Compared with wild grass carp (
), intensively cultured fish displayed disordered lipid metabolism, showing excess lipid deposition in the hepatopancreas and muscle. Lotus leaf prevents fat ...accumulation in humans and may have similar effects on fish. This study explored the regulatory mechanisms by which the dietary addition of an alcoholic extract of lotus leaf (AELL) reduced lipid deposition in the hepatopancreas and muscle of juvenile grass carp. The fish (average initial weight: 34.00 ± 0.40 g) were fed four experimental diets containing different AELL levels (0, 0.07, 0.14, and 0.21%) for 8 weeks. Serum components, lipid droplet size, triacylglycerol (TAG) content, enzymatic activities, and mRNA levels of genes related to lipid metabolism in the hepatopancreas and muscle were analyzed. The results show that dietary AELL supplementation significantly reduced the TAG content and lipid droplet area in the histological sections as well as the fatty acid synthase (FAS) activity in both the hepatopancreas and muscle but enhanced the activities of lipoprotein lipase (LPL) and carnitine palmitoyltransferase I (CPT1) in both tissues. In addition, dietary AELL supplementation decreased the mRNA expression of genes involved in fatty acid uptake (
,
,
,
) and
lipid synthesis (
,
, and
) as well as the transcription factors
and
in the hepatopancreas and muscle but increased the mRNA levels of genes relating to lipid catabolism (
,
,
,
), lipid transportation (
), and the transcription factor
in both tissues. In conclusion, dietary AELL supplementation reduced lipid accumulation in the hepatopancreas and muscle by affecting the gene expression of proteins with known effects on lipid metabolism in juvenile grass carp.
The past several decades have seen China undergo a rapid urbanization process. During periods of economic prosperity, cities expropriate outlying lands, often villages, for economic development with ...the support of various local and national government programs designed to encourage urban expansion. However, the autonomy of the villages has not been paid enough attention. How does incorporation into an urban development zone affect the community identity and autonomy of a village? How does the village bargain with external urban institutions? This research is based on ethnographic research and interviews conducted in 2013, 2014, 2017, and 2021. The results reveal that villagers are generally willing to accept the loss of their collective land in exchange for a larger share of the promised prosperity of industrialization, but over time they tend to find that the immediate benefits of expropriation are outweighed by long-term costs. They lose the support of the state and are exposed to new vulnerabilities, such as pollution and economic instability. Indeed, they agree to undertake unknown future risks in exchange for short-term gains. They cannot gain the right to the city, but gradually lose control of the village.
Currently, the L-malic acid titer achieved through
fermentation reaches 201 g/L, meeting industrial demands satisfactorily. However, the co-presence of structurally similar fumaric acid and succinic ...acid in fermentation products suggests a theoretical potential for further improvement in L-malic acid production. In the tricarboxylic acid cycle, fumarate reductase mediates the conversion of succinic acid to fumaric acid. Subsequently, fumarase catalyzes the conversion of fumaric acid to L-malic acid. Notably, both enzymatic reactions are reversible. Our investigation revealed that
contains only one mitochondria-located fumarase FumA. Employing CRISPR-Cas9 technology, we performed a replacement of the
promoter with a doxycycline-induced promoter Tet. Under non-inducing condition, the conditional strain exhibited increased levels of fumaric acid and succinic acid. It strongly suggests that FumA mainly promotes the flow of fumaric acid to L-malic acid. Furthermore, a promoter PmfsA that is exclusively activated in a fermentation medium by calcium carbonate was identified through RNA-sequencing screening. Utilizing PmfsA to regulate
expression led to a 9.0% increase in L-malic acid titer, an 8.75% increase in yield (glucose to L-malic acid), and an 8.86% enhancement in productivity. This research serves as a significant step toward expediting the industrialization of L-malic acid synthesis via biological fermentation. Additionally, it offers valuable insights for the biosynthesis of other organic acids.IMPORTANCEThis study focuses on enhancing L-malic acid synthesis by modifying the tricarboxylic acid cycle within the mitochondria of
. We emphasize the significant role of fumarase in converting fumaric acid into L-malic acid, enhancing our understanding of metabolic pathways in
. The precise regulation of
is highlighted as a key factor in enhancing L-malic acid production. Furthermore, this research introduces a stringent conditional promoter (PmfsA), exclusively activated by CaCO
. The utilization of PmfsA for
expression resulted in heightened L-malic acid titers. The progress in metabolic engineering and bioprocess optimization holds promise for expediting industrial L-malic acid synthesis via biological fermentation. Moreover, it carries implications for the biosynthesis of various other organic acids.
