Metagenomic analysis revealing the metabolic role of microbial communities in the free amino acid biosynthesis of Monascus rice vinegar during fermentation

Free amino acid(FAA)is the important component of vinegar that infl uences quality perception and consumer acceptance.FAA is one of the major metabolites produced by microorganisms;however,the microbial metabolic network on FAA biosynthesis remains unclear.Through metagenomic analysis,this work aimed to elucidate the roles of microbes in FAA biosynthesis during Monascus rice vinegar fermentation.Taxonomic profiles from functional analyses showed 14 dominant genera with high contributions to the metabolism pathways.The metabolic network for FAA biosynthesis was then constructed,and the microbial distribution in different metabolic pathways was illuminated.The results revealed that 5 functional genera were closely involved in FAA biosynthesis.This study illuminated the metabolic roles of microorganisms in FAA biosynthesis and provided crucial insights into the functional attributes of microbiota in vinegar fermentation.

Exploring nitrogen reduction reaction mechanisms in electrocatalytic ammonia synthesis:A comprehensive review

The electrochemical nitrogen reduction reaction(eNRR)holds significant promise as a sustainable alternative to the conventional large-scale Haber Bosch process,offering a carbon footprint-free approach for ammonia synthesis.While the process is thermodynamically feasible at ambient temperature and pressure,challenges such as the competing hydrogen evolution reaction,low nitrogen solubility in electrolytes,and the activation of inert dinitrogen(N_(2))gas adversely affect the performance of ammonia production.These hurdles result in low Faradaic efficiency and low ammonia production rate,which pose obstacles to the commercialisation of the process.Researchers have been actively designing and proposing various electrocatalysts to address these issues,but challenges still need to be resolved.A key strategy in electrocatalyst design lies in understanding the underlying mechanisms that govern the success or failure of the electrocatalyst in driving the electrochemical reaction.Through mechanistic studies,we gain valuable insights into the factors affecting the reaction,enabling us to propose optimised designs to overcome the barriers.This review aims to provide a comprehensive understanding of the various mechanisms involved in eNRR on the electrocatalyst surface.It delves into the various mechanisms such as dissociative,associative,Mars-van Krevelen,lithium-mediated nitrogen reduction and surface hydrogenation mechanisms of nitrogen reduction.By unravelling the intricacies of eNRR mechanisms and exploring promising avenues,we can pave the way for more efficient and commercially viable ammonia synthesis through this sustainable electrochemical process by designing an efficient electrocatalyst.

Reaction of Mo(CO)_6 with Alkoxide: Synthesis and Structure of the Mo(0)-OR Complex [Et_4N]_3[Mo_2(CO)_6(μ-OC_6H_4OCH_2C_6H_5)_3]

The reaction of molybdenum hexacarbonyl with C6H5CH2OC6H4ONa and Et4NBr in CH3CN at 60 ℃ afforded the di-nuclear Mo（0） compound [Et4N]3[Mo2（CO）6（μ-OC6H4OCH2C6H5）3] 1. 1 crystallizes in monoclinic, space group P21/c with a = 15.359（2）, b = 18.378（3）, c = 24.952（2） A, β = 102.268（4）°, V = 6882.3（1 6） A^3, Mr = 1348.34, Z = 4, Dc = 1.301 g/cm^3, F（000） = 2832 and μ= 0.424 mm^-1 The final R = 0.0606 and wR = 0.1552 for 9396 observed reflections （I 〉 2σ（I））. I contains a [Mo2O3]^3 core in triangular bi-pyralnidal configuration and each Mo atom adopts a distorted octahedral geometry with three carbon atoms from carbonyls and three ,μ-O atoms from C6H5CH2OC6H4O^- bridging ligands. The Mo…Mo distance is 3.30（8） A, indicating no metalmetal bonding. A formation pathway via forming a di-molybdenum（0） di-bridging OR compound [Mo2（μ-OR）2（CO）8]2 has been figured out and the reaction of Mo（CO）6 with alkoxide has also been discussed.

