Rhenium-188 is prospectively effective for both diagnosis and radiotherapy as it appropriately emits gamma rays and beta particles.Lacosamide(LCM)is a newly approved antiepileptic medication for focal drug-resistant e...Rhenium-188 is prospectively effective for both diagnosis and radiotherapy as it appropriately emits gamma rays and beta particles.Lacosamide(LCM)is a newly approved antiepileptic medication for focal drug-resistant epilepsy.Rhenium-188 was separated with high elution yield and high purity using the new 188W/188Re generator based on the ZrSiW gel matrix.188Re-LCM was prepared with high radiochemical yield and high purity.Biodistribution of 188Re-LCM in normal Swiss albino mice was investigated to determine its utility as a potential brain therapy agent.The 188W/188Re generator was used to obtain 188Re based on the ZrSi188W gel matrix,and the chemical,radiochemical,and radionuclidic purity of the obtained 188Re was determined using inductively coupled plasma optical emission spectrometry(ICP-AES),a paper chromatography technique,and high-purity germanium(HPGe)detection,respectively,to assess its validity for LCM labeling.Various factors,such as the pH,reaction time,and LCM quantity,were therefore studied in order to improve the yield and purity of 188Re-LCM,as determined by various chromatographic techniques such as electrophoresis,thin layer chromatography(TLC),and highpressure liquid chromatography(HPLC).188Re was obtained with a high elution yield(75±3%)and a low 188W breakthrough(0.001±0.0001%).The maximum radiochemical yield of 188Re-LCM(87.5±1.8%)was obtained using 50 ll LCM(4 mM),250 ll stannous chloride(4.4 mM)at pH 4,100 ll 188Re(37 MBq),within 30 min,at room temperature(25±3C),as determined by TLC,electrophoresis,and HPLC techniques.Biodistribution analysis showed that 188Re-LCM was primarily localized in the brain(5.1%)with a long residence time(240 min).展开更多
As a robust platform for genome editing,CRISPR/Cas9 is currently being explored for engineering biology or therapeutics,yet means for quantitative detection of Cas9 proteins remain to be fully realized.Here,we express...As a robust platform for genome editing,CRISPR/Cas9 is currently being explored for engineering biology or therapeutics,yet means for quantitative detection of Cas9 proteins remain to be fully realized.Here,we expressed Cas9 proteins and developed a novel detection method that traced Cas9 based on radiolabeled iodine.Through optimizing the reaction conditions of reaction time,temperature and cycles,we obtained ^(125)I-Cas9 of high labeling yield.The prepared ^(125)I-Cas9 was stable in various media and preserved excellent genome editing efficiency.Thus,our strategy provides a convenient and efficient tool for further tracing biological behaviors of Cas9 proteins in living systems.展开更多
α,ε-N,N'-bis(L-cysteinyl)-L-lysine was synthesized and char- acterized for the first time.It was then employed as a bifunctional chelating agent to chelate technetium-99m and subsequently conjugated to fragment ...α,ε-N,N'-bis(L-cysteinyl)-L-lysine was synthesized and char- acterized for the first time.It was then employed as a bifunctional chelating agent to chelate technetium-99m and subsequently conjugated to fragment F(ab')_2 of anti-gastric tumor monoclonal antibody 3G9.The radiolabelled antibody was satisfactorily stable and immunoreactive.展开更多
Molecular imaging techniques are increasingly being used in the localization of disease, the staging of disease and for therapy control. The objective of current study focused on the optimization of synthesis, quality...Molecular imaging techniques are increasingly being used in the localization of disease, the staging of disease and for therapy control. The objective of current study focused on the optimization of synthesis, quality control, in vitro and in vivo evaluation of 123I radiopharmaceuticals based on the chemotactic peptide N-formyl-Met-Leu-Phe. Labeling studies were done both by direct method using chloramine-Y according to Khawli （1989） and indirect method using [125I and 131I] S1B according to Zalutsky （1987）. Then, biodistribution studies were performed both in normal mice and the one bearing 50 laL