Breakthroughs in the generation of programmable sequence-specific nucleases (SSNs), such as zinc finger nucleases (ZFNs),TAL effector nucleases (TALENs) and the RNA-directed nuclease CRISPR-associated protein 9 (Cas9)...Breakthroughs in the generation of programmable sequence-specific nucleases (SSNs), such as zinc finger nucleases (ZFNs),TAL effector nucleases (TALENs) and the RNA-directed nuclease CRISPR-associated protein 9 (Cas9), have greatly increased the ease of plant genome engineering (Voytas, 2013; Malzahn et al.,2017). Programmable SSNs introduce a DNA double-strand break展开更多
Summary:The COVID-19 pandemic caused by SARS-CoV2 is characterized by a remarkable variation in clinical severity ranging from a mild illness to a fatal multi-organ disease.Understanding the dysregulated human immune ...Summary:The COVID-19 pandemic caused by SARS-CoV2 is characterized by a remarkable variation in clinical severity ranging from a mild illness to a fatal multi-organ disease.Understanding the dysregulated human immune responses in the fatal subjects is critical for management of COVID-19 patients and the pandemic.In this study,we examined the immune cell compositions in the lung tissues and hilar lymph nodes using immunohistochemistry on 6 deceased COVID-19 patients and 4 focal organizing pneumonia(FOP)patients who underwent lung surgery and served as controls.We found a dominant presence of macrophages and a general deficiency of T cells and B cells in the lung tissues from deceased COVID-19 patients.In contrast to the FOP patients,Tfh cells and germinal center formation were largely absent in the draining hilar lymph nodes in the deceased COVID-19 patients.This was correlated with reduced IgM and IgG levels compared to convalescent COVID-19 patients.In summary,our data highlight a defect of germinal center structure in deceased COVID-19 patients leading to an impaired humoral immunity.Understanding the mechanisms of this deficiency will be one of the key points for the management of this epidemic.展开更多
Genetically modified pigs represent a great promise for generating models of human diseases and producing new breeds.Generation of genetically edited pigs using somatic cell nuclear transfer(SCNT)or zygote cytoplasmic...Genetically modified pigs represent a great promise for generating models of human diseases and producing new breeds.Generation of genetically edited pigs using somatic cell nuclear transfer(SCNT)or zygote cytoplasmic microinjection is a tedious process due to the low developmental rate or mosaicism of the founder(FO).Herein,we developed a method termed germinal vesicle oocyte gene editing(GVGE)to produce non-mosaic porcine embryos by editing maternal alleles during the GV to MII transition.Injection of Cas9 mRNA and X-linked Dmd gene-specific gRNA into GV oocytes did not affect their developmental potential.The MII oocytes edited during in vitro maturation(IVM)could develop into blastocysts after parthenogenetic activation(PA)or in vitro fertilization(IVF).Genotyping results indicated that the maternal gene X-linked Dmd could be efficiently edited during oocyte maturation.Up to81.3% of the edited IVF embryos were non-mosaic Dmd gene mutant embryos.In conclusion,GVGE might be a valuable method for the generation of non-mosaic maternal allele edited FO embryos in a short simple step.展开更多
Germinal centers （GC） of secondary lymphoid tissues are critical to mounting a high-affinity humoral immune response. B cells within the GC undergo rapid clonal expansion and selection while diversifying their antib...Germinal centers （GC） of secondary lymphoid tissues are critical to mounting a high-affinity humoral immune response. B cells within the GC undergo rapid clonal expansion and selection while diversifying their antibody genes. Although it is generally believed that GC B cells employ a unique proliferative program to accommodate these processes, little is known about how the GC-associated cell cycle is orchestrated. The D-type cyclins constitute an important component of the cell cycle engine that enables the cells to respond to physiological changes. Cell type- and developmental stage-specific roles of D-type cyclins have been described but the cyclin D requirement during GC reaction has not been addressed. In this study, we report that cyclin D3 is largely dispensable for proliferation and Ig class switching of in vitro activated B cells. In contrast, GC development in Ccnd3^-/- mice is markedly impaired, as is the T cell-dependent antibody response. Within the GC, although both switched and unswitched B cells are affected by cyclin D3 inactivation, the IgM^- pool is more severely reduced. Interestingly, despite a compensatory increase in cyclln D2 expression, a significant number of Ccnd3^-/- GC B cells accumulate in quiescent GO state. Lastly, although cyclin D3 inactivation did not disrupt BCL6 expression in GC B cells, it completely blocked the GC promoting effect of BCL6 overexpression, suggesting that cyclin D3 acts downstream of BCL6 to regulate GC formation. This is the first demonstration that cyclin D3 plays an important and unique role at the GC stage of B cell development.展开更多
