Lacidipine,thiamine pyrophosphate and their combination on the ocular ischemic syndrome induced by bilateral common carotid artery ligation

AIM:To investigate the effect of lacidipine,thiamine pyrophosphate(TPP)and the combination of lacidipine and TPP against oxidative and inflammatory eye damage induced by bilateral common carotid artery ligation in rats.METHODS:Male albino Wistar rats were categorized as those who underwent sham surgery(SG),right and left common carotid cross-clamping and unclamping procedure(CCU),lacidipine+CCU(LCCU),TPP+CCU(TCCU),and combination of lacidipine and TPP(LTC)+CCU(LTCCU).One hour before anesthesia,the LCCU(n=6)received lacidipine(4 mg/kg,orally)and the TCCU(n=6)received TPP(20 mg/kg,intraperitoneally).The SG(n=6)and CCU(n=6)received the same volume of distilled water from the same route.After anesthesia(60 mg/kg ketamine,intraperitoneally),the necks of the rats were opened in the midline.Ischemia was created for 10min by placing clips on the right and left common carotid arteries.Rats in the SG only underwent subcutaneous incision.After 10min,the clips were removed and reperfusion was achieved for six days.Then,the animals were euthanized(120 mg/kg ketamine,intraperitoneally)and the levels of oxidant,antioxidant and proinflammatory cytokines in the eye tissues were determined.The retinal tissue of the eye was also examined histopathologically.RESULTS:Lacidipine,TPP,and LTC significantly prevent the increase in malondialdehyde,tumor necrosis factoralpha,interleukin-1β(IL-1β),and IL-6 levels,decrease in total glutathione levels,superoxide dismutase and catalase activities and histopathological retinal damage in eye tissue induced by bilateral common carotid artery ligation in rats.The impact of these drugs on protection is determined to be LTC>lacidipine>TPP.CONCLUSION:As a result of the study,it is concluded that LTC may be more effective than lacidipine and TPP alone in treating ocular ischemic syndrome.

Remodeling Isoprene Pyrophosphate Metabolism for Promoting Terpenoids Bioproduction

Terpenoids are the largest family of natural products.They are made from the building block isoprene pyrophosphate(IPP),and their bioproduction using engineered cell factories has received a great deal of attention.To date,the insufficient metabolic supply of IPP remains a great challenge for the efficient synthesis of terpenoids.In this work,we discover that the imbalanced metabolic flux distribution between the central metabolism and the IPP supply hinders IPP accumulation in Bacillus subtilis(B.subtilis).Therefore,we remodel the IPP metabolism using a series of genetically encoded two-input-multioutput(TIMO)circuits that are responsive to pyruvate or/and malonyl-CoA,resulting in an IPP pool that is significantly increased by up to four-fold.As a proof-of-concept validation,we design an IPP metabolism remodeling strategy to improve the production of three valuable terpenoids,including menaquinone-7(MK-7,4.1-fold),lycopene(9-fold),andβ-carotene(0.9-fold).In particular,the titer of MK-7 in a 50-L bioreactor reached 1549.6 mg·L^(-1),representing the highest titer reported so far.Thus,we propose a TIMO genetic circuits-assisted IPP metabolism remodeling framework that can be generally used for the synergistic fine-tuning of complicated metabolic modules to achieve the efficient bioproduction of terpenoids.

Mo/Fe bimetallic pyrophosphates derived from Prussian blue analogues for rapid electrocatalytic oxygen evolution

