Metformin attenuates lipid accumulation in hepatocytes of blunt snout bream (Megalobrama amblycephala) via activation of AMP-activated protein kinase

Currently, there is a trend to use high-fat diets in intensive aquaculture that is accompanied with incidence of fatty liver when dietary lipid level surpasses an upper limit. So, it is necessary to develop appropriate strategies to reduce the risk of fatty liver in commercial fish farming. Studies in mammals have revealed a correlation between fatty liver and AMP-activated protein kinase (AMPK) activity, which has been recognized as a key modulator of lipid metabolism. Considering the frequent occurrence of fatty liver in blunt snout bream farming, an in-vitro study was designed to evaluate the efficiency of metformin, as a stimulator of AMPK, in activation of AMPK and its subsequent effects on lipid metabolism in primary hepatocytes. Fish hepatocytes were seeded at a density of 1 × 106 ml−1 in 6-well tissue culture plates and treated with three different media including: 1) Leibovitz's L-15 medium [L15] as control, 2) high-fat medium [L15 + 400 μM oleic acid], and 3) metformin medium [L15 + 400 μM oleic acid+200 μM metformin]. After 48 h of culture, the cells and supernatant were collected for analysis. The results showed significant (P

Differential distribution patterns and assembly processes of soil microbial communities under contrasting vegetation types at distinctive altitudes in the Changbai Mountain

Diversity patterns and community assembly of soil microorganisms are essential for understanding soil biodiversity and ecosystem processes. Investigating the impacts of environmental factors on microbial community assembly is crucial for comprehending the functions of microbial biodiversity and ecosystem processes. However, these issues remain insufficiently investigated in related studies despite their fundamental significance. The present study aimed to assess the diversity and assembly of soil bacterial and fungal communities to altitude and soil depth variations in mountain ecosystems by using 16S and ITS rRNA gene sequence analyses. In addition, the major roles of environmental factors in determining soil microbial communities and assembly processes were further investigated. The results showed a U-shaped pattern of the soil bacterial diversity at 0–10  cm soil depth along altitudes, reaching a minimum value at 1800 m, while the fungal diversity exhibited a monotonically decreasing trend with increasing altitude. At 10–20  cm soil depth, the soil bacterial diversity showed no apparent changes along altitudinal gradients, while the fungal Chao1 and phylogenetic diversity (PD) indices exhibited hump-shaped patterns with increasing altitude, reaching a maximum value at 1200 m. Soil bacterial and fungal communities were distinctively distributed with altitude at the same depth of soil, and the spatial turnover rates in fungi was greater than in bacteria. Mantel tests suggested soil physiochemical and climate variables significantly correlated with the β diversity of microbial community at two soil depths, suggesting both soil and climate heterogeneity contributed to the variation of bacterial and fungal community. Correspondingly, a novel phylogenetic null model analysis demonstrated that the community assembly of soil bacterial and fungal communities were dominated by deterministic and stochastic processes, respectively. The assembly processes of bacterial community were significantly related to the soil DOC and C:N ratio, while the fungal community assembly processes were significantly related to the soil C:N ratio. Our results provide a new perspective to assess the responses of soil microbial communities to variations with altitude and soil depth

Effects of Spartina alterniflora invasion on the benthic invertebrate community in intertidal wetlands

Exotic species invasions have profound effects on native ecosystems, with the ecological effects of non-native plants being especially pervasive. We investigated the impacts of a plant invasion on benthic invertebrate assemblages in intertidal wetlands of the Yellow River Delta, comparing benthic communities associated with exotic Spartina alterniflora against those associated with native plants (Tamarix chinensis, Suaeda salsa, and mudflat). Our study surprisingly found that the density, diversity, and richness of benthic invertebrates associated with S. alterniflora were higher than with native habitats. Multivariate analysis also revealed that the structure of benthic invertebrates in S. alterniflora habitats was different than in T. chinensis and mudflat habitats. The structure of invertebrates associated with the invasive S. alterniflora and native S. salsa was more similar, although the dominant species differed. Indicator species analyses indicated that each habitat was characterized by unique taxa. S. alterniflora invasion increased the beta diversity of the community, with the species turnover component being of most importance. Mollusks were most likely to be influenced by Spartina invasions. Given the extent of the S. alterniflora invasion in the Yellow River Delta, altered benthic invertebrate communities will likely have important implications for the ecology of the intertidal wetland ecosystems and deserve increased attention

