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N Dai

Publications and source records attributed to N Dai.

12 recordsLinked to original sources
PubMed1998

Tomato fructokinases exhibit differential expression and substrate regulation

Two divergent genes encoding fructokinase, Frk1 and Frk2, have been previously shown to be expressed in tomato (Lycopersicon esculentum L.) and have now been further characterized with regard to their spatial expression and the enzymic properties of the encoded proteins. Frk1 and Frk2 mRNA levels were coordinately induced by exogenous sugar, indicating that both belong to the growing class of sugar-regulated genes. However, in situ hybridization indicated that Frk1 and Frk2 were expressed in a spatially distinct manner, with Frk2 mRNA primarily localized in cells of the fruit pericarp, which store starch, and Frk1 mRNA distributed ubiquitously in pericarp tissue. To evaluate the biochemical characteristics of the products of the Frk1 and Frk2 genes, each cDNA was expressed in a mutant yeast (Saccharomyces cerevisiae) line defective in hexose phosphorylation and unable to grow on glucose or fructose (Fru). Both Frk1 and Frk2 proteins expressed in yeast conferred the ability to grow on Fru and exhibited fructokinase activity in vitro. Although both Frk1 and Frk2 both utilized Fru as a substrate, only Frk2 activity was inhibited at high Fru concentrations. These results indicate that Frk2 can be distinguished from Frk1 by its sensitivity to substrate inhibition and by its temporal and spatial pattern of expression, which suggests that it plays a primary role in plant cells specialized for starch storage.

Journal Article↗
PubMed1997

Divergent fructokinase genes are differentially expressed in tomato.

Two cDNA clones (Frk1 and Frk2) encoding fructokinase (EC 2.7.1.4) were isolated from tomato (Lycopersicon esculentum). The Frk2 cDNA encoded a deduced protein of 328 amino acids that was more than 90% identical with a previously characterized potato (Solanum tuberosum) fructokinase. In contrast, the Frk1 cDNA encoded a deduced protein of 347 amino acids that shared only 55% amino acid identity with Frk2. Both deduced proteins possessed and ATP-binding motif and putative substrate recognition site sequences identified in bacterial fructokinases. The Frk1 cDNA was expressed in a mutant yeast (Saccharomyces cerevisiae) line, which lacks the ability to phosphorylate glucose and fructose and is unable to grow on glucose or fructose. Mutant cells expressing Frk1 were complemented to grow on fructose but not glucose, indicating that Frk1 phosphorylates fructose but not glucose, and this activity was verified in extracts of transformed yeast. The mRNA corresponding to Frk2 accumulated to high levels in young, developing tomato fruit, whereas the Frk1 mRNA accumulated to higher levels late in fruit development. The results indicate that fructokinase in tomato is encoded by two divergent genes, which exhibit a differential pattern of expression during fruit development.

Amino Acid Sequence↗
PubMed1997

[Experimental study on effect of bushen shengjing decoction on kidney yang and testicular dysfunction in rats].

OBJECTIVE: To explore the therapeutical mechanism of Bushen Shengjing Decoction (BSSJD) in treating infertility. METHODS: Fed Wistar male rats with adenine 30 mg/100 g.d continuously for 30 days. The rats manifested the symptom which was similar to the human Kidney Yang Deficiency, the genitality dropped, the function of sperm-producing in the testis was disturbed, the contents of luteinizing hormone (LH), testosterone (T) and compound F (F) in blood were all lower than rats of normal group, P < 0.01. The model rats took the BSSJD 3 ml/100 g.d (each ml contains crude drugs 2 g) continuously for 10 days, interval for three days, then medicated again and total medication of BSSJD was 30 days. RESULTS: The symptom of Kidney Yang Deficiency in rats was improved obviously, the genitality, sperm quality and function of sperm producing in testis were all enhanced obviously, so did the hormone level of LH, T, F in blood. Comparing to untreated control group, the difference was significant (P < 0.05). CONCLUSION: BSSJD has the function of reinforcing Yang and replenishing essence and regulate the endocrinological function.

Adenine↗
PubMed1996

The 5' untranslated region of Arabidopsis thaliana calmodulin cDNA is an independent cDNA containing an open reading frame.

A cDNA clone, pAUK1, with an open reading frame (ORF) coding for a hypothetical 164-amino-acid protein was isolated from an Arabidopsis thaliana (L.) Heynh cDNA library. The clone was attached, tail to tail, to the 3' end of A. thaliana hexokinase cDNA. An almost identical sequence had been previously described as the 5' untranslated region (5' UTR) of A. thaliana calmodulin cDNA (ACaM-2). Sequence comparison with three additional A. thaliana truncated cDNA clones which appear in a database (GenBank) supports the conclusion that pAUK1 is identical to the 5' UTR of ACaM-2 and that the 5' UTR of ACaM-2 is an independent cDNA artificially linked to A. thaliana calmodulin cDNA.

Amino Acid Sequence↗
PubMed1996

[Eighty-seven cases of male infertility treated by bushen shengjing pill in clinical observation and evaluation on its curative effect].

Eighty-seven cases of male infertility with semen abnormality were treated and observed by Bushen Shengjing Pill, its curative effect was evaluated with quantitative assessment and analytical comparison comprehensive scoring of semen routine analysis. These patients were treated for one to three courses of treatment, the semen quality was enhanced obviously, the comprehensive semen routine analysis score was enhanced significantly (P < 0.001) as compared with that before treatment, the spouse pregnant rate was 56.32% (49/87), and total effective rate was 95.40% (83/87). The result showed that this prescription had bidirectional regulatory function in folliclestimulating hormone, luteotropic hormone, testosterone, corticosterone, and could make the enhanced or reduced hormone level to normal value.

Adult↗
PubMed1990

Pyoderma gangrenosum in Papua New Guinea.

A severe case of pyoderma gangrenosum in a Papua New Guinean girl aged 11 years in reported. Multiple lesions of the arms, legs, buttocks and mouth were present. There was no associated disease. She was treated with very high doses of prednisolone and slow resolution over 3 months in hospital was observed.

Acute Disease↗