turpentine for 24h, promoted inflammation in right leg. Furthermore, the ability of the labeled peptide conjugate to bind to human polymorph nuclear leukocytes was determined using in vitro assay. With increasing in pl-l, yield of labeled FMLF （N-formyl-Met-Leu-Phe） decreased perhaps because of interaction OH to carboxyl group of SIB. The maximum activity was observed in the right leg which injected with turpentine due to infection and increase in blood circulation. Also, this peptide was conjugated to PMN （Poly morph nuclear） specifically and maximum activity was 66%. The highest absorption of FLMF was seen in kidney, liver, stomach and gut. The small size of this protein causes passing through the glomerular of kidney, so high activity was observed in urine and bladder.展开更多
Small peptide-based compounds have attracted an enormous interest as carrier molecules to selectively de- liver radionuclides to target tissues, sparing critical normal organs. When looking for "matched pairs&quo...Small peptide-based compounds have attracted an enormous interest as carrier molecules to selectively de- liver radionuclides to target tissues, sparing critical normal organs. When looking for "matched pairs" of radionuclides, suitable for radiolabeling of peptides for diagnosis and therapy, technetium and rhenium represent an almost ideal constellation. The important role of technetium-99m and Re-186/188 is based on the decay characteristics, suitable for tumor diagnosis and therapy. Tc-99m and Re-188 are readily available by either a 99Mo/99mTc or the 188W/188Re ra- dionuclide generator system. Furthermore, technetium and rhenium are chemically related and share structural as well as reactive similarities, which prompt an attractive "matched-pair" situation. This article shows an overview of 99mTc- and 186/188Re-radiolabeled peptides that have been tested for their potential use as imaging and therapeutic agents in oncological diseases.展开更多
^(99m)Tc-BnAO, as a nonnitroaromatic hypoxia marker, is the subject of intensive research in recent years. In this study, a butene amine oxime–nitrotriazole(Bn AO–NT)was synthesized and radiolabeled with ^(99m)Tc in...^(99m)Tc-BnAO, as a nonnitroaromatic hypoxia marker, is the subject of intensive research in recent years. In this study, a butene amine oxime–nitrotriazole(Bn AO–NT)was synthesized and radiolabeled with ^(99m)Tc in high yield.Cellular uptakes of^(99m)Tc-Bn AO–NT and ^(99m)Tc-Bn AO were tested using murine sarcoma S180 and hepatoma H22 cell lines. The highest hypoxic cellular uptake of^(99m)TcBn AO–NT was 27.11 ± 0.73 and 14.85 ± 0.83 % for the S180 and H22 cell lines, respectively, whereas the normoxic cellular uptake of the complex was about 4–8 % for both cell lines. For^(99m)Tc-Bn AO, the highest hypoxic cellular uptake was 30.79 ± 0.44 and 9.66 ± 1.20 % for the S180 and H22 cell lines, respectively, while the normoxic cellular uptake was about 5 % for both cell lines. Both^(99m)Tc-Bn AO–NT and^(99m)Tc-Bn AO complexes showed hypoxic/normoxic differentials in the two cell lines, but the results were more significant for the S180 cell line. The in vitro results suggested that S180 may be better than H22 cell line in hypoxic biological evaluation of Bn AO complexes. The biodistribution study was tested using a S180 tumor model. The complex^(99m)Tc-Bn AO–NT showed a selective enrichment in tumor tissues: At 4 h, the tumor-to-muscle ratio was 3.79 ± 0.98 and the tumor-to-blood ratio was 2.31 ± 0.34.Compared with the results of ^(99m)Tc-Bn AO, the latter was at the same level. In vitro and in vivo studies demonstrated that ^(99m)Tc-Bn AO–NT could be a hypoxia-sensitive radiotracer for monitoring hypoxic regions in a sarcoma S180 tumor.展开更多
