De novo transcriptome analysis of high growth rate Pyropia yezoensis (Bangiales, Rhodophyta) mutant with high utilization of nitrogen

Pyropia yezoensis (Ueda) M.S.Hwang et H.G.Choi (Bangiales, Rhodophyta) has potentially high economic value. P. yezoensis has been used as food in East Asian countries for a long time, and, in addition to that its consumption is increasing worldwide owing to the growing interest in healthy seaweed food. A mutant (Py2K) with a high growth rate was developed using gamma rays to increase the production of P. yezoensis. De novo transcriptome analysis was performed to determine the mechanism underlying the high growth rate of this mutant. The transcriptomes from wild-type (PyWT) and mutant (Py2K) strains were assembled, and 167,165 genes were analyzed. A total of 15,979 genes were differentially expressed. Transcriptome analysis of nitrogen pathway revealed the increase in nitrogen availability through the upregulation of nitrate transporter gene (nrt) expression. Activation of nitrogen assimilation and re-assimilation and upregulation in alternative oxidase (aox) gene contributed to the increase in cellular nitrogen availability, thereby affecting the synthesis of phycobiliprotein. As a consequence, the efficiency of photosynthesis and the subsequent growth rate increased, which contributed to the color differences in thalli between PyWT and Py2K

Comparative transcriptome analysis of high-growth and wild-type strains of Pyropia yezoensis

Pyropia yezoensis (Ueda) M.S.Hwang et H.G.Choi is a popular edible macro-alga that is found mostly in intertidal zones. It is one of the most economically important seaweed species and has been cultivated extensively in the cold waters of East Asia. Various reports have been published on the isolation and characterization of improved strains of Pyropia. However, there are few studies focusing on the molecular basis underlying these mutant strains. In this study, we performed a comparative analysis of whole transcriptomes of wild-type (PyWT) and high-growth (Py500G) strains of P. yezoensis using next generation RNA sequencing (RNA-seq). After sequencing, a total of 167,110,896 paired-end reads with a length of 151 nucleotides, were obtained. De novo transcriptome assembly and redundancy removal generated 19,441 transcripts. The assembly was annotated in NCBI nr, Swiss-Prot, Pfam, KEGG, GO and KOG databases. To unravel the differences in Py500G and PyWT, we mapped Py500G and PyWT reads to the assembly and calculated the expression levels. In total, there were 454 transcripts that were differentially expressed. Among the differentially expressed transcripts, candidate genes were identified with well-known growth and development functions. This study not only identifies candidate genes responsible for the high-growth phenotype of Py500G, but it also provides more comprehensive genomic data for future research on P. yezoensis

Description of the Diadegma fenestrale (Hymenoptera: Ichneumonidae: Campopleginae) Attacking the Potato Tuber Moth, Phthorimaea operculella (Lep.: Gelechiidae) New to Korea

Diadegma fenestrale is known as a parasitoid of the potato tuber moth, Phthorimaea operculella. The potato tuber moth, Phthorimaea operculella (Zeller) is one of the most destructive pest of potatoes. Also, we found this species attacking the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae). Ratio of parasitism is 20-30% and cocoon of lepidopteran was parasitic ichneumonid species after 3 days. This species and the genus Diadegma are recorded for the first time from Korea. In this paper, description of the parasitoid and photographs of the diagnostic characteristics are provided

Two-Phase Flow Boiling Heat Transfer Of R-410A and R-134A in Horizontal Small Tubes

Experimental investigation on two-phase flow boiling heat transfer of R-410A and R-134A in horizontal small tubes is reported. The pressure drop and local heat transfer coefficients were obtained over heat flux range of 5 to 40 kW/m2 , mass flux range of 70 to 600kg/ m2 s, saturation temperature range of 2 to 12°C, and quality up to 1.0 in test section with inner tube diameters of 3.0 and 0.5mm, and lengths of 2000 and 330mm, respectively. The section was heated uniformly by applying a direct electric current to the tubes. The effects of mass flux, heat flux, and inner tube diameter on pressure drop and heat transfer coefficients are presented. The experimental results are compared against several existing correlations. A new boiling heat transfer coefficient correlation based on the superposition model for refrigerants in small tubes is also presented

Condensation heat transfer of R22, R410A and R32 inside a multiport mini-channel tube

In the present study, the heat transfer coefficients are investigated experimentally for condensation of R22, R410A, and R32 inside a horizontal multiport rectangular mini-channel tube. The multiport tube having nine channels in 0.969mm of hydraulic diameter, the experimental measurements were carried out at the fixed saturation temperature of 48oC, by the varying refrigerant mass flux from 50 to 500kg/m2s, and the heat flux range from 3 to 15kW/m2. The test section was a double tube of counter-flow type; the refrigerant was flowed condensation inside the test tube by heat exchange with cooling water flowing in the annular side. The temperature and pressure of refrigerant were measured at the inlet and outlet of the test section, and the surface temperature of tubes was measured. The effect of vapor quality, mass flux and heat flux on condensation characteristics is clarified. The experiment results were compared with the existing heat transfer coefficient correlations, and a new correlation was proposed using the present data with good prediction

A General Correlation to Predict The Flow Boiling Heat Transfer of R410A in Macro/Mini Channels

This study demonstrated a general correlation to predict the saturated flow boiling heat transfer of R410A in horizontal macro and mini-channels. The experimental data were observed in various tube diameters of 1.5, 3.0, 6.61 and 7.49 mm, mass fluxes of 100 – 600 kW m-2s-1 heat fluxes of 10 – 40 kW m-2 , saturation temperature of 5 – 15 ºC and vapor quality from 0.2 to 1. The database was compared with numerous well-known correlations. The proposed correlation was based on the superposition model of nucleate boiling and force convective evaporation contribution. The new modified correlation showed a good prediction with using our database

Pressure Drop and Boiling Heat Transfer Characteristics of R410A in Macro-Scale and Mini-Scale Channels

This chapter demonstrates the two‐phase flow pressure drop and heat transfer of R410A during boiling in various tube types. The pressure drop and local heat transfer coefficients were obtained for heat fluxes ranging from 10 to 40 kW/m2, mass fluxes ranging from 100 to 600 kg/m2s, the vapour quality up to 1.0 and the saturation temperatures of 5–15°C. The test sections were made of various tube diameters of 1.5, 3.0, 6.61 and 7.49 mm, respectively. The effect of mass flux, heat flux, saturation temperature and inner tube diameter on pressure drop and heat transfer coefficient was analysed. The experimental results were compared against several existing pressure drop and heat transfer coefficient correlation. New correlations of pressure drop and boiling heat transfer coefficient were also developed in this present study

An Experimental Investigation of Convective Boiling Heat Transfer Using Alternative and Natural Refrigerants Inside Horizontal Microchannels

In present study, the two phase flow boiling heat transfer coefficient and pressure drop of R32 , R410A and R290 in microchannels are demonstrated. The experimental data were conducted in horizontal stainless steel tubes with the inner diameter of 0.3 mm and 1.5 mm. The testing conditions were performed with the mass fluxes range from 200 to 500 kg/m2s, the heat fluxes from 5 to 15 kW/m2, the saturation temperature of 5 and 10˚C and the vapor quality from 0.1 to dry-out. The effects of mass flux, heat flux and saturation temperature on the heat transfer coefficient and pressure drop were analyzed. The experimental data were also compared with some well-known heat transfer coefficient and pressure drop correlations. A modified heat transfer coefficient correlation for alternative and natural refrigerants was proposed and predicted well the present experimental data