The effect of dietary nutrients on novel farm species has always garnered wide research and economic interest. Chinese perch, an economically important carnivorous fish, accepts an artificial diet after taming, so it is essential to evaluate and optimize the nutritional and metabolic demands of this species. However, little is known about the effect of an artificial diet on the growth and metabolism of Chinese perch. Therefore, the present study evaluated the growth and metabolic responses of Chinese perch to experimental diets with different dietary protein/energy (P/E) ratios. Five isoenergetic diets (18 kJ/g) with graded levels of P/E ratios of 30.58, 33.22, 35.90, 38.6, and 41.35 mg/kJ (named A, B, C, D, and E) were formulated. A total of 225 Chinese perch (64.89 ± 0.28 g) were divided into five groups (triplicate tanks for each group), distributed into 15 (350 L) fiberglass tanks, and fed twice a day at 4% of fish wet body weight with the respective P/E ratio diets for 10 weeks. Compared with the other groups, Chinese perch in Group C showed significantly improved growth performance, weight gain (WG), specific growth rate (SGR), viscerosomatic index (VSI), hepatosomatic index (HSI), intraperitoneal fat (IPF), feed utilization, feed intake (FI), feed conversion ratio (FCR), protein efficiency ratio (PER), protein retention efficiency (PRE), energy retention efficiency (ERE), and feed efficiency (FE) as well as whole-body, muscle, and liver composition. Chinese perch in Group A, on the other hand, had the lowest growth performance, feed utilization, and body composition compared with the other groups. The activities of nitrogen metabolism-related enzymes (alanine aminotransferase (ALT), aspartate aminotransferase (AST) glutamate dehydrogenase (GDH), and adenosine 5′-monophosphate deaminase (AMPD)) as well as the mRNA expression of the GDH and AMPD genes were significantly lower than those in the other groups. Similarly, the expression of NPY and AgRp were significantly higher in Group C compared with the other groups. However, the gene expression of CART and POMC was not affected by the dietary P/E ratios. In Group A, the expression of mTOR, S6K, and 4EBP1 was significantly lower and that of AMPK, LKB1, and eEF2 was significantly higher when compared with the other groups. Biochemical analysis of blood showed that ALT, AST, total protein (TP), alkaline phosphatase (ALP), glucose (GLU), blood urea nitrogen (BUN), and triglyceride (TG) levels were also affected by the dietary P/E ratio. From our results, we concluded that Chinese perch growth performance and nutrient metabolism were significantly affected by the P/E ratio of the artificial diet. Second-order polynomial regression analysis revealed that Chinese perch growth performance was optimal at a P/E ratio of 37.98 in the artificial diet.

Cytoplasmic male sterility (CMS) is an important agronomic feature and provides an effective tool for heterosis utilization of crops. This study reports the comparative transcriptomic sketches between a novel allohexaploid cotton progeny CMS line LD6A and its maintainer line LD6B using de novo transcriptome sequencing technology at the pollen abortion stage. A total of 128,901 Unigenes were identified, in which 2007 were upregulated and 11,864 were downregulated. The significantly differentially expressed genes (DEGs) in LD6A show a distant and diverse genetic nature due to their distant hybrid hexaploidy progeny. Further analysis revealed that most of the DEGs participated in the tricarboxylic acid (TCA) cycle, oxidative phosphorylation, histone acetyltransferase activity, sepal development, stigma development, cotyledon development and microsporogenesis. A highly differentially expressed toxic protein, Abrin, was identified in the CMS line LD6A, which can catalyze the inactivation of ribosomes and consequently lead to cell death through the mitochondrial pathway in human cells. Twelve DEGs were selected randomly to validate transcriptome data using quantitative reverse-transcribed PCR (qRT-PCR). This study will contribute to new ideas and foundations related to the molecular mechanism of CMS and the innovation of cotton germplasm resources.

Male sterility (MS) plays a key role in the hybrid breed production of plants. Researchers have focused on the association between genetic male sterility (GMS) and cytoplasmic male sterility (CMS) in kenaf. In this study, P9BS (a natural GMS mutant of the kenaf line P9B) and male plants of P9B were used as parents in multiple backcross generations to produce P9SA, a CMS line with stable sterility, to explore the molecular mechanisms of the association between GMS and CMS. The anthers of the maintainer (P9B), GMS (P9BS), and CMS (P9SA) lines were compared through phenotypic, cell morphological, physiological, biochemical observations, and transcriptome analysis. Premature degradation of the tapetum was observed at the mononuclear stage in P9BS and P9SA, which also had lower activity of reactive oxygen species (ROS) scavenging enzymes compared with P9B. Many coexpressed differentially expressed genes were related to ROS balance, including ATP synthase, electron chain transfer, and ROS scavenging processes were upregulated in P9B. CMS plants had a higher ROS accumulation than GMS plants. The MDA content in P9SA was 3.2 times that of P9BS, and therefore, a higher degree of abortion occurred in P9SA, which may indicate that the conversion between CMS and GMS is related to intracellular ROS accumulation. Our study adds new insights into the natural transformation of GMS and CMS in plants in general and kenaf in particular.

The skin mucus of fish is an important part of the innate immune system, which is poorly understood at the proteomic level. The study established a complete map of the proteins in the skin mucus of Ctenopharangdon idella (C. idella) and discussed the Differentially Expressed Proteins (DEPs) after Aeromonas hydrophila (A. hydrophila) infection. Using Label Free Liquid Chromatography-Mass Spectrometry (LC–MS/MS) analysis, a total of 126 proteins were identified as differentially expressed, 89 proteins of which were upregulated, and 37 proteins were downregulated. Functional annotations of DEPs showed that the upregulated proteins in the skin mucus of the treated group were mostly associated with complement system and cytoskeleton proteins, whereas downregulated proteins were associated with metabolism. The key upregulated immune proteins were transferrin variant C, lysozyme g, annexin A11, 26S proteasome non-ATPase regulatory subunit 8, hypothetical protein ROHU_000884, 60S ribosomal L7a, calpain-2 catalytic subunit-like protein, calpain-9-like protein, complement component C9, complement C3, cathepsin S, cathepsin Z, 14 kDa apolipo, heat shock protein and intelectin, whereas, leukocyte elastase inhibitor, annexin A11, C-factor-like protein, biotinidase isoform X1 and epidermal growth factor receptor substrate 15-like were the downregulated proteins. Moreover, we for the first-time report proteins such as coactosin, lamin-B2 and kelch 12, which were never reported in fish. Our study directly pointing out the possible immunological biomarkers in the skin mucus of C. idella after A. hydrophila treatment. Each of the protein we report in this study could be used as base to establish their mechanism of action during bacterial infection that may contribute to the strategies against bacterial prevention and control in fishes.