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Ya-Chun Chang

Publications and source records attributed to Ya-Chun Chang.

2 recordsLinked to original sources

Integrated minimum-set primers and unique probe design algorithms for differential detection on symptom-related pathogens.

MOTIVATION: Differential detection on symptom-related pathogens (SRP) is critical for fast identification and accurate control against epidemic diseases. Conventional polymerase chain reaction (PCR) requires a large number of unique primers to amplify selected SRP target sequences. With multiple-use primers (mu-primers), multiple targets can be amplified and detected in one PCR experiment under standard reaction condition and reduced detection complexity. However, the time complexity of designing mu-primers with the best heuristic method available is too vast. We have formulated minimum-set mu-primer design problem as a set covering problem (SCP), and used modified compact genetic algorithm (MCGA) to solve this problem optimally and efficiently. We have also proposed new strategies of primer/probe design algorithm (PDA) on combining both minimum-set (MS) mu-primers and unique (UniQ) probes. Designed primer/probe set by PDA-MS/UniQ can amplify multiple genes simultaneously upon physical presence with minimum-set mu-primer amplification (MMA) before intended differential detection with probes-array hybridization (PAH) on the selected target set of SRP. RESULTS: The proposed PDA-MS/UniQ method pursues a much smaller number of primers set compared with conventional PCR. In the simulation experiment for amplifying 12 669 target sequences, the performance of our method with 68% reduction on required mu-primers number seems to be superior to the compared heuristic approaches in both computation efficiency and reduction percentage. Our integrated PDA-MS/UniQ method is applied to the differential detection on 9 plant viruses from 4 genera with MMA and PAH of 11 mu-primers instead of 18 unique ones in conventional PCR while amplifying overall 9 target sequences. The results of wet lab experiments with integrated MMA-PAH system have successfully validated the specificity and sensitivity of the primers/probes designed with our integrated PDA-MS/UniQ method.

Algorithms↗

A new combination of RT-PCR and reverse dot blot hybridization for rapid detection and identification of potyviruses.

Three degenerate primers, located at the NIb and CP gene regions, were designed for potyvirus detection. Using these primer pairs, 1.0-1.2 kb cDNA fragments of the 3'-terminal region of six potyviruses were successfully amplified from infected plant tissues. RT-PCR products were sequenced and found to be derived from the expected viruses. To identify further these potyviruses, sequences located between the 3' end of the NIb gene and the 5' end of the CP gene were chosen to design a series of species-specific probes. The probes were prepared by PCR with species-specific primers, immobilized onto nylon membrane, and then hybridized with DIG-labeled RT-PCR products amplified by potyvirus degenerate primers. The results suggested that species-specific cDNA probes plus reverse dot blot hybridization was able to identify correctly different species of potyviruses in single as well as mixed infections.

Amino Acid Sequence↗