• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.681-686
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• 2011

SPLITT Fractionation (SF) provides separation of sample into two subpopulations. Separation into more than two subpopulations requires repeated SF operations. In this study, two Gravitation SF (GSF) channels were connected in a series (Tandem GSF) to obtain a separation into three subpopulations and to improve the fractionation efficiency (FE) of the fraction-b in the full-feed depletion (FFD) mode. In a single channel FFD-GSF operation, the fraction-a contained mostly the beads smaller than the cutoff diameter ($d_c$), while the fraction-b contained beads smaller than $d_c$ as well as those larger than dc, as expected. The measured FE's of the fraction-b are much lower than those of the fraction-a in all cases. The FE's of the fraction-a are higher than 84% with the average of about 91%, while those of the fraction-b are lower than 60% with the average of about 43%. No particular trends were found between FE and $d_c$, indicating the performance of FFD-GSF does not change with $d_c$ in the range where tested. Also no clear trends were observed between the FE and the sample-feeding flow rate, indicating higher sample-feeding rate can be used to increase the sample throughput without losing resolution. When two GSF channels were connected so that the flow stream emerging from the outlet-b of the channel-1 is fed directly into the channel-2, all three FE's measured for the fraction-1a were high with the average value of 99%, indicating it contains almost purely the beads smaller than $d_c$. The FE's measured for the fraction-2a are still good with the average value of 92%. The FE's measured for the fraction-2b are 64% in average, which is about 20% improvement from those obtained in a single channel FFD-GSF at the same conditions.

• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.180-186
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• 2003

The full-length cDNA encoding the pre-protein growth hormone (sfGH) from spotted flounder (Verasper variegatus) was amplified by the rapid amplification of cDNA ends (RACE) using degenerated oligonucleotide primers derived from conserved growth hormone sequences. It consists of 901 nucleotides in length, including the coding region of 609 nucleotides, 111 nucleotides of a 5' untranslated region, and 181 nucleotides of a 3' untranslated region. The conserved polyadenylation signal (AATAAA) lies 12 bases upstream from the poly (A) tail. The deduced amino acid sequence shows an open reading frame encoding a pre-protein of 203 amino acids and a putative signal peptide of 17 amino acids, suggesting that the mature hormone consists of 186 amino acids. The analyses of sfGH reveal some unique structural features. The repetitive sequences are located in the 5' untranslated region of sfGH cDNA and consist of tandem arrays of imperfect direct repeat monomers. Moreover, sfGH contains six Cys residues, as opposed to four or five in other GHs, and it is clearly distinguishable from olive flounder (Paralichthys olivaceus) GH, which lacks a region corresponding to residues 175-188 in alignment positions. It has important implications from an evolutionary standpoint, suggesting possible divergence among flatfishes.