Rice is the world's largest food crop, and its yield and quality are directly related to food security and human health. Grain size, as one of the important factors determining the rice yield, has been widely concerned by breeders and researchers for a long time. To decipher the regulatory mechanism of rice grain size, we obtained a multi-tiller, dwarf, and small-grain mutant htd1 by ethyl methanesulfonate (EMS) mutation from the Japonica rice cultivar 'Zhonghua 11' ('ZH11'). Genetic analysis indicated that the phenotype of htd1 was controlled by a single recessive gene. Using the mutation site map (Mutmap) method, we identified the candidate gene OsHTD1, which encoded a carotenoid cleavage dioxygenase involved in the biosynthesis of strigolactone (SL). The SL content in htd1 was significantly lower than that in 'ZH11'. Cytological analysis showed that the grain size of the mutant decreased due to the reductions in the length and width of glume cells. The function of htd1 was further verified by the CRISPR/cas9 gene editing technology. The plants with the gene knockout exhibited similar grain size to the mutant. In addition, gene expression analysis showed that the expression levels of multiple grain size-related genes in the mutant changed significantly, suggesting that HTD1 may interact with other genes regulating grain size. This study provides a new theoretical basis for research on the regulatory mechanism of rice grain size and potential genetic resources for breeding the rice cultivars with high yields.
Oryza/growth & development* ; Mutation ; Edible Grain/growth & development* ; Alleles ; Plant Proteins/genetics* ; Dioxygenases/genetics* ; Lactones/metabolism* ; Gene Expression Regulation, Plant ; Genes, Plant ; Gene Editing ; CRISPR-Cas Systems ; Phenotype

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective:To evaluate the efficacy and safety of the pegaspargase, etoposide, methotrexate, and dexamethasone (PEMD) regimen in patients with early-stage nonupper respiratory digestive tract or advanced extranodal natural killer/T-cell lymphoma (ENKTL) .Methods:This retrospective analysis included 38 patients with newly diagnosed early-stage non-upper respiratory digestive tract or advanced ENKTL who received PEMD regimen for induction chemotherapy at the First Affiliated Hospital of Nanjing Medical University from January 2016 to December 2022. Survival outcomes and prognostic factors were examined by Kaplan-Meier, and the Log-rank test was used to compare survival.Results:The study population had a median age of 48 years (range, 26-72 years) and included 30 males (78.9%) and 8 females (21.1%). 7 patients’ age >60 years (18.4%). The Eastern Cooperative Oncology Group (ECOG) performance score was >1 in 7 patients (18.4%) ; 20 patients (52.6%) had elevated lactate dehydrogenase levels; and 37 patients (97.4%) exhibited extranodal involvement. Using the Ann Arbor staging system, 37 patients (97.4%) were classified as stage Ⅲ-Ⅳ. The median number of treatment cycles was 5 (1-6), and the median follow-up duration was 60 months (24 - 101 months). Interim efficacy assessment revealed an overall response rate of 52.7%. At 2 and 4 years, the progression-free survival (PFS) rates were 34.2% (95% CI 22.0%-53.2%) and 25.5% (95% CI 14.7%-44.4%), respectively, and the overall survival rates were 50.0% (95% CI 36.4%-68.7%) and 45.5% (95% CI 31.4%-65.7%), respectively. The risk factors for worse PFS were ECOG performance score >1 [ HR=3.711 (95% CI 1.494-9.218), P=0.005]; bone marrow infiltration [ HR=2.251 (95% CI 1.026 - 4.938), P=0.043]; and Prognostic Index for Natural Killer/T-Cell Lymphoma score of 3 - 5 [ HR=2.350 (95% CI 1.009 - 5.476), P=0.048]. Multivariate analysis identified ECOG performance score >1 as an independent risk factor for PFS [ HR=7.971 (95% CI 2.222 - 28.591), P=0.001]. The main adverse effect was anemia in 31 patients (81.6%) . Conclusion:The PEMD regimen was safe and effective for patients with newly diagnosed early-stage non-upper respiratory digestive tract or advanced ENKTL.