The purpose of this study was to evaluate the viability and subsequent developmental ability of porcine germinal vesicle（GV） oocytes vitrified step-wise exposure to cryoprotectants. Oocytes were transferred to a vit...The purpose of this study was to evaluate the viability and subsequent developmental ability of porcine germinal vesicle（GV） oocytes vitrified step-wise exposure to cryoprotectants. Oocytes were transferred to a vitrification solution composed of 10% ethylene glycol（EG）,10% dimethyl sulfoxide（DMSO）, 300 g/L-1 Ficoll and 0.5 mol/L-1 sucrose（EDFS40） in a direct manner （non-preequilibrium） or in step-wise manner（ single- and two-step preequilibrium）. After vitrification and storage in liquid nitrogen, the oocytes were thawed,washed and in vitro maturation, fertilization and culture. In the non-preequilibrium group, the rates of post-thawed oocytes surviving, maturing to metaphase-Ⅱ, cleavage rate and blastocysts rate was significantly lower than that of sigle- and two-step preequilubrium groups（P<0.05）. In the single- and two- step groups, the rates of metaphase-Ⅱ stage were 46.8%, 42.7% and 49.7%, respectively, the rates which developed to blastocysts were 10.5%,11.1% and 14.8%, respectivaly. In the non-vitrified control group,the rates of oocytes maturing to metaphase-Ⅱ, developing to blastocysts was significantly higher than that vitrified groups（P<0.05）. The present study shows that the vitrification of porcine GV oocytes by a step-wise method involving two-steps preequilibrium may have advantage in maintaining the viability and subsequent production of blastocysts.展开更多
Monoclonal antibodies were used to label cutaneous germinal center cell-derived lymphomas <CGCCL) obtained from 10 patients. According to the Kiel classification, they were classified into 2 types. Eight patients h...Monoclonal antibodies were used to label cutaneous germinal center cell-derived lymphomas <CGCCL) obtained from 10 patients. According to the Kiel classification, they were classified into 2 types. Eight patients had centroblastic/centrocytic <CB/CC) lymphomas while 2 patients and centrocytic (CC) lymphomas. After monoclonal antibody labelling, the results were consistent with those of the clinical and morphologic analyses. Of the 10 cases, 9 were B1 positive, 6 were K positive, and 4 were λ positive. In 8 cases labeled with immunoglobulin, 6 were IgGFab positive, 2 were IgM positive and 8 were IgA negative. Five cases (CB/CC 3, CC 2) were both Bl, K and IgG positive (γ K). Four cases CB/CC were both Bl and A positive. Only one case (CB/CC) was both K and IgM positive (μ K). Two cases (CB CC) were both A and IgG positive (γ λ). The results indicate that Bl, K and A are the most important markers to phenotype cutaneous B-cell lymphomas. Our findings also show a higher percentage of y K types in CGCCL as compared with Western countries.展开更多
The germinal matrix being an accumulation of immature blood vessels in the premature infant brain is known to be the main cause of the intracranial hemorrhage. To investigate the injuring mechanism to the blood vessel...The germinal matrix being an accumulation of immature blood vessels in the premature infant brain is known to be the main cause of the intracranial hemorrhage. To investigate the injuring mechanism to the blood vessels of the germinal matrix, a modeling scenario that consists of three basic steps is proposed. First, the cerebral blood flow that depends on autoregulation, CO2 reactivity, and variations of intracranial pressure is modeled. Second, the chaotic blood vessel network of the germinal matrix is generated, and blood pressures in the vessels of this network are computed dependent on the outcome of the first step. In the third step, the pressures computed on the second step are used in finite element simulations of separate blood vessels of the germinal matrix to detect critical values for vessels impairment.展开更多
B cells,a pivotal constituent of the lymphatic system,undergo differentiation into plasma cells and memory B cells upon antigen stimulation,thereby primarily facilitating humoral immunity(Zhang et al.,2024).Most B cel...B cells,a pivotal constituent of the lymphatic system,undergo differentiation into plasma cells and memory B cells upon antigen stimulation,thereby primarily facilitating humoral immunity(Zhang et al.,2024).Most B cells necessitate transit through germinal centers(GCs)to achieve complete differentiation and maturation.Abnormal transformation of GC B cells represents a fundamental etiological factor in the development of diffuse large B-cell lymphoma(DLBCL)(Mlynarczyk et al.,2019)and multiple myeloma(MM)(Rizq et al.,2023).展开更多