Phage display technique is a powerful approach for discovering new tumor-and organ-targeting ligands,and radiolabeled phage has a potential to analyze the phage-binding sensitivity and specific imaging.In this study,p...Phage display technique is a powerful approach for discovering new tumor-and organ-targeting ligands,and radiolabeled phage has a potential to analyze the phage-binding sensitivity and specific imaging.In this study,phage Ⅱ (the spleen-targeting phage) in mice was isolated after three rounds biopanning,and labeled by 99mTc using mercaptoacetyltriglycine (MAG3) as chelator to evaluate their binding properties in vivo.The amount of phage Ⅱ eluted from spleen was enriched by plague assay each round.99mTc-MAG3-phage Ⅱ showed the less retention in blood at any time point than half that of 99mTc-MAG3-phage Ⅰ (the radiolabeled original Ph.D-12 phage as control).The accumulation in spleen between 99mTc-MAG3-phage Ⅰ and Ⅱ was of different tendency.The highest uptake of 99mTc-MAG3-phage Ⅱ in spleen was 24.80 %ID/g at 30 min;and of 99mTc-MAG3-phage I,30.93% ID/g at 5 min.After circulating 99mTc-MAG3-phage Ⅱ for 120 min,its accumulation in spleen decreased though higher than that of 99mTc-MAG3-phage Ⅰ.In other organs,the 99mTc-MAG3-phage Ⅱ showed low retention and high spleen-to-organ or tissue ratios.In conclusion,the radiolabeled phage Ⅱ is convenient for studying the binding and specificity of spleen-targeting peptides found via phage display in vivo.展开更多
To study the radioiodinating condition of interleukin-8(IL-8) and observe its biodistribution in mice for understanding the possibility of its application in nuclear medicine, we labelled IL-8 with 125I using Bolton-H...To study the radioiodinating condition of interleukin-8(IL-8) and observe its biodistribution in mice for understanding the possibility of its application in nuclear medicine, we labelled IL-8 with 125I using Bolton-Hunter reagent, and the distributions in mice at 5 min, 30 min, 1h, 6h and 24h after injection of 125I –IL-8 were measured. The blood clearance curve was obtained and fitted with the two-compartment model. The results showed that 125I-IL-8 was obtained with a labeling efficiency of 12.2% ±6.5% and a radiochemical purity of 91.4%±6.5%. Its spe- cific activity was 14.8 kBq/μg IL-8. A fast phase half – life T1/2 of 0.32 h and a slow phase half – life T1/2 of 8.01 h α β were calculated from the blood clearance curve. The uptakes of radioactivities in kidneys and lung had the peaks of 85.87%ID /g and 16.17%ID /g at 30 min after intravenous injection, respectively. The uptakes in liver and spleen were 12.05%ID /g and 8.97%ID /g as the maximum at 5 min after injection. The clearance in blood and other organs was fast. Except for kidneys and lung, 125I –IL-8 was less than 1%ID/ g 24 h after administration. It is concluded that radioiodinated IL-8 is a promising radiopharmaceutical in nuclear medicine, especially for imaging infection. But to enhance the labeling efficiency of radioiodinated IL-8 and to decrease its in vivo deiodination are the subjects neces- sary to be further investigated.展开更多
188Re labeled monoclonal antibodies are potential candidates for use in radioimmunotherapy. S-Bz-MAG3 as a bifunctional chelating agent was used for labeling of IgG with carrier free 188Re by pre-radiolabeling of the ...188Re labeled monoclonal antibodies are potential candidates for use in radioimmunotherapy. S-Bz-MAG3 as a bifunctional chelating agent was used for labeling of IgG with carrier free 188Re by pre-radiolabeling of the chelating approach. The conjugation conditions were optimized. The stability of 188Re-MAG3-IgG in vitro was high. The results may be useful to the studies of 188Re labeled MAbs for radioimmunotherapy.展开更多
Increased nighttime respiratory losses decrease the amount of photoassimilates available for plant growth and yield. We hypothesized that the increased respiratory carbon loss under high night temperatures(HNT) could ...Increased nighttime respiratory losses decrease the amount of photoassimilates available for plant growth and yield. We hypothesized that the increased respiratory carbon loss under high night temperatures(HNT) could be compensated for by increased photosynthesis during the day following HNT exposure. Two rice genotypes, Vandana(HNT-sensitive) and Nagina 22(HNT-tolerant), were exposed to HNT(4 ℃ above the control) from flowering to physiological maturity. They were assessed for alterations in the carbon balance of the source(flag leaf) and its subsequent impact on grain filling dynamics and the quality of spatially differentiated sinks(superior and inferior spikelets). Both genotypes exhibited significantly