The Flow of Information from Nucleus to Golgi Is Contingent upon Nuclear Membrane Synthesis and Protraction of the Ceramide-Containing Membrane to Endoplasmic Reticulum

The nucleus-initiated augmentation of ER membrane is reflected in a coordinated synthesis and intercalation of the explicit proteins and lipids required for the replacement, repair and function of the cell and its organelles. The direct connection between nucleus and the membranes containing labeled sphingosine (SphN) and ceramide (Cer) was affirmed by determining synthetic activity of serine palmitoyltransferase (SPT). The SPT and the newly synthesized serine-labeled lipid products were identified in the Outer- and Inner-Nuclear Membrane (ONM, INM) and ER. The pulse-chase experiments disclosed that the incorporation of radiolabeled lipids into both nuclear membranes declined upon their simultaneous increase in Endoplasmic Reticulum (ER). These results, and prior findings regarding metabolic transfer of nuclear membrane phosphoinositides to the outer leaflet of ER [Slomiany and Slomiany, Health, 2011, 3, 187-199], allowed us to reason that INM and ONM are not distinct entities, but uninterrupted continuum facing nucleosol and then cytosol when protracted into segment known as ER. Consequently, the identification of SPT and its products in the inner leaflet of nuclear and ER microsomes lent credence to the luminal presence of Cer in Golgi, luminal synthesis of glycosphingolipids (GSphLs), sphingomyelin (SM), and their delivery to the outer leaflet of apical and basolateral cell membrane, respectively. The findings presented in this communication provide further support to our concept that the factual intercalation of proteins and lipids into the cell membranes can only take place during their simultaneous synthesis that is guided by the nuclear and cytosolic processes enacted in nuclear-ER membrane continuum. At the nuclear stage, the signal-specific genes expression promotes active synthesis and intercalation of lipids into the organelles’ customized membrane that is protracted and articulated in ER in form of transport vesicles.

Roles of vitamin A in the regulation of fatty acid synthesis

Dietary macronutrients and micronutrients play important roles in human health.On the other hand,the excessive energy derived from food is stored in the form of triacylglycerol.A variety of dietary and hormonal factors affect this process through the regulation of the activities and expression levels of those key player enzymes involved in fatty acid biosynthesis such as acetyl-CoA carboxylase,fatty acid synthase,fatty acid elongases,and desaturases.As a micronutrient,vitamin A is essential for the health of humans.Recently,vitamin A has been shown to play a role in the regulation of glucose and lipid metabolism.This review summarizes recent research progresses about the roles of vitamin A in fatty acid synthesis.It focuses on the effects of vitamin A on the activities and expression levels of mRNA and proteins of key enzymes for fatty acid synthesis in vitro and in vivo.It appears that vitamin A status and its signaling pathway regulate the expression levels of enzymes involved in fatty acid synthesis.Future research directions are also discussed.

BmSLC7A5 is essential for silk protein synthesis and larval development in Bombyx mori

Insects produce silk to form cocoons,nests,and webs,which are important for their survival and reproduction.However,little is known about the molecular mecha-nism of silk protein synthesis at the translation level.The solute carrier family 7(SLC7)genes are involved in activating the target of rapamycin complex 1(TORC1)signaling pathway and protein translation process,but the physiological roles of SLC7 genes in silk-producing insects have not been reported.Here,we found that amino acid signaling regulates silk protein synthesis and larval development via the L-type amino acid trans-porter 1(LAT1;also known as SLC7A5)in Bombyx mori.A total of 12 SLC7 homologs were identified in the silkworm genome,among which BmSLC7A5 was found to be a silk gland-enriched gene and may be involved in leucine transport.Bioinformatics analy-sis indicated that SLC7A5 displays high homology and a close phylogenetic relationship in silk-producing insects.Subsequently,we found that leucine treatment significantly in-creased silk protein synthesis by improving the transcription and protein levels of silk genes.Furthermore,systemic and silk gland-specific knockout of BmSLC7A5 led to de-creased silk protein synthesis by inhibiting TORC1 signaling,and somatic mutation also resulted in arrested development from the 5th instar to the early pupal stage.Altogether,our study reveals that BmSLC7A5 is involved in regulating silk protein synthesis and larval development by affecting the TORC1 signaling pathway,which provides a new strategy and target for improving silk yield.

