Lignin is a significant secondary metabolite produced through the phenylpropanoid pathway.As a vital component of the plant cell wall,lignin affects various fruit characteristics,including size,seed quantity,and firmn...Lignin is a significant secondary metabolite produced through the phenylpropanoid pathway.As a vital component of the plant cell wall,lignin affects various fruit characteristics,including size,seed quantity,and firmness.In this study,we conducted comprehensive identification and phylogenetic analysis of 265 Caffeic acid O-methyltransferase(COMT)genes across ten different plant species,including Vaccinium corymbosum and four other Vaccinium species.The results reveal that VcCOMT38 is a promising structural gene for the biosynthesis of lignin in blueberry.An in vitro enzymatic assay of VcCOMT38 demonstrated that it is a special enzyme in the lignin biosynthesis pathway and prefers to use caffeic acid as a substrate over 5-hydroxyferulic acid.Transient overexpression and silencing of VcCOMT38 in Vaccinium corymbosum‘Northland’fruits demonstrated that VcCOMT38 participates in lignin biosynthesis and contributes to both an increased number of immature seeds and enhanced fruit firmness.The heterologous overexpression of VcCOMT38 in Nicotiana benthamiana revealed that this gene could increase the lignin content and the syringyl/guaiacyl(S/G)ratio,which determines the maximum monomer yield during lignin depolymerization.These results highlight VcCOMT38 as a crucial gene in lignin biosynthesis and its potential for improving lignin production in industry through genetically modified woody plants.展开更多
Background:Excessive use of inorganic trace minerals(ITMs)in swine production leads to high fecal mineral excretion and environmental risks,while most studies on organic trace minerals(OTMs)focus on single elements,wi...Background:Excessive use of inorganic trace minerals(ITMs)in swine production leads to high fecal mineral excretion and environmental risks,while most studies on organic trace minerals(OTMs)focus on single elements,with limited data on the synergistic effects and molecular mechanisms of combined OTMs(Fe,Cu,Mn,Zn)in growing-finishing pigs.Methods:This study aimed to investigate the effects of graded levels of micromineral proteinates(combined OTMs)on growth performance,mineral metabolism,and mRNA expression of mineral regulatory proteins.A total of 360 crossbred Duroc×Landrace×Large White pigs(initial body weight 47.1±4.8 kg)were randomly assigned to 6 dietary treatments:basal diet without microminerals(CON),basal diet with ITMs at commercially recommended levels(IT),and basal diets with 15%(OT 15%),25%(OT 25%),35%(OT 35%)commercially recommended levels(CRL)of combined micromineral proteinates.After a 70-day feeding trial,samples were analyzed using ICP-OES,ELISA,and RT-qPCR.Results:Results showed that reduced levels(15-35%CRL)of micromineral proteinates did not significantly affect average daily gain,average daily feed intake,or feed conversion ratio(gain-to-feed ratio)compared to IT(P>0.05),but significantly increased plasma Cu(1.73-1.83μg/mL)and Zn(1.72-1.97μg/mL)concentrations(P<0.05)and elevated activities of Cu/Zn-superoxide dismutase(32.9-35.9 U/L)and manganese superoxide dismutase(20.5-24.1 U/L)compared to CON(P<0.05),with no significant differences from IT(P>0.05).Fecal excretion of Fe,Cu,Mn,and Zn was significantly reduced by 35-50%in OT 15%-OT 35%groups compared to IT(P<0.05).OT 25%group exhibited the highest apparent absorptivity of Fe(38.5%),Cu(27.8%),and Zn(42.4%)(P<0.05),which was associated with significantly regulated mRNA expression of mineral regulatory proteins:upregulated DMT1,FPN1,ZIP4,and MT1A in the duodenum,and modulated HAMP,ATP7B,ZIP14,and ZnT1 in the liver(P<0.05).Conclusion:In conclusion,dietary supplementation with 25%CRL or less of combined micromineral proteinates can fully meet the nutritional needs of growing-finishing pigs,improve mineral absorptivity,and reduce fecal mineral excretion by regulating intestinal and hepatic mineral transport and homeostatic proteins,providing a sustainable alternative to high-dose ITMs.展开更多
Lodging is a major constraint limiting oil flax production efficiency in northern China.Crop lodging susceptibility is closely related to stem lignin content,and the regulatory mechanisms by which nitrogen and potassi...Lodging is a major constraint limiting oil flax production efficiency in northern China.Crop lodging susceptibility is closely related to stem lignin content,and the regulatory mechanisms by which nitrogen and potassium fertilization interactively influence lignin biosynthesis in oil flax stems require further investigation.Therefore,this study aimed to enhance lodging resistance and increase grain yield in oil flax.We examined the interactive effects of different nitrogen (75,150,and 225 kg N ha^(–1)) and potassium (60 and 90 kg K_(2)O ha^(–1)) fertilizer rates on lignin metabolism,lodging resistance,and grain yield during the 2022 and 2023 growing seasons.Results indicated that nitrogen and potassium fertilizer levels and their interactions promoted lignin accumulation,improved lodging resistance,and increased grain yield.Compared to the control (CK),the75–150 kg N ha^(–1) combined with 60 kg K_(2)O ha^(–1) treatments significantly enhanced the activities of key lignin-synthesizing enzymes (tyrosine ammonia-lyase (TAL),phenylalanine ammonia-lyase (PAL),cinnamyl alcohol dehydrogenase (CAD),and peroxidase (POD)) and upregulated the expression of 4CL1 and F5H3 genes,leading to a 29.63–43.30%increase in lignin content,improved stem bending strength and lodging resistance index,and a 23.27–32.34%increase in grain yield.Correlation analysis revealed that nitrogen and potassium fertilizers positively regulated enzyme activities and gene expression related to lignin biosynthesis,thereby facilitating lignin accumulation and enhancing stem mechanical strength and lodging resistance.Positive correlations were observed among lignin-related enzyme activities,gene expression,lodging resistance traits,and grain yield.In summary,the application of 75–150 kg N ha^(–1) in conjunction with 60 kg K_(2)O ha^(–1)promoted lignin biosynthesis and accumulation,enhanced lodging resistance,and increased grain yield in oil flax grown in the dryland farming region of central Gansu,China.Furthermore,this treatment provides a technical basis for cultivating stress-tolerant and high-yield oil flax in arid regions.展开更多
Spinal cord injury is a severe neurological condition with limited neuronal regeneration and functional recovery.Currently,no effective treatments exist to improve spinal cord injury prognosis.Neuronal guidance protei...Spinal cord injury is a severe neurological condition with limited neuronal regeneration and functional recovery.Currently,no effective treatments exist to improve spinal cord injury prognosis.Neuronal guidance proteins are a diverse group of molecules that play crucial roles in axon and dendrite growth during nervous system development.Increasing evidence highlights their regulatory functions in spinal cord injury.This review provides a brief overview of the modulation patterns of key neuronal guidance proteins in neuronal axon growth during nervous system formation and subsequently focuses on their roles in neuronal regeneration and functional recovery following spinal cord injury.Neuronal guidance proteins include,but are not limited to,semaphorins and their receptors,plexins;netrins and their receptors,deleted in colorectal cancer and UNC5;Eph receptors and their ligands,ephrins;Slit and its receptor,Robo;repulsive guidance molecules and their receptor,neogenin;Wnt proteins and their receptor,Frizzled;and protocadherins.Localized Netrin-1 at the injury site inhibits motor axon regeneration after adult spinal cord injury while promoting oligodendrocyte growth.Slit2 enhances synapse formation in the injured spinal cord of rats.EphA7 regulates acute apoptosis in the early pathophysiological stages of spinal cord injury,while ephrinA1 plays a role in the nervous system’s injury response,with its reduced expression leading to impaired motor function in rats.EphA3 is upregulated following spinal cord injury,promoting an inhibitory environment for axonal regeneration.After spinal cord injury,bidirectional activation of ephrinB2 and EphB2 in astrocytes and fibroblasts results in the formation of a dense astrocyte-meningeal fibroblast scar.EphB1/ephrinB1 signaling mediates pain processing in spinal cord injury by regulating calpain-1 and caspase-3 in neurons.EphB3 expression increases in white matter after spinal cord injury,further inhibiting axon regeneration.Sema3A,expressed by neurons and fibroblasts in the scar surrounding the injury,inhibits motor neuron and sensory nerve growth after spinal cord injury.Sema4D suppresses neuronal axon myelination and axon regeneration,while its inhibition significantly enhances axon regeneration and motor recovery.Sema7A is involved in glial scar formation and may influence serotonin channel remodeling,thereby affecting motor coordination.Given these findings,the local or systemic application of neuronal guidance proteins represents a promising avenue for spinal cord injury treatment.展开更多