Experimental Study on Desorption Hysteresis Characteristic for Shale Gas

 Compared with the adsorption isotherms, desorption isotherms could evaluate accurately shale absorbed gas reserves in different pressure stage, the desorption hysteresis characteristics exists in shale gas formation. In order to discover the adsorption hysteresis phenomenon and the influence factor of adsorption hysteresis in high pressure range, The physical properties test and adsorption/ desorption test of shale gas were Carried out by shale outcrop samples from horse Creek group in Eastern Sichuan. The results show that the shale gas adsorption isotherm curve and desorption isotherm curve are not coincided. It has obvious adsorption hysteresis loop, which hysteresis degree relate to shale physical parameter. It shows that the worse shale gas physical property is, the more complicated pore structure is, the more hysteresis degree appears. Meanwhile, three theoretical models were used to fit the measured isotherm adsorption and desorption curves. The results show that comparing to the Langmuir-Freudlich equation and Freundlich equation, Langmuir equation fits the adsorption and desorption characteristic of shale gas betterly

Substituting dietary fishmeal with soybean meal isolate influences hepatic lipid metabolism and gut microbiota in spotted seabass (<em>Lateolabrax maculatus</em>)

This study was conducted to investigate the effects of partial substitution of dietary fishmeal (FM) by soy protein isolate (SPI) on lipid metabolism and gut microbiota of spotted seabass. A diet containing 30% FM formed the basal diet (FM), and two SPI diets were formulated in which 25% (SPI25) and 50% (SPI50) of FM were replaced by SPI. Each diet was fed to triplicates of fish for 56 days. The results showed that replacing dietary FM with SPI reduced triglyceride and cholesterol contents in the liver and serum, and the hepatic lipid droplets area was also decreased by dietary SPI inclusion. Furthermore, replacement of dietary FM with SPI markedly down-regulated the mRNA expression of genes involved in lipogenesis (srebpc-1c, fas, acc1, hmgcr, pparγ and chrebp) and lipolysis (atgl, hsl, pparα, and cpt1). Moreover, high-throughput sequencing analyses of gut microbiota revealed that dietary SPI inclusion dramatically decreased the Firmicutes/Bacteroidetes ratio. Overall, this study indicated that replacing 25-50% of dietary FM with SPI could reduce lipid accumulation in serum and liver of spotted seabass, which was associated with the suppressed hepatic lipogenesis and the remodeled gut microbiota

Experimental Study on Desorption Hysteresis Characteristic for Shale Gas

 Compared with the adsorption isotherms, desorption isotherms could evaluate accurately shale absorbed gas reserves in different pressure stage, the desorption hysteresis characteristics exists in shale gas formation. In order to discover the adsorption hysteresis phenomenon and the influence factor of adsorption hysteresis in high pressure range, The physical properties test and adsorption/ desorption test of shale gas were Carried out by shale outcrop samples from horse Creek group in Eastern Sichuan. The results show that the shale gas adsorption isotherm curve and desorption isotherm curve are not coincided. It has obvious adsorption hysteresis loop, which hysteresis degree relate to shale physical parameter. It shows that the worse shale gas physical property is, the more complicated pore structure is, the more hysteresis degree appears. Meanwhile, three theoretical models were used to fit the measured isotherm adsorption and desorption curves. The results show that comparing to the Langmuir-Freudlich equation and Freundlich equation, Langmuir equation fits the adsorption and desorption characteristic of shale gas betterly

Effects of substituting dietary fish meal with soybean meal isolate on growth performance, digestive enzyme activity, and intestinal morphology of spotted seabass (<em>Lateolabrax maculatus</em>)

Soy protein isolate (SPI) is a promising plant protein source to replace fish meal (FM) in aquatic feeds. This study investigated the growth performance, digestive enzyme activity, and intestinal morphology of spotted seabass (Lateolabrax maculatus) fed diets with FM partially substituted by SPI. Three iso-nitrogenous and iso-lipidic diets were formulated to replace 0, 25, and 50% of FM with SPI, being abbreviated as FM, SPI25, and SPI50, respectively. Each diet was allocated to triplicates of fish for 8 weeks. The results indicated that the weight gain was gradually reduced with increasing dietary SPI levels, as did intestinal trypsin and lipase activities. However, these traits were not significantly decreased until 50% of FM was substituted by SPI. Furthermore, feed intake and lipid digestibility significantly decreased with dietary SPI inclusion. Moreover, replacing 50% of dietary FM with SPI significantly reduced the intestinal villus height and perimeter ratio, whereas these traits did not markedly differ between FM and SPI25 groups. In conclusion, this study indicated that up to 25% of dietary FM could be substituted with SPI without significantly affecting the growth, digestive enzyme activity, or intestinal morphology in spotted seabass

Villagers&rsquo; Satisfaction Evaluation System of Rural Human Settlement Construction: Empirical Study of Suzhou in China&rsquo;s Rapid Urbanization Area