Low rumen degradable starch promotes the growth performance of goats by increasing protein synthesis in skeletal muscle via the AMPK-mTOR pathway

Since starch digestion in the small intestine provides more energy than digestion in the rumen of ru-minants,reducing dietary rumen degradable starch(RDS)content is beneficial for improving energy utilization of starch in ruminants.The present study tested whether the reduction of rumen degradable starch by restricting dietary corn processing for growing goats could improve growth performance,and further investigated the possible underlying mechanism.In this study,twenty-four 12-wk-old goats were selected and randomly allocated to receive either a high RDS diet(HRDS,crushed corn-based concen-trate,the mean of particle sizes of corn grain=1.64 mm,n=12)or a low RDS diet(LRDS,non-processed corn-based concentrate,the mean of particle sizes of corn grain>8 mm,n=12).Growth performance,carcass traits,plasma biochemical indices,gene expression of glucose and amino acid transporters,and protein expression of the AMPK-mTOR pathway were measured.Compared to the HRDS,LRDS tended to increase the average daily gain(ADG,P=0.054)and decreased the feed-to-gain ratio(F/G,P<0.05).Furthermore,LRDS increased the net lean tissue rate(P<0.01),protein content(P<0.05)and total free amino acids(P<0.05)in the biceps femoris(BF)muscle of goats.LRDS increased the glucose concen-tration(P<0.01),but reduced total amino acid concentration(P<0.05)and tended to reduce blood urea nitrogen(BUN)concentration(P=0.062)in plasma of goats.The mRNA expression of insulin receptors(INSR),glucose transporter 4(GLUT4),L-type amino acid transporter 1(LAT1)and 4F2 heavy chain(4F2hc)in BF muscle,and sodium-glucose cotransporters 1(SGLT1)and glucose transporter 2(GLUT2)in the small intestine were significantly increased(P<0.05)in LRDS goats.LRDS also led to marked activation of p70-S6 kinase(S6K)(P<0.05),but lower activation of AMP-activated protein kinase(AMPK)(P<0.05)and eukaryotic initiation factor 2a(P<0.01).Our findings suggested that reducing the content of dietary RDS enhanced postruminal starch digestion and increased plasma glucose,thereby improving amino acid utilization and promoting protein synthesis in the skeletal muscle of goats via the AMPK-mTOR pathway.These changes may contribute to improvement in growth performance and carcass traits in LRDS goats.

Defective g-C_(3)N_(4)supported Ru_(3)single-cluster catalyst for ammonia synthesis through parallel reaction pathways

Designing catalyst to achieve ammonia synthesis at mild conditions is a meaningful challenge in catalysis community.Defective g-C_(3)N_(4)nanosheet supported single-cluster ruthenium and iron catalysts were investigated for their ammonia synthesis performance.Based on density functional theory(DFT)calculations and microkinetic simulations,Ru_(3)single-cluster anchored on defective g-C3N4 nanosheet(Ru_(3)/Nv-g-C_(3)N_(4))has a turnover frequency(TOF)5.8 times higher than the Ru(0001)step surface at industrial reaction conditions of 673 K and 100 bar for ammonia synthesis.In other words,similar TOFs could be achieved on Ru_(3)/Nv-g-C_(3)N_(4)at much milder conditions(623 K,30 bar)than on Ru(0001)(673 K,100 bar).Our computations reveal the reaction proceeds parallelly on Ru_(3)/Nv-g-C_(3)N_(4)through both dissociative and alternative associative mechanisms at typical reaction conditions(600–700 K,10–100 bar);N–N bond cleavage of*N2 and*NNH from the two respective pathways controls the reaction collectively.With increasing temperatures or decreasing pressures,the dissociative mechanism gradually prevails and associative mechanism recedes.In comparison,Fe_(3)/Nv-g-C_(3)N_(4)catalyst shows a much lower catalytic activity than Ru3/Nv-g-C_(3)N_(4)by two orders of magnitude and the reaction occurs solely through the dissociative pathway.The finding provides a prospective candidate and deepens the mechanistic understanding for ammonia synthesis catalyzed by single-cluster catalysts(SCCs).

Metalloproteins/metalloenzymes for the synthesis of acetyl-CoA in the Wood-Ljungdahl pathway

This paper focuses on the group of metalloproteins/metalloenzymes in the acetyl-coenzyme A synthesis pathway of anaerobic microbes called Wood-Ljungdahl pathway,including formate dehydrogenase (FDH),corrinoid iron sulfur protein (CoFeSP),acetyl-CoA synthase (ACS) and CO dehydrogenase (CODH). FDH,a key metalloenzyme involved in the conversion of carbon dioxide to methyltetrahydrofolate,catalyzes the reversible oxidation of formate to carbon dioxide. CoFeSP,as a methyl group transformer,accepts the methyl group from CH3-H4 folate and then transfers it to ACS. CODH reversibly catalyzes the reduction of CO2 to CO and ACS functions for acetyl-coenzyme A synthesis through condensation of the methyl group,CO and coenzyme A,to finish the whole pathway. This paper introduces the structure,function and reaction mechanisms of these enzymes.

