Search

Isoamyl alcohol is a clear, unpleasantly odorous, colorless liquid of higher alcohol that emits a fruity aroma when heavily diluted. It has received much attention in recent years as a new fuel with a high energy density. Isoamyl alcohol can be produced industrially by microbial fermentation. Still, its toxicity to host cells has limited its potential for industrial production, and the molecular mechanism of its toxic effects has not yet been elucidated. In this study, RNA-Seq technology was used to analyze the transcripts of Saccharomyces cerevisiae under normal conditions and in the presence of isoamyl alcohol (0.5 g/L and 2.5 g/L). The results showed that the expression of the cell wall (CCW12, BGL2, NCW2 and SUN4), cell membrane (ELO1, ERG2, FAA1, and OPI3), translation and other structural genes were significantly down-regulated. The expression of genes related to ATP biosynthesis, NADPH biosynthesis (ZWF1), and metal ion transport (PMC1) proteins were up-regulated. Strains with key genes knocked out were cultured without isoamyl alcohol. Combined results suggested that isoamyl alcohol may affect cell wall stability and cell membrane fluidity, and the expression of genes related to ion homeostasis and energy production may play a protective role against isoamyl alcohol stress. By maintaining cell wall stability/membrane fluidity under isoamyl alcohol pressure, improving certain ion homeostasis, and generating energy/NADPH, it is possible to overcome the toxicity of isoamyl alcohol in industrial fermentation processes to a certain extent.

The Pacific white shrimp Litopenaeus vannamei is an economically important penaeid species worldwide. Under farming conditions, the full ovarian maturation of L. vannamei generally depends on the combination of artificial ablation of unilateral eyestalk and feeding high-quality natural diets, suggesting that nutrient accumulation is important to ovarian maturation. In this study, we aimed to investigate the gene expression related to nutritional accumulation in L. vannamei during ovarian development by transcriptomic analysis. A total of 52.45 Gb of high-quality transcriptome data were obtained from 8 samples from the hepatopancreas and ovaries from shrimp in gonadal developmental stages I-IV. A total of 23,149 expressed genes were detected, of which 19,852 were known genes and 3,297 were novel genes. Our study found that genes related to amino acid, carbohydrate and lipid metabolism were expressed at higher levels in the hepatopancreas than in the ovary. The genes for most lipoproteins and their receptors were predominantly expressed in the hepatopancreas, while vitellogenin receptor (VgR) was specifically expressed in the ovary. Moreover, two vitellogenin (Vg) genes were identified, in which one was specifically expressed in the hepatopancreas and defined as Hp-Vg, and the other was specifically expressed in the ovary and defined as Ov-Vg. In addition, genes related to carotenoid metabolism were enriched in the hepatopancreas. This study provides solid evidence that the hepatopancreas is the major exogenous vitellogenesis site for ovarian maturation of L. vannamei. Two distinct Vg genes perform exogenous and endogenous vitellogenesis in the hepatopancreas and ovary in L. vannamei, respectively. The results of this study also presented some new insights for understanding the nutritional dynamics from the hepatopancreas to ovary during ovarian maturation in penaeids.

Abstract The female inflorescence of hops is traditionally used in the brewing industry to impart bitterness, aroma, flavour and longer shelf life to beer, where the bittering acids are the main compounds that enhance the quality of the beer. In recent years, a wide variety of bioactive compounds have been reported to be present in female flowers. Due to the growing consumer interests in natural ingredients, a great deal of research has been carried out in the last few years to find new sources of functional biomolecules. This paper reviews the recent applications of hops in the food, pharmaceutical and cosmetic industries and provides an overview of the bioactive potential of hops. In addition, the analytical techniques of hops compound are reviewed. The biological activities of hops compound such as antibacterial, antifungal, cardioprotective, antioxidant, anti‐inflammatory and anticancer are reviewed and the recent effects of hop bittering derivatives on beer‐related microbial activity are also presented. It is thus clear that hops have a high potential as bioactive components for use as preservatives in fresh foods to extend shelf life and as cosmetic formulations for skin care products as well as nutraceutical and health implications.

