phylogenetic analysis

MSShtayeh's picture

Squash Leaf Curl Virus (SLCV): A Serious Disease Threatening Cucurbits Production in Palestine

Journal Title, Volume, Page: 
Virus Genes November 2013
Year of Publication: 
2013
Authors: 
M S Ali-Shtayeh
Biodiversity & Biotechnology Research Unit, Biodiversity and Environmental Research Center-BERC, Til, Nablus, Palestine
Current Affiliation: 
Department of Biology and Biotechnology, Faculty of Science, An-Najah National University, Nablus, Palestine
R M Jamous
Biodiversity & Biotechnology Research Unit, Biodiversity and Environmental Research Center-BERC, Til, Nablus, Palestine
E Y Hussein
Biodiversity & Biotechnology Research Unit, Biodiversity and Environmental Research Center-BERC, Til, Nablus, Palestine
O B Mallah
Biodiversity & Biotechnology Research Unit, Biodiversity and Environmental Research Center-BERC, Til, Nablus, Palestine
S Y Abu-Zeitoun
Biodiversity & Biotechnology Research Unit, Biodiversity and Environmental Research Center-BERC, Til, Nablus, Palestine
Preferred Abstract (Original): 

The incidence of squash leaf curl disease and molecular characterization of the Palestinian isolate of Squash leaf curl virus [SLCV-(PAL)] are described in this study. Symptomatic leaf samples obtained from squash (Cucurbita pepo), watermelon [Citrullus lanatus (Thunb.)], and cucumber (Cucumis sativus L.) plants were tested for SLCV-[PAL] infection by PCR and RCA. SLCV was also found to occur naturally in Chenopodium murale, Convolvulus sp, and Prosporis farcta which showed yellowing. The disease incidence was 85 % in samples collected from Nablus in summer season, while it was 98 % in samples collected from Qalqilia in autumn. On the other hand, SLCV incidence did not exceed 25 % in winter season. The full-length DNA-A and DNA-B genomes of SLCV-[PAL] were amplified and sequenced, and the sequences were deposited in the GenBank. Sequence analysis reveals that SLCV-[PAL] is closely related to other isolates from Lebanon (SLCV-LB2), Jordan (SLCV-JO), Israel (SLCV-IL), and Egypt (SLCV-EG). DNA-A of SLCV-[PAL] showed the highest nucleotide identity (99.4 %) with SLCV-JO, and SLCV-LB2, while DNA-B had the highest nucleotide identity (99.3 %) with SLCV-IL. However, following genome sequencing, it was found that due to two separate point mutations, two viral open reading frames (ORF) were altered in some SLCV Palestinian isolates. The AC2 ORF was extended by 141 nucleotides, while the AC4 ORF was extended by 36 nucleotides.

adwank's picture

Genotypic Variation In The Brucella Melitensis Hemagglutinin Gene In Vaccine Strains And Field Isolates In Palestine

Journal Title, Volume, Page: 
Turk. J. Vet. Anim. Sci. 2012; 36: 395-399
Year of Publication: 
2012
Authors: 
Elena AWWAD
Master Program in Clinical Laboratory Science (MCLS), Birzeit University, Birzeit - PALESTINE
Mohammad A. FARRAJ
Master Program in Clinical Laboratory Science (MCLS), Birzeit University, Birzeit - PALESTINE
Kamel ADWAN
Department of Biology and Biotechnology, An-Najah N. University, Nablus - PALESTINE
Current Affiliation: 
Department of Biology, Faculty of Science, An-Najah National University, Nablus. Palestine
Tamer A. ESSAWI
Master Program in Clinical Laboratory Science (MCLS), Birzeit University, Birzeit - PALESTINE
Preferred Abstract (Original): 
In Palestine, as in other countries, brucellosis is an endemic disease, even in highly vaccinated zones. Many reports suggest that a decline in vaccine productivity may be due to antigenic shifts in the circulating Brucella melitensis. To address this aspect, the hemagglutinin gene from B. melitensis field isolates was amplified by polymerase chain reaction (PCR), sequenced, digested with the EcoRV and HaeIII, and compared to the Rev.1 strain of the B. melitensis vaccine. From January to December 2008, 80 milk samples were collected from infected flocks, from different West Bank regions of Palestine. From these, 77.5% (62/80) were shown to be positive for specific B. melitensis PCR. However, from the PCR-positive milk samples, only 38 strains could be isolated by culture on Brucella agar plates. The nucleotide alignment and phylogenetic tree for the hemagglutinin gene showed a mismatch between the vaccine strain and field isolates. This is also suggested by the observation of EcoRV and HaeIII digestion profiles for the vaccine strain and field isolates. Although a limited number of isolates and genes encoding immunologically relevant proteins were analyzed, we observed antigenic divergence between the current B. melitensis field isolates and the vaccine strain, in particular with respect to the hemagglutinin gene. Therefore, more research will be necessary to rule out the possibility of reduced efficacy of Brucella whole-cell vaccines.
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