The study of target proteins is crucial for understanding molecular interactions and developing analytical platforms,therapeutic agents and functional tools.Herein,we present a novel nanoplatform activated by near-inf...The study of target proteins is crucial for understanding molecular interactions and developing analytical platforms,therapeutic agents and functional tools.Herein,we present a novel nanoplatform activated by near-infrared(NIR) light for triple-modal proteins study,which enabling target protein labeling,enrichment and visualization.Azido-naphthalimide-coated upconversion nanoparticles(UCNPs) serve as NIR light-responsive nanoplatforms,showing promising applications in studying interactions between various bioactive molecules and proteins in living systems.Under NIR light irradiation,azido-naphthalimides are activated by ultraviolet(UV) and blue light emitted from UCNPs and the resulting amino-naphthalimides intermediate not only crosslink nearby target proteins but also enable imaging performance.We demonstrate that this nanoplatform is capable of selective protein labeling and imaging in complex protein environments,achieving specific labeling and imaging of both intracellular and extracellular proteins in mammalian cells as well as bacteria.Furthermore,in vivo protein labeling has been achieved using this novel NIR light-activatable nanoplatform.This technique will open new avenues for discoveries and mechanistic interrogation in chemical biology.展开更多
Multienzyme cascades enable the sequential synthesis of complex chemicals by combining multiple catalytic processes in one pot,offering considerable time and cost savings compared to a series of separate batch reactio...Multienzyme cascades enable the sequential synthesis of complex chemicals by combining multiple catalytic processes in one pot,offering considerable time and cost savings compared to a series of separate batch reactions.However,challenges related to coordination and regulatory interplay among multiple enzymes reduce the catalytic efficiency of such cascades.Herein,we genetically programmed a scaffold framework that selectively and orthogonally recruits enzymes as designed.The system was then used to generate multienzyme complexes of D-allulose 3-epimerase(DAE),ribitol dehydrogenase(RDH),and formate dehydrogenase(FDH)for rare sugar production.This scaffolded multienzymatic assembly achieves a 10.4-fold enhancement in the catalytic performance compared to its unassembled counterparts,obtaining allitol yield of more than 95%.Molecular dynamics simulations revealed that shorter distances between neighboring enzymes in scaffold-mounted complexes facilitated the transfer of reaction intermediates.A dual-module catalytic system incorporating(1)scaffold-bound complexes of DAE,RDH,and FDH and(2)scaffold-bound complexes of alcohol dehydrogenase and NADH oxidase expressed intracellularly in E.coli was used to synthesize D-allulose from D-fructose.This system synthesized 90.6%D-allulose from 300 g L^(−1)D-fructose,with a space-time yield of 13.6 g L^(−1)h^(−1).Our work demonstrates the programmability and versatility of scaffold-based strategies for the advancement of multienzyme cascades.展开更多
<span style="font-family:;" "=""><span style="font-family:Verdana;">Methane production by archaea depends on tetrahydromethanopterin (H</span><sub><span st...<span style="font-family:;" "=""><span style="font-family:Verdana;">Methane production by archaea depends on tetrahydromethanopterin (H</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">MPT), a pterin-containing cofactor that carries one-carbon units. Two redox reactions within the nine steps of H</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">MPT side chain biosynthesis have been hypothesized. Biochemical assays have demonstrated that the archaeal iron-sulfur flavoprotein dihydromethanopterin reductase X (DmrX or MM1854) catalyzes the final reaction of the pathway, the reduction of dihydromethanopterin to H</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">MPT</span></span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> using dithiothreitol (DTT) as an artificial electron donor. The crystal structure of DmrB, a bacterial DmrX homolog that lacks iron-sulfur clusters, has led to a proposed ping-pong mechanism of electron transfer between FMNH</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> and the FMN prosthetic group of DmrB. However, an enzymatic assay to test the hypothetical DmrB mechanism is lacking because a suitable electron donor has not previously been identified. Furthermore, a second uncharacterized archaeal flavoprotein (MM1853) has been hypothesized to function in H</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">MPT side chain biosynthesis. In this </span><span style="font-family:Verdana;">work, to facilitate the development of assays to elucidate the functions of DmrB </span><span style="font-family:Verdana;">and MM1853, we tested a variety of electron donors, including dithiothreitol, ferredoxin, and a system consisting of NADH and an NADH-dependent fla</span><span style="font-family:Verdana;">vin-reducing enzyme (Fre).</span><span style="font-family:Verdana;"> Reduction of the DmrB prosthetic group (FMN) was measured as a decrease in absorbance at 460 nm. NADPH, NADH, and </span><span style="font-family:Verdana;">DTT were unable to reduce DmrB. However, NADH/Fre was able to reduce </span><span style="font-family:Verdana;">DmrB within 70 min (initial rate of 1.3 μM/min), providing the basis for a future DmrB activity assay. Carbon monoxide (CO)/CO dehydrogenase/ferredoxin reduced DmrB more rapidly within 6 min. Both electr</span><span style="font-family:Verdana;">on transfer systems reduced a second flavin-containing archaeal protein MM1853, which is predicted to catalyze the third step of H</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">MPT biosynthesis. While NADH and NADPH were incapable of directly reducing the FMN cofactor of MM1853, DTT or NADH/Fre could eliminate the FMN peaks. These results establish the basis for new oxidoreductase assays that will facilitate testing several proposed DmrB mechanisms and defining the specific function of MM1853 in methanogen cofactor biosynthesis.</span></span>展开更多
Our previous studies showed a predominance of high molecular weight protein group in tumor nuclear matrices. Contrary to normal cells, proteins of this group are preferentially phosphorylated. Phosphoproteins of hepat...Our previous studies showed a predominance of high molecular weight protein group in tumor nuclear matrices. Contrary to normal cells, proteins of this group are preferentially phosphorylated. Phosphoproteins of hepatoma nuclear matrix are selectively subjected to rapid proteolysis. By alkali treatment and a monoclonal antibody against phosphotyrosyl residue the presence of two high molecular weight bands of phosphotyrosyl-containing proteins was detected in nuclear matrices of tumor but not of normal liver cells. High molecular weight protein group of tumor nuclear matrices revealed also a rapid turnover and preferential incorporation of labeled amino acids selectively inhibited by chloramphenicol.展开更多
Chitin is an abundant aminopolysaccharide found in insect pests and phytopathogenic microorganisms but absent in higher plants and vertebrates. It is crucial for mitigating threats posed by chitin-containing organisms...Chitin is an abundant aminopolysaccharide found in insect pests and phytopathogenic microorganisms but absent in higher plants and vertebrates. It is crucial for mitigating threats posed by chitin-containing organisms to human health, food safety, and agriculture. Therefore, targeting the chitin biosynthesisassociated bioprocess holds a promise for developing human-safe and eco-friendly antifungal agents or pesticides. Chitin biosynthesis requires chitin synthase and associated factors, which are involved in the modification, regulation, organization or turnover of chitin during its biosynthesis. A number of enzymes such as chitinases, hexosaminidases, chitin deacetylases are closely related and therefore are promising targets for designing novel agrochemicals that target at chitin biosynthesis. This review summarizes the advances in understanding chitin biology over the past decade by our research group and collaborates,specifically regarding essential proteins linked to chitin biosynthesis that can be exploited as promising pesticide targets. Examples of small bioactive molecules that against the activity of these targets are given.展开更多
