Implications of vitamin D for flesh quality of grass carp(Ctenopharyngodon idella):antioxidant ability,nutritional value,sensory quality,and myofiber characteristics

Background Muscle represents a unique and complex system with many components and comprises the major edible part of animals.Vitamin D is a critical nutrient for animals and is known to enhance calcium absorption and immune response.In recent years,dietary vitamin D supplementation in livestock has received increased attention due to biological responses including improving shear force in mammalian meat.However,the vitamin D acquisition and myofiber development processes in fish differ from those in mammals,and the effect of vitamin D on fish flesh quality is poorly understood.Here,the influence of dietary vitamin D on fillet quality,antioxidant ability,and myofiber development was examined in grass carp(Ctenopharyngodon idella).Methods A total of 540 healthy grass carp,with an initial average body weight of 257.24±0.63 g,were allotted in 6 experimental groups with 3 replicates each,and respectively fed corresponding diets with 15.2,364.3,782.5,1,167.9,1,573.8,and 1,980.1 IU/kg vitamin D for 70 d.Results Supplementation with 1,167.9 IU/kg vitamin D significantly improved nutritional value and sensory quality of fillets,enhancing crude protein,free amino acid,lipid,and collagen contents;maintaining an ideal pH;and reduc-ing lactate content,shear force,and cooking loss relative to respective values in the control(15.2 IU/kg)group.Average myofiber diameter and the frequency of myofibers>50μm in diameter increased under supplementation with 782.5–1,167.9 IU/kg vitamin D.Levels of oxidative damage biomarkers decreased,and the expression of antioxi-dant enzymes and nuclear factor erythroid 2-related factor 2 signaling molecules was upregulated in the 1,167.9 IU/kg vitamin D treatment compared to respective values in the control group.Furthermore,vitamin D supplementation activated cell differentiation by enhancing the expression of myogenic regulatory factors and myocyte enhancer factors compared to that in the control group.In addition,supplementation with 1,167.9 IU/kg vitamin D improved protein deposition associated with protein synthesis molecule(target of rapamycin)signaling and vitamin D receptor paralogs,along with inhibition of protein degradation(forkhead box protein 1)signaling.Conclusions Overall,the results demonstrated that vitamin D strengthened antioxidant ability and myofiber devel-opment,thereby enhancing nutritional value and sensory quality of fish flesh.These findings suggest that dietary vitamin D supplementation is conducive to the production of nutrient-rich,high quality aquaculture products.

Establishment and Functional Evaluation of a Rat Model of Spinal Cord Injury

Objective:To explore the modified Allen impactor method in establishing a rat model of spinal cord injury,and to preliminarily evaluate the motor function of the forelimbs and hindlimbs of rats.Methods:Thirty female SD rats with a body weight of 255±21g were randomly divided into two groups,namely the sham-operated group and the operated group,with 15 rats in each group.The spinal cord injury SD rat model was established by exposing but not injuring the spinal cord in the sham-operated group,while the SD rat model was established by the modified Allen impactor method in the operated group.The Basso-Beattie-Bresnahan(BBB)rating scale was used to assess the rats’hindlimb motor neurobehavior.A rat model of spinal cord injury was established by the modified Allen impactor method.After the cells were transplanted,the BBB score was used to evaluate the motor function;the changes in the motor function of rats with spinal cord injury were detected.Results:The motor function and sensory function of the forelimbs and hindlimbs of the rats showed significant changes after five days.The motor function of the forelimbs and hindlimbs of the rats in the sham-operated group were essentially normal after three days(about 20 points);the sensory function of the rats in the operated group decreased significantly after five days;however,in the sham-operated group,it decreased to 0.The motor function scores of the rats in the operated group at each point of time were significantly lower than those in the sham-operated group(p<0.05),while the forelimb motor function scores were significantly higher than those in the sham-operated group(p<0.05).Conclusion:The modified Allen impactor method that was used to establish a rat model of spinal cord injury in this study can significantly reduce the motor function of rats.