higher night respiration rates. However, only Nagina 22 compensated for the high respiration rates with an increased photosynthetic rate, resulting in a steady production of total dry matter under HNT. Nagina 22 also recorded a higher grain-filling rate, particularly at 5 and 10 d after flowering, with 1.5- and 4.0-fold increases in the translocation of ^(14)C sugars to the superior and inferior spikelets, respectively. The ratio of photosynthetic rate to respiratory rate on a leaf area basis was negatively correlated with spikelet sterility, resulting in a higher filled spikelet number and grain weight per plant, particularly for inferior grains in Nagina 22. Grain quality parameters such as head rice recovery, high-density grains, and gelatinization temperature were maintained in Nagina 22. An increase in the rheological properties of rice flour starch in Nagina 22 under HNT indicated the stability of starch and its ability to reorganize during the cooling process of product formation. Thus, our study showed that sink adjustments between superior and inferior spikelets favored the growth of inferior spikelets, which helped to offset the reduction in grain weight under HNT in the tolerant genotype Nagina 22.展开更多
The prevalence of positron emission tomography(PET)imaging has advanced biomedical applications for its ultrahigh sensitivity,deep tissue penetration and quantitative visualization of diseases in vivo.^(64)Cu with ide...The prevalence of positron emission tomography(PET)imaging has advanced biomedical applications for its ultrahigh sensitivity,deep tissue penetration and quantitative visualization of diseases in vivo.^(64)Cu with ideal half-life and decay characteristics has been designed as radioactive probes for disease diagnosis.The currently reported ^(64)Cu-labeled nanomaterials have the advantages of long circulation time in serum,good biocompatibility and mature preparation methods,and have been used in vivo PET imaging,biodistribution and pharmacokinetic monitoring,and imaging guided therapy.At the same time,suitable carrier characteristics and radiolabeling strategies are particularly important in the ^(64)Cu PET imaging process.In this review,we summarize different imaging probe designs and ^(64)Cu radiolabeling strategies,as well as their eventual applications in biomedicine.The potential challenges and prospects of ^(64)Cu labeled nanomaterials are also described,which provides broad prospects for radiolabeling strategies and further applications.展开更多
文摘Rhenium-188 is prospectively effective for both diagnosis and radiotherapy as it appropriately emits gamma rays and beta particles.Lacosamide(LCM)is a newly approved antiepileptic medication for focal drug-resistant epilepsy.Rhenium-188 was separated with high elution yield and high purity using the new 188W/188Re generator based on the ZrSiW gel matrix.188Re-LCM was prepared with high radiochemical yield and high purity.Biodistribution of 188Re-LCM in normal Swiss albino mice was investigated to determine its utility as a potential brain therapy agent.The 188W/188Re generator was used to obtain 188Re based on the ZrSi188W gel matrix,and the chemical,radiochemical,and radionuclidic purity of the obtained 188Re was determined using inductively coupled plasma optical emission spectrometry(ICP-AES),a paper chromatography technique,and high-purity germanium(HPGe)detection,respectively,to assess its validity for LCM labeling.Various factors,such as the pH,reaction time,and LCM quantity,were therefore studied in order to improve the yield and purity of 188Re-LCM,as determined by various chromatographic techniques such as electrophoresis,thin layer chromatography(TLC),and highpressure liquid chromatography(HPLC).188Re was obtained with a high elution yield(75±3%)and a low 188W breakthrough(0.001±0.0001%).The maximum radiochemical yield of 188Re-LCM(87.5±1.8%)was obtained using 50 ll LCM(4 mM),250 ll stannous chloride(4.4 mM)at pH 4,100 ll 188Re(37 MBq),within 30 min,at room temperature(25±3C),as determined by TLC,electrophoresis,and HPLC techniques.Biodistribution analysis showed that 188Re-LCM was primarily localized in the brain(5.1%)with a long residence time(240 min).
