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Sand pear (Pyrus pyrifolia) russet pericarp is an important trait affecting both the quality and stress tolerance of fruits. This trait is controlled by a relative complex genetic process, with some fundamental biological questions such as how many and which genes are involved in the process remaining elusive. In this study, we explored differentially expressed genes between the russet- and green-pericarp offspring from the sand pear (Pyrus pyrifolia) cv. ‘Qingxiang’ × ‘Cuiguan’ F1 group by RNA-seq-based bulked segregant analysis (BSA). A total of 29,100 unigenes were identified and 206 of which showed significant differences in expression level (log2fold values>1) between the two types of pericarp pools. Gene Ontology (GO) analyses detected 123 unigenes in GO terms related to ‘cellular_component’ and ‘biological_process’, suggesting developmental and growth differentiations between the two types. GO categories associated with various aspects of ‘lipid metabolic processes’, ‘transport’, ‘response to stress’, ‘oxidation-reduction process’ and more were enriched with genes with divergent expressions between the two libraries. Detailed examination of a selected set of these categories revealed repressed expressions of candidate genes for suberin, cutin and wax biosynthesis in the russet pericarps.Genes encoding putative cinnamoyl-CoA reductase (CCR), cinnamyl alcohol dehydrogenase (CAD) and peroxidase (POD) that are involved in the lignin biosynthesis were suggested to be candidates for pigmentation of sand pear russet pericarps. Nine differentially expressed genes were analyzed for their expressions using qRT-PCR and the results were consistent with those obtained from Illumina RNA-sequencing. This study provides a comprehensive molecular biology insight into the sand pear pericarp pigmentation and appearance quality formation. [ABSTRACT FROM AUTHOR]

The oxygen consumption and ammonia excretion rates of juvenile brook trout (Salvelinus fontinalus) under satiation and starvation were measured at different levels of water temperature [(5.5 +/- 0.5), (8.5 +/- 0.5), (11.5 +/- 0.5), (14.5 +/- 0.5), (17.5 +/- 0.5) degrees C], aimed to study the effects of water temperature and feeding on the respiratory metabolism of the fish. Under satiation, the oxygen consumption and ammonia excretion rates of juvenile S. fontinalus at the five temperature levels increased rapidly to the maximum, and then decreased gradually to the initial state. The regression equations of oxygen consumption rate (OR) and ammonia excretion rate (NR) to water temperature (t) were OR = -0.0601 t4 + 2.5542 t3 - 39.256 t2 + 276.26 t - 598.75 (R2 = 1, 4.5 degrees C < t < 17.5 degrees C) and NR = - 0.0020 t4 + 0.0826 t3 - 1.2318 t2 + 8.6186 t - 18.838 (R2 = 1, 4.5 degrees C < t < 17.5 degrees C), respectively. Under starvation, the regression equations were OR = 13.723 t(0.9738) (R2 = 0.9974, 4.5 degrees C < t < 17.5 degrees C) and NR = 0.1687 t(1.0896) (R2 = 0.9977, 4.5 degrees C < t < 17.5 degrees C), respectively. The optimal temperature range was 11.5 degrees C-14.5 degrees C. The juvenile S. fontinalus in starvation was heavily depended on fat and carbohydrates.