Pulmonary T and B cells are important for protection of this mucosal barrier site.While viral infections lead to the development of ectopic lymphoid structures highly similar to those in germinal centers in secondary ...Pulmonary T and B cells are important for protection of this mucosal barrier site.While viral infections lead to the development of ectopic lymphoid structures highly similar to those in germinal centers in secondary lymphoid organs,little is known about how T/B cooperation occurs in the unstructured,diffuse tissue infiltrates characteristic of autoimmune diseases and nonviral infections.Using a mouse model of interstitial lung inflammation,we found that naive B cells are directly activated in lung tissue.Despite the absence of any germinal center-like structures,the interaction of B cells with peripheral T helper cells results in efficient somatic hypermutation and class switching.As antigen-presenting cells,macrophages are critical for this process.Unique B-cell repertoires indicated that the lung response was autonomous from the lung-draining lymph node.Only lung GC-like B cells were switched to IgA and had a broader repertoire,making them ideal candidates for producing broadly neutralizing immunoglobulins against respiratory pathogens.展开更多
Initially,identified as a Hodgkin lymphoma marker,CD30 was subsequently detected on a subset of human B cells within and around germinal centers(GCs).While CD30 expression is typically restricted to a few B cells,expa...Initially,identified as a Hodgkin lymphoma marker,CD30 was subsequently detected on a subset of human B cells within and around germinal centers(GCs).While CD30 expression is typically restricted to a few B cells,expansion of CD30-expressing B cells occurs in certain immune disorders and during viral infections.The role of CD30 in B cells remains largely unclear.To address this gap in knowledge,we established a conditional CD30-knockin mouse strain.In these mice,B-cell-specific CD30 expression led to a normal B-cell phenotype in young mice,but most aged mice exhibited significant expansion of B cells,T cells and myeloid cells and increased percentages of GC B cells and IgG1-switched cells.This may be driven by the expansion of CD4+senescence-associated T cells and T follicular helper cells,which partially express CD30-L(CD153)and may stimulate CD30-expressing B cells.Inducing CD30 expression in antigen-activated B cells accelerates the GC reaction and augments plasma cell differentiation,possibly through the posttranscriptional upregulation of CXCR4.Furthermore,CD30 expression in GC B cells promoted the expansion of IgG1-switched cells,which displayed either a GC or memory-like B-cell phenotype,with abnormally high IgG1 levels compared with those in controls.These findings shed light on the role of CD30 signaling in GC B cells and suggest that elevated CD30+B-cell numbers lead to pathological lymphocyte activation and proliferation.展开更多
Porcine epidemic diarrhea virus(PEDV),an enteric coronavirus,is widely spread worldwide and causes huge economic losses.The effective measure to control the viral infection is to develop ideal vaccines.Here,the collag...Porcine epidemic diarrhea virus(PEDV),an enteric coronavirus,is widely spread worldwide and causes huge economic losses.The effective measure to control the viral infection is to develop ideal vaccines.Here,the collagenase equivalent domain(COE)of PEDV was displayed on the surface of nanoparticles(NPs)in order to develop a newer,safer and more effective subunit vaccine against PEDV.The monomeric COE was displayed on the mi3 protein,which self-assembles into nanoparticles composed of 60 subunits,using the SpyTag/SpyCatcher system.The size,zeta potential,microstructure of the COE-mi3 virus-like particles(VLPs)were investigated.The COE-mi3 VLPs that possessed good security,stability and better retention can be more efficiently taken up by antigen-presenting cells(APCs)and help promote dendritic cells(DCs)maturation.Moreover,COE-mi3 VLPs could prominently improve specifc antibody levels including neutralizing antibodies(NAbs),and serum IgG,mucosal IgA.Moreover,COE-mi3 VLPs elicited more activation of CD4^(+)and CD8^(+)T cells and production of IFN-γand IL-4 cytokines.In particular,COE-mi3 VLPs is an effectual antigen-delivery platform to enhance germinal center(GC)B cell responses.This structure-based self-assembly of NP gives great potential to be developed as a new subunit vaccines attractive platform,and may also provide new ideas for the development of other enteric coronavirus vaccines.展开更多