Objective:To evaluate the efficacy and safety of the Chi-BEAM regimen (chidamide combined with carmustine, etoposide, cytarabine, and melphalan) followed by autologous hematopoietic stem cell transplantation (ASCT) in patients with high-risk or relapsed/refractory lymphoma.Methods:This retrospective case series included 78 patients with newly treated high-risk or relapsed/refractory lymphoma who underwent ASCT with the Chi-BEAM conditioning regimen in the Department of Hematology, the First Affiliated Hospital of Nanjing Medical University (Jiangsu Province Hospital), from June 2021 to May 2024. Descriptive statistics were employed to evaluate clinical characteristics, efficacy, and adverse events. The Kaplan-Meier method was applied to calculate cumulative progression-free survival (PFS) and overall survival (OS) rates.Results:The median age of the 78 evaluable patients was 47 years (range 16-68), with 8 patients (10.3%) aged ≥60 years. At the first post-transplant assessment (3 months), the objective response rate was 94.9% (74/78). The median follow-up was 20.1 months (range 2.9-44.9). The median PFS time was 20.1 months (range 1.6-45.1), with a 2-year cumulative PFS rate of 81.8%. The median OS time was 20.6 months (range 3.1-45.1), with a cumulative 2-year OS rate of 93.2%. The regimen was well-tolerated; mild-to-moderate hypocalcemia within 1 week post-infusion and transient mild erythrocyturia on the infusion day were the primary adverse reactions.Conclusion:The Chi-BEAM regimen combined with ASCT demonstrates both safety and clinical benefit in patients with high-risk or relapsed/refractory lymphoma.

Objective:To evaluate the efficacy and safety of the pegaspargase, etoposide, methotrexate, and dexamethasone (PEMD) regimen in patients with early-stage nonupper respiratory digestive tract or advanced extranodal natural killer/T-cell lymphoma (ENKTL) .Methods:This retrospective analysis included 38 patients with newly diagnosed early-stage non-upper respiratory digestive tract or advanced ENKTL who received PEMD regimen for induction chemotherapy at the First Affiliated Hospital of Nanjing Medical University from January 2016 to December 2022. Survival outcomes and prognostic factors were examined by Kaplan-Meier, and the Log-rank test was used to compare survival.Results:The study population had a median age of 48 years (range, 26-72 years) and included 30 males (78.9%) and 8 females (21.1%). 7 patients’ age >60 years (18.4%). The Eastern Cooperative Oncology Group (ECOG) performance score was >1 in 7 patients (18.4%) ; 20 patients (52.6%) had elevated lactate dehydrogenase levels; and 37 patients (97.4%) exhibited extranodal involvement. Using the Ann Arbor staging system, 37 patients (97.4%) were classified as stage Ⅲ-Ⅳ. The median number of treatment cycles was 5 (1-6), and the median follow-up duration was 60 months (24 - 101 months). Interim efficacy assessment revealed an overall response rate of 52.7%. At 2 and 4 years, the progression-free survival (PFS) rates were 34.2% (95% CI 22.0%-53.2%) and 25.5% (95% CI 14.7%-44.4%), respectively, and the overall survival rates were 50.0% (95% CI 36.4%-68.7%) and 45.5% (95% CI 31.4%-65.7%), respectively. The risk factors for worse PFS were ECOG performance score >1 [ HR=3.711 (95% CI 1.494-9.218), P=0.005]; bone marrow infiltration [ HR=2.251 (95% CI 1.026 - 4.938), P=0.043]; and Prognostic Index for Natural Killer/T-Cell Lymphoma score of 3 - 5 [ HR=2.350 (95% CI 1.009 - 5.476), P=0.048]. Multivariate analysis identified ECOG performance score >1 as an independent risk factor for PFS [ HR=7.971 (95% CI 2.222 - 28.591), P=0.001]. The main adverse effect was anemia in 31 patients (81.6%) . Conclusion:The PEMD regimen was safe and effective for patients with newly diagnosed early-stage non-upper respiratory digestive tract or advanced ENKTL.

Objective:To evaluate the efficacy and safety of the Chi-BEAM regimen (chidamide combined with carmustine, etoposide, cytarabine, and melphalan) followed by autologous hematopoietic stem cell transplantation (ASCT) in patients with high-risk or relapsed/refractory lymphoma.Methods:This retrospective case series included 78 patients with newly treated high-risk or relapsed/refractory lymphoma who underwent ASCT with the Chi-BEAM conditioning regimen in the Department of Hematology, the First Affiliated Hospital of Nanjing Medical University (Jiangsu Province Hospital), from June 2021 to May 2024. Descriptive statistics were employed to evaluate clinical characteristics, efficacy, and adverse events. The Kaplan-Meier method was applied to calculate cumulative progression-free survival (PFS) and overall survival (OS) rates.Results:The median age of the 78 evaluable patients was 47 years (range 16-68), with 8 patients (10.3%) aged ≥60 years. At the first post-transplant assessment (3 months), the objective response rate was 94.9% (74/78). The median follow-up was 20.1 months (range 2.9-44.9). The median PFS time was 20.1 months (range 1.6-45.1), with a 2-year cumulative PFS rate of 81.8%. The median OS time was 20.6 months (range 3.1-45.1), with a cumulative 2-year OS rate of 93.2%. The regimen was well-tolerated; mild-to-moderate hypocalcemia within 1 week post-infusion and transient mild erythrocyturia on the infusion day were the primary adverse reactions.Conclusion:The Chi-BEAM regimen combined with ASCT demonstrates both safety and clinical benefit in patients with high-risk or relapsed/refractory lymphoma.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.