Xylo-oligosaccharides(XOSs)are a category of functional oligosaccharides primarily composed of 2-7 xylose units linked byβ-1,4 glycosidic bonds.They are recognized as soluble dietary fibers with prebiotic properties....Xylo-oligosaccharides(XOSs)are a category of functional oligosaccharides primarily composed of 2-7 xylose units linked byβ-1,4 glycosidic bonds.They are recognized as soluble dietary fibers with prebiotic properties.Recently, there has been significant interest in manufacturing XOSs from xylan extracted from lignocellulosic biomass using enzyme catalysis under mild conditions. In this work, the arabinofuranosidase Abf62A gene was cloned from Aspergillus usamii genomic DNA through sequential molecular processes and expressed in Pichia pastoris X33. The xylan (100 g/L) extracted xylan in wheat straw (WS) was biologically hydrolyzed into 50.32 g/L of XOSs by xylanase Xyn11A (300 U/g substrate) and arabinofuranase Abf62A (20 U/g substrate), which indicated a notable synergistic effect compared to the 34.42 g/L XOSs produced via Xyn11A. The 50.32 g/L of XOSs products comprised xylobiose (31.71 g/L), xylotriose (15.92 g/L), xylotetraose (1.65 g/L) and xylopentaose (1.04 g/L). Notably, the combined content of xylobiose and xylotriose accounted for up to 94.7%. The XOSs purified from the enzyme hydrolysate could effectually scavenge free radicals, and the antioxidant activity was more than 90%. In summary, XOSs were biologically manufactured from wheat straw xylan through the synergistic biocatalysis via xylanase and arabinofuranosidase Abf62A in a green and sustainable way, rending one kind of prebiotic oligosaccharides with substantial positive effects on human and animal health.展开更多
Objective To investigate effect of inhibiting melatonin biosynthesis on activities of protein kinase A (PKA), glycogen synthase kinase-3 (GSK-3) and tau phosphorylation at PS214 and M4 epitopes using haloperidol, a sp...Objective To investigate effect of inhibiting melatonin biosynthesis on activities of protein kinase A (PKA), glycogen synthase kinase-3 (GSK-3) and tau phosphorylation at PS214 and M4 epitopes using haloperidol, a specific inhibitor of 5-hydroxyindole-O-methyltransferase. Methods Brain ventricular and intraperitoneal injections were used for haloperidol administration, Western blots for tau phosphorylation, 32P-labeling for PKA and GSK-3 activity, and high performance liquid chromatograph for detection of serum melatonin levels. Results Haloperidol injection through the lateral ventricle and intraperitoneal reinforcement significantly stimulated PKA activity with a concurrent hyperphosphorylation of tau at M4 (Thr231/Ser235) and PS214 (Ser214) sites. Prior treatment of the rats using melatonin supplement for one week and reinforcement during the haloperidol administration arrested PKA activity and attenuated tau hyperphosphorylation. GSK-3 activity showed no obvious change after haloperidol injection, however, melatonin supplements and reinforcements during haloperidol infusion inactivated basal activity of GSK-3. Conclusion Decreased melatonin may be involved in Alzheimer-like tau hyperphosphorylation, and overactivation of PKA may play a crucial role in this process.展开更多
Meiotic resumption in mammalian oocytes involves nuclear and organelle structural changes,notably the chromatin configuration transition from a non-surrounding nucleolus(NSN)to surrounding nucleolus(SN)in germinal ves...Meiotic resumption in mammalian oocytes involves nuclear and organelle structural changes,notably the chromatin configuration transition from a non-surrounding nucleolus(NSN)to surrounding nucleolus(SN)in germinal vesicle oocytes.In the current study,we found that nuclear speckles(NSs),a subnuclear structure mainly composed of serine-arginine(SR)proteins,changed from a diffuse spotted distribution in mouse NSN oocytes to an aggregated pattern in SN oocytes.We also found that the SR protein-specific kinase 1(SRPK1),an enzyme that phosphorylates SR proteins,co-localized with NSs at the SN stage,and that NSN oocytes failed to transition to SN oocytes after the inhibition of SRPK1 activity.Furthermore,the typical structure of the chromatin ring around the nucleolus in SN oocytes collapsed after treatment with an SRPK1 inhibitor.Mechanistically,phosphorylated SR proteins were found to be related to chromatin as shown by a salt extraction experiment,and in situ DNaseⅠassay showed that the accessibility of chromatin was enhanced in SN oocytes when SRPK1 was inhibited,accompanied by a decreased repressive modification on histone and the abnormal recurrence of a transcriptional signal.In conclusion,our results indicated that SRPK1-regulated phosphorylation of SR proteins was involved in the NSN-SN transition and played an important role in maintaining the condensed nucleus of SN oocytes via interacting with chromatin.展开更多
Selenocysteine (Sec) tRNAs serve as carrier molecules for the biosynthesis of Sec from serine and to donate Sec to protein in response to specific UGA codons. In this study, we describe the current status of Sec tRNAs...Selenocysteine (Sec) tRNAs serve as carrier molecules for the biosynthesis of Sec from serine and to donate Sec to protein in response to specific UGA codons. In this study, we describe the current status of Sec tRNAs in higher animals and further we exarnine: (i) the Sec tRNA population in Drosophila; (ii) transcription of the Sec tRNA in vivo (in Xenopus oocytes) and in vitro (in Xenopus oocyte extracts); (iii) the effect of selenium on the Sec tRNA population in various rat tissues following replenishment of extremely selenium deficient rats with this element; and (iv) the biosynthesis of the modified bases on Sec tRNA in Xenopus oocytes展开更多
Background Post-weaning diarrhea(PWD)in piglets,often caused by F4^(+)enterotoxigenic Escherichia coli(ETEC),poses significant challenges in pig production.Traditional solutions like antibiotics and zinc oxide face in...Background Post-weaning diarrhea(PWD)in piglets,often caused by F4^(+)enterotoxigenic Escherichia coli(ETEC),poses significant challenges in pig production.Traditional solutions like antibiotics and zinc oxide face increasing restrictions due to growing concerns over antibiotic resistance and environmental sustainability.This study investigates the application of bivalent heavy chain variable domain(V_(H)H)constructs(BL1.2 and BL2.2)targeting ETEC virulence factors,administered in feed to mitigate ETEC-induced PWD in weaned piglets.Results The supplementation of BL1.2 and BL2.2 in both mash and pelleted feed significantly reduced the diarrhea incidence and fecal shedding of F4^(+)ETEC in challenged piglets.Pelleted feed containing V_(H)H constructs helped to preserve gut barrier integrity by maintaining levels of the tight junction protein occludin in the small intestine.Additionally,the constructs maintained blood granulocyte counts at a similar level to the non-challenged control group,including neutrophils,and ameliorated the acute phase protein response after challenge.Notably,even at low feed intake immediately after weaning,V_(H)H constructs helped maintain piglet health by mitigating ETEC-induced inflammation and the resulting diarrhea.Conclusions Our findings demonstrated that using V_(H)H constructs as feed additives could serve as an effective strategy to help manage ETEC-associated PWD,by reducing F4^(+)ETEC gut colonization and supporting gut barrier function of weaned piglets.The high stability of these V_(H)H constructs supports their incorporation into industrial feed manufacturing processes,offering a more sustainable preventive strategy compared to traditional antimicrobial interventions,which could contribute to sustainable farming practices.展开更多
The present study was carried out to evaluate the pollution and its effect on the quality of catfish. Four sites in Eygpt were chosen for the research, Ras El-Bar (Site 1) as control, Shatta (Site 2), Kafr El-Bateekh ...The present study was carried out to evaluate the pollution and its effect on the quality of catfish. Four sites in Eygpt were chosen for the research, Ras El-Bar (Site 1) as control, Shatta (Site 2), Kafr El-Bateekh (Site 3), and Talkha (Site 4). The research was carried out on water, sediments and catfish (serum and muscles). Nitrite, nitrate and ammonia were determined in water and sediment. Also, RNA and DNA were determined in serum samples and the muscles of the catfish. In addition, the concentrations of heavy metals (Pb, Cd, Fe, Zn and Cu) were estimated in water, sediments and the muscles of catfish. Also, hepatosomatic index, liver water content, condition factor, lipid and protein contents were determined in the fish. The concentrations of nitrite, nitrate and ammonia in water and sediment of Site 4 and the levels of heavy metals especially Pb and Cd in water, sediment and muscle of catfish from Sites 3 and 4 were highly elevated compared to those of the control. On the other hand, DNA, RNA and protein contents in the catfish of Sites 3 and 4 decreased. The results illustrated that, Cd and Pb levels in the muscle of catfish were negatively correlated with DNA, RNA and with the protein contents. In conclusion, the accumulation of heavy metals in catfish tissues therefore, can cause health problems in human after catfish intake.展开更多