Continuous improvement of rural human settlements is a major realistic requirement of China&rsquo;s economic and social development in the context of rural revitalization. Tracking and evaluating the phased progress of human settlement construction in stages represent important techniques for ensuring continual improvement. To improve the current objective data-based index system, this paper focuses on the villager-centered evaluation system at the village level. Factor analysis is used to screen the original data from the questionnaire and minimize the dimensions to synthesize common factors on the basis of empirical results. The main conclusions are as follows: (1) according to weight, the satisfaction evaluation system includes five common factors: living support facilities, nonagricultural industry income, agriculture production income, transportation infrastructure, and comprehensive ecological improvement. The results show that construction investment is beneficial, but not directly proportional to the villagers&rsquo; satisfaction. Actual improvement is not keeping up with the demand for public fitness, cultural, and recreational facilities. On the other hand, changes in villagers&rsquo; lifestyles may reduce the need for commercial facilities; (2) according to the evaluation model, the indicators can be classified into four categories on the basis of the weight assessment score, all of which can provide differentiated construction strategies to avoid duplication and inefficient resource waste. The survey data&rsquo;s indicators of major differences between villages, such as public transportation and sanitation, need further discussion; (3) the gap between actual improvement actions and villagers&rsquo; needs gives an optimization path for rural construction. The experiences of sample villages in well-developed areas can be used as a model for policy formulation in other regions, and a long-term follow-up investigation should be included in future studies

Effects of Hydrological Connectivity on Snail Assemblages in the Intertidal Zone of Coastal Wetlands

Hydrological connectivity controls the patterns of invertebrate assemblages in wetland ecosystems. With degradation of intertidal wetlands, artificial freshwater release has become an important restoration technique. Hydrological connectivity with tidal creeks is also a key ecological process for intertidal wetlands. However, how hydrologic connectivity affects snail assemblages remains poorly investigated in intertidal wetlands. We studied the differences in snail assemblages in wetlands to understand the effects of hydrological connectivity, wetland to river, and wetland to ocean. We found freshwater connectivity can transform intertidal snail assemblages into freshwater snail assemblages; restored wetlands primarily had freshwater snail species and natural intertidal wetlands mainly supported marine or salt-adapted snail species. Cluster analysis, nMDS plot and ANOSIM analysis showed snail assemblages were influenced strongly by hydrological connectivity.Stenothyra glabra,Oncomelaniasp. andNassarius festivuswere indicators of natural intertidal wetlands.Hippeutis cantori,Radix swinhoeiandSuccinea pfeifferiwere indicators of restored wetlands. Our results suggest natural hydrological connectivity with the ocean needs to be maintained when attempting to restore intertidal wetlands. Without this connection, connecting impaired wetlands only to rivers, may not achieve restoration of natural biotic assemblages

Dietary calcium requirement of bullfrog (Lithobates catesbeiana)

This study was conducted to determine dietary calcium (Ca) requirement of bullfrog (Lithobates catesbeiana). Six diets were formulated to contain 0.55% (control), 0.96%, 1.30%, 1.72%, 2.02% and 2.53% Ca. Each diet was fed to triplicate tanks of bullfrogs (24.96 ± 0.03 g), and each tanks was stocked with 13 bullfrogs. Bullfrogs were fed twice daily (8:30 and 17:30) to apparent satiation for 8 weeks. Weight gain rate of bullfrogs fed the 1.72% Ca diet was significantly higher than the control group (P < 0.05). The content of Ca was significantly increased in the whole body and vertebrae of bullfrogs fed the 1.72%, 2.02% and 2.53% diets compared to those fed the 0.55%, 0.96% and 1.30% Ca diets (P < 0.05). Furthermore, bullfrogs fed the 1.30%, 1.72% and 2.02% diets had higher activity of trypsin than those fed the 0.55% and 2.53% Ca diets (P < 0.05). Apparent digestibility coefficient of dry matter was higher in bullfrogs fed the 1.72% Ca diet than those fed the 0.55% and 2.53% diets (P < 0.05). Bullfrogs fed the 1.72% Ca diet had higher activity of superoxide dismutase in the serum than those fed the 0.55% and 2.53% diets (P < 0.05). Compared to the control group, contents of 1,25 dihydroxyvitamin D3 and parathyroid hormone in the serum as well as vitamin D receptor and sodium-calcium exchanger genes expression in the kidney were significantly decreased in bullfrogs fed the 1.72%, 2.02% and 2.53% Ca diets (P < 0.05). Compared to the control group, intestinal sodium-calcium exchanger gene expression was significantly decreased in bullfrogs fed the 1.72% and 2.02% Ca diets (P < 0.05). Based on second order polynomial analysis of weight gain rate, dietary Ca requirement of bullfrog was 1.89%