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N N Malik

Publications and source records attributed to N N Malik.

4 recordsLinked to original sources
PubMed2003

Transgenic tobacco expressing geminiviral RNAs are resistant to the serious viral pathogen causing cotton leaf curl disease.

Cotton, the major cash crop in Pakistan, suffers 30% losses to cotton leaf curl disease, caused by the geminivirus, cotton leaf curl virus DNA A, plus a satellite component, DNA beta responsible for symptom development with plants failing to produce cotton bolls. We constructed transgenic tobacco expressing sense and antisense RNAs representing: [i] the 5' half of the viral DNA replication gene, AC1, [ii] the 3' half of AC1, [iii] two overlapping genes, AC2, a transcription activator, and AC3, a replication enhancer. In contrast to controls, 25% of 72 transgenic tobacco lines tested showed heritable resistance [T(1) - T(3) generations]: symptom-free and no replication of DNA A or DNA beta even after 120 days of continuous exposure to viruliferous whiteflies. As geminiviral and transgene RNAs are not detected in resistant lines following infection, and selected uninfected resistant tobacco sense lines reveal double-stranded and small interfering RNAs, the most likely mechanism is via post-transcriptional gene silencing.

DNA Replication↗
PubMed1997

Disintegration of cervical intervertebral BOP grafts with neurological sequelae: a report of two cases.

We report the case histories of two patients treated in our unit for cervical radiculopathy by anterior cervical discectomy and BOP grafting. Both grafts disintegrated within 6 weeks of insertion resulting in increased neurological deficit from cervical cord compression. At reoperation fibres from the grafts were found to have separated and the larger fragments had extruded into the vertebral canal. No evidence of infection was seen, but a foreign body reaction was found in one case. Following graft removal the patients improved symptomatically although one was left with permanent mild biceps weakness.

Biocompatible Materials↗