Cyclocarya paliurus(Batalin)Iljinskaja,as a unique and rare monocotyledonous plant in Southern China,is a promising and economical Chinese herbal medicine and functional food.People have conducted a number of research...Cyclocarya paliurus(Batalin)Iljinskaja,as a unique and rare monocotyledonous plant in Southern China,is a promising and economical Chinese herbal medicine and functional food.People have conducted a number of research on C.paliurus because of its rich triterpenoids.However,no comprehensive review has illustrated the composition and pharmacological activity of triterpenoids from C.paliurus.This review summarizes 177 triterpenoids from different parts of C.paliurus.The structures of compounds were elucidated,and their biosynthesis was inferred.The biological activities of compounds and triterpenoid-rich extracts,including anti-diabetes,antihyperlipidemia,anti-inflammatory,anticancer or cytotoxicity,antioxidation,etc.,were discussed.C.paliurus can be an important and valuable supplement to the food market.This review provides a reference for the further research and application of C.paliurus triterpenoids in the fields of foods and pharmaceuticals.展开更多
Camptothecin,a plant-derived pentacyclic pyrroloquinoline alkaloid,and its derivatives like topotecan and irinotecan have been used as clinical anticancer agents for decades.However,the complete biosynthetic pathway o...Camptothecin,a plant-derived pentacyclic pyrroloquinoline alkaloid,and its derivatives like topotecan and irinotecan have been used as clinical anticancer agents for decades.However,the complete biosynthetic pathway of camptothecin still remains unelucidated due to the unknown complex formation processes and corresponding enzymes for the downstream biosynthetic pathway including the committed hydrolysis of glycosides.Herein,a novel glycoside hydrolase(CaGH1)responsible for the deglycosylation of biosynthetic glycoside intermediates including both quinoline-type alkaloids pumiloside(1),(3S)-deoxypumiloside(2)and indole-type alkaloid strictosamide(3)has been functionally identified.Moreover,CaGH1 exhibits the highly strict stereoselectivity towards the substrates with 3S configuration.Furthermore,a combined strategy for the discovery of the unknown biosynthetic enzyme by employing activity-guided enzyme verification,transcriptome-based gene mining,biochemical assay in vitro,and structurally characterizing the unstable enzymatic products by derivatization,is reported.These findings not only provide a better understanding of the deglycosylation in camptothecin biosynthesis,also lay the foundation for the complete elucidation of camptothecin biosynthetic pathway and biological production of camptothecin.展开更多
The surface macromolecules of probiotic bacteria play crucial roles in modulating immune responses in the host.Exopolysaccharide(EPS)from lactic acid bacteria(LAB)have been widely reported to exhibit immunomodulatory ...The surface macromolecules of probiotic bacteria play crucial roles in modulating immune responses in the host.Exopolysaccharide(EPS)from lactic acid bacteria(LAB)have been widely reported to exhibit immunomodulatory activity.In this study,the EPS biosynthesis gene cluster of Lacticaseibacillus paracasei S-NB was analyzed and a deletion mutant S-NBΔ7576(two genes S-NB_2175/wze and S-NB_2176/wzd were responsible for the chain length determination and export of EPS)was successfully constructed,resulting a 40.02%decrease in the production of EPS.The deletion of wze and wzd had little effect on the monosaccharide composition and major groups of the two EPS fractions(BEPS1 and BEPS2).Both BEPS1 and BEPS2 could inhibit the transcriptional level of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),inducible nitric oxide synthase(i NOS)and cyclooxygenase-2(COX-2)mRNA in RAW 264.7 cells induced by lipopolysaccharide(LPS),and enhance host immune tolerance via suppressing NF-κB and MAPK signaling.Notably,the S-NBΔ7576 mutant supplied with the BEPS1/BEPS2 exhibited more significant inhibition of cytokines production and the phosphorylation of p65 and c-Jun N-terminal kinase(JNK)in LPS-stimulated cells compared with the S-NBΔ7576 mutant alone.Our study provided the immunomodulatory effect of BEPS1 and BEPS2 from L.paracasei S-NB,in which the wze and wzd genes associated with EPS biosynthesis may play an important role.展开更多
The awn can contribute to photosynthesis and carbohydrates,enhancing grain yield in wheat.We mapped QAwn.sxau-5A,a major QTL for awn development in wheat(Triticum aestivum).This QTL was delimited to a 994-kb interval ...The awn can contribute to photosynthesis and carbohydrates,enhancing grain yield in wheat.We mapped QAwn.sxau-5A,a major QTL for awn development in wheat(Triticum aestivum).This QTL was delimited to a 994-kb interval at the B1 locus on chromosome 5A,which included the candidate gene encoding a zinc finger protein(TraesCS5A01G542800)as an awn length inhibitor(ALI).The Ali-A1 allele for the awnless trait showed abundant sequence differences in the promoter regions compared to the ali-A1 allele for the long-awn trait.The results of the swap experiment on the promoters from the two ALI-A1 alleles showed that the two promoters caused a difference in the protein level,indicating the gene was regulated at the transcript level.However,the ali-A1 allele contained an SNP that caused a premature stop codon in its coding region,resulting in a truncated protein compared to the functional Ali-A1 protein.The Ali-A1 protein contained two ethylene-responsive element binding factor-associated amphiphilic repression(EAR)motifs,one at the N terminus(EAR-N)and the other at the C terminus(EAR-C),and they were involved in interactions with the wheat co-repressor protein TOPLESS(TPL1).The ali-A1 protein retained the EAR-N motif but lost the EAR-C motif,resulting in the attenuated ability to interact with TPL1.The tpl1 mutant produced a longer awn compared to the wild type.Ali-A1 repressed the transcription of two downstream genes,TaLRP-A1 and TaARF-B1,involved in endogenous auxin concentrations and auxin responses in wheat.We concluded that the awn length is regulated not only by the ALI-A1 gene at transcript levels but also by Ali-A1 and TPL1 at the protein level in wheat.展开更多
Mammalian scent glands mediate species-specific chemical communication,yet the mechanistic basis for convergent musk production remain incompletely understood.Forest musk deer and muskrat have independently evolved sp...Mammalian scent glands mediate species-specific chemical communication,yet the mechanistic basis for convergent musk production remain incompletely understood.Forest musk deer and muskrat have independently evolved specialized musk-secreting glands,representing a striking case of convergent evolution.Through an integrated multi-omics approach,this study identified cyclopentadecanone as a shared key metabolic precursor in musk from both forest musk deer and muskrat,although downstream metabolite profiles diverged between the two lineages.Single-cell RNA sequencing revealed that these specialized apocrine glands possessed unique secretory architecture and exhibited transcriptional profiles associated with periodic musk production,distinct from those in conventional apocrine glands.Convergent features were evident at the cellular level,where acinar,ductal,and basal epithelial subtypes showed parallel molecular signatures across both taxa.Notably,acinar cells in both species expressed common genes involved in fatty acid and glycerolipid metabolism(e.g.,ACSBG1,HSD17B12,HACD2,and HADHA),suggesting a conserved molecular framework for musk precursor biosynthesis.Metagenomic analysis of musk samples further revealed parallel microbial community structures dominated by Corynebacterium and enriched in lipid metabolic pathways.These findings suggest multi-level convergence in musk biosynthesis,from molecular pathways to microbial communities,providing novel insights into mammalian chemical signaling and artificial musk production.展开更多
文摘Lignin is a significant secondary metabolite produced through the phenylpropanoid pathway.As a vital component of the plant cell wall,lignin affects various fruit characteristics,including size,seed quantity,and firmness.In this study,we conducted comprehensive identification and phylogenetic analysis of 265 Caffeic acid O-methyltransferase(COMT)genes across ten different plant species,including Vaccinium corymbosum and four other Vaccinium species.The results reveal that VcCOMT38 is a promising structural gene for the biosynthesis of lignin in blueberry.An in vitro enzymatic assay of VcCOMT38 demonstrated that it is a special enzyme in the lignin biosynthesis pathway and prefers to use caffeic acid as a substrate over 5-hydroxyferulic acid.Transient overexpression and silencing of VcCOMT38 in Vaccinium corymbosum‘Northland’fruits demonstrated that VcCOMT38 participates in lignin biosynthesis and contributes to both an increased number of immature seeds and enhanced fruit firmness.The heterologous overexpression of VcCOMT38 in Nicotiana benthamiana revealed that this gene could increase the lignin content and the syringyl/guaiacyl(S/G)ratio,which determines the maximum monomer yield during lignin depolymerization.These results highlight VcCOMT38 as a crucial gene in lignin biosynthesis and its potential for improving lignin production in industry through genetically modified woody plants.