基金supported by the National Key Research and Development Program(No.2016YFA0400902)the Ministry of Science and Technology of China(Nos.2012CB825805,2012CB932600)+3 种基金the National Natural Science Foundation of China(Nos.11675251 and 11275251)Shanghai Rising-Star Program(No.14QA1404400)Distinguished Scientist Fellowship Program of King Saud Universitythe Youth Innovation Promotion Association of CAS(No.2016236)
文摘As a robust platform for genome editing,CRISPR/Cas9 is currently being explored for engineering biology or therapeutics,yet means for quantitative detection of Cas9 proteins remain to be fully realized.Here,we expressed Cas9 proteins and developed a novel detection method that traced Cas9 based on radiolabeled iodine.Through optimizing the reaction conditions of reaction time,temperature and cycles,we obtained ^(125)I-Cas9 of high labeling yield.The prepared ^(125)I-Cas9 was stable in various media and preserved excellent genome editing efficiency.Thus,our strategy provides a convenient and efficient tool for further tracing biological behaviors of Cas9 proteins in living systems.
文摘α,ε-N,N'-bis(L-cysteinyl)-L-lysine was synthesized and char- acterized for the first time.It was then employed as a bifunctional chelating agent to chelate technetium-99m and subsequently conjugated to fragment F(ab')_2 of anti-gastric tumor monoclonal antibody 3G9.The radiolabelled antibody was satisfactorily stable and immunoreactive.
文摘Molecular imaging techniques are increasingly being used in the localization of disease, the staging of disease and for therapy control. The objective of current study focused on the optimization of synthesis, quality control, in vitro and in vivo evaluation of 123I radiopharmaceuticals based on the chemotactic peptide N-formyl-Met-Leu-Phe. Labeling studies were done both by direct method using chloramine-Y according to Khawli （1989） and indirect method using [125I and 131I] S1B according to Zalutsky （1987）. Then, biodistribution studies were performed both in normal mice and the one bearing 50 laL turpentine for 24h, promoted inflammation in right leg. Furthermore, the ability of the labeled peptide conjugate to bind to human polymorph nuclear leukocytes was determined using in vitro assay. With increasing in pl-l, yield of labeled FMLF （N-formyl-Met-Leu-Phe） decreased perhaps because of interaction OH to carboxyl group of SIB. The maximum activity was observed in the right leg which injected with turpentine due to infection and increase in blood circulation. Also, this peptide was conjugated to PMN （Poly morph nuclear） specifically and maximum activity was 66%. The highest absorption of FLMF was seen in kidney, liver, stomach and gut. The small size of this protein causes passing through the glomerular of kidney, so high activity was observed in urine and bladder.
文摘Small peptide-based compounds have attracted an enormous interest as carrier molecules to selectively de- liver radionuclides to target tissues, sparing critical normal organs. When looking for "matched pairs" of radionuclides, suitable for radiolabeling of peptides for diagnosis and therapy, technetium and rhenium represent an almost ideal constellation. The important role of technetium-99m and Re-186/188 is based on the decay characteristics, suitable for tumor diagnosis and therapy. Tc-99m and Re-188 are readily available by either a 99Mo/99mTc or the 188W/188Re ra- dionuclide generator system. Furthermore, technetium and rhenium are chemically related and share structural as well as reactive similarities, which prompt an attractive "matched-pair" situation. This article shows an overview of 99mTc- and 186/188Re-radiolabeled peptides that have been tested for their potential use as imaging and therapeutic agents in oncological diseases.