Regulation of protein thermal stability and its potential application in the development of thermo-attenuated vaccines

The coronavirus disease 2019(COVID-19)pandemic has highlighted the importance of developing novel vaccines.An ideal vaccine should trigger an intense immune reaction without causing significant side effects.In this study we found that substitution of tryptophan located in the cores of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)protein structures with certain smaller amino acids resulted in variants with melting temperatures of 33-37℃.An enzyme activity assay indicated that the proteolytic activity of the main proteinase(3CLpro)decreased sharply when the environmental temperature exceeded the melting temperature,implying that other protein variants may lose most of their functions under the same conditions.This finding suggests that a virus variant containing engineered proteins with melting temperatures of 33-37℃ may only be functional in the upper respiratory tract where the temperature is about 33℃,but will be unable to invade internal organs,which maintain temperatures above 37℃,thus making it possible to construct temperature-sensitive attenuated vaccines.

A Study on Post-Traumatic Stress Disorder and Its Influencing Factors in Patients with Spinal Cord Injury

Objective:To investigate on post-traumatic stress disorder(PTSD)and its influencing factors in patients with spinal cord injury.Methods:From January 2019 to December 2021,168 patients with spinal cord injury in The First Affiliated Hospital of Xi’an Medical University were selected as the research subjects.Among the patients,77 were female patients,with an average age of 56.39±13.98,and 91 were male patients,with an average age of 58.12±14.01.Clinical data were collected,and the factors influencing PTSD in patients with spinal cord injury were analyzed and observed.Results:The patients were divided into two groups according to diagnosis(98 cases with PTSD,and 70 cases with non-PTSD).Among them,there were 62 male and 36 female patients in the PTSD group,and 29 male and 41 female patients in the non-PTSD group;in the PTSD group,62 patients were≥50 years old,while 36 patients were<50 years old,whereas in the non-PTSD group,31 patients were≥50 years old,while 39 patients were<50 years old;46 and 52 patients in the PTSD group and 33 and 37 patients in the non-PTSD group were single and married,respectively;in the PTSD group,the number of patients that fall under each demographic factor can be summarized as follows:education level(29 junior high school and below,12 high school/secondary school,57 college and above),religious belief(69 none,29 yes),personality(31 introverted,24 ambiverted,43 extroverted),complications(52 yes,46 no),type of injury(34 complete,64 incomplete),post-traumatic coma(25 yes,73 no),degree of pain(51 mild,14 moderate,33 severe),resilience(36 low,62 high),and social support(12 low,39 moderate,47 high);in the non-PTSD group,the number of patients that fall under each demographic factor can be summarized as follows:education level(7 junior high school and below,37 high school/secondary school,26 college and above),religious beliefs(53 none,17 yes),personality(18 introverted,47 ambiverted,5 extroverted),complications(32 yes,38 no),type of injury(45 complete,25 incomplete),post-traumatic coma(49 yes,21 no),degree of pain(31 mild,38 moderate,1 severe),resilience(55 low,13 high),and social support(51 low,13 moderate,6 high);there was statistical difference between the two groups in terms of gender,age,education level,personality,injury type,post-traumatic coma,degree of pain,resilience,and social support(p<0.05).Conclusion:PTSD in patients with spinal cord injury is positively correlated with gender,education level,degree of pain,psychological resilience,and social support.Clinically,more emphasis should be on its influencing factors,and early intervention should be reinforced to reduce the risk of PTSD.

Effect of Ketoprofenphonophoresis and Femoral Nerve Block in Knee Osteoarthritis

Objective:To evaluate the effect of ketoprofenphonophoresis and femoral nerve block in knee osteoarthritis.Methods:One hundred and fourteen patients with knee osteoarthritis were randomly divided into two groups.The control group consisted of 57 patients who were treated with only ketoprofenphonophoresis.The experimental group consisted of patients were treated with ketoprofenphonophoresis and femoral nerve block.The patients were followed for more than one month.The treatment effect assessed by observing their WOMAC index before and after therapy.Results:All the patients finished the follow-up.Their WOMAC indexes were reduced after therapy and one month after treatment,especially in the experimental group(P<0.05).The effective efficiency of ketoprofenphonophoresis and femoral nerve block were higher than that in the control group after treatment and after one month of follow-up(P<0.05).Conclusion:Compared with only ketoprofenphonophoresis,the combined treatment of ketoprofenphonophoresis and femoral nerve block was more appropriate in knee osteoarthritis.