基金financially supported by the Hainan Province Science and Technology Special Fund(Grant no:ZDYF2024XDNY187).
文摘Background:Excessive use of inorganic trace minerals(ITMs)in swine production leads to high fecal mineral excretion and environmental risks,while most studies on organic trace minerals(OTMs)focus on single elements,with limited data on the synergistic effects and molecular mechanisms of combined OTMs(Fe,Cu,Mn,Zn)in growing-finishing pigs.Methods:This study aimed to investigate the effects of graded levels of micromineral proteinates(combined OTMs)on growth performance,mineral metabolism,and mRNA expression of mineral regulatory proteins.A total of 360 crossbred Duroc×Landrace×Large White pigs(initial body weight 47.1±4.8 kg)were randomly assigned to 6 dietary treatments:basal diet without microminerals(CON),basal diet with ITMs at commercially recommended levels(IT),and basal diets with 15%(OT 15%),25%(OT 25%),35%(OT 35%)commercially recommended levels(CRL)of combined micromineral proteinates.After a 70-day feeding trial,samples were analyzed using ICP-OES,ELISA,and RT-qPCR.Results:Results showed that reduced levels(15-35%CRL)of micromineral proteinates did not significantly affect average daily gain,average daily feed intake,or feed conversion ratio(gain-to-feed ratio)compared to IT(P>0.05),but significantly increased plasma Cu(1.73-1.83μg/mL)and Zn(1.72-1.97μg/mL)concentrations(P<0.05)and elevated activities of Cu/Zn-superoxide dismutase(32.9-35.9 U/L)and manganese superoxide dismutase(20.5-24.1 U/L)compared to CON(P<0.05),with no significant differences from IT(P>0.05).Fecal excretion of Fe,Cu,Mn,and Zn was significantly reduced by 35-50%in OT 15%-OT 35%groups compared to IT(P<0.05).OT 25%group exhibited the highest apparent absorptivity of Fe(38.5%),Cu(27.8%),and Zn(42.4%)(P<0.05),which was associated with significantly regulated mRNA expression of mineral regulatory proteins:upregulated DMT1,FPN1,ZIP4,and MT1A in the duodenum,and modulated HAMP,ATP7B,ZIP14,and ZnT1 in the liver(P<0.05).Conclusion:In conclusion,dietary supplementation with 25%CRL or less of combined micromineral proteinates can fully meet the nutritional needs of growing-finishing pigs,improve mineral absorptivity,and reduce fecal mineral excretion by regulating intestinal and hepatic mineral transport and homeostatic proteins,providing a sustainable alternative to high-dose ITMs.
基金funded by the National Natural Science Foundation of China (31760363)the Earmarked Fund for CARS (CARS-14-1-16)+1 种基金the Gansu Education Science and Technology Innovation Industry Support Program,China (2021CYZC-38)the Gansu Provincial Key Laboratory of Arid Land Crop Science,Gansu Agricultural University,China (GSCS-2020-Z6)。
文摘Lodging is a major constraint limiting oil flax production efficiency in northern China.Crop lodging susceptibility is closely related to stem lignin content,and the regulatory mechanisms by which nitrogen and potassium fertilization interactively influence lignin biosynthesis in oil flax stems require further investigation.Therefore,this study aimed to enhance lodging resistance and increase grain yield in oil flax.We examined the interactive effects of different nitrogen (75,150,and 225 kg N ha^(–1)) and potassium (60 and 90 kg K_(2)O ha^(–1)) fertilizer rates on lignin metabolism,lodging resistance,and grain yield during the 2022 and 2023 growing seasons.Results indicated that nitrogen and potassium fertilizer levels and their interactions promoted lignin accumulation,improved lodging resistance,and increased grain yield.Compared to the control (CK),the75–150 kg N ha^(–1) combined with 60 kg K_(2)O ha^(–1) treatments significantly enhanced the activities of key lignin-synthesizing enzymes (tyrosine ammonia-lyase (TAL),phenylalanine ammonia-lyase (PAL),cinnamyl alcohol dehydrogenase (CAD),and peroxidase (POD)) and upregulated the expression of 4CL1 and F5H3 genes,leading to a 29.63–43.30%increase in lignin content,improved stem bending strength and lodging resistance index,and a 23.27–32.34%increase in grain yield.Correlation analysis revealed that nitrogen and potassium fertilizers positively regulated enzyme activities and gene expression related to lignin biosynthesis,thereby facilitating lignin accumulation and enhancing stem mechanical strength and lodging resistance.Positive correlations were observed among lignin-related enzyme activities,gene expression,lodging resistance traits,and grain yield.In summary,the application of 75–150 kg N ha^(–1) in conjunction with 60 kg K_(2)O ha^(–1)promoted lignin biosynthesis and accumulation,enhanced lodging resistance,and increased grain yield in oil flax grown in the dryland farming region of central Gansu,China.Furthermore,this treatment provides a technical basis for cultivating stress-tolerant and high-yield oil flax in arid regions.
基金supported by Shenzhen University General Hospital Scientific Research Project,No.SUGH2019QD002Shenzhen Science and Technology Development Foundation,No.20220810173216001(both to ZS).