Urban-centric growth resulting from urban expansion and land redevelopment may result in rural-urban conflicts. Over time, in China, the affected social groups, such as urban residents in the poorer ...neighbourhoods, peri-urban farmers and urban population living in the peri-urban areas have found their voices in the academic literature, and some have even developed ways to negotiate compensation for the lost properties and livelihoods. This paper analyses the impact of urban-centric growth on the livelihoods of a much less studied group: tenant farmers. Using the cases of Beishan and Nanshan Villages of Guangzhou, with first-hand data collected in 2008, 2009 and 2017, this research found that tenant farmers had to face 'dual social exclusion'. They were excluded by the urban authorities and the urban society, and by the rural authorities and rural communities. The dual social exclusion was imposed on tenant farmers through cultural and institutional settings that were systematically against 'outsiders'. Incentivised by the institutional settings, local farmers were not just victims of predatory urbanisation; they could also be oppressors of tenant farmers. However, as important food suppliers to cities, the tenant farmers exercised agency to overcome the difficulties, which sowed the seeds of urban food insecurity.
The efficient production of l-malic acid using Aspergillus niger requires overcoming challenges in synthesis efficiency and excessive byproduct buildup. This study addresses these hurdles, improving ...the activity of NADH-dependent malate dehydrogenase (Mdh) in the early stages of the fermentation process. By employing a constitutive promoter to express the Escherichia coli sthA responsible for the transfer of reducing equivalents between NAD(H) and NADP(H) in A. niger, the l-malic acid production was significantly elevated. However, this resulted in conidiation defects of A. niger, limiting industrial viability. To mitigate this, we discovered and utilized the PmfsA promoter, enabling the specific expression of sthA during the fermentation stage. This conditional expression strain showed similar phenotypes to its parent strain while exhibiting exceptional performance in a 5 L fermenter. Notably, it achieved a 65.5% increase in productivity, reduced fermentation cycle by 1.5 days, and lowered succinic acid by 76.2%. This work marks a promising advancement in industrial l-malic acid synthesis via biological fermentation, showcasing the potential of synthetic biology in A. niger for broader applications.
Grass carp (Ctenopharyngodon idellus) is one of the most important aquaculture fish in China. This study tried to explore the effects of dietary alcoholic extract of lotus leaf (AELL) addition on the ...growth performance and health status of grass carp by feeding juvenile fish (average weight: 34 ± 1 g) with four different experimental diets: control, AELL7, AELL14 and AELL21 for 8 weeks. At the end of the growth trial, the highest values of final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR) and feed intake (FI) all occurred in group AELL14 (P < 0.05). Compared to control, the crude lipid content of whole-body and the serum malondialdehyde (MDA) in the three experimental groups decreased, while the serum superoxide dismutase (SOD), glutathione peroxidase (GSH) and total antioxidant capacity (T-AOC) values almost all increased in the three experimental groups. The highest serum immunoglobulin M (IgM) concentration occurred in AELL14 group (P < 0.05). In AELL14 and AELL21 groups, both the serum complement 3 (C3) concentration and lysozyme (LYS) activity were significantly higher, whereas the final cumulative mortality in challenge test was significantly lower, when compared to those in control group (P < 0.05). The AELL exerted dose-dependent beneficial effects on grass carp health through up-regulating related gene expressions and enzyme activity. In conclusion, the optimal dietary AELL level is 0.14% for juvenile grass carp.
•Lotus leaf extract can improve growth performance and health status of grass carp.•Lotus leaf extract exhibited dose-dependent beneficial effects on grass carp.•Optimal lotus leaf extract inclusion level in the grass carp diet is 0.14%.
The present study was conducted to investigate the regulative function of FGF6 in the muscle growth of grass carp (
Ctenopharyngodon idellus
) by the bioinformatics analysis and expression pattern ...analyses of FGF6 genes in different developmental stages and tissues, as well as the correlation analysis between muscle growth and FGF6 expression after fish were fed with different levels of dietary lotus leaf flavonoids (LLF) (0, 0.03%, 0.06%, 0.09%). Results showed that the FGF6a and FGF6b genes are two homologs of the FGF6 family, encoding 205 and 209 amino acids, respectively. Alignment of amino acid sequences and phylogenetic analysis demonstrated that FGF6a and FGF6b are highly conserved with other vertebrates. Quantitative RT-PCR analysis showed both FGF6a and FGF6b expressions were high in brain and muscle but low in other examined tissues. During embryonic development, FGF6a and FGF6b mRNA expressions could be detected as early as at fertilized egg stage and displayed the highest value at cleavage stage. Dietary LLF affected the gene expression of FGF6 in white muscle. The relative expression of FGF6a of 0.06% LLF group was significantly higher than that of 0.09% LLF group, while FGF6b expression of 0.06% LLF group was higher than those of other groups (
P
< 0.05). The muscle fiber diameter was significantly higher in 0.06% LLF group in comparison with other groups, while the fiber density in this group was lower (
P
< 0.05). Both FGF6a and FGF6b expressions were positively correlated with fiber diameter but negatively correlated with fiber density. These results collectively suggest that FGF6a and FGF6b play an important role in muscle growth regulation in grass carp.