基金supported by the National Natural Science Foundation of China (Grant Nos. 21371017 and 81371592)
文摘^(99m)Tc-BnAO, as a nonnitroaromatic hypoxia marker, is the subject of intensive research in recent years. In this study, a butene amine oxime–nitrotriazole(Bn AO–NT)was synthesized and radiolabeled with ^(99m)Tc in high yield.Cellular uptakes of^(99m)Tc-Bn AO–NT and ^(99m)Tc-Bn AO were tested using murine sarcoma S180 and hepatoma H22 cell lines. The highest hypoxic cellular uptake of^(99m)TcBn AO–NT was 27.11 ± 0.73 and 14.85 ± 0.83 % for the S180 and H22 cell lines, respectively, whereas the normoxic cellular uptake of the complex was about 4–8 % for both cell lines. For^(99m)Tc-Bn AO, the highest hypoxic cellular uptake was 30.79 ± 0.44 and 9.66 ± 1.20 % for the S180 and H22 cell lines, respectively, while the normoxic cellular uptake was about 5 % for both cell lines. Both^(99m)Tc-Bn AO–NT and^(99m)Tc-Bn AO complexes showed hypoxic/normoxic differentials in the two cell lines, but the results were more significant for the S180 cell line. The in vitro results suggested that S180 may be better than H22 cell line in hypoxic biological evaluation of Bn AO complexes. The biodistribution study was tested using a S180 tumor model. The complex^(99m)Tc-Bn AO–NT showed a selective enrichment in tumor tissues: At 4 h, the tumor-to-muscle ratio was 3.79 ± 0.98 and the tumor-to-blood ratio was 2.31 ± 0.34.Compared with the results of ^(99m)Tc-Bn AO, the latter was at the same level. In vitro and in vivo studies demonstrated that ^(99m)Tc-Bn AO–NT could be a hypoxia-sensitive radiotracer for monitoring hypoxic regions in a sarcoma S180 tumor.
基金Supported by National Natural Science Foundation of China (No. 20771011 and 21071010)the Ministry of Science and Technology of China (No.2006CB705700)
文摘Phage display technique is a powerful approach for discovering new tumor-and organ-targeting ligands,and radiolabeled phage has a potential to analyze the phage-binding sensitivity and specific imaging.In this study,phage Ⅱ (the spleen-targeting phage) in mice was isolated after three rounds biopanning,and labeled by 99mTc using mercaptoacetyltriglycine (MAG3) as chelator to evaluate their binding properties in vivo.The amount of phage Ⅱ eluted from spleen was enriched by plague assay each round.99mTc-MAG3-phage Ⅱ showed the less retention in blood at any time point than half that of 99mTc-MAG3-phage Ⅰ (the radiolabeled original Ph.D-12 phage as control).The accumulation in spleen between 99mTc-MAG3-phage Ⅰ and Ⅱ was of different tendency.The highest uptake of 99mTc-MAG3-phage Ⅱ in spleen was 24.80 %ID/g at 30 min;and of 99mTc-MAG3-phage I,30.93% ID/g at 5 min.After circulating 99mTc-MAG3-phage Ⅱ for 120 min,its accumulation in spleen decreased though higher than that of 99mTc-MAG3-phage Ⅰ.In other organs,the 99mTc-MAG3-phage Ⅱ showed low retention and high spleen-to-organ or tissue ratios.In conclusion,the radiolabeled phage Ⅱ is convenient for studying the binding and specificity of spleen-targeting peptides found via phage display in vivo.
文摘To study the radioiodinating condition of interleukin-8(IL-8) and observe its biodistribution in mice for understanding the possibility of its application in nuclear medicine, we labelled IL-8 with 125I using Bolton-Hunter reagent, and the distributions in mice at 5 min, 30 min, 1h, 6h and 24h after injection of 125I –IL-8 were measured. The blood clearance curve was obtained and fitted with the two-compartment model. The results showed that 125I-IL-8 was obtained with a labeling efficiency of 12.2% ±6.5% and a radiochemical purity of 91.4%±6.5%. Its spe- cific activity was 14.8 kBq/μg IL-8. A fast phase half – life T1/2 of 0.32 h and a slow phase half – life T1/2 of 8.01 h α β were calculated from the blood clearance curve. The uptakes of radioactivities in kidneys and lung had the peaks of 85.87%ID /g and 16.17%ID /g at 30 min after intravenous injection, respectively. The uptakes in liver and spleen were 12.05%ID /g and 8.97%ID /g as the maximum at 5 min after injection. The clearance in blood and other organs was fast. Except for kidneys and lung, 125I –IL-8 was less than 1%ID/ g 24 h after administration. It is concluded that radioiodinated IL-8 is a promising radiopharmaceutical in nuclear medicine, especially for imaging infection. But to enhance the labeling efficiency of radioiodinated IL-8 and to decrease its in vivo deiodination are the subjects neces- sary to be further investigated.