文摘Spinal cord injury is a severe neurological condition with limited neuronal regeneration and functional recovery.Currently,no effective treatments exist to improve spinal cord injury prognosis.Neuronal guidance proteins are a diverse group of molecules that play crucial roles in axon and dendrite growth during nervous system development.Increasing evidence highlights their regulatory functions in spinal cord injury.This review provides a brief overview of the modulation patterns of key neuronal guidance proteins in neuronal axon growth during nervous system formation and subsequently focuses on their roles in neuronal regeneration and functional recovery following spinal cord injury.Neuronal guidance proteins include,but are not limited to,semaphorins and their receptors,plexins;netrins and their receptors,deleted in colorectal cancer and UNC5;Eph receptors and their ligands,ephrins;Slit and its receptor,Robo;repulsive guidance molecules and their receptor,neogenin;Wnt proteins and their receptor,Frizzled;and protocadherins.Localized Netrin-1 at the injury site inhibits motor axon regeneration after adult spinal cord injury while promoting oligodendrocyte growth.Slit2 enhances synapse formation in the injured spinal cord of rats.EphA7 regulates acute apoptosis in the early pathophysiological stages of spinal cord injury,while ephrinA1 plays a role in the nervous system’s injury response,with its reduced expression leading to impaired motor function in rats.EphA3 is upregulated following spinal cord injury,promoting an inhibitory environment for axonal regeneration.After spinal cord injury,bidirectional activation of ephrinB2 and EphB2 in astrocytes and fibroblasts results in the formation of a dense astrocyte-meningeal fibroblast scar.EphB1/ephrinB1 signaling mediates pain processing in spinal cord injury by regulating calpain-1 and caspase-3 in neurons.EphB3 expression increases in white matter after spinal cord injury,further inhibiting axon regeneration.Sema3A,expressed by neurons and fibroblasts in the scar surrounding the injury,inhibits motor neuron and sensory nerve growth after spinal cord injury.Sema4D suppresses neuronal axon myelination and axon regeneration,while its inhibition significantly enhances axon regeneration and motor recovery.Sema7A is involved in glial scar formation and may influence serotonin channel remodeling,thereby affecting motor coordination.Given these findings,the local or systemic application of neuronal guidance proteins represents a promising avenue for spinal cord injury treatment.
基金supported by the National Natural Science Foundation of China (No.22007008)the LiaoNing Revitalization Talents Program (No.XLYC1907021)the Fundamental Research Funds for the Central Universities (Nos.DUT23YG120,DUT19RC(3)009)。
文摘The study of target proteins is crucial for understanding molecular interactions and developing analytical platforms,therapeutic agents and functional tools.Herein,we present a novel nanoplatform activated by near-infrared(NIR) light for triple-modal proteins study,which enabling target protein labeling,enrichment and visualization.Azido-naphthalimide-coated upconversion nanoparticles(UCNPs) serve as NIR light-responsive nanoplatforms,showing promising applications in studying interactions between various bioactive molecules and proteins in living systems.Under NIR light irradiation,azido-naphthalimides are activated by ultraviolet(UV) and blue light emitted from UCNPs and the resulting amino-naphthalimides intermediate not only crosslink nearby target proteins but also enable imaging performance.We demonstrate that this nanoplatform is capable of selective protein labeling and imaging in complex protein environments,achieving specific labeling and imaging of both intracellular and extracellular proteins in mammalian cells as well as bacteria.Furthermore,in vivo protein labeling has been achieved using this novel NIR light-activatable nanoplatform.This technique will open new avenues for discoveries and mechanistic interrogation in chemical biology.
文摘Multienzyme cascades enable the sequential synthesis of complex chemicals by combining multiple catalytic processes in one pot,offering considerable time and cost savings compared to a series of separate batch reactions.However,challenges related to coordination and regulatory interplay among multiple enzymes reduce the catalytic efficiency of such cascades.Herein,we genetically programmed a scaffold framework that selectively and orthogonally recruits enzymes as designed.The system was then used to generate multienzyme complexes of D-allulose 3-epimerase(DAE),ribitol dehydrogenase(RDH),and formate dehydrogenase(FDH)for rare sugar production.This scaffolded multienzymatic assembly achieves a 10.4-fold enhancement in the catalytic performance compared to its unassembled counterparts,obtaining allitol yield of more than 95%.Molecular dynamics simulations revealed that shorter distances between neighboring enzymes in scaffold-mounted complexes facilitated the transfer of reaction intermediates.A dual-module catalytic system incorporating(1)scaffold-bound complexes of DAE,RDH,and FDH and(2)scaffold-bound complexes of alcohol dehydrogenase and NADH oxidase expressed intracellularly in E.coli was used to synthesize D-allulose from D-fructose.This system synthesized 90.6%D-allulose from 300 g L^(−1)D-fructose,with a space-time yield of 13.6 g L^(−1)h^(−1).Our work demonstrates the programmability and versatility of scaffold-based strategies for the advancement of multienzyme cascades.
文摘<span style="font-family:;" "=""><span style="font-family:Verdana;">Methane production by archaea depends on tetrahydromethanopterin (H</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">MPT), a pterin-containing cofactor that carries one-carbon units. Two redox reactions within the nine steps of H</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">MPT side chain biosynthesis have been hypothesized. Biochemical assays have demonstrated that the archaeal iron-sulfur flavoprotein dihydromethanopterin reductase X (DmrX or MM1854) catalyzes the final reaction of the pathway, the reduction of dihydromethanopterin to H</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">MPT</span></span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> using dithiothreitol (DTT) as an artificial electron donor. The crystal structure of DmrB, a bacterial DmrX homolog that lacks iron-sulfur clusters, has led to a proposed ping-pong mechanism of electron transfer between FMNH</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> and the FMN prosthetic group of DmrB. However, an enzymatic assay to test the hypothetical DmrB mechanism is lacking because a suitable electron donor has not previously been identified. Furthermore, a second uncharacterized archaeal flavoprotein (MM1853) has been hypothesized to function in H</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">MPT side chain biosynthesis. In this </span><span style="font-family:Verdana;">work, to facilitate the development of assays to elucidate the functions of DmrB </span><span style="font-family:Verdana;">and MM1853, we tested a variety of electron donors, including dithiothreitol, ferredoxin, and a system consisting of NADH and an NADH-dependent fla</span><span style="font-family:Verdana;">vin-reducing enzyme (Fre).</span><span style="font-family:Verdana;"> Reduction of the DmrB prosthetic group (FMN) was measured as a decrease in absorbance at 460 nm. NADPH, NADH, and </span><span style="font-family:Verdana;">DTT were unable to reduce DmrB. However, NADH/Fre was able to reduce </span><span style="font-family:Verdana;">DmrB within 70 min (initial rate of 1.3 μM/min), providing the basis for a future DmrB activity assay. Carbon monoxide (CO)/CO dehydrogenase/ferredoxin reduced DmrB more rapidly within 6 min. Both electr</span><span style="font-family:Verdana;">on transfer systems reduced a second flavin-containing archaeal protein MM1853, which is predicted to catalyze the third step of H</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">MPT biosynthesis. While NADH and NADPH were incapable of directly reducing the FMN cofactor of MM1853, DTT or NADH/Fre could eliminate the FMN peaks. These results establish the basis for new oxidoreductase assays that will facilitate testing several proposed DmrB mechanisms and defining the specific function of MM1853 in methanogen cofactor biosynthesis.</span></span>
文摘Our previous studies showed a predominance of high molecular weight protein group in tumor nuclear matrices. Contrary to normal cells, proteins of this group are preferentially phosphorylated. Phosphoproteins of hepatoma nuclear matrix are selectively subjected to rapid proteolysis. By alkali treatment and a monoclonal antibody against phosphotyrosyl residue the presence of two high molecular weight bands of phosphotyrosyl-containing proteins was detected in nuclear matrices of tumor but not of normal liver cells. High molecular weight protein group of tumor nuclear matrices revealed also a rapid turnover and preferential incorporation of labeled amino acids selectively inhibited by chloramphenicol.
基金supported by the National Key Research and Development Program of China (No. 2022YFD1700200)the National Natural Science Foundation of China (Nos. 32161133010, 3230170969)+1 种基金the Innovation Program of Chinese Academy of Agricultural Sciences, the Shenzhen Science and Technology Program (No. KQTD20180411143628272)the Special Funds for Science Technology Innovation and Industrial Development of Shenzhen Dapeng New District (No. PT202101–02)。
文摘Chitin is an abundant aminopolysaccharide found in insect pests and phytopathogenic microorganisms but absent in higher plants and vertebrates. It is crucial for mitigating threats posed by chitin-containing organisms to human health, food safety, and agriculture. Therefore, targeting the chitin biosynthesisassociated bioprocess holds a promise for developing human-safe and eco-friendly antifungal agents or pesticides. Chitin biosynthesis requires chitin synthase and associated factors, which are involved in the modification, regulation, organization or turnover of chitin during its biosynthesis. A number of enzymes such as chitinases, hexosaminidases, chitin deacetylases are closely related and therefore are promising targets for designing novel agrochemicals that target at chitin biosynthesis. This review summarizes the advances in understanding chitin biology over the past decade by our research group and collaborates,specifically regarding essential proteins linked to chitin biosynthesis that can be exploited as promising pesticide targets. Examples of small bioactive molecules that against the activity of these targets are given.