Fish endure long periods of fasting and demonstrate an extensive capacity for rapid and complete recovery after refeeding. The aim of this study was to investigate the effects of refeeding after ...fasting on growth, muscle characteristics and the related gene expressions of juvenile grass carp (Ctenopharyngodon idellus). Fish were divided into three groups with triplicates: continuous feeding for 28 days (F28), 14 days of fasting and 14 days of refeeding (S14F14), and continuous fasting for 28 days (S28). Fish were sampled every 7 days for morphological, histological and gene expression analyses. Results showed that fasted fish gained weight continuously during refeeding, displaying compensatory growth. The muscle fiber diameter in S14F14 group decreased gradually during fasting and then increased with refeeding, but didn't reach the value in F28 group on 28d, while the muscle fibers density showed the opposite trend (P < 0.05). Fsih in S14F14 group recovered the intramuscular fat accumulatation during refeeding, accompanied by the upregulated expressions of fas and acc and the downregulated expressions of cpt1 and lpl in muscle on 21d. With the prolongation of fasting time, the expression of several key genes involved in myogenesis (myf5, mrf4, myog, myod, cyclind1) and muscle growth (fst, fgf6a, fgf6b) in S14F14 group decreased firstly and then increased briefly, while igf-II decreased and mstn increased continuously. All genes in S14F14 group eventually reached the same level as those in F28 group at the end of the experiment except fst and fgf6a. In conclusion, this study showed that 14 days of fasting resulted in muscle fiber atrophy in grass carp while refeeding after fasting presented compensatory mass gain, along with a coordinated regulation of several genes involved in a strong resumption of myogenesis to promote muscle growth. These results helped to understand the physiological regulation mechanism of refeeding on muscle growth of fish.
•The refeeding after 2-week fasting caused compensatory mass gain of juvenile grass carp.•The muscle fiber diameter decreased gradually during fasting and then increased after refeeding.•Muscle growth in response to feeding regime was regulated through a series of genes involved in myogenesis and hypertrophy.
An increasingly common approach for creating photo-realistic digital avatars is through the use of volumetric neural fields. The original neural radiance field (NeRF) allowed for impressive novel ...view synthesis of static heads when trained on a set of multi-view images, and follow up methods showed that these neural representations can be extended to dynamic avatars. Recently, new variants also surpassed the usual drawback of baked-in illumination in neural representations, showing that static neural avatars can be relit in any environment. In this work we simultaneously tackle both the motion and illumination problem, proposing a new method for relightable and animatable neural heads. Our method builds on a proven dynamic avatar approach based on a mixture of volumetric primitives, combined with a recently-proposed lightweight hardware setup for relightable neural fields, and includes a novel architecture that allows relighting dynamic neural avatars performing unseen expressions in any environment, even with nearfield illumination and viewpoints.
Abstract
Developing active single-atom-catalyst (SAC) for alkaline hydrogen evolution reaction (HER) is a promising solution to lower the green hydrogen cost. However, the correlations are not clear ...between the chemical environments around the active-sites and their desired catalytic activity. Here we study a group of SACs prepared by anchoring platinum atoms on NiFe-layered-double-hydroxide. While maintaining the homogeneity of the Pt-SACs, various axial ligands (−F, −Cl, −Br, −I, −OH) are employed
via
a facile irradiation-impregnation procedure, enabling us to discover definite chemical-environments/performance correlations. Owing to its high first-electron-affinity, chloride chelated Pt-SAC exhibits optimized bindings with hydrogen and hydroxide, which favor the sluggish water dissociation and further promote the alkaline HER. Specifically, it shows high mass-activity of 30.6 A mgPt
−1
and turnover frequency of 30.3 H
2
s
−1
at 100 mV overpotential, which are significantly higher than those of the state-of-the-art Pt-SACs and commercial Pt/C catalyst. Moreover, high energy efficiency of 80% is obtained for the alkaline water electrolyser assembled using the above catalyst under practical-relevant conditions.
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