The transcriptional repressor B cell lymphoma 6(BCL6) controls a large transcriptional network that is required for the formation and maintenance of germinal centers(GC). GC B cells represent the normal counterpart of...The transcriptional repressor B cell lymphoma 6(BCL6) controls a large transcriptional network that is required for the formation and maintenance of germinal centers(GC). GC B cells represent the normal counterpart of most human B-cell lymphomas, which are often characterized by deregulated BCL6 expression or BCL6-mediated pathways. BCL6 suppresses gene transcription largely through recruitment of its co-repressors through its distinct repression domain. Understanding the precise biological roles of each repression domain in normal and malignant B cells is helpful for development of targeted inhibition of BCL6 functions that is emerging as the basis for design of anti-lymphoma therapies. This review focuses on recent progress in the molecular mechanisms of action of BCL6 in B cells and discusses remaining unresolved questions related to how these mechanisms are linked to normal and malignant B cell development.展开更多
Cytosine and adenine base editors are promising new tools for introducing precise genetic modifications that are required to generate disease models and to improve traits in pigs. Base editors can catalyze the convers...Cytosine and adenine base editors are promising new tools for introducing precise genetic modifications that are required to generate disease models and to improve traits in pigs. Base editors can catalyze the conversion of C→T(C>T) or A→G(A>G) in the target site through a single guide RNA. Injection of base editors into the zygote cytoplasm can result in the production of offspring with precise point mutations, but most F0 are mosaic, and breeding of F1 heterozygous pigs is time-intensive. Here, we developed a method called germinal vesicle oocyte base editing(GVBE) to produce point mutant F0 porcine embryos by editing the maternal alleles during the GV to MⅡ transition. Injection of cytosine base editor 3(BE3) mRNA and X-linked Dmdspecific guide RNAs into GVoocytes efficiently edited maternal Dmd during in vitro maturation and did not affect the maturation potential of the oocytes. The edited MⅡ oocytes developed into blastocysts after parthenogenetic activation(PA) or in vitro fertilization(IVF). However, BE3 may reduce the developmental potential of IVF blastocysts from 31.5%±0.8% to 20.4%±2.1%. There 40%–78.3% diploid PA blastocysts had no more than two different alleles, including up to 10% embryos that had only C>T mutation alleles. Genotyping of IVF blastocysts indicated that over 70% of the edited embryos had one allele or two different alleles of Dmd. Since the male embryos had only a copy of Dmd allele, all five(5/19) F0 male embryos are homozygous and three of them were Dmd precise C>T mutation. Nine(9/19) female IVF embryos had two different alleles including a WT and a C>T mutation. DNA sequencing showed that some of them might be heterozygous embryos. In conclusion, the GVBE method is a valuable method for generating F0 embryos with maternal point mutated alleles in a single step.展开更多
B cells play essential roles in immunity,mainly through the production of high affinity plasma cells(PCs)and memory B(Bmem)cells.The affinity maturation and differentiation of B cells rely on the integration of B-cell...B cells play essential roles in immunity,mainly through the production of high affinity plasma cells(PCs)and memory B(Bmem)cells.The affinity maturation and differentiation of B cells rely on the integration of B-cell receptor(BCR)intrinsic and extrinsic signals provided by antigen binding and the microenvironment,respectively.In recent years,tumor infiltrating B(TIL-B)cells and PCs(TIL-PCs)have been revealed as important players in antitumor responses in human cancers,but their interplay and dynamics remain largely unknown.In lymphoid organs,B-cell responses involve both germinal center(GC)-dependent and GC-independent pathways for Bmem cell and PC production.Affinity maturation of BCR repertoires occurs in GC reactions with specific spatiotemporal dynamics of signal integration by B cells.In general,the reactivation of high-affinity Bmem cells by antigens triggers GC-independent production of large numbers of PC without BCR rediversification.Understanding B-cell dynamics in immune responses requires the integration of multiple tools and readouts such as single-cell phenotyping and RNA-seq,in situ analyses,BCR repertoire analysis,BCR specificity and affinity assays,and functional tests.Here,we review how those tools have recently been applied to study TIL-B cells and TIL-PC in different types of solid tumors.We assessed the published evidence for different models of TIL-B-cell dynamics involving GC-dependent or GC-independent local responses and the resulting production of antigen-specific PCs.Altogether,we highlight the need for more integrative B-cell immunology studies to rationally investigate TIL-B cells as a leverage for antitumor therapies.展开更多