Community assemblage of free-living diazotrophs along the elevational gradient of Mount Gongga

Mountain systems are unique for studying the responses of species distribution and diversity to environmental changes along elevational gradients.It is well known that free-living diazotrophic microorganisms are important to nitrogen cycling in mountain systems.However,the elevational patterns of free-living diazotrophs and the underlying ecological processes in controlling their turnover along broader gradients are less well documented.Here,we investigated the pattern of diazotrophic diversity along the elevational gradient(1800 m-4100 m)in Mount Gongga of China.The results showed that the α-diversity of diazotrophs did not change with the elevation from 1800 m to 2800 m,but decreased at elevations above 3000 m.Such diversity pattern was driven mainly by soil total carbon,nitrogen,and plant richness.Various diazotrophic taxa showed differential abundance-elevation relationships.Ecological processes determining diazotrophic community assemblage shift along the elevations.Deterministic processes were relatively stronger at both low and high elevations,whereas stochastic processes were stronger at the middle elevation.This study also suggested a strong relationship among aboveground plants and diazotrophs,highlighting their potential interactions,even for free-living diazotrophs.

DHD4,a CONSTANS-like family transcription factor,delays heading date by affecting the formation of the FAC complex in rice

Heading date(or flowering time)is one of the most important agronomic traits in rice,influencing its regional adaptability and crop yield.Many major-effect genes for rice heading date have been identified,but in practice they are difficult to be used for rice molecular breeding because of their dramatic effects on heading date.Genes with minor effects on heading date,which are more desirable for fine-tuning flowering time without significant yield penalty,were seldom reported.In this study,we identified a new minor-effect heading date repressor,Delayed Heading Date 4(DHD4).The dhd4 mutant shows a slightly earlier flowering phenotype without a notable yield penalty compared with wild-type plants under natural long-day conditions.DHD4 encodes a CONSTANS-like transcription factor localized in the nucleus.Molecular,biochemical,and genetic assays show that DHD4 can compete with 14-3-3 to interact with OsFD1,thus affecting the formation of the Hd3a-14-3-3-OsFD1 triprotein FAC complex,resulting in reduced expression of OsMADS14 and OsMADS15,and ultimately delaying flowering.Taken together,these results shed new light on the regulation of flowering time in rice and provide a promising target for fine-tuning flowering time to improve the regional adaptability of rice.

CHD3 chromatin-remodeling factor PICKLE regulates floral transition partially via modulating LEAFY expression at the chromatin level in Arabidopsis

PICKLE(PKL), a putative CHD3 chromatin remodeling factor, has been suggested to be involved in multiple processes in Arabidopsis. Here, we confirmed the late-flowering phenotype caused by pkl mutation with pkl mutants in two different ecotypes, and investigated the possible mechanisms that account for PKL regulation of flowering time. Quantitative RT-PCR and RNA-seq assays showed that expression of the LEAFY gene(LFY) and a number of LFY-regulated floral homeotic genes were down-regulated in seedlings of the pkl mutants. As predicted, overexpression of LFY restored normal flowering time of pkl mutants. Our results suggest that PKL may be involved in regulating flowering time via LFY expression. To uncover the underlying mechanism, Ch IP-PCR using anti-PKL was performed on materials from three developmental stages of seedlings. Our results showed that PKL associated with the genomic sequences of LFY, particularly at 10-day and 25-day after germination. We also showed that loss of PKL affected H3K27me3 level at the promoter of LFY. Taken together, our data suggest that transcriptional regulation of LFY at the chromatin level by PKL may at least partially account for the late-flowering phenotype of pkl mutants.

