183 research outputs found
Temporary Cultivation and Live Transport with Water Based on Gradient Cooling of Grass Carp (Ctenopharyngodon idellas)
The study investigated the semi-hibernation and critical temperature of grass carp based on gradient cooling, and explore the effects of temperature (12–24 ℃) on the survival of grass carp and the concentration of ammonia nitrogen in the water. The temperature was reduced from room temperature (23–25 ℃) to the semi-dormant temperature (16 ℃) at cooling rate of 1, 3, or 5 ℃/h. The control group was reared at room temperature, and sampling was conducted after 0, 12, 24, 36, and 48 h. Serum biochemical and antioxidant parameters were measured to obtain the maximum cooling rate for grass crap. The results showed that the semi-dormant temperature of grass carp was 16 ℃, the critical temperature was 6–8 ℃, and the optimal cooling rate was 3 ℃/h. At 16 ℃, grass carp exhibited delayed stress response and decreased metabolism, and lower concentrations of ammonia nitrogen in the water. Except for aspartate aminotransferase level, the maximum values of other serum biochemical indexes at the cooling rate of 3 ℃/h, were significantly lower than those at 1 and 5 ℃/h (P < 0.05). The activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) exhibited a trend of initially increasing and then decreasing with survival time, whereas the content of malondialdehyde (MDA) showed an opposite trend, reaching a minimum value of 5.27 mmol/mg after 36 h. Compared to the control group, the contents of all biochemical and antioxidant indexes in the three cooling groups showed significant changes with survival time. Therefore, cooling grass carp at a rate of 3 ℃/h could reduce the stress response and allowed it to enter a semi-hibernation state at a more suitable time. The results from this study provide key parameters for the temporary cultivation and transport of grass carp, as well as useful guidelines for reducing the transport mortality
miR-182 Regulates Metabolic Homeostasis by Modulating Glucose Utilization in Muscle
SummaryUnderstanding the fiber-type specification and metabolic switch in skeletal muscle provides insights into energy metabolism in physiology and diseases. Here, we show that miR-182 is highly expressed in fast-twitch muscle and negatively correlates with blood glucose level. miR-182 knockout mice display muscle loss, fast-to-slow fiber-type switching, and impaired glucose metabolism. Mechanistic studies reveal that miR-182 modulates glucose utilization in muscle by targeting FoxO1 and PDK4, which control fuel selection via the pyruvate dehydrogenase complex (PDHC). Short-term high-fat diet (HFD) feeding reduces muscle miR-182 levels by tumor necrosis factor α (TNFα), which contributes to the upregulation of FoxO1/PDK4. Restoration of miR-182 expression in HFD-fed mice induces a faster muscle phenotype, decreases muscle FoxO1/PDK4 levels, and improves glucose metabolism. Together, our work establishes miR-182 as a critical regulator that confers robust and precise controls on fuel usage and glucose homeostasis. Our study suggests that a metabolic shift toward a faster and more glycolytic phenotype is beneficial for glucose control
Aflatoxin B1 Degradation and Detoxification by Escherichia coli CG1061 Isolated From Chicken Cecum
Aflatoxin B1 (AFB1) is one of the most hazardous mycotoxins contamination in food and feed products, which leads to hepatocellular carcinoma in humans and animals. In the present study, we isolated and characterized an AFB1 degrading bacteria CG1061 from chicken cecum, exhibited an 93.7% AFB1 degradation rate by HPLC. 16S rRNA gene sequence analysis and a multiplex PCR experiment demonstrated that CG1061 was a non-pathogenic Escherichia coli. The culture supernatant of E. coli CG1061 showed an 61.8% degradation rate, whereas the degradation rates produced by the intracellular extracts was only 17.6%, indicating that the active component was constitutively secreted into the extracellular space. The degradation rate decreased from 61.8 to 37.5% when the culture supernatant was treated with 1 mg/mL proteinase K, and remained 51.3% when that treated with 100°C for 20 min. We postulated that AFB1 degradation was mediated by heat-resistant proteins. The content of AFB1 decreased rapidly when it was incubated with the culture supernatant during the first 24 h. The optimal incubation pH and temperature were pH 8.5 and 55°C respectively. According to the UPLC Q-TOF MS analysis, AFB1 was bio-transformed to the product C16H14O5 and other metabolites. Based on the results of in vitro experiments on chicken hepatocellular carcinoma (LMH) cells and in vivo experiments on mice, we confirmed that CG1061-degraded AFB1 are less toxic than the standard AFB1. E. coli CG1061 isolated from healthy chicken cerum is more likely to colonize the animal gut, which might be an excellent candidate for the detoxification of AFB1 in food and feed industry
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TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution
The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a
satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A
ton-level liquid scintillator detector will be placed at about 30 m from a core
of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be
measured with sub-percent energy resolution, to provide a reference spectrum
for future reactor neutrino experiments, and to provide a benchmark measurement
to test nuclear databases. A spherical acrylic vessel containing 2.8 ton
gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon
Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full
coverage. The photoelectron yield is about 4500 per MeV, an order higher than
any existing large-scale liquid scintillator detectors. The detector operates
at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The
detector will measure about 2000 reactor antineutrinos per day, and is designed
to be well shielded from cosmogenic backgrounds and ambient radioactivities to
have about 10% background-to-signal ratio. The experiment is expected to start
operation in 2022
Global Expression Analysis Revealed Novel Gender-Specific Gene Expression Features in the Blood Fluke Parasite Schistosoma japonicum