Germinal centers(GCs)are essential for the establishment of long-lasting antibody responses.GC B cells rely on post-transcriptional RNA mechanisms to translate activation-associated transcriptional programs into funct...Germinal centers(GCs)are essential for the establishment of long-lasting antibody responses.GC B cells rely on post-transcriptional RNA mechanisms to translate activation-associated transcriptional programs into functional changes in the cell proteome.However,the critical proteins driving these key mechanisms are still unknown.Here,we show that the RNA binding proteins TIA1 and TIAL1 are required for the generation of long-lasting GC responses.TIA1-and TIAL1-deficient GC B cells fail to undergo antigen-mediated positive selection,expansion and differentiation into B-cell clones producing high-affinity antibodies.Mechanistically,TIA1 and TIAL1 control the transcriptional identity of dark-and light-zone GC B cells and enable timely expression of the prosurvival molecule MCL1.Thus,we demonstrate here that TIA1 and TIAL1 are key players in the post-transcriptional program that selects high-affinity antigen-specific GC B cells.展开更多
Germinal center kinases （GCKs） participate in a variety of signaling pathways needed to regulate cellular functions including apoptosis, cell proliferation, polarity and migration. Recent studies have shown that GCK...Germinal center kinases （GCKs） participate in a variety of signaling pathways needed to regulate cellular functions including apoptosis, cell proliferation, polarity and migration. Recent studies have shown that GCKs are participants in both adaptive and innate immune regulation. However, the differential activation and regulatory mechanisms of GCKs, as well as upstream and downstream signaling molecules, remain to be fully defined. It remains unresolved whether and how GCKs may cross-talk with existing signaling pathways. This review stresses the progresses in research of GCKs relevant to the immune system.展开更多
Strontium has similar chemical properties to calcium and has recently been recognized as a non-essential beneficial element for plants.In order to compare the effects of strontium and calcium on improving salt toleran...Strontium has similar chemical properties to calcium and has recently been recognized as a non-essential beneficial element for plants.In order to compare the effects of strontium and calcium on improving salt tolerance of Chinese cabbage during the germination stage,2,4,and 8 mmol/L of SrCl_(2),CaCl_(2) or an equimolar mixture of both were added separately to a 150 mmol/L NaCl solution.The results showed that Ca-Sr addition significantly increased seed viability,seed vigor,seed germination rate and seed germination uniformity of Chinese cabbage compared with the salt-control group.The differences in germination percentage(GP)and germination energy(GE)among the Ca-addition and Sr-addition groups were not significant,and the differences in coefficient of rate of germination(CRG),index of rate of germination(IRG)and coefficient of variation of the germination time(CVT)were relatively small,but clear differences were observed in germination index(GI),vigor index(VI)and coefficient of uniformity of germination(CUG).The results of GI and VI indicated that the higher the concentration of Ca-addition or Sr-addition,the more significant the enhancement of seed vigor.Under saline stress(150 mmol/L NaCl),the Ca-Sr co-addition outperformed Sr-treatment alone,and Ca-addition achieved the highest seed vigor at equivalent concentrations.Furthermore,all Ca-Sr treatments significantly enhanced the uniformity of Chinese cabbage sprouts exposed to 150 mM NaCl,with the best uniformity improved by the addition of 2 and 4 mmol/L SrCl_(2).Ca-Sr treatments increased the salt tolerance of Chinese cabbage sprouts during the germination stage mainly because the Ca2+and Sr2+significantly enhanced plasma membrane stability and reduced oxidative stress(as indicated by decreased contents of malondialdehyde and O2⋅-contents)in sprouts.The decrease of soluble sugar and proline content caused by Ca-Sr addition implies that elevated levels of these osmolytes were not the primary contributors to improved seed germinability in Chinese cabbage.These findings demonstrate that Sr is a beneficial element for enhancing salt tolerance in plants,laying a theoretical foundation for the development and application of strontium in agriculture.展开更多