Efficient and stable oxygen evolution electrocatalysts are indispensable for industrial applications of water splitting and hydrogen production.Herein,a simple and practical method was applied to fabricate(Mo,Fe)P2O7@NF electrocatalyst by directly growing Mo/Fe bimetallic pyrophosphate derived from Prussian blue analogues on three-dimensional porous current collector.In alkaline media,the developed material possesses good hydrophilic features and exhibits best-in-class oxygen evolution reaction(OER)performances.Surprisingly,the(Mo,Fe)P_(2)O_(7)@NF only requires overpotentials of 250 and 290 mV to deliver 100 and 600 mA cm^(-2)in 1 mol L^(-1)KOH,respectively.Furthermore,the(Mo,Fe)P_(2)O_(7)@NF shows outstanding performances in alkaline salty water and 1 mol L^(-1)high purity KOH.A worthwhile pathway is provided to combine bimetallic pyrophosphate with commercial Ni foam to form robust electrocatalysts for stable electrocatalytic OER,which has a positive impact on both hydrogen energy application and environmental restoration.

Single-cell analysis identifies phospholysine phosphohistidine inorganic pyrophosphate phosphatase as a target in ulcerative colitis

BACKGROUND Ulcerative colitis(UC)is a chronic gastrointestinal disorder characterized by inflammation and ulceration,representing a significant predisposition to colorectal cancer.Recent advances in single-cell RNA sequencing(scRNA-seq)technology offer a promising avenue for dissecting the complex cellular interactions and molecular signatures driving UC pathology.AIM To utilize scRNA-seq technology to dissect the complex cellular interactions and molecular signatures that underlie UC pathology.METHODS In this research,we integrated and analyzed the scRNA-seq data from UC patients.Moreover,we conducted mRNA and protein level assays as well as pathology-related staining tests on clinical patient samples.RESULTS In this study,we identified the sustained upregulation of inflammatory response pathways during UC progression,characterized the features of damaged endothelial cells in colitis.Furthermore,we uncovered the downregulation of phospholysine phosphohistidine inorganic pyrophosphate phosphatase(LHPP)has a negative correlation with signal transducer and activator of transcription 3.Significant downregulation of LHPP in UC patient tissues and plasma suggests that LHPP may serve as a potential therapeutic target for UC.This paper highlights the importance of LHPP as a potential key target in UC and unveils its potential role in inflammation regulation.CONCLUSION The findings suggest that LHPP may serve as a potential therapeutic target for UC,emphasizing its importance as a potential key target in UC and unveiling its role in inflammation regulation.

Preparation of nano-sized cerium and titanium pyrophosphates via solid-state reaction at room temperature

Nano-sized cerium-titanium pyrophosphates Ce1-xTixP2O7 （with x = 0, 0.2, 0.5, 0.7, 0.9, and 1.0） were obtained by grinding a mixture of Ce（SO4）2·4H2O, Ti（SO4）2, and Na4P2O7·10H2O in the presence of surfactant PEG-400 at room temperature, washing the mixture with water to remove soluble inorganic salts, and drying at 100℃. The products and their calcined samples were characterized using ultraviolet-visible spectroscopy （UV-vis）, thermogravimetry and differential thermal analyses （TG/DTA）, X-ray powder diffraction （XRD）, and transmission electron microscopy （TEM）. The results show that nano-sized Ce1-xTixP2O7 behave as an excellent UV-shielding material. Thereinto, the CeP2O7 has the most excellent UV-shielding effect, and the amorphous state of Ce0.8Ti0.2P2O7 can keep at a higher temperature than CeP2O7. Therefore, the stabilization of the amorphous state of the cerium pyrophosphates was carded out by doping titanium. This stabilization is a significant improvement, which enables to apply these amorphous pyrophosphates not only to cosmetics and paints, but also plastics and films.

