Year-round flowering gene e1, a mutation at the E1 locus on rice chromosome 7 and its combination with green revolution gene sd1 in an isogenic cell line

Genetic analysis on the year-round flowering gene e1, which was derived from Kanto No. 79, an induced mutant by Koshihikari gamma-ray irradiated, was conducted through the backcross process to combine e1 and sd1 in the genetic background of Koshihikari. e1 strongly forwarded flowering 14 days earlier than the original variety Koshihikairi. Isogenic Koshihiakri combining e1 and sd1 was developed by four times of backcross with either Koshihikari or Koshihikari sd1 as recurrent parents by using the e1sd1 homozygous F₃ plant in Koshihikari sd1 × Kanto No. 79 as a non-recurrent parent. As a result, "Koshihikari e1sd1" maturing 14 days earlier was approximately 30 cm shorter than Koshihikari. e1 was linked with DNA markers, which were near to Ghd7 on the short arm of chromosome 7. The whole genome sequencing revealed a single candidate SNP, which is specific to Koshihikari e1sd1, in the Xa21-like sequence, at 35213 bp downstream from Ghd7 on chromosome 7. Koshihikari e1sd1-specific SNP beside Ghd7 is expected to downregulate with Ghd7.

Preparation, stability and commutability of candidate reference materials for lactate dehydrogenase (LDH)

BACKGROUND

Lactate dehydrogenase (LDH) is a key enzyme that functions as a marker of cell damage. Its activity can be measured by a variety of laboratory methods. To eliminate inter-method bias and enhance equivalence among different measurement procedures, LDH detection needs to be standardized.

METHODS

Optimized sequences coding for lactate dehydrogenase subunit A (LDH-A) and subunit B (LDH-B) were synthesized and cloned into the pRSFDuet vector, and then the constructed 6His-LDHA-pRSFDuet, 6His-LDHB-pRSFDuet, and 6His-LDHA-LDHB-pRSFDuet plasmids were transformed into Escherichia coli BL21 (DE3) for expression. The enzyme activity and specific activity of recombinant LDHs were detected. Electrophoresis of LDH isoenzymes was performed. The stability of recombinant LDHs and serum LDH was evaluated. Commutability of recombinant LDH-B was studied by the IFCC reference method and six routine methods.

RESULTS

Three plasmids were constructed and three highly concentrated recombinant LDH isoenzymes were obtained. The specific activities of LDH-A, LDH-AB, and LDH-B were 18.08 U/mg, 21.74 U/mg, and 14.18 U/mg, respectively. There was a desirable linear correlation between the activities of recombinant LDH isoenzymes and their protein concentrations. Electrophoresis of LDH isoenzymes showed that the recombinant LDH-B corresponded to LDH1 and it demonstrated good stability at 4 °C and 25 °C for 5 weeks. LDH-B formulations in saline-bovine serum albumin solution and human serum matrix were commutable for six routine methods.

CONCLUSION

Human recombinant LDH-B has great potential to become an improved and less expensive standard or reference material in external quality assessment for clinical LDH measurement.

Perspectives of gene combinations in phenotype presentation

Cells exhibit a variety of phenotypes in different stages and diseases. Although several markers for cellular phenotypes have been identified, gene combinations denoting cellular phenotypes have not been completely elucidated. Recent advances in gene analysis have revealed that various gene expression patterns are observed in each cell species and status. In this review, the perspectives of gene combinations in cellular phenotype presentation are discussed. Gene expression profiles change during cellular processes, such as cell proliferation, cell differentiation, and cell death. In addition, epigenetic regulation increases the complexity of the gene expression profile. The role of gene combinations and panels of gene combinations in each cellular condition are also discussed.