprints of Verticillium dahliae Kleb. (the causal agent of olive vascular wilt disease). The primers include several combinations of the internal transcribed spacer (ITS) regions of nuclear ribosomal RNA (rRNA) genes and one pair from repetitive nuclear DNA sequences. Deoxyoligonucleotide primers specific to V. dahliae were synthesized based on the identified variable nucleotide sequences of the nuclear ITS regions of different Verticillium species that cause vascular wilt diseases. The PCR primers of nuclear repetitive DNA showed variable band intensities for the different isolates of V. dahliae isolated from olive trees in Jordan. This suggests genetic variabilities of the local isolates collected from olive. Primers based on the ITS sequences produced more consistently homogeneous and characteristic fingerprints using purified DNA from V. dahliae isolates. The detection limit of these ITS primers was further improved using nested PCR and to show the high specificity of the ITS primers. The first amplification reaction of nested PCR contained primers from the highly conserved DNA sequences of the 18S and 28S genes that flank the ITS regions. No PCR amplification produced using DNA isolated from different fungi in the same taxonomic class or other classes. These ITS-specific primer pair may be useful in developing diagnostic procedures of Verticillium wilt disease using single or nested PCR. تمت مقارنة ثلثة أزواج من بادئات تفاعل البلمرة التسلسلي(PCR (لتضخيم بصصصمات وراثية خاصة بفطر الفيرتسيليوم دالي المسبب لمرض الذبول الوعائي في الزيتصصون . أشصصتملت البادئات على مزيج من تسلسل المناطق المستنسخة والفاصلة بين جينات بناء الريبوسومات (ITS( وزوج بادئات من تسلسل النيوكليتدات المكررة فصصي الحصصامض النصصووي الريبصصوزي منقصصوص الوكسجين (DNA . (تم تحديد وبناء بادئات من مناطق (ITS (خاصة بالفيرتسيليوم دالي وفصصي المناطق التي تختلف بالتسلسل عن الفطريات الخرى التي تسصبب الصذبول الوعصائي . أنتجصت البادئات من تسلسل النيوكليتدات المكررة وباستعمال أل (PCR (حزم تختلف مصن حيصث الحصدة للعزلت المختلفة من الزيتون في الردن ، ومما يشير لختلفات وراثية بيصن عصزلت الفطصر المختلفة ، بينما أنتجت بادئات أل(ITS (حزم متجانسة لهذه العزلت . كما تم زيادة الحد الدنصصى للكشف عن DNA الفطر باستعمال(PCR (مزدوج وباستعمال بادئات في التفاعل الول مصن جينات (18S (و (28S (المحيطة في منطقة أل (ITS (واستعمال بادئات أل(ITS (في التفاعل الثاني . استعمل هذا الفحص لتأكيد خصوصية البادئات لفطر الفيرتسيليوم دالي وليس لفطريصصات أخرى في نفس الصف التصنيفي أو صفوف أخرى . وسيكون استعمال هذه البادئات في تفاعصصل مفرد أو مزدوج من أل(PCR (مفيدا في تطوير طرق تشخيصية لمرض الذبول الوعصصائي فصصي الزيتون .

Keywords: olive vascular wilt disease

Research Title: Over-expression of cinnamate 4-hydroxylase leads to increased accumulation of acetosyringone in elicited tobacco cell-suspension cultures.

Author: Sameer Masoud, Published Year: 2002

Planta, 214

Faculty: Science

Abstract: Cell-suspension cultures were produced from transgenic tobacco (Nicotiana tabacum L. ) plants harboring a constitutively expressed alfalfa cinnamate 4-hydroxylase (C4H) transgene. Increased levels of C4H enzyme activity in the transgenic cultures were observed only following exposure of the cells to yeast elicitor, although alfalfa C4H transcripts were expressed at a high level from the cauliflower mosaic virus 35S promoter in the absence of elicitation. Increased expression of C4H in elicited cell-suspension cultures had no appreciable effect on the HPLC profiles of soluble phenolic compounds. However, levels of one compound, subsequently identified as 3,5-dimethoxy-4-hydroxy acetophenone (acetosyringone), were strongly elevated in the wall-bound phenolic fraction. The results are discussed in relation to the correlation between C4H activity and the synthesis of 3,5-dimethylated hydroxycinnamic acid derivatives in tobacco.