Drug-Excipient Interactions: Case Studies and Overview of Drug Degradation Pathways

The objective of the current research article is to provide a comprehensive review of excipients impact on the stability of the drug product and their implications during the product development. Recent developments in the understanding of the degradation pathways further impact methodologies used in the pharmaceutical industry for potential stability assessment. The formation of drug excipient adducts was very common based on the sensitive chemical moieties in the drugs and the excipients. The formation of the impurities was not limited to drug related impurities but there were several possibilities of the drug-excipient adduct formations as well as excipient impurities reaction with Active Pharmaceutical Ingredients. Identification of drug degradation in presence of excipients/excipient impurities requires extensive knowledge and adequate analytical characterization data. Systematic literature review and understanding about the drug formulation process, give you a smooth platform in establishing the finished product in the drug market. This paper discusses mechanistic basis of known drug-excipient interactions with case studies and provides an overview of common underlying themes in solid, semisolid and parenteral dosage forms.

Characteristics and expression of the TCP transcription factors family in Allium senescens reveal its potential roles in drought stress responses

Allium senescens,is an important economic and ecological grassland plant with drought-resistant characteristics.A TCP protein transcription factor is important in the regulation of plant development and adverse responses.However,the mechanism by which TCP transcription functions in drought resistance in Allium senescens is still not clear.Here,we obtained a total of 190,305 transcripts with 115,562 single gene clusters based on RNA-Seq sequencing of Allium senescens under drought stress.The total number of bases was 97,195,096 bp,and the average length was 841.06 bp.Furthermore,we found that there were eight genes of the TCP family that showed an upregulated expression trend under drought stress in Allium senescens.We carried out an investigation to determine the evolution and function of the AsTCP family and how they produce an effect in drought resistance.The 14 AsTCP genes were confirmed and divided into class I and class II containing CIN and CYC/TBI subfamilies,respectively.We also found that the expression of AsTCP17 was remarkably upregulated with drought treatment.Besides,the transformation of AsTCP17 in Arabidopsis revealed that the protective enzymes,namely polyphenol oxidase(POD)and superoxide dismutase(SOD),were increased by 0.4 and 0.8 times,respectively.Chlorophyll content was also increased,while the H2O2 and malondialdehyde(MDA)contents were decreased.Staining assays with 3,3′-diaminobenzidine(DAB)also suggested that the AsTCP17 downregulates reactive oxygen species(ROS)accumulation.In addition,overexpression of the AsTCP17 affected the accumulation of drought-related hormones in plants,and the synthesis of ABA.The expression of AtSVP and AtNCED3,related ABA synthesis pathway genes,indicated that the level of expression of AtSVP and AtNCED3 was obviously enhanced,with the overexpression of line 6 showing a 20.6-fold and 7.0-fold increase,respectively.Taken together,our findings systematically analyze the AsTCPs family at the transcriptome expression level in Allium senescens,and we also demonstrated that AsTCP17 protein,as a positive regulator,was involved in drought resistance of Allium senescens.In addition,our research contributes to the comprehensive understanding of the drought stress defense mechanism in herbaceous plants.

Experimental study on the synergistic inhibition of malignant biological behavior of hepatocellular carcinoma cells by the combination of DMDD and sorafenib

