Here the transcriptome and differential gene expression in the adult brain and gonads of the Chinese sea perch Lateolabrax maculatus were reported. A total of 78 256 909 clean reads were generated from the adult brain, ovary and testis by using the Illumina HiSeq2000 platform and assembled into 274 909 contigs. A total of 31 683 unigenes were annotated based on sequence similarity and 20 702 unigenes were found to exhibit 8237 gene ontology terms and 3888 signal pathways. Transcripts of 26 623 unigenes were present in all of the tissues, whereas pairwise comparisons revealed that 671/367, 496/315 and 1668/580 unigenes were up-down regulated by at least two-fold between the brain and ovary, ovary and testis and brain and testis, respectively. Homology search led to the identification of reproduction-associated genes of the brain-gonad axis, including those involved in sex differentiation and maintenance. The data provided an integrated and comprehensive transcriptome resource for L. maculatus, which could be used for further research on hypothalamus-pituitary-gonad axis gene function, reproduction regulation and sex-biased gene expression.

MATERIALS AND METHODSFlight Hardware. Flight hardware consisted of four concentrically sealed bags of heat-sealable Kapak plastic (Fisher Scientific, Springfield, NJ). The innermost bag measured approximately 10 x 10 cm and contained approximately 100 ml of 2% (v/v) glutaraldehyde in 0.05 M sodium cacodylate buffer (pH 6.9). This 'fixative bag' was placed inside a 'growth chamber' bag measuring approximately 25 x 30 cm containing the plant material (see below) and inflated to near capacity with air. This bag was then sealed inside two other Kapak bags. We launched 12 of these bags, each containing 2 to 6 seeds. Ground controls were also grown in Kapak bags.Plant Material. Seeds of Zea mays cv Bear Hybrid (Custom Farm Seed Co., Momence, IL) were soaked in distilled H2O for 8 h, placed against moist pieces of filter paper, and loaded into the growth chamber bag of the flight hardware. Due to loading restrictions, imbibed seeds were loaded onto the orbiter Columbia 13 h before launch. We used data from a temperature recorder in the flight locker to ensure that controls were grown at the same temperature (±2°C) as flight-grown seedlings. Plants were grown in darkness throughout the experiment.Protocol on Orbit. Our experiment was terminated after approximately 4.8 d on orbit. Mission Specialist Franklin ChangDiaz ruptured the inner fixative bag of glutaraldehyde and kneeded its contents into the growth chamber bag, thereby submerging the seedlings in fixative.Microscopy and Morphometry. Preparation of tissue for microscopical observation was as described previously (8). We examined randomly selected columella cells from random radial sections of 8 caps of primary roots of flight-grown seedlings and Earth-grown controls. Methods of sample randomization, point counting, and calculating relative and absolute volumes were as described by Steer (15). The formula Pt = [(0.453)(1-Vv)/ (Vv)(E2)(Vv)] was used to determine the total number of points (Pt) necessary to obtain relative volumes (Vv) with relative errors (E) less than 5% (18). Morphometric analyses were facilitated by use ofthe MORPHO computer program ofVodopich and Moore (16). Student's t test (14) was used to determine the significance level of differences between means. Differences with probability (P) levels >5% were considered insignificant. RESULTS AND DISCUSSIONThe influence of microgravity on the dimensions and volumes of columella cells of primary roots of Z. mays is shown in Table I. Table II