基金Supported partially by Key Project of Knowledge Innovation Program of the Chinese Academy of Sciences(KJCX1-SW-08)
文摘188Re labeled monoclonal antibodies are potential candidates for use in radioimmunotherapy. S-Bz-MAG3 as a bifunctional chelating agent was used for labeling of IgG with carrier free 188Re by pre-radiolabeling of the chelating approach. The conjugation conditions were optimized. The stability of 188Re-MAG3-IgG in vitro was high. The results may be useful to the studies of 188Re labeled MAbs for radioimmunotherapy.
基金the financial assistance provided by ICAR-IARI in the form of IARI Fellowship and Department of Science and Technology, Innovation in Science Pursuit for Inspired Research during the PhD programme。
文摘Increased nighttime respiratory losses decrease the amount of photoassimilates available for plant growth and yield. We hypothesized that the increased respiratory carbon loss under high night temperatures(HNT) could be compensated for by increased photosynthesis during the day following HNT exposure. Two rice genotypes, Vandana(HNT-sensitive) and Nagina 22(HNT-tolerant), were exposed to HNT(4 ℃ above the control) from flowering to physiological maturity. They were assessed for alterations in the carbon balance of the source(flag leaf) and its subsequent impact on grain filling dynamics and the quality of spatially differentiated sinks(superior and inferior spikelets). Both genotypes exhibited significantly higher night respiration rates. However, only Nagina 22 compensated for the high respiration rates with an increased photosynthetic rate, resulting in a steady production of total dry matter under HNT. Nagina 22 also recorded a higher grain-filling rate, particularly at 5 and 10 d after flowering, with 1.5- and 4.0-fold increases in the translocation of ^(14)C sugars to the superior and inferior spikelets, respectively. The ratio of photosynthetic rate to respiratory rate on a leaf area basis was negatively correlated with spikelet sterility, resulting in a higher filled spikelet number and grain weight per plant, particularly for inferior grains in Nagina 22. Grain quality parameters such as head rice recovery, high-density grains, and gelatinization temperature were maintained in Nagina 22. An increase in the rheological properties of rice flour starch in Nagina 22 under HNT indicated the stability of starch and its ability to reorganize during the cooling process of product formation. Thus, our study showed that sink adjustments between superior and inferior spikelets favored the growth of inferior spikelets, which helped to offset the reduction in grain weight under HNT in the tolerant genotype Nagina 22.
基金supported by the National Natural Science Foundation of China(Nos.U2067214,21727817)Beijing municipal education commission-Beijing natural science foundation joint funding project(No.KZ202010005006)。
文摘The prevalence of positron emission tomography(PET)imaging has advanced biomedical applications for its ultrahigh sensitivity,deep tissue penetration and quantitative visualization of diseases in vivo.^(64)Cu with ideal half-life and decay characteristics has been designed as radioactive probes for disease diagnosis.The currently reported ^(64)Cu-labeled nanomaterials have the advantages of long circulation time in serum,good biocompatibility and mature preparation methods,and have been used in vivo PET imaging,biodistribution and pharmacokinetic monitoring,and imaging guided therapy.At the same time,suitable carrier characteristics and radiolabeling strategies are particularly important in the ^(64)Cu PET imaging process.In this review,we summarize different imaging probe designs and ^(64)Cu radiolabeling strategies,as well as their eventual applications in biomedicine.The potential challenges and prospects of ^(64)Cu labeled nanomaterials are also described,which provides broad prospects for radiolabeling strategies and further applications.