DIW1 encoding a cladeⅠPP2C phosphatase negatively regulates drought tolerance by de-phosphorylating TaSnRK1.1 in wheat

Drought seriously impacts wheat production(Triticum aestivum L.),while the exploitation and utilization of genes for drought tolerance are insufficient.Leaf wilting is a direct reflection of drought tolerance in plants.Clade A PP2Cs are abscisic acid(ABA)co-receptors playing vital roles in the ABA signaling pathway,regulating drought response.However,the roles of other clade PP2Cs in drought tolerance,especially in wheat,remain largely unknown.Here,we identified a gain-of-function drought-induced wilting 1(DIW1)gene from the wheat Aikang 58 mutant library by map-based cloning,which encodes a cladeⅠprotein phosphatase 2C(TaPP2C158)with enhanced protein phosphatase activity.Phenotypic analysis of overexpression and CRISPR/Cas9 mutant lines demonstrated that DIW1/TaPP2C158 is a negative regulator responsible for drought resistance.We found that TaPP2C158 directly interacts with TaSnRK1.1 and de-phosphorylates it,thus inactivating the TaSnRK1.1–Ta AREB3 pathway.TaPP2C158 protein phosphatase activity is negatively correlated with ABA signaling.Association analysis suggested that C-terminal variation of TaPP2C158 changing protein phosphatase activity is highly correlated with the canopy temperature,and seedling survival rate under drought stress.Our data suggest that the favorable allele with lower phosphatase activity of TaPP2C158 has been positively selected in Chinese breeding history.This work benefits us in understanding the molecular mechanism of wheat drought tolerance,and provides elite genetic resources and molecular markers for improving wheat drought tolerance.

The protective effects of a D-tetra-peptide hydrogel adjuvant vaccine against H7N9 influenza virus in mice

Repeated waves of influenza virus H7N9 epidemics after 2013 have caused severe influenza in humans,with mortality reaching approximately 40%–50%.To prevent possible pandemics,the development of highly effective vaccines against influenza virus H7N9 is highly desired.In the present study,by taking advantage of the D-tetra-peptide adjuvant(G^(D)F^(D)F^(D)Y),we reported a simple method to prepare H7N9 vaccines.Naproxen(Npx),with good anti inflammatory and broad anti-viral effects,was employed as an N-terminal capping group to construct a hydrogel precursor,Npx-G^(D)F^(D)F^(D)Y.The hydrogel adjuvant was prepared using a routine heating cooling protocol and the final vaccine was ready after mixing with the split A/Zhejiang/DTID-ZJU01/2013(H7N9)antigen by vortexing.Compared with the traditional Al(OH)_(3) adjuvant vaccine and the split vaccine,our hydrogel adjuvant vaccine showed the best preventive effects against H7N9 infection.A mechanistic study illustrated that higher antibody responses and variations in cytokine expression might account for its increased protective effects.Our strategy demonstrated the advantages of a peptide hydrogel adjuvant in the application of vaccines against H7N9 and demonstrated its potential application in vaccines against emerging threats from other viruses.

Soil total organic carbon/total nitrogen ratio as a key driver deterministically shapes diazotrophic community assemblages during the succession of biological soil crusts

The diazotrophic community in biological soil crusts(biocrusts)is the key supplier of nitrogen in dryland.To date,there is still limited information on how biocrust development influences the succession of diazotrophic community,and what are the most important factors mediating diazotrophic communities during biocrust succession.Using the high throughput nifH amplicon sequencing,the diazotrophs in soils at different developmental stages of biocrust were comparatively studied.The results evidenced the decreases of TOC/TN ratio and pH value with biocrust development.Nostoc and Scytonema were the most dominant diazotrophic genera at all biocrust stages,while Azospirillum and Bradyrhizobium were abundant only in bare soil.Diazotrophic co-occurrence networks tended to be less complex and less connected with biocrust succession.The soil TOC/TN ratio was the most dominant factor mediating diazotrophic diversity,community composition and assembly processes,while diazotrophic-diversity and NO3–-N/NH4+-N ratio were positively correlated with the nitrogenase activity during biocrust succession.This study provided novel understandings of nitrogen fixation and succession patterns of diazotrophic community,by showing the effects of biocrust succession on diazotrophic diversity,community composition,community assembly and co-occurrence networks,and recognizing TOC/TN ratio as the most dominant factor mediating diazotrophs during biocrust succession.