Promotional Effect of Bismuth as Dopant in Bi-Doped Vanadyl Pyrophosphate Catalysts for Selective Oxidation of n-Butane to Maleic Anhydride

Bismuth-promoted （1% and 3%） vanadyl pyrophosphate catalysts were prepared by refluxing Bi（NO3）4.5H2O and VOPO4.2H2O in isobutanol. The incorporation of Bi into the catalysts lattice increased the surface area and lowered the overall V oxidation state. Profiles of temperature programmed reduction （TPR） in H2 show a significant shift of the maxima of major reduction peaks to lower temperatures for the Bi-promoted catalysts. A new peak was also observed at the low temperature region for the catalyst with 3% of Bi dopant. The addition of Bi also increased the total amount of oxygen removed from the catalysts. The reduction pattern and reactivity information provide fundamental insight into the catalytic properties of the catalysts. Bi-promoted catalysts were found to be highly active （71% and 81% conversion for 1% and 3% Bi promoted catalysts, respectively, at 703 K）, as compared to the unpromoted material （47% conversion）. The higher activity of the Bi-promoted catalysts is due to that these catalysts possess highly active and labile lattice oxygen. The better catalytic performance can also be attributed to the larger surface area.

A biomimetic antitumor nanovaccine based on biocompatible calcium pyrophosphate and tumor cell membrane antigens

Currently,the cancer immunotherapy has made great progress while antitumor vaccine attracts substantial attention.Still,the selection of adjuvants as well as antigens are always the most crucial issues for better vaccination.In this study,we proposed a biomimetic antitumor nanovaccine based on biocompatible nanocarriers and tumor cell membrane antigens.Briefly,endogenous calcium pyrophosphate nanogranules with possible immune potentiating effect are designed and engineered,both as delivery vehicles and adjuvants.Then,these nanocarriers are coated with lipids and B16-OVA tumor cell membranes,so the biomembrane proteins can serve as tumor-specific antigens.It was found that calcium pyrophosphate nanogranules themselves were compatible and possessed adjuvant effect,while membrane proteins including tumor associated antigen were transferred onto the nanocarriers.It was demonstrated that such a biomimetic nanovaccine could be well endocytosed by dendritic cells,promote their maturation and antigen-presentation,facilitate lymph retention,and trigger obvious immune response.It was confirmed that the biomimetic vaccine could induce strong T-cell response,exhibit excellent tumor therapy and prophylactic effects,and simultaneously possess nice biocompatibility.In general,the present investigation might provide insights for the further design and application of antitumor vaccines.

Phylogenetic analysis of aerobic anoxygenic phototrophic bacteria and their relatives based on farnesyl pyrophosphate synthase gene

The study aims to reveal phylogenetic and evolutionary relationship between aerobic anoxygenic phototrophic bacteria（AAnPB） and their relatives,anaerobic anoxygenic phototrophic bacteria（AnAnPB） and nonphototrophic bacteria（NPB,which had high homology of 16S rDNA gene with AAnPB and fell into the same genus）,and validate reliability and usefulness of farnesyl pyrophosphate synthase（FPPS） gene for the phylogenetic determination.FPPS genes with our modified primers and 16S rDNA genes with general primers,were amplified and sequenced or retrieved from GenBank database.In contrast to 16S rDNA gene phylogenetic tree,AAnPB were grouped into two clusters and one branch alone with no intermingling with NPB and AnAnPB in the tree constructed on FPPS.One branch of AAnPB,in both trees,was located closer to outgroup species than AnAnPB,which implicated that some AAnPB would be diverged earlier in FPPS evolutionary history than AnAnPB and NPB.Some AAnPB and NPB were closer located in both trees and this suggested that they were the closer relatives than AnAnPB.Combination codon usage in FPPS with phylogenetic analysis,the results indicates that FPPS gene and 16S rRNA gene have similar evolutionary pattern but the former seems to be more reliable and useful in determining the phylogenic and evolutionary relationship between AAnPB and their relatives.This is the first attempt to use a molecular marker beside 16S rRNA gene for studying the phylogeny of AAnPB,and the study may also be helpful in understanding the evolutionary relationship among phototrophic microbes and the trends of photosynthetic genes transfer.