Low-salinity tolerance and growth are crucial economic traits of shrimp in areas with low-salinity water. In the current study, an F1 full-sib family of Pacific white shrimp (Litopenaeus vannamei) was obtained by the “semidirectional cross” method, and 2 parents and 146 progenies were genotyped using double-digest restriction site-associated DNA sequencing technology (ddRAD-Seq). A total of 3335 high-quality markers were identified and used to construct a genetic linkage map. This genetic map comprised 48 linkage groups (LGs), and the total map length spanned 3954.462 centimorgan (cM) with an average marker interval of 1.186 cM. Three quantitative trait loci (QTLs) for low-salinity tolerance and 3 QTLs for growth (body weight) were detected under the condition of restricted logarithmic odds (LOD) score ≥ 2.50. With the assistance of the genome of L. vannamei and relevant annotations, 3 potential growth-related genes (sob, TJP1 and ZBTB24) and 3 low-salinity response candidate genes (Rnf168, CNOT2 and RPB3) were identified from the genomic scaffolds. Moreover, the qPCR results showed that the expression levels of the 3 candidate genes were significantly affected by low-salinity stress, indicating that they possibly play an important role in low-salinity stress. Here, we present the first report of mapping of low-salinity tolerance QTLs in the genetic mapping of L. vannamei, which will be beneficial for the selection of shrimp breeding markers and might help promote the study of the L. vannamei genome.

In this study, we sequenced the circular mitochondrial genome (mitogenome) of Cercodemas anceps. This genome was determined to measure 16,539 bp in length and contain 13 protein-coding genes (PCGs), 22 tRNA genes, and 2 rRNA genes. The longest gene was observed to be nad5, which measures 1,641 bp in length and is located at position 6,540 ∼ 8,180 of the C. anceps mitogenome. One PCG, nad6, and five tRNA genes (tRNASer(UCN), tRNAGln, tRNAAla, tRNAVal, and tRNAAsp) were located on the light chain, and the other genes were located on the heavy chain. A phylogenetic tree was constructed with the mitogenome sequences of 26 types of echinoderm species, and the results show that C. anceps is most closely related to C. quadrangularis.

Minichromosome maintenance complex component 2 (MCM2) plays an important role in DNA replication induced by cold stress. In this study, MCM2 cDNA and genomic DNA (gDNA) sequences were isolated from Pacific white shrimp (Litopenaeus vannamei), and the gene was designated Lv-MCM2. The full-length Lv-MCM2 cDNA was 3,138 bp in length, with an open reading frame (ORF) of 2,721 bp encoding 906 amino acids. The Lv-MCM2 gDNA sequence was 7,322 bp in length and consisted of 16 coding segments in the L. vannamei genome. The expression of Lv-MCM2 mRNA was detected in all selected tissues, with the highest levels being observed in the stomach and gills of the shrimp. The transcript levels of Lv-MCM2 in the stomach and gills were found to be significantly affected by low-temperature, high-pH, low-pH, poly(I:C), and lipopolysaccharide (LPS) stimuli, indicating that Lv-MCM2 might play roles in coping with various stresses. Specifically, under low-temperature stress (13 °C), the knockdown of Lv-MCM2 with siRNA significantly decreased the shrimp survival rate, indicating its key roles in the response to low-temperature stress. Additionally, four single-nucleotide polymorphisms (SNPs) in the Lv-MCM2 gene were identified as being significantly associated (P < 0.001) with the cold tolerance trait in a full-sib family of L. vannamei. Our study suggests that the Lv-MCM2 gene itself or closely linked genes might play important roles in the cold tolerance trait in L. vannamei, and the SNPs from the Lv-MCM2 gene provide a basis for developing molecular markers for breeding cold-tolerant Pacific white shrimp seeds in the future.

Acute cold snaps induce a sudden reduction in water temperature and lead to high mortality of cultured Pacific white shrimp (Litopenaeus vannamei); however, little is known about the regulatory mechanisms in this shrimp species when adapting to acute cold stress. Mitogen-activated protein kinase (MAPK) signaling pathways are highly conserved and well known for their important roles in transducing environmental stress signals into the cell nucleus. In this study, the potential roles of p38MAPK in the response to acute cold stress in L. vannamei were identified. The transcript levels of p38MAPK in the gills were found to be significantly upregulated after challenge with acute cold stress for the first 12 h, while no distinctly differential expression was detected in the other two types of MAPKs (JNK and ERK). The phosphorylation levels of p38MAPK under acute cold stress continued to increase and reached a peak 1 h after cold exposure. The phosphorylation signaling of p38MAPK in re-chilled shrimp (5 min) appeared more quickly than that in primary shrimp (15 min). The results suggest that p38MAPK might play an essential role in transducing acute cold stress signals from the environment to the cell nucleus in L. vannamei. Our study is the first to characterize p38MAPK during acute cold stress adaptation, and the results will contribute to further research.