The oilseed crop Camelina sativa exhibits salinity tolerance,but the effects on early growth stages across a range of different salts and in combination with salicylic acid(SA)have not been thoroughly evaluated.In thi...The oilseed crop Camelina sativa exhibits salinity tolerance,but the effects on early growth stages across a range of different salts and in combination with salicylic acid(SA)have not been thoroughly evaluated.In this study,seeds were germinated in varying concentrations of six salts(NaCl,CaCl_(2),ZnCl_(2),KCl,MgSO_(4),and Na2SO_(4))with or without 0.5 mM SA.Using the halotime model,we estimated salt thresholds for germination and parameters of seedling growth.Germination and seedling growth parameters of camelina significantly decreased with increasing salt concentration across all salt types.Salts containing Zn and SO_(4) were most detrimental to germination and seedling growth.Except for KCl,0.5 mM SA generally reduced the salinity tolerance threshold(Saltb(50))of camelina.Specifically,Saltb(50)was 21.5%higher for KCl and 16.1%,25.0%,54.9%,21.0%,and 5.6%lower for CaCl_(2),NaCl,MgSO_(4),Na2SO_(4),and ZnCl_(2),respectively,when 0.5 mM SA was compared to 0 mM SA.Furthermore,camelina seedling growth was consistently more sensitive than germination across all salt types.SA did not significantly enhance germination or seedling growth and was harmful when combined with certain salts or at the germination stage.It can be concluded that both the type of salt and the concentration of SA are as critical as the salt concentration in saline irrigation water.展开更多
[Objectives]To identify the drought resistance of main wheat varieties in Shandong Province and screen suitable cultivars for dryland cultivation.[Methods]Employing eight varieties including Jimai 60 as test materials...[Objectives]To identify the drought resistance of main wheat varieties in Shandong Province and screen suitable cultivars for dryland cultivation.[Methods]Employing eight varieties including Jimai 60 as test materials,this study simulated drought stress using 20%PEG-6000 and measured changes in germination-stage indicators.A comprehensive evaluation was conducted using the membership function method,incorporating relative coleoptile length,relative germ length,relative radicle length,relative germination rate,relative germination potential,and stress germination index.[Results]Drought stress not only reduced wheat seed germination rate but also inhibited the growth of the germ,coleoptile,and radicle.The D values of the eight varieties were ranked as follows:Jimai 60>Linmai 9>Yannong 999>Shannong 30>Shannong 28>Luyuan 502>Yannong 1212>Jimai 22.Based on D values,the eight dominant wheat varieties were classified into three categories:highly drought-resistant varieties(Linmai 9 and Jimai 60),moderately drought-resistant varieties(Yannong 999 and Shannong 30),and sensitive varieties(the others).Linmai 9 and Jimai 60 are recommended as suitable wheat varieties for dryland cultivation in Shandong Province.[Conclusions]Drought stress induced by 20%PEG-6000 reduced germination rate,germination potential,and germination index of wheat varieties while inhibiting the growth of coleoptiles and radicles.These indicators can provide a preliminary assessment of drought resistance in wheat cultivars.However,since filter paper was selected as the growth medium,root length measurement errors were introduced during root washing,leading to variations in final experimental results.Futuer studies could attempt using sterilized sand as an alternative growth medium.展开更多
The present study examines the toxicological effects and bioaccumulation of strontium(Sr^(2+))in two Moroccan wheat species,Triticum durum(Nachit)and Triticum aestivum(Ibtissam).Germination rates and seedling growth p...The present study examines the toxicological effects and bioaccumulation of strontium(Sr^(2+))in two Moroccan wheat species,Triticum durum(Nachit)and Triticum aestivum(Ibtissam).Germination rates and seedling growth parameters were evaluated under Sr^(2+)concentrations of 0,10,100,and 1000 mM.Results revealed a significant decline in germination rates as Sr^(2+)concentrations increased,with T.aestivum showing higher sensitivity compared to T.durum.Low Sr^(2+)concentrations(10 mM)initially promoted stem growth in T.aestivum,but growth declined sharply at higher concentrations.Both species sustained growth at moderate Sr^(2+)concentrations(100 mM),but experienced a substantial reduction at 1000 mM,with T.durum demonstrating slightly better tolerance.Elevated Sr^(2+)concentrations notably affