Improved Synthesis of Deoxyadenosine Triphosphate by Saccharomyces cerevisiae Using an Efficient ATP Regeneration System: Optimization of Response Surface Analysis

Deoxyadenosine triphosphate (dATP) is an important biochemical molecule. In this paper, the synthesis of dATP from deoxyadenosine monophosphate (dAMP), catalyzed by Saccharomyces cerevisiae, was studied. By adding chemical effectors, an efficient ATP regeneration and coupling system was constructed to achieve efficient synthesis of dATP. Factorial and response surface designs were used to optimize process conditions. Optimal reaction conditions were as follows: dAMP 1.40 g/L, glucose 40.97 g/L, MgCl₂·6H₂O 4.00 g/L, KCl 2.00 g/L, NaH₂PO₄ 31.20 g/L, yeast 300.00 g/L, ammonium chloride 0.67 g/L, acetaldehyde 11.64 mL/L, pH 7.0, temperature 29.6 °C. Under these conditions, the substrate conversion was 93.80% and the concentration of dATP in the reaction system was 2.10 g/L, which was 63.10% higher than before optimization, and the concentration of product was 4 times higher than before optimization. The effects of glucose, acetaldehyde, and temperature on the accumulation of dATP were analyzed.

Transcriptome analysis of Capsicum annuum varieties Mandarin and Blackcluster: assembly, annotation and molecular marker discovery

Next generation sequencing technologies have proven to be a rapid and cost-effective means to assemble and characterize gene content and identify molecular markers in various organisms. Pepper (Capsicum annuum L., Solanaceae) is a major staple vegetable crop, which is economically important and has worldwide distribution. High-throughput transcriptome profiling of two pepper cultivars, Mandarin and Blackcluster, using 454 GS-FLX pyrosequencing yielded 279,221 and 316,357 sequenced reads with a total 120.44 and 142.54Mb of sequence data (average read length of 431 and 450 nucleotides). These reads resulted from 17,525 and 16,341 'isogroups' and were assembled into 19,388 and 18,057 isotigs, and 22,217 and 13,153 singletons for both the cultivars, respectively. Assembled sequences were annotated functionally based on homology to genes in multiple public databases. Detailed sequence variant analysis identified a total of 9701 and 12,741 potential SNPs which eventually resulted in 1025 and 1059 genotype specific SNPs, for both the varieties, respectively, after examining SNP frequency distribution for each mapped unigenes. These markers for pepper will be highly valuable for marker-assisted breeding and other genetic studies.