Institute of Hydrobiology, Chinese Academy Of Sciences
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甘草在水产养殖中的应用
No full text甘草(Glycyrrhiza uralensis Fiseh)因其具有调和诸药的特性,被誉为“百草之王”,是我国常见廉价药材,被应用于水产养殖。其有效成分主要是多糖、甙类、生物碱、有机酸和挥发油等。在水产养殖中,常见的甘草给药方法包括投喂、灌服、注射、浸泡以及泼洒等,用于水产动物的免疫调理、病害防治以及其他用途。然而,甘草在使用过程中也存在着一些问题,比如药材质量不稳定、使用方法较为粗放、规范化药方较少、命名和描述不够准确等。本文对甘草的渔用价值进行了综述
西藏温泉两种中国新记录纤毛虫第一双小核草履虫和明布雷斯四膜虫 的形态学和系统发育学研究
No full text研究利用活体观察、蛋白银和氨银染色技术对采自西藏温泉的寡膜纲咽膜类纤毛虫第一双小核草履虫(Paramecium primaurelia)和膜口类纤毛虫明布雷斯四膜虫(Tetrahymena mimbres)进行了形态学研究,首次描述了这两种纤毛虫细胞核器的形态和位置、纤毛图式和口膜的排布模式;并且测定了SSU rDNA和COXⅠ标记基因序列,基于这两种基因的系统发育树均支持P.primaurelia聚在草履虫P.aurelia复合种中,T.mimbres聚在四膜虫T.borealis类群中。两种纤毛虫均为中国新记录种,且首次在高原温泉中发现,不仅为西藏地区温泉原生动物生物资源的发掘提供新的方法和思路,也为原生动物环境适应性研究提供基础资料
光色和光照周期对大西洋鲑银化期生长及生理的影响
No full text为探讨大西洋鲑(Salmo salar)银化期间光色和光照周期对其生长及生理的影响,采用单因素分析法,设计3种光照周期和3种光源颜色,在红光条件下,设置24 h开灯(24L∶0D)(全光照)、24 h关灯(0L∶24D)(无光照)以及12 h开灯12 h关灯(12L∶12D)(半光照)3种光照周期,在半光照条件下,设置红光、白光和蓝光3种LED光源颜色。试验周期为4个月,测定各组大西洋鲑的生长性能指标及血清生化指标。结果显示,半光照时,大西洋鲑的日增重和特定生长率显著高于无光照组(P<0.05),而饲料系数显著低于其他两组(P<0.05)。光源颜色对大西洋鲑银化期的生长具有显著影响(P<0.05),采用红光时,大西洋鲑的日增重最高,白光组次之,蓝光组最低,而饲料系数呈现相反的规律。盐度耐受试验表明,半光照组的死亡率为10%,显著低于其他两组(P<0.05),而红光组死亡率约为10%,显著低于白光组和蓝光组(P<0.05)。血清指标分析表明,半光照组的钠离子和氯离子含量低于其他两组,说明该组的大西洋鲑在海水中具备了渗透压调节的能力。综上,红光光源半光照为大西洋鲑银化期的适宜养殖条件
Nanog safeguards early embryogenesis against global activation of maternal beta-catenin activity by interfering with TCF factors
No full textMaternal beta-catenin activity is essential and critical for dorsal induction and its dorsal activation has been thoroughly studied. However, how the maternal beta-catenin activity is suppressed in the nondorsal cells remains poorly understood. Nanog is known to play a central role for maintenance of the pluripotency and maternal -zygotic transition (MZT). Here, we reveal a novel role of Nanog as a strong repressor of maternal beta-catenin signaling to safeguard the embryo against hyperactivation of maternal beta-catenin activity and hyperdorsalization. In zebrafish, knockdown of nanog at different levels led to either posteriorization or dorsalization, mimicking zygotic or maternal activation of Wnt/beta-catenin activities, and the maternal zygotic mutant of nanog (MZnanog) showed strong activation of maternal beta-catenin activity and hyperdorsalization. Although a constitutive activator-type Nanog (Vp16-Nanog, lacking the N terminal) perfectly rescued the MZT defects of MZnanog, it did not rescue the phenotypes resulting from beta-catenin signaling activation. Mechanistically, the N terminal of Nanog directly interacts with T-cell factor (TCF) and interferes with the binding of beta-catenin to TCF, thereby attenuating the transcriptional activity of beta-catenin. Therefore, our study establishes a novel role for Nanog in repressing maternal beta-catenin activity and demonstrates a transcriptional switch between beta-catenin/TCF and Nanog/TCF complexes, which safeguards the embryo from global activation of maternal beta-catenin activity
Xylanase supplementation in plant protein-enriched diets improves growth performance by optimizing the intestinal microflora and enhancing the intestinal immune function in grass carp grow-out (Ctenopharyngodon idella)
No full textThis study investigated the effect of xylanase supplementation of a plant protein-enriched diet on the growth performance and intestinal immune function of grass carp grow-out (Ctenopharyngodon idella). Five hundred forty healthy grass carp grow-out (232.74 +/- 0.12 g) were fed diets containing graded levels of xylanase for 60 days. The fish were then challenged with Aeromonas hydrophila for 14 days. The results indicated that xylanase supplementation (a) improved fish growth performance and optimized the intestinal microflora; (b) increased lysozyme and acid phosphatase activities, complement and immunoglobulin M levels and antibacterial peptide hepcidin mRNA levels, thereby enhancing fish intestinal immune function; and (c) attenuated intestinal inflammation associated with the inhibition of the NF-kappa B signalling pathway and activation of the TOR signalling pathway, resulting in the down-regulation of pro-inflammatory cytokines [except IL-1 beta and IL-12p40 in the distal intestine (DI) and IL-6 in the proximal intestine (PI)] and up-regulation of anti-inflammatory cytokines [except IL-4/13B and TGF-beta 1 in the mid intestine (MI) and DI]. Finally, on the premise of a basal diet containing 45.8 g/kg araboxylans (AXs), the appropriate supplementation levels based on the ability to improve per cent weight gain (PWG) and prevent enteritis were estimated to be 1,527 and 1,608 U/kg, respectively.</p
Ecosystem-Based Restoration to Mitigate Eutrophication: A Case Study in a Shallow Lake
No full textUnder the influence of human activities, eutrophication has become an increasingly serious global phenomenon, especially in shallow lakes. Many studies have shown that aquatic macrophytes play a significant role in controlling eutrophication, but only few of these studies are ecosystem based. In this paper, we applied a mass-balance ecosystem model to a shallow eutrophic lake (Lake Datong, China) as a case study with the aims of evaluating the status of ecosystem restoration via the recovery of aquatic vegetation and providing adaptive management suggestions. Results showed that the ecosystem was immature with weak energy flows and nutrient cycling largely due to the excessive submerged macrophytes and the lack of fish as consumer. In the early stages of restoration, the number of fish should be reduced, and aquatic vegetation needs to be recovered to mitigate eutrophication. When the aquatic vegetation community tends to be stable, herbivorous and omnivorous fish should be moderately stocked, and dead aquatic macrophytes should be harvested to maintain the healthy and sustainable development of the ecosystem. This study provided insights for the ecological restoration of shallow eutrophic lakes and revealed the urgent need for ecosystem-based restoration