Objective:To investigate the effects and possible mechanisms of the combination of DMDD(2-dodecyl-6-methoxycyclohexa-2-5-diene-1-4-dione),a traditional Chinese medicine monomer,and sorafenib on the malignant biological behavior of human hepatocellular carcinoma Huh7 cells.Methods:The experiment was divided into four groups:Huh7 cells control group,DMDD group,sorafenib group and DMDD and sorafenib combination group.The CCK-8 assay was used to measure the viability of Huh7 cells,and the Kim's formula was used to determine the synergistic effect.The plate cloning experiment was conducted to test colony formation ability of Huh7 cells.The scratch and Transwell experiments were performed to evaluate the migration ability and the invasion ability of Huh7 cells.The cell cycle of Huh7 cells was detected by flow cytometry.RT-qPCR and Western blot were used to measure the mRNA transcription level and protein expression level of PHGDH in the serine synthesis pathway.Results:The plate cloning experiment,scratch experiment,and Transwell migration experiment showed that the combined application of DMDD and Sorafenib significantly enhanced the inhibitory effect on the proliferation,migration,and invasion ability of Huh7 cells compared to the control group,DMDD group,and Sorafenib group(P<0.05).According to the Kim's formula,the combination of DMDD(final concentrations of 2,4,8μmol/L)and Sorafenib(final concentrations of 1,2,4μmol/L)had a synergistic inhibitory effect on the proliferation of Huh7 cells(Q>1.15).6,10μmol/L DMDD combined with 3,5μmol/L Sorafenib showed additive effect.The cell cycle of Huh7 cells was detected by flow cytometry,and the results showed that after 48 hours of drug intervention,the proportion of G2/M phase cells in the control group,DMDD group,Sorafenib group,and combination group were(10.63±0.32)%,(35.77±1.22)%,(30.03±2.22)%,and(38.97±0.60)%,respectively.Compared with the control group,the proportion of G2/M phase cells in the three groups significantly increased(P<0.0001).Compared with the Sorafenib group,the proportion of G2/M phase cells in the combination group significantly increased(P<0.0001).RT-qPCR and Western blot results showed that the combined application of DMDD and Sorafenib significantly inhibited the mRNA transcription level and protein expression level of PHGDH(P<0.05).Conclusion:The combined application of DMDD and Sorafenib has a synergistic effect that can enhance the inhibitory effect on the proliferation,invasion,and migration ability of Huh7 cells.The mechanism of this effect is related to the synergistic inhibition of the gene transcription and protein expression of PHGDH in the serine synthesis pathway.

Cell-free synthesis system-assisted pathway bottleneck diagnosis and engineering in Bacillus subtilis

Metabolic engineering is a key technology for cell factories construction by rewiring cellular resources to achieve efficient production of target chemicals.However,the existence of bottlenecks in synthetic pathway can seriously affect production efficiency,which is also one of the core issues for metabolic engineers to solve.Therefore,developing an approach for diagnosing potential metabolic bottlenecks in a faster and simpler manner is of great significance to accelerate cell factories construction.The cell-free reaction system based on cell lysates can transfer metabolic reactions from in vivo to in vitro,providing a flexible access to directly change protein and metabolite variables,thus provides a potential solution for rapid identification of bottlenecks.Here,bottleneck diagnosis of the N-acetylneuraminic acid(NeuAc)biosynthesis pathway in industrially important chassis microorganism Bacillus subtilis was performed using cell-free synthesis system.Specifically,a highly efficient B.subtilis cell-free system for NeuAc de novo synthesis was firstly constructed,which had a 305-fold NeuAc synthesis rate than that in vivo and enabled fast pathway dynamics analysis.Next,through the addition of all potential key intermediates in combination with substrate glucose respectively,it was found that insufficient phosphoenolpyruvate supply was one of the NeuAc pathway bottlenecks.Rational in vivo metabolic engineering of NeuAc-producing B.subtilis was further performed to eliminate the bottleneck.By down-regulating the expression level of pyruvate kinase throughout the growth phase or only in the stationary phase using inhibitory Nterminal coding sequences(NCSs)and growth-dependent regulatory NCSs respectively,the maximal NeuAc titer increased 2.0-fold.Our study provides a rapid method for bottleneck diagnosis,which may help to accelerate the cycle of design,build,test and learn cycle for metabolic engineering.

Ab-Induced Insulin Resistance and the Effects of Insulin on the Cholesterol Synthesis Pathway and Ab Secretion in Neural Cells

Alzheimer＇s disease（AD） is characterized by amyloid-b（Ab） toxicity,tau pathology,insulin resistance,neuroinflammation,and dysregulation of cholesterol homeostasis,all of which play roles in neurodegeneration.Insulin has polytrophic effects on neurons and may be at the center of these pathophysiological changes.In this study,we investigated possible relationships among insulin signaling and cholesterol biosynthesis,along with the effects of Ab42 on these pathways in vitro.We found that neuroblastoma 2a（N2a） cells transfected with the human gene encoding amyloid-b protein precursor（Ab PP）（N2aAb PP） produced Ab and exhibited insulin resistance by reduced p-Akt and a suppressed cholesterol-synthesis pathway following insulin treatment,and by increased phosphorylation of insulin receptor subunit-1 at serine 612（p-IRS-S612） as compared to parental N2 a cells.Treatment of human neuroblastoma SH-SY5 Y cells with Ab42 also increased p-IRS-S612,suggesting that Ab42 is responsible for insulin resistance.The insulin resistance was alleviated when N2a-Ab PP cells were treated with higher insulin concentrations.Insulin increased Ab release from N2 aAb PP cells,by which it may promote Ab clearance.Insulin increased cholesterol-synthesis gene expression in SHSY5 Y and N2 a cells,including 24-dehydrocholesterol reductase（DHCR24） and 3-hydroxy-3-methyl-glutaryl-Co A reductase（HMGCR） through sterol-regulatory element-binding protein-2（SREBP2）.While Ab42-treated SH-SY5 Y cells exhibited increased HMGCR expression and c-Jun phosphorylation as pro-inflammatory responses,they also showed down-regulation of neuro-protective/antiinflammatory DHCR24.These results suggest that Ab42 may cause insulin resistance,activate JNK for c-Jun phosphorylation,and lead to dysregulation of cholesterol homeostasis,and that enhancing insulin signaling may relieve the insulin-resistant phenotype and the dysregulated cholesterol-synthesis pathway to promote Ab release for clearance from neural cells.

L-leucine stimulates glutamate dehydrogenase activity and glutamate synthesis by regulating mTORC1/SIRT4 pathway in pig liver

The liver is the most essential organ for the metabolism of ammonia, in where most of ammonia is removed by urea and glutamine synthesis. Regulated by leucine, glutamate dehydrogenase(GDH) catalyzes the reversible inter-conversion of glutamate to ammonia. To determine the mechanism of leucine regulating GDH, pigs weighing 20 ± 1 kg were infused for 80 min with ammonium chloride or alanine in the presence or absence of leucine. Primary pig hepatocytes were incubated with or without leucine. In the in vivo experiments with either ammonium or alanine as the nitrogen source, addition of leucine significantly inhibited ureagenesis and promoted the production of glutamate and glutamine in the perfused pig liver(P < 0.05). Similarly, leucine stimulated GDH activity and inhibited sirtuin4(SIRT4)gene expression(P < 0.01). Leucine could also activate mammalian target of rapamycin complex 1(m TORC1) signaling(P < 0.05), as evidenced by the increased phosphorylation levels of ribosomal protein S6 kinase 1(S6 K1) and ribosomal protein S6(S6). Interestingly, the leucine-induced m TORC1 pathway activation suitably correlated with increased GDH activity and decreased expression of SIRT4.Similar results were observed in primary cultured hepatocytes. Notably, leucine exerted no significant change in GDH activity in SIRT4-deficient hepatocytes(P > 0.05), while m TORC1 signaling was activated.Leucine exerted no significant changes in both GDH activity and SIRT4 gene expression in rapamycin treated hepatocytes(P > 0.05). In conclusion, L-leucine increases GDH activity and stimulates glutamate synthesis from different nitrogen sources by regulating m TORC1/SIRT4 pathway in the liver of pigs.

An Uncanonical CCCH-Tandem Zinc-Finger Protein Represses Secondary Wall Synthesis and Controls Mechanical Strength in Rice

Secondary walls, which represent the bulk of biomass, have a large impact on plant growth and adaptation to environments. Secondary wall synthesis is switched and regulated by a sophisticated signaling transduction network. However, there is limited understanding of these regulatory pathways. Here, we report that ILAl-interacting protein 4 （lIP4） can repress secondary wall synthesis, lIP4 is a phosphorylation sub- strate of an Raf-like MAPKKK, but its function is unknown. By generating lip4 mutants and relevant transgenic plants, we found that lesions in lIP4 enhance secondary wall formation. Gene expression and transactivation activity assays revealed that lIP4 negatively regulates the expression of MYB61 and CESAs but does not bind their promoters, lIP4 interacts with NAC29/NAC31, the upstream regulators of secondary wall synthesis, and suppresses the downstream regulatory pathways in plants. Mutagenesis analyses showed that phosphomimic UP4 proteins translocate from the nucleus to the cytoplasm, which releases interacting NACs and attenuates its repression function. Moreover, we revealed that liPs are evolutionarily conserved and share unreported CCCH motifs, referred to as uncanonical CCCH-tandem zinc-finger proteins. Collectively, our study provides mechanistic insights into the control of secondary wall synthesis and presents an opportunity for improving relevant agronomic traits in crops.

Diabetes,insulin and cancer risk

There is a consensus that both type 1 and type 2 diabetes are associated with a spectrum of cancers but the underlying mechanisms are largely unknown.On the other hand,there are ongoing debates about the risk association of insulin use with cancer.We have briefly reviewed recent related research on exploration of risk factors for cancer and pharmacoepidemiological investigations into drug use in diabetes on the risk of cancer,as well as the current understanding of metabolic pathways implicated in intermediary metabolism and cellular growth.Based on the novel findings from the Hong Kong Diabetes Registry and consistent experimental evidence,we argue that use of insulin to control hyperglycemia is unlikely to contribute to increased cancer risk and that dysregulations in the AMPactivated protein kinase pathway due to reduced insulin action and insulin resistance,the insulin-like growth factor-1(IGF-1)-cholesterol synthesis pathway and renin-angiotensin system,presumably due to reduced insulin secretion and hyperglycemia,may play causal roles in the increased risk of cancer in diabetes.Further exploration into the possible causal relationships between abnormalities of these pathways and the risk of cancer in diabetes is warranted.

Cell-free protein synthesis enabled rapid prototyping for metabolic engineering and synthetic biology

Advances in metabolic engineering and synthetic biology have facilitated the manufacturing of many valuable-added compounds and commodity chemicals using microbial cell factories in the past decade.However,due to complexity of cellular metabolism,the optimization of metabolic pathways for maximal production represents a grand challenge and an unavoidable barrier for metabolic engineering.Recently,cell-free protein synthesis system(CFPS)has been emerging as an enabling alternative to address challenges in biomanufacturing.This review summarizes the recent progresses of CFPS in rapid prototyping of biosynthetic pathways and genetic circuits(biosensors)to speed up design-build-test(DBT)cycles of metabolic engineering and synthetic biology.

Construction of acetyl-CoA and DBAT hybrid metabolic pathway for acetylation of 10-deacetylbaccatin Ⅲ to baccatin Ⅲ

10-DeacetylbaccatinⅢ(10-DAB)C10 acetylation is an indispensable procedure for Taxol semi-synthesis,which often requires harsh conditions.10-DeacetylbaccatinⅢ-10-β-O-acetyltransferase(DBAT)catalyzes the acetylation but acetyl-CoA supply remains a key limiting factor.Here we refactored the innate biosynthetic pathway of acetyl-CoA in Escherichia coli and obtained a chassis with acetyl-CoA productivity over three times higher than that of the host cell.Then,we constructed a microbial cell factory by introducing DBAT gene into this chassis for efficiently converting 10-DAB into baccatinⅢ.We found that baccatinⅢcould be efficiently deacetylated into 10-DAB by DBAT with CoASH and K+under alkaline condition.Thus,we fed acetic acid to the engineered strain both for serving as a substrate of acetyl-CoA biosynthesis and for alleviating the deacetylation of baccatinⅢ.The fermentation conditions were optimized and the baccatinⅢtiters reached 2,3 and 4.6 g/L,respectively,in a 3-L bioreactor culture when 2,3 and 6 g/L of 10-DAB were supplied.Our study provides an environmentfriendly approach for the large scale 10-DAB acetylation without addition of acetyl-CoA in the industrial Taxol semi-synthesis.The finding of DBAT deacetylase activity may broaden its application in the structural modification of pharmaceutically important lead compounds.

Protein Supplementation for the Prevention and Management of Sarcopenia in the Elderly

Sarcopenia is common in patients with many physiological or pathological conditions, especially in aging people. Nutrition plays an important role in the prevention and treatment of sarcopenia. Sarcopenia is often related to insufficient protein intake in the elderly. Muscle protein synthesis occurs mainly through mTORC1 pathway, and degradation occurs by ubiquitination-mediated pathways. This review summarizes the growing body of evidence, including substantial clinical trials, which increasing the protein intake can serve as the basis for preventing and managing muscle loss in patients with sarcopenia. Supplementation of essential amino acids (EAA), branched chain amino acids (BCAA), and especially leucine-rich whey protein may promote muscle protein synthesis by activating the mTORC1 signaling pathway, and may inhibit protein degradation by decreasing ubiquitin-mediated degradation. Taking in sufficient energy and protein and engaging in active exercise are the main methods of stimulating muscle protein synthesis and preventing or managing sarcopenia. Therefore, it is necessary to strengthen research on the use of protein supplements for not only elderly patients, but also those with tumor cachexia and other diseases related to sarcopenia.