PubMed Health⌕ Search

Biomedical subjects

L Tu

Publications and source records attributed to L Tu.

25 records · Page 2Linked to original sources
PubMed1984

Pepsin digestibility of proteins in sorghum and other major cereals.

We have shown previously that sorghum is highly digestible in the rat. However, other workers have shown that sorghum is much less digestible than wheat, maize, and rice in young children. Because the rat does not show these digestibility differences, we developed an empirical pepsin digestion method, first reported in 1981, which simulates the digestion values found in children. In this report the method has been improved and used to analyze wheat, maize, rice, millet, and sorghum and certain processed samples of millet and sorghum. The pepsin digestion values parallel those found in children for wheat, maize, rice, and sorghum. In addition, a processed sorghum product that gave a high digestion value in children also gave a high value with the in vitro pepsin method.

Journal Article↗
PubMed1977

Molecular interactions between adriamycin and x-ray damage in mammalian tumor cells.

The effect of the anthracycline antibiotic, Adriamycin (Ad), on the sedimentation properties of pre-labelled mammalian DNA has been studied. Ad induces DNA degradation in vivo in both excision repair-competent (HeLa and Me-180) cells and in excision repair-deficient (REQ) cells. When X-irradiated cells are exposed to Ad during the period of repair of DNA single-strand breaks, small numbers of residual breaks persist following completion of repair. These are attributable to those induced by Ad alone. The effects of Ad and X-rays therefore appear to be similar and additive. No clear-cut evidence that Ad can inhibit the repair of X-ray-induced DNA single-strand breakage was found. Ad also induced the formation of DNA double-strand breaks and inhibits the repair of X-ray-induced base damage (repair replication). The induction of DNA strand breakage may be responsible for Ad cell toxicity and may contribute to its capacity to enhance primary X-irradiation damage when the two types of lesions co-exist.

Animals↗
PubMed1976

Molecular interactions of the combined effects of bleomycin and x-rays on mammalian cell survival.

The interactions between bleomycin and X-ray damage and repair have been examined in rat and human tumor cells. Bleomycin itself indices extensive DNA single-strand breaks but does not appear to inhibit the repair of X-ray-induced DNA single-strand breaks. Quantitative analysis of these interactions is complicated by the retention of active bleomycin within cells that remains capable of further DNA degradation even under the conditions of alkaline sucrose gradient cell lysis. DNA double-strand breaks and/or disruptions of DNA-lipid complexes also occur following bleomycin exposure. X-ray-induced excision repair replication is only minimally influenced by even high concentrations of bleomycin. A small amount of excision repair is demonstrable in nonirradiated cells treated with high concentrations of bleomycin consistent with repair of bleomycin-induced nucleotide damage in cellular DNA by a "cut and patch" repair mechanism. Repair of bleomycin-induced DNA single-strand breaks also occurs. The data indicate that bleomycin and X-ray damage are quite similar both in their induction and repair, but that lesions occur and are repaired independently. The enzymatic mechanisms appear similar in the two cell types despite substantial differences in their sensitivity to bleomycin.

Animals↗
PubMedDate not supplied

[Isolation by suppression-subtractive hybridization of genes preferentially expressed during early and late fiber development stages in cotton].

As a main natural fiber source, cotton plays an important role in human life. To identify genes preferentially expressed during early and late cotton fiber development, we constructed two fiber subtracted libraries on the basis of PCR-selected subtraction using a pool of nonfiber tissues as the same driver and 10 days postanthesis (DPA) and 20 DPA fiber cells as testers, respectively. Through differential screening, 292 clones in both libraries were identified as being preferentially expressed during fiber development. Sequence analysis showed that 31 unique sequences were found in the library of 10 DPA fibers and 48 unique sequences were obtained in the library of 20 DPA fibers. In addition, there were 13 unique clones in common in both libraries. Many previously reported cotton fiber-related genes were included in both libraries. Northern hybridization was performed to further confirm the differential expression and to determine the pattern of mRNA accumulation of selected clones. As a result, all selected cDNAs showed highly preferential expression in developing cotton fibers. Four genes-putative gibberellin-regulated protein, putative tonoplast intrinsic protein, putative plasma membrane intrinsic protein, and Gossypium hirsutum putative membrane protein-were identified in 10 DPA fiber subtracted library, and they were found to be expressed a lot during early fiber development. On the other hand, those genes screened out of 20 DPA fiber subtracted library, like arabinogalactan protein and fiber glycosyl hydrolase family 19 protein, were found highly expressed in fibers with the maximal transcription level during developmental switch from elongation to cellulose deposition. By subtraction between fibers and five nonfiber tissues, two sets of genes were identified, and their fiber-specific or fiber-preferential expression indicated that they are involved in the network that controls cotton fiber development.

Cloning, Molecular↗