John S. Zhang

Bio: John S. Zhang is an academic researcher from Children's Medical Research Institute. The author has contributed to research in topics: Gel electrophoresis & Complementary DNA. The author has an hindex of 1, co-authored 1 publications receiving 64 citations.

Differential display of mRNA.

Abstract: Differential display of mRNA (DD) is a technique in which mRNA species expressed by a cell population are reverse transcribed and then amplified by many separate polymerase chain reactions (PCR). PCR primers and conditions are chosen so that any given reaction yields a limited number of amplified cDNA fragments, permitting their visualization as discrete bands following gel electrophoresis. This robust and relatively simple procedure allows identification of genes that are differentially expressed in different cell populations. Here we review DD including some recent modifications, and compare it with other techniques for analyzing differential mRNA expression.

Overexpression of legumain in tumors is significant for invasion/metastasis and a candidate enzymatic target for prodrug therapy.

Abstract: Expression of legumain, a novel asparaginyl endopeptidase, in tumors was identified from gene expression profiling and tumor tissue array analysis. Legumain was demonstrated in membrane-associated vesicles concentrated at the invadopodia of tumor cells and on cell surfaces where it colocalized with integrins. Legumain was demonstrated to activate progelatinase A. Cells overexpressing legumain possessed increased migratory and invasive activity in vitro and adopted an invasive and metastatic phenotype in vivo, inferring significance of legumain in tumor invasion and metastasis. A prodrug strategy incorporating a legumain-cleavable peptide substrate onto doxorubicin was developed. The prototype compound, designated legubicin, exhibited reduced toxicity and was effectively tumoricidal in vivo in a murine colon carcinoma model.

Malaria infection of the mosquito Anopheles gambiae activates immune-responsive genes during critical transition stages of the parasite life cycle.

Abstract: Six gene markers have been used to map the progress of the innate immune response of the mosquito vector, Anopheles gambiae, upon infection by the malaria parasite, Plasmodium berghei. In addition to four previously reported genes, the set of markers included NOS (a nitric oxide synthase gene fragment) and ICHIT (a gene encoding two putative chitin-binding domains separated by a polythreonine-rich mucin region). In the midgut, a robust response occurs at 24 h post-infection, at a time when malaria ookinetes traverse the midgut epithelium, but subsides at later phases of malaria development. In contrast, the salivary glands show no significant response at 24 h, but are activated in a prolonged late phase when sporozoites are released from the midgut into the haemolymph and invade the glands, between 10 and 25 days after blood feeding. Furthermore, the abdomen of the mosquito minus the midgut shows significant activation of immune markers, with complex kinetics that are distinct from those of both midgut and salivary glands. The parasite evidently elicits immune responses in multiple tissues of the mosquito, two of which are epithelia that the parasite must traverse to complete its development. The mechanisms of these responses and their significance for malaria transmission are discussed.

Mechanical culture conditions effect gene expression: gravity-induced changes on the space shuttle

Abstract: Hammond, T. G., E. Benes, K. C. O’Reilly, D. A. Wolf, R. M. Linnehan, J. H. Kaysen, P. L. Allen, and T. J. Goodwin. Mechanical culture conditions effect gene expression: gravity-induced changes on ...