Synthesis and Biodegradation of St-g-poly(MMA-co-VAc) Initiated by Manganic Pyrophosphate

Methyl methacrylate(MMA) and vinyl acetate(VAc) were grafted onto corn starch with manganic pyrophosphate{[Mn(H 2P 2O 7) 3] 3-} as the initiator and water as the reaction medium. The influences of reaction conditions, including pH value, initiator concentration, monomer concentration and its composition, on percent grafting and grafting efficiency were investigated. The graft copolymer was characterized by means of IR spectroscopy, scanning electron micrograph(SEM) and 1H NMR spectroscopy. The biodegradation experiment showed that the degradation of corn starch-g-poly(MMA-co-VAc) was mainly from starch. However, after poly VAc in the side chain was transformed into poly vinyl alcohol(PVA), both starch and the grafted side chain could be degraded completely.

Two farnesyl pyrophosphate synthases,GhFPS1–2,in Gossypium hirsutum are involved in the biosynthesis of farnesol to attract parasitoid wasps

Sesquiterpenoids play an import role in the direct or indirect defense of plants.Farnesyl pyrophosphate synthases(FPSs)catalyze the biosynthesis of farnesyl pyrophosphate,which is a key precursor of farnesol and(E)-β-farnesene.In the current study,two FPS genes in Gossypium hirsutum,GhFPS1 and GhFPS2,were heterologously cloned and functionally characterized in a greenhouse setting.The open reading frames for full-length GhFPS1 and GhFPS2 were each 1029 nucleotides,and encoded two proteins of 342 amino acids with molecular weights of 39.4 kDa.The deduced amino acid sequences of GhFPS1–2 showed high identity to FPSs of other plants.Quantitative real-time PCR analysis revealed that GhFPS1 and GhFPS2 were highly expressed in G.hirsutum leaves,and were upregulated in methyl jasmonate(MeJA)-,methyl salicylate(MeSA)-and aphid infestation-treated cotton plants.The recombinant proteins of either GhFPS1 or GhFPS2 plus calf intestinal alkaline phosphatase could convert geranyl diphosphate(GPP)or isopentenyl diphosphate(IPP)to one major product,farnesol.Moreover,in electrophysiological response and Y-tube olfactometer assays,farnesol showed obvious attractiveness to female Aphidius gifuensis,which is an important parasitic wasp of aphids.Our findings suggest that two GhFPSs are involved in farnesol biosynthesis and they play a crucial role in indirect defense of cotton against aphid infestation.

Calcium pyrophosphate dihydrate crystals in a 9-year-old with osteomyelitis of the knee:A case report

BACKGROUND Calcium pyrophosphate dihydrate deposition disease(CPPD),or pseudogout,is an inflammatory arthritis common among elderly patients,but rarely seen in patients under the age of 40.In the rare cases presented of young patients with CPPD,genetic predisposition or related metabolic conditions were almost always identified.CASE SUMMARY The authors report the case of a 9-year-old boy with no past medical history who presented with acute knee pain and swelling after a cat scratch injury 5 d prior.Synovial fluid analysis identified calcium pyrophosphate dihydrate crystals.Further MRI analysis identified osteomyelitis and a small soft tissue abscess.CONCLUSION This case presents the extremely rare diagnostic finding of calcium pyrophosphate dihydrate crystals in a previously healthy pediatric patient.The presence of osteomyelitis presents a unique insight into the pathogenesis of these crystals in pediatric patients.More research needs to be done on the role of CPPD in pediatric arthritis and joint infection.

Gene expression and histopathological evaluation of thiamine pyrophosphate on optic neuropathy induced with ethambutol in rats

AIM： To compare the effects of thiamine pyrophosphate（TPP） and thiamine（TM） in oxidative optic neuropathy in rats induced by ethambutol.METHODS： The animals were divided into four groups：a control group（CG）,an ethambutol control（ETC） group,TM plus ethambutol group（TMG）,and TPP plus ethambutol group（TPPG）.One hour after intraperitoneal administration of TM 20 mg/kg to the TMG group and TPP 20 mg/kg to TPPG group,30 mg/kg ethambutol was given via gavage to all the groups but the CG.This procedure was repeated once daily for 90 d.After that period,all rats were exposed to high levels of anaesthesia in order to investigate the gene expression of malondialdehyde and glutathione in removed optic nerve tissue and histopathologically to examine these tissues. RESULTS： Malondialdehyde gene expression significantly increased,whereas glutathione gene expression significantly decreased in the ETC group compared to the CG.TM could not prevent the increase of malondialdehyde gene expression and the decrease of glutathione,while TPP significantly could suppress.Histopathologically,significant vacuolization in the opticnerve,single-cell necrosis in the glial cells,and a decrease in oligodendrocytes were observed in the ETC group.Vacuolization in the optic nerve,a decrease in oligodendrocytes and single-cell necrosis were found in the TMG group,while no pathological finding was observed in the TPPG group except for mild vacuolization.CONCLUSION： TPP protects the optic nerve against the ethambutol-induced toxicity but TM does not.TPP can be beneficial in prophilaxis of optic neuropathy in ethambutol therapy.

Nanocrystalline Iron Pyrophosphate-Regulated Amorphous Phosphate Overlayer for Enhancing Solar Water Oxidation

A rational regulation of the solar water splitting reaction pathway by adjusting the surface composition and phase structure of catalysts is a substantial approach to ameliorate the sluggish reaction kinetics and improve the energy conversion efficiency.In this study,we demonstrate a nanocrystalline iron pyrophosphate(Fe_(4)(P_(2)O_(7))_(3),FePy)-regulated hybrid overlayer with amorphous iron phosphate(FePO_(4),FePi)on the surface of metal oxide nanostructure with boosted photoelectrochemical(PEC)water oxidation.By manipulating the facile electrochemical surface treatment followed by the phosphating process,nanocrystalline FePy is localized in the FePi amorphous overlayer to form a heterogeneous hybrid structure.The FePy-regulated hybrid overlayer(FePy@FePi)results in significantly enhanced PEC performance with long-term durability.Compared with the homogeneous FePi amorphous overlayer,FePy@FePi can improve the charge transfer efficiency more significantly,from 60% of FePi to 79%of FePy@FePi.Our density-functional theory calculations reveal that the coexistence of FePi and FePy phases on the surface of metal oxide results in much better oxygen evolution reaction kinetics,where the FePi was found to have a typical down-hill reaction for the conversion from OH*to O_(2),while FePy has a low free energy for the formation of OH*.

Distinguishing erosive osteoarthritis and calcium pyrophosphate deposition disease

Erosive osteoarthritis is a term utilized to describe a specific inflammatory condition of the interphalangeal and first carpal metacarpal joints of the hands. The term has become a part of medical philosophical semantics and paradigms, but the issue is actually more complicated. Even the term osteoarthritis(nonerosive) has been controversial, with some suggesting osteoarthrosis to be more appropriate in view of the perspective that it is a non-inflammatory process undeserving of the "itis" suffix. The term "erosion" has also been a source of confusion in osteoarthritis, as it has been used to describe cartilage, not bone lesions. Inflammation in individuals with osteoarthritis actually appears to be related to complicating phenomena, such as calcium pyrophosphate and hydroxyapatite crystal deposition producing arthritis. Erosive osteoarthritis is the contentious term. It is used to describe a specific form of joint damage to specific joints. The damage has been termed erosions and the distribution of the damage is to the interphalangeal joints of the hand and first carpal metacarpal joint. Inflammation is recognized by joint redness and warmth, while X-rays reveal alteration of the articular surfaces, producing a smudged appearance. This ill-defined, joint damage has a crumbling appearance and is quite distinct from the sharply defined erosions of rheumatoid arthritis and spondyloarthropathy. The appearance is identical to those found with calcium pyrophosphate deposition disease, both in character and their unique responsiveness to hydroxychloroquine treatment. Low doses of the latter often resolve symptoms within weeks, in contrast to higher doses and the months required for response in other forms of inflammatory arthritis. Reconsidering erosive osteoarthritis as a form of calcium pyrophosphate deposition disease guides physicians to more effective therapeutic intervention.

Calcium pyrophosphate deposition disease of the temporomandibular joint invading the middle cranial fossa:Two case reports

BACKGROUND Pseudogout is a benign joint lesion caused by the deposition of calcium pyrophosphate dihydrate crystals,but it is invasive.Pseudogout of the temporomandibular joint(TMJ)is uncommon,and it rarely invades the skull base or penetrates into the middle cranial fossa.The disease has no characteristic clinical manifestations and is easily misdiagnosed.CASE SUMMARY We present two cases of tophaceous pseudogout of the TMJ invading the middle cranial fossa.A 46-year-old woman with a history of diabetes for more than 10 years was admitted to the hospital due to swelling and pain in the right temporal region.Another patient,a 52-year-old man with a mass in the left TMJ for 6 years,was admitted to the hospital.Maxillofacial imaging showed a calcified mass and severe bone destruction of the skull base in the TMJ area.Both patients underwent excision of the lesion.The lesion was pathologically diagnosed as tophaceous pseudogout.The symptoms in these patients were relieved after surgery.CONCLUSION Tophaceous pseudogout should be considered when there is a calcified mass in the TMJ with or without bone destruction.A pathological examination is the gold standard for diagnosing this disease.Surgical treatment is currently the recommended treatment,and the prognosis is good after surgery.

I₂/Nanostructured Pyrophosphate : A Mild and Efficient Catalyst for the Selective Protection of Carbonyl Compounds

A new solvent free method for protection of carbonyl compounds as their thioacetals has been accomplished through the use of iodine supported on nanostructured pyrophosphate. Advantages of the methodology include very short reaction time, the requirement for minimum amounts of catalyst, the remarkably simple experimental procedure, and no necessity for solvents or inert atmospheres, excellent yields and recyclability of the catalyst used. An efficient method for the chemoselective thioacetalization of ketones in the presence of aldehydes using I2/nanostructured pyrophosphate is also reported in this article. The nanostructured pyrophosphate was characterized by scanning electron microscopy, X-ray diffraction, infrared spectroscopy, Transmission electron microscopy and thermal gravimetric analysis, respectively.

Oxidative dissolution of Cr(OH)_(3) and mixed Fe-Cr(Ⅲ)phases by aqueous Mn(Ⅲ)-pyrophosphate complex

The key role of manganese(Mn)in the biogeochemical cycle of trace elements has been of great interest in recent years.Nevertheless,the redox properties of aqueous Mn(Ⅲ)have been studied to a lesser extent.Mn(Ⅲ)is not stable in solution by itself.However,when complexed with inorganic ligands,it has shown potential to oxidize and reduce trace elements.In the present study,we are exploring the redox characteristics of the complex Mn(Ⅲ)-Pyrophosphate(Mn(Ⅲ)-PP).This complex is stable over a wide range of pH values but requires the ratio of Mn:PP to be less than 1:6.Specifically,the redox reaction of chromium(Cr(Ⅲ))and Mn(Ⅲ)-PP is investigated.A solid,Cr(OH)_(3),is used as a source of Cr(Ⅲ).For this reaction,environmentally relevant parameters,such as pH,ionic strength,ratio Mn(Ⅲ)/Cr(Ⅲ),and excess of ligand,were assessed.Results showed that Mn(Ⅲ)can effectively oxidize Cr(Ⅲ)to Cr(Ⅵ),taking about 15 days for the reaction to complete.This reaction occurs only under acidic conditions(pH4),and with a low excess of Pyrophosphate.The initial Mn(Ⅲ)concentration decreases as the Cr(Ⅵ)is produced,and Cr(Ⅵ)can be adsorbed back into the Cr(OH)_(3)surface,limiting the mobility of this toxic species.Despite this adsorption,significant amounts of Cr(VI)are release in the aqueous phase.This study shows the importance of a mobile species(Mn-PP complex)in the oxidation of Cr(Ⅲ)and the release of Cr(Ⅵ)to the environment.

Tunable catalytic activity of FeWO_(4) nanomaterials for sensitive assays of pyrophosphate ion and alkaline phosphatase activity

Alkaline phosphatase(ALP)activity and pyrophosphate ion(PPi)levels are remarkable for the human body functions such as signal transduction pathways and metabolism.Current quantitative methods mainly focus on developing complicated organic substrates or employing unstable metal ions as signal-regulated medium.Herein,we have developed a facile hydrothermal method for preparing Fe WO_(4)nanomaterials with intrinsic peroxidase-like activity and further confirmed that such a catalytic activity could be significantly enhanced by adjusting the size and oxygen vacancy content.More encouragingly,PPi can easily inhibit the catalytic activity of Fe WO_(4),whereas orthophosphate ions(Pi)cannot.Therefore,we constructed an Fe WO_(4)-based colorimetric assay for sensing PPi by means of the classical 3,3′,5,5′-tetramethylbenzidine-peroxidase chromogenic reaction.A facile and reliable ALP activity assay was also designed and developed because of the logical regulation of the peroxidase-like activity of Fe WO_(4)through the ALP-catalyzed hydrolysis of PPi into Pi.Based on the clear mechanism and mimetic-enzyme Fe WO_(4)-catalyzed amplification,the sensing system exhibited excellent performance and was able to evaluate ALP activity in real serum samples and screen for potential ALP inhibitors.The proposed mimetic enzyme-involved colorimetric assay provides an alternative pathway,and Fe WO_(4)nanomaterials with excellent performance have great potential for further biosensing and biomedical applications.

Inositol Pyrophosphate lnsP8 Acts as an Intracellular Phosphate Signal in Arabidopsis

The maintenance of cellular phosphate(Pi)homeostasis is of great importance in living organisms.The SPX domain-containing protein 1(SPX1)proteins from both Arabidopsis and rice have been proposed to act as sensors of Pi status.The molecular signal indicating the cellular Pi status and regulating Pi homeostasis in plants,however,remains to be identified,as Pi itself does not bind to the SPX domain.Here,we report the identification of the inositol pyrophosphate lnsP8 as a signaling molecule that regulates Pi homeostasis in Arabidopsis.Polyacrylamide gel electrophoresis profiling of InsPs revealed that lnsP8 level positively cor­relates with cellular Pi concentration.We demonstrated that the homologs of diphosphoinositol pentaki-sphosphate kinase(PPIP5K),VIH1 and VIH2,function redundantly to synthesize lnsP8,and that the vih1 vih2 double mutant overaccumulates Pi.SPX1 directly interacts with PHR1,the central regulator of Pi star­vation responses,to inhibit its function under Pi-replete conditions.However,this interaction is compro­mised in the vih1 vih2 double mutant,resulting in the constitutive induction of Pi starvation-induced genes,indicating that plant cells cannot sense cellular Pi status without lnsP8.Furthermore,we showed that lnsP8 could directly bind to the SPX domain of SPX1 and is essential for the interaction between SPX1 and PHR1.Collectively,our study suggests that lnsP8 is the intracellular Pi signaling molecule serving as the ligand of SPX1 for controlling Pi homeostasis in plants.

Effect of pyrophosphate on the light scatter in KDP crystal

Pyrophosphate doped potassium dihydrogen phosphate (KDP) crystal was grown from aqueous solution by the temperature lowering method. Light scatter in KDP crystal was detected with the ultramicroscopic method. The light scatter in KDP crystal was aggravated when pyro-phosphate was doped into the growth solution, which was distributed ununiformly in prism and pyramidal sectors of KDP crystal. Different effects of pyrophosphate on prism and pyramidal sectors of KDP crystal can explain this case. The transmission in this crystal was measured, showing that pyrophosphate affects the transmission evidently.