BACKGROUND: Schistosoma japonicum is one of the remarkable Platyhelminths that are endemic in China and Southeast Asian countries. The parasite is dioecious and can reside inside the host for many years. Rapid reproduction by producing large number of eggs and count-react host anti-parasite responses are the strategies that benefit long term survival of the parasite. Praziquantel is currently the only drug that is effective against the worms. Development of novel antiparasite reagents and immune-prevention measures rely on the deciphering of parasite biology. The decoding of the genomic sequence of the parasite has made it possible to dissect the functions of genes that govern the development of the parasite. In this study, the polyadenylated transcripts from male and female S. japonicum were isolated for deep sequencing and the sequences were systematically analysed. RESULTS: First, the number of genes actively expressed in the two sexes of S. japonicum was similar, but around 50% of genes were biased to either male or female in expression. Secondly, it was, at the first time, found that more than 50% of the coding region of the genome was transcribed from both strands. Among them, 65% of the genes had sense and their cognate antisense transcripts co-expressed, whereas 35% had inverse relationship between sense and antisense transcript abundance. Further, based on gene ontological analysis, more than 2,000 genes were functionally categorized and biological pathways that are differentially functional in male or female parasites were elucidated. CONCLUSIONS: Male and female schistosomal parasites differ in gene expression patterns, many metabolic and biological pathways have been identified in this study and genes differentially expressed in gender specific manner were presented. Importantly, more than 50% of the coding regions of the S. japonicum genome transcribed from both strands, antisense RNA-mediated gene regulation might play a critical role in the parasite biology
The Mitochondrial Genome of Baylisascaris procyonis
BACKGROUND: Baylisascaris procyonis (Nematoda: Ascaridida), an intestinal nematode of raccoons, is emerging as an important helminthic zoonosis due to serious or fatal larval migrans in animals and humans. Despite its significant veterinary and public health impact, the epidemiology, molecular ecology and population genetics of this parasite remain largely unexplored. Mitochondrial (mt) genomes can provide a foundation for investigations in these areas and assist in the diagnosis and control of B. procyonis. In this study, the first complete mt genome sequence of B. procyonis was determined using a polymerase chain reaction (PCR)-based primer-walking strategy. METHODOLOGY/PRINCIPAL FINDINGS: The circular mt genome (14781 bp) of B. procyonis contained 12 protein-coding, 22 transfer RNA and 2 ribosomal RNA genes congruent with other chromadorean nematodes. Interestingly, the B. procyonis mtDNA featured an extremely long AT-rich region (1375 bp) and a high number of intergenic spacers (17), making it unique compared with other secernentean nematodes characterized to date. Additionally, the entire genome displayed notable levels of AT skew and GC skew. Based on pairwise comparisons and sliding window analysis of mt genes among the available 11 Ascaridida mtDNAs, new primer pairs were designed to amplify specific short fragments of the genes cytb (548 bp fragment) and rrnL (200 bp fragment) in the B. procyonis mtDNA, and tested as possible alternatives to existing mt molecular beacons for Ascaridida. Finally, phylogenetic analysis of mtDNAs provided novel estimates of the interrelationships of Baylisasaris and Ascaridida. CONCLUSIONS/SIGNIFICANCE: The complete mt genome sequence of B. procyonis sequenced here should contribute to molecular diagnostic methods, epidemiological investigations and ecological studies of B. procyonis and other related ascaridoids. The information will be important in refining the phylogenetic relationships within the order Ascaridida and enriching the resource of markers for systematic, population genetic and evolutionary biological studies of parasitic nematodes of socio-economic importance
Real-time Monitoring for the Next Core-Collapse Supernova in JUNO
Core-collapse supernova (CCSN) is one of the most energetic astrophysical
events in the Universe. The early and prompt detection of neutrinos before
(pre-SN) and during the SN burst is a unique opportunity to realize the
multi-messenger observation of the CCSN events. In this work, we describe the
monitoring concept and present the sensitivity of the system to the pre-SN and
SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is
a 20 kton liquid scintillator detector under construction in South China. The
real-time monitoring system is designed with both the prompt monitors on the
electronic board and online monitors at the data acquisition stage, in order to
ensure both the alert speed and alert coverage of progenitor stars. By assuming
a false alert rate of 1 per year, this monitoring system can be sensitive to
the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos
up to about 370 (360) kpc for a progenitor mass of 30 for the case
of normal (inverted) mass ordering. The pointing ability of the CCSN is
evaluated by using the accumulated event anisotropy of the inverse beta decay
interactions from pre-SN or SN neutrinos, which, along with the early alert,
can play important roles for the followup multi-messenger observations of the
next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure
Potential of Core-Collapse Supernova Neutrino Detection at JUNO
JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
Detection of the Diffuse Supernova Neutrino Background with JUNO
As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO
High Pressure Driven Isostructural Electronic Phase Separation in 2D BiOI
The crystal structures of BiOI under different pressures are predicted, inwhich the phase transformation from tetragonal BiOI into orthorhombic BiOIis observed at 100 GPa due to the appearance of Bi-I bonds (Bi-6s2lone pairand I-pzobital) between interlayer Bi and I atoms. Most interestingly, fororthorhombic BiOI, an isostructural electronic phase separation is observedat 160 GPa. The electronic structure of BiOI separates into semiconductorstate (contributed by intralayer O-Bi-O) and metal state, which originatefrom the interlayer I-I bonds. More specifically, conversion from interlayerBi-I interaction to interlayer I-I interaction under higher pressure, results inthe continuous decline of the I-dx2-y2energy band, which then crosses theFermi-level. In comparison, the O-Bi-O layer shows almost no change,owing to its strong covalent bonds. These results demonstrate that thedramatic variation of the interaction between the van der Waals layers canlead to the metallic iodine character in BiOI
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