文摘Xylo-oligosaccharides(XOSs)are a category of functional oligosaccharides primarily composed of 2-7 xylose units linked byβ-1,4 glycosidic bonds.They are recognized as soluble dietary fibers with prebiotic properties.Recently, there has been significant interest in manufacturing XOSs from xylan extracted from lignocellulosic biomass using enzyme catalysis under mild conditions. In this work, the arabinofuranosidase Abf62A gene was cloned from Aspergillus usamii genomic DNA through sequential molecular processes and expressed in Pichia pastoris X33. The xylan (100 g/L) extracted xylan in wheat straw (WS) was biologically hydrolyzed into 50.32 g/L of XOSs by xylanase Xyn11A (300 U/g substrate) and arabinofuranase Abf62A (20 U/g substrate), which indicated a notable synergistic effect compared to the 34.42 g/L XOSs produced via Xyn11A. The 50.32 g/L of XOSs products comprised xylobiose (31.71 g/L), xylotriose (15.92 g/L), xylotetraose (1.65 g/L) and xylopentaose (1.04 g/L). Notably, the combined content of xylobiose and xylotriose accounted for up to 94.7%. The XOSs purified from the enzyme hydrolysate could effectually scavenge free radicals, and the antioxidant activity was more than 90%. In summary, XOSs were biologically manufactured from wheat straw xylan through the synergistic biocatalysis via xylanase and arabinofuranosidase Abf62A in a green and sustainable way, rending one kind of prebiotic oligosaccharides with substantial positive effects on human and animal health.
基金Supported by grands from theNaturalScience Foundation of China(39925012 and 30170221 ),and the Scienceand Technology Committee of China (G1999054007).
文摘Objective To investigate effect of inhibiting melatonin biosynthesis on activities of protein kinase A (PKA), glycogen synthase kinase-3 (GSK-3) and tau phosphorylation at PS214 and M4 epitopes using haloperidol, a specific inhibitor of 5-hydroxyindole-O-methyltransferase. Methods Brain ventricular and intraperitoneal injections were used for haloperidol administration, Western blots for tau phosphorylation, 32P-labeling for PKA and GSK-3 activity, and high performance liquid chromatograph for detection of serum melatonin levels. Results Haloperidol injection through the lateral ventricle and intraperitoneal reinforcement significantly stimulated PKA activity with a concurrent hyperphosphorylation of tau at M4 (Thr231/Ser235) and PS214 (Ser214) sites. Prior treatment of the rats using melatonin supplement for one week and reinforcement during the haloperidol administration arrested PKA activity and attenuated tau hyperphosphorylation. GSK-3 activity showed no obvious change after haloperidol injection, however, melatonin supplements and reinforcements during haloperidol infusion inactivated basal activity of GSK-3. Conclusion Decreased melatonin may be involved in Alzheimer-like tau hyperphosphorylation, and overactivation of PKA may play a crucial role in this process.
基金National Natural Science Foundation of China(Grant Nos.32070838 and 82301874)Open Fund of State Key Laboratory of Reproductive Medicine,Nanjing Medical University(Grant No.SKLRM K202102)。
文摘Meiotic resumption in mammalian oocytes involves nuclear and organelle structural changes,notably the chromatin configuration transition from a non-surrounding nucleolus(NSN)to surrounding nucleolus(SN)in germinal vesicle oocytes.In the current study,we found that nuclear speckles(NSs),a subnuclear structure mainly composed of serine-arginine(SR)proteins,changed from a diffuse spotted distribution in mouse NSN oocytes to an aggregated pattern in SN oocytes.We also found that the SR protein-specific kinase 1(SRPK1),an enzyme that phosphorylates SR proteins,co-localized with NSs at the SN stage,and that NSN oocytes failed to transition to SN oocytes after the inhibition of SRPK1 activity.Furthermore,the typical structure of the chromatin ring around the nucleolus in SN oocytes collapsed after treatment with an SRPK1 inhibitor.Mechanistically,phosphorylated SR proteins were found to be related to chromatin as shown by a salt extraction experiment,and in situ DNaseⅠassay showed that the accessibility of chromatin was enhanced in SN oocytes when SRPK1 was inhibited,accompanied by a decreased repressive modification on histone and the abnormal recurrence of a transcriptional signal.In conclusion,our results indicated that SRPK1-regulated phosphorylation of SR proteins was involved in the NSN-SN transition and played an important role in maintaining the condensed nucleus of SN oocytes via interacting with chromatin.
文摘Selenocysteine (Sec) tRNAs serve as carrier molecules for the biosynthesis of Sec from serine and to donate Sec to protein in response to specific UGA codons. In this study, we describe the current status of Sec tRNAs in higher animals and further we exarnine: (i) the Sec tRNA population in Drosophila; (ii) transcription of the Sec tRNA in vivo (in Xenopus oocytes) and in vitro (in Xenopus oocyte extracts); (iii) the effect of selenium on the Sec tRNA population in various rat tissues following replenishment of extremely selenium deficient rats with this element; and (iv) the biosynthesis of the modified bases on Sec tRNA in Xenopus oocytes
基金financially supported by the Green Development and Demonstration Programme(GUDP)(case number 34009-19-1585)。
文摘Background Post-weaning diarrhea(PWD)in piglets,often caused by F4^(+)enterotoxigenic Escherichia coli(ETEC),poses significant challenges in pig production.Traditional solutions like antibiotics and zinc oxide face increasing restrictions due to growing concerns over antibiotic resistance and environmental sustainability.This study investigates the application of bivalent heavy chain variable domain(V_(H)H)constructs(BL1.2 and BL2.2)targeting ETEC virulence factors,administered in feed to mitigate ETEC-induced PWD in weaned piglets.Results The supplementation of BL1.2 and BL2.2 in both mash and pelleted feed significantly reduced the diarrhea incidence and fecal shedding of F4^(+)ETEC in challenged piglets.Pelleted feed containing V_(H)H constructs helped to preserve gut barrier integrity by maintaining levels of the tight junction protein occludin in the small intestine.Additionally,the constructs maintained blood granulocyte counts at a similar level to the non-challenged control group,including neutrophils,and ameliorated the acute phase protein response after challenge.Notably,even at low feed intake immediately after weaning,V_(H)H constructs helped maintain piglet health by mitigating ETEC-induced inflammation and the resulting diarrhea.Conclusions Our findings demonstrated that using V_(H)H constructs as feed additives could serve as an effective strategy to help manage ETEC-associated PWD,by reducing F4^(+)ETEC gut colonization and supporting gut barrier function of weaned piglets.The high stability of these V_(H)H constructs supports their incorporation into industrial feed manufacturing processes,offering a more sustainable preventive strategy compared to traditional antimicrobial interventions,which could contribute to sustainable farming practices.
文摘The present study was carried out to evaluate the pollution and its effect on the quality of catfish. Four sites in Eygpt were chosen for the research, Ras El-Bar (Site 1) as control, Shatta (Site 2), Kafr El-Bateekh (Site 3), and Talkha (Site 4). The research was carried out on water, sediments and catfish (serum and muscles). Nitrite, nitrate and ammonia were determined in water and sediment. Also, RNA and DNA were determined in serum samples and the muscles of the catfish. In addition, the concentrations of heavy metals (Pb, Cd, Fe, Zn and Cu) were estimated in water, sediments and the muscles of catfish. Also, hepatosomatic index, liver water content, condition factor, lipid and protein contents were determined in the fish. The concentrations of nitrite, nitrate and ammonia in water and sediment of Site 4 and the levels of heavy metals especially Pb and Cd in water, sediment and muscle of catfish from Sites 3 and 4 were highly elevated compared to those of the control. On the other hand, DNA, RNA and protein contents in the catfish of Sites 3 and 4 decreased. The results illustrated that, Cd and Pb levels in the muscle of catfish were negatively correlated with DNA, RNA and with the protein contents. In conclusion, the accumulation of heavy metals in catfish tissues therefore, can cause health problems in human after catfish intake.
基金financially supported by the National Natural Science Foundation of China(31960090,32160562)the Natural Science Foundation of Jiangxi Province(20224BAB215046)the Project Program of State Key Laboratory of Food Science and Resources,Nanchang University(SKLF-ZZB-202129,SKLF-ZZB-202324,SKLF-KF-202216)。
文摘Cyclocarya paliurus(Batalin)Iljinskaja,as a unique and rare monocotyledonous plant in Southern China,is a promising and economical Chinese herbal medicine and functional food.People have conducted a number of research on C.paliurus because of its rich triterpenoids.However,no comprehensive review has illustrated the composition and pharmacological activity of triterpenoids from C.paliurus.This review summarizes 177 triterpenoids from different parts of C.paliurus.The structures of compounds were elucidated,and their biosynthesis was inferred.The biological activities of compounds and triterpenoid-rich extracts,including anti-diabetes,antihyperlipidemia,anti-inflammatory,anticancer or cytotoxicity,antioxidation,etc.,were discussed.C.paliurus can be an important and valuable supplement to the food market.This review provides a reference for the further research and application of C.paliurus triterpenoids in the fields of foods and pharmaceuticals.
基金financially supported by the National Key Research and Development Program of China(No.2020YFA0908000)CAMS Innovation Fund for Medical Sciences(No.CIFMS-2023I2M-2–006)。
文摘Camptothecin,a plant-derived pentacyclic pyrroloquinoline alkaloid,and its derivatives like topotecan and irinotecan have been used as clinical anticancer agents for decades.However,the complete biosynthetic pathway of camptothecin still remains unelucidated due to the unknown complex formation processes and corresponding enzymes for the downstream biosynthetic pathway including the committed hydrolysis of glycosides.Herein,a novel glycoside hydrolase(CaGH1)responsible for the deglycosylation of biosynthetic glycoside intermediates including both quinoline-type alkaloids pumiloside(1),(3S)-deoxypumiloside(2)and indole-type alkaloid strictosamide(3)has been functionally identified.Moreover,CaGH1 exhibits the highly strict stereoselectivity towards the substrates with 3S configuration.Furthermore,a combined strategy for the discovery of the unknown biosynthetic enzyme by employing activity-guided enzyme verification,transcriptome-based gene mining,biochemical assay in vitro,and structurally characterizing the unstable enzymatic products by derivatization,is reported.These findings not only provide a better understanding of the deglycosylation in camptothecin biosynthesis,also lay the foundation for the complete elucidation of camptothecin biosynthetic pathway and biological production of camptothecin.
基金co-financed by the International Science&Technology Cooperation Program of Hainan Province(GHYF2023009)Jiangsu Provincial Key Research and Development Program(BE2022325)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_0777)Qing Lan Project of Jiangsu Province and Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘The surface macromolecules of probiotic bacteria play crucial roles in modulating immune responses in the host.Exopolysaccharide(EPS)from lactic acid bacteria(LAB)have been widely reported to exhibit immunomodulatory activity.In this study,the EPS biosynthesis gene cluster of Lacticaseibacillus paracasei S-NB was analyzed and a deletion mutant S-NBΔ7576(two genes S-NB_2175/wze and S-NB_2176/wzd were responsible for the chain length determination and export of EPS)was successfully constructed,resulting a 40.02%decrease in the production of EPS.The deletion of wze and wzd had little effect on the monosaccharide composition and major groups of the two EPS fractions(BEPS1 and BEPS2).Both BEPS1 and BEPS2 could inhibit the transcriptional level of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),inducible nitric oxide synthase(i NOS)and cyclooxygenase-2(COX-2)mRNA in RAW 264.7 cells induced by lipopolysaccharide(LPS),and enhance host immune tolerance via suppressing NF-κB and MAPK signaling.Notably,the S-NBΔ7576 mutant supplied with the BEPS1/BEPS2 exhibited more significant inhibition of cytokines production and the phosphorylation of p65 and c-Jun N-terminal kinase(JNK)in LPS-stimulated cells compared with the S-NBΔ7576 mutant alone.Our study provided the immunomodulatory effect of BEPS1 and BEPS2 from L.paracasei S-NB,in which the wze and wzd genes associated with EPS biosynthesis may play an important role.
基金supported by the Grand Science and Technology Special Project in Shanxi Province(202201140601025-2)the National Natural Science Foundation of China(32201749)supported by the Agriculture and Food Research Initiative Competitive Grant 2022-68013-36439(WheatCAP)from the USDA National Institute of Food and Agriculture.
文摘The awn can contribute to photosynthesis and carbohydrates,enhancing grain yield in wheat.We mapped QAwn.sxau-5A,a major QTL for awn development in wheat(Triticum aestivum).This QTL was delimited to a 994-kb interval at the B1 locus on chromosome 5A,which included the candidate gene encoding a zinc finger protein(TraesCS5A01G542800)as an awn length inhibitor(ALI).The Ali-A1 allele for the awnless trait showed abundant sequence differences in the promoter regions compared to the ali-A1 allele for the long-awn trait.The results of the swap experiment on the promoters from the two ALI-A1 alleles showed that the two promoters caused a difference in the protein level,indicating the gene was regulated at the transcript level.However,the ali-A1 allele contained an SNP that caused a premature stop codon in its coding region,resulting in a truncated protein compared to the functional Ali-A1 protein.The Ali-A1 protein contained two ethylene-responsive element binding factor-associated amphiphilic repression(EAR)motifs,one at the N terminus(EAR-N)and the other at the C terminus(EAR-C),and they were involved in interactions with the wheat co-repressor protein TOPLESS(TPL1).The ali-A1 protein retained the EAR-N motif but lost the EAR-C motif,resulting in the attenuated ability to interact with TPL1.The tpl1 mutant produced a longer awn compared to the wild type.Ali-A1 repressed the transcription of two downstream genes,TaLRP-A1 and TaARF-B1,involved in endogenous auxin concentrations and auxin responses in wheat.We concluded that the awn length is regulated not only by the ALI-A1 gene at transcript levels but also by Ali-A1 and TPL1 at the protein level in wheat.
基金supported by the National Natural Science Foundation of China(32225009,32370452,82274046)Jilin Agricultural University High-level Talent Introduction Fund(202020218)。
文摘Mammalian scent glands mediate species-specific chemical communication,yet the mechanistic basis for convergent musk production remain incompletely understood.Forest musk deer and muskrat have independently evolved specialized musk-secreting glands,representing a striking case of convergent evolution.Through an integrated multi-omics approach,this study identified cyclopentadecanone as a shared key metabolic precursor in musk from both forest musk deer and muskrat,although downstream metabolite profiles diverged between the two lineages.Single-cell RNA sequencing revealed that these specialized apocrine glands possessed unique secretory architecture and exhibited transcriptional profiles associated with periodic musk production,distinct from those in conventional apocrine glands.Convergent features were evident at the cellular level,where acinar,ductal,and basal epithelial subtypes showed parallel molecular signatures across both taxa.Notably,acinar cells in both species expressed common genes involved in fatty acid and glycerolipid metabolism(e.g.,ACSBG1,HSD17B12,HACD2,and HADHA),suggesting a conserved molecular framework for musk precursor biosynthesis.Metagenomic analysis of musk samples further revealed parallel microbial community structures dominated by Corynebacterium and enriched in lipid metabolic pathways.These findings suggest multi-level convergence in musk biosynthesis,from molecular pathways to microbial communities,providing novel insights into mammalian chemical signaling and artificial musk production.