Keywords: Cell-suspension cultures, cinnamate 4-hydroxylase

Research Title: Altering expression of cinnamic acid 4-hydroxylase in transgenic plants identifies a feedback loop at the entry point into the phenylpropanoid pathway

Author: Sameer Masoud, Published Year: 2000

Plant Physiology , 122

Faculty: Science

Abstract: Pharmacological evidence implicates trans-cinnamic acid as a feedback modulator of the expression and enzymatic activity of the first enzyme in the phenylpropanoid pathway, Lphenylalanine ammonia-lyase (PAL). To test this hypothesis independently of methods that utilize potentially non-specific inhibitors, we generated transgenic tobacco lines with altered activity levels of the second enzyme of the pathway, cinnamic acid 4-hydroxylase (C4H), by sense or antisense expression of an alfalfa C4H cDNA. PAL activity and levels of phenylpropanoid compounds were reduced in leaves and stems of plants in which C4H activity had been genetically down-regulated. However, C4H activity was not reduced in plants in which PAL activity had been down-regulated by gene silencing. In crosses between a tobacco line over-expressing PAL from a bean PAL transgene and a C4H antisense line, progeny populations harboring both the bean PAL sense and C4H antisense transgenes had significantly lower extractable PAL activity than progeny populations harboring the PAL transgene alone. Our data provide genetic evidence for a feedback loop at the entry point into the phenylpropanoid pathway that had previously been inferred from potentially artifactual pharmacological experiments.

Keywords: phenylpropanoid pathway, cinnamic acid 4-hydroxylase

Research Title: The corn inhibitor of activated Hageman factor: purification and properties of two recombinant forms of the protein

Author: Sameer Masoud, Published Year: 1998

Expression and Purification , 13

Faculty: Science

Abstract: A cDNA clone that encodes the 14-kDa bifunctional inhibitor from corn seeds (L. Wenet al., Plant Mol. Biol.18, 813–814, 1992) has been expressed inEscherichia coliafter being incorporated into the pT7 expression vector. This inhibitor protein, referred to as CHFI (for the corn inhibitor of activated Hageman factor) or as the popcorn inhibitor, is an important tool for specific inhibition of human activated Hageman factor (activated forms of coagulation Factor XII) and has been well characterized as isolated from corn seeds. Recombinant CHFI was expressed inE. coliin high levels but was insoluble. We solubilized the expressed protein by sonication in 5 M urea and 1% Triton X-100. Several steps of purification, culminating with reversed-phase HPLC, yielded pure, recombinant corn inhibitor in about 5% yield (about 1 mg per liter of culture). The form with which we have worked most, 7N-CHFI, contains 7 amino acid residues at its N-terminus that are encoded by the expression vector. Physical properties of this recombinant protein indicate it has the expected mass and is properly folded. Functionally, 7N-CHFI is indistinguishable from the inhibitor isolated from corn seeds in its inhibition of porcine trypsin, human β-Factor XIIa, failure to inhibit human plasma kallikrein, and its inhibition of an insect α-amylase. A second recombinant form, (4N-11)-CHFI, which lacks 11 residues from the corn inhibitor's N-terminus, is indistinguishable from 7NCHFI in its pattern of inhibition of the three test proteinases but is inactive against the insect α-amylase. This suggests that the N-terminal region of 7N-CHFI forms at least part of the protein's site of interaction with α-amylase.

Keywords: pT7 expression vector, corn bifunctional inhibitor, Hageman factor

Research Title: Reduced lignin content and altered lignin composition in transgenic tobacco down-regulated in expression of L-phenylalnine ammonia-lyase or cinnamate 4-hydroxylase.

Author: Sameer Masoud, Published Year: 1997

Plant Physiology , 115

Faculty: Science

Abstract: We analyzed lignin content and composition in transgenic tobacco (Nicotiana tabacum) lines altered in the expression of the early phenylpropanoid biosynthetic enzymes Lphenylalanine ammonia-lyase and cinnamate 4-hydroxylase (C4H). The reduction of C4H activity by antisense expression or sense suppression resulted in reduced levels of Klason lignin, accompanied by a decreased syringyl/guaiacyl monomer ratio as determined by pyrolysis gas chromatography/mass spectrometry Similar reduction of lignin levels by down -regulation of L-phenylalanine ammonia-lyase, the enzyme preceding C4H in the central phenylpropanoid pathway, did not result in a decreased syringyl/guaiacyl ratio. Rather, analysis of lignin methoxyl content and pyrolysis suggested an increased syringyl/guaiacyl ratio. One possible explanation of these results is that monolignol biosynthesis from L-phenylalanine might occur by more than one route, even at the early stages of the core phenylpropanoid pathway, prior to the formation of specific monolignol precursors.

Keywords: L-phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, lignin