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| Articles
by
K. Yusoff |
Total Records (
4 ) for
K. Yusoff |
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N. Ghiasi
,
Z.A. Rashid
,
S. Hooshmand
,
K. Yusoff
,
S.G. Tan
and
S. Bhassu
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This study is to demonstrated that microsatellites markers
developed for Tor tambroides can be used to amplify microsatellite
loci in other family. It is assumed that microsatellite loci are more
conserved for aquatic species compared to terrestrial ones due to aquatic
environments are less mutagenic than terrestrial ones. Development of
microsatellites still requires investment of time and resources. Thus
using loci already developed in a related species may provide a cost-effective
alternative to microsatellite isolation and development in a species of
interest in present study, Probarbus jullieni. In this study we
investigated the possibility of the conservation of microsatellite flanking
regions among different species. Nine pairs of SSR primers, five gave
very strong banding profile (SYK1, SYK 2, SYK 5 SYK 8 and SYK 9) which
could be used for population studies by using the nested protocol. Results
showed that SYK 2 and SYK 9 flanked the same (CA)n repeats
and thus are highly conserved in a different species. The products of
the SYK 5, 8 and 1 primer pairs showed differences in the microsatellite
regions which they flanked in Probarbus jullieni when compared
to those of the source species, Tor tambroides. The mean observed
heterozygosity levels for all the primers ranged 0.23-0.81. The primers
are all polymorphic with the mean number of alleles from 2-5. |
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R. Ahmad-Raus
,
M. Mel
,
S.N. Mohd-Abdullah
and
K. Yusoff
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Cell rupture is one of the earlier steps in downstream processing which are required for the recovery of biological products that are located inside cells. Cells could be disrupted either by using chemicals or mechanical method. In this study, cell rupture was carried out by mechanical force using High Pressure Homogenizer (HPH). The aim of this study is to identify optimal conditions of HPH to disrupt the cell wall of recombinant Escherichia coli harboring nucleocapsid (NP) gene of Newcastle Disease Virus (NDV). The optimized conditions were achieved by manipulating the independent variables of HPH such as pressure, pump speed and number of cycles through an optimization process. The efficiency of the cell disruption was determined by estimating the percentage of cell rupture as well as the amount of NP protein released from the cell lysis. Through the means plot analysis of Minitab Software (Version 14.12), pressure was recognized as the main factor for achieving the highest cell rupture and the release of NP protein. The optimized conditions for obtaining the highest NP protein yield were by operating three cycles of cell rupture, homogenizer pressure of 800 bars and pump speed of 7 psi. |
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Y.M. Abdel-Hadi
,
Mariana Nor Shamsudin
,
K. Yusoff
and
Shater Zakaria
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Monovalent, killed and live attenuated vaccines of Aeromonas hydrophila and Pseudomonas putida were used in the immunization of red tilapia against Motile Aeromonad and Pseudomonad septicemias. There were 4 treatments and a 5th control group with 3 replicates per each. A 4th replicate was kept for replacement of natural mortality among the experimented fish. The 4 treatments included, Heat-killed vaccine of A. hydrophila, Live-attenuated vaccine of A. hydrophila (using herbs), Heat-killed vaccine of P. putida and Live-attenuated vaccine of P. putida. A total of 160 brood stocks of O. niloticus with 250 g average body weight were used for all treatments (8 fish per each glass aquarium). Vaccination was conducted via the Intra Peritoneal route (I/P) as an initial dose followed by 2 booster doses every 2 weeks. The last dose was applied via the immersion route. The evaluation of vaccination was carried out through periodical antibody titration of the serum of the examined fish (every 2 weeks) using direct agglutination method as well as by the experimental challenge 3 months after the initial immunization. Results revealed that there were a significant difference between the vaccinated and non vaccinated fish of the control group regarding antibody titers and Relative Percent Survival (RPS) of the challenge test. Differences in immunity levels within the vaccinated groups themselves were demonstrated. |
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T. Haryanti
,
N.S. Mariana
,
S.Y. Latifah
,
K. Yusoff
and
A.R. Raha
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The ctxB gene, the causative agent of cholera
epidemic was successfully cloned from V. cholerae in E. coli.
The insertion of the gene was confirmed by PCR as well as restriction
digestion analyses. The sequencing results for the gene confirmed that
the insert was in the correct orientation and in-frame with the PBAD
promoter and it showed that the gene was 99% homologous to the published
ctxB sequence. The CTB protein was successfully expressed in
E. coli using the pBAD/His vector system. The expected protein
of ~14 kDa was detected by SDS-PAGE and Western blot. The use of pBAD/His
vector to express the cholera toxin gene in E. coli would facilitate
future study of toxin gene products. |
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