A stable simultaneous anammox, denitrifying anaerobic methane oxidation and denitrification process in integrated vertical constructed wetlands for slightly polluted wastewater (vol 262, 114363, 2020)
No full textA phylogenetic and trait-based analysis of community assembly in a subtropical forest in central China
No full textDespite several decades of study in community ecology, the relative importance of the ecological processes that determine species co-occurrence across spatial scales remains uncertain. Some of this uncertainty may be reduced by studying the scale dependency of community assembly in the light of environmental variation. Phylogenetic information and functional trait information are often used to provide potentially valuable insights into the drivers of community assembly. Here, we combined phylogenetic and trait-based tests to gain insights into community processes at four spatial scales in a large stem-mapped subtropical forest dynamics plot in central China. We found that all of the six leaf economic traits measured in this study had weak, but significant, phylogenetic signal. Nonrandom phylogenetic and trait-based patterns associated with topographic variables indicate that deterministic processes tend to dominate community assembly in this plot. Specifically, we found that, on average, co-occurring species were more phylogenetically and functionally similar than expected throughout the plot at most spatial scales and assemblages of less similar than expected species could only be found on finer spatial scales. In sum, our results suggest that the trait-based effects on community assembly change with spatial scale in a predictable manner and the association of these patterns with topographic variables, indicates the importance of deterministic processes in community assembly relatively to random processes
Use of a paraprobiotic and postbiotic feed supplement (HWF (TM)) improves the growth performance, composition and function of gut microbiota in hybrid sturgeon (Acipenser baerii x Acipenser schrenckii)
No full textThe contribution of cold water aquaculture for the world fish production is significant. Although sturgeon farming is an important part of China's cold water aquaculture industry, its production is less compared with the current potentiality of the country. There are many reasons for the lower production of cold water fish farming including feed and disease. The aim of the present study was to investigate the effect of a paraprobiotic and postbiotic feed supplement (Herpes Worry Free or HWF (TM)) on the growth, feeding efficiency and gut microbiota balance of hybrid sturgeon. Besides, the effect of sturgeon gut microbiota fed on the diet supplemented with HWF (TM) on the expression of growth promoter, and immune regulatory genes of germ free (GF) zebrafish was evaluated. Sturgeon were fed for three weeks with HWF (TM) supplemented or basal diet. At the end of the experiment gut content of sturgeon, fed on either experimental diet was transferred and colonized to GF zebrafish. Sturgeon fed with HWF (TM) supplemented diet showed significantly higher weight gain rate and lower feed conversion ratio (FCR) as compared with the control (P < 0.05). Compared with the control group, the relative abundance of Firmicutes, were significantly higher in the HWF (TM) group (P < 0.05), whereas Proteobacteria, Actinobacteria and Chlamydiae were significantly higher in the control group (P < 0.05). Furthermore, at the genus level Clostridium (64.50 +/- 5.99%) and Lactococcus (29.5 +/- 3.05%) were the most dominant gut bacteria in the HWF (TM) group and the control group of sturgeon, respectively. The expression of genes related to growth, inflammation and non-specific immunity was significantly upregulated in GF zebrafish colonized with gut microbiota of HWF (TM) sturgeon group. In conclusion, HWF (TM) played significant role in growth, feed efficiency and modulation of gut microbiota of sturgeon. The gut microbiota of sturgeon fed on the diet supplemented with HWF (TM) upregulated the expression of genes related to growth, inflammation and non-specific immunity in GF zebrafish model
The circadian clock and darkness control natural competence in cyanobacteria
No full textThe cyanobacterium Synechococcus elongatus is a model organism for the study of circadian rhythms. It is naturally competent for transformation-that is, it takes up DNA from the environment, but the underlying mechanisms are unclear. Here, we use a genome-wide screen to identify genes required for natural transformation in S. elongatus, including genes encoding a conserved Type IV pilus, genes known to be associated with competence in other bacteria, and others. Pilus biogenesis occurs daily in the morning, while natural transformation is maximal when the onset of darkness coincides with the dusk circadian peak. Thus, the competence state in cyanobacteria is regulated by the circadian clock and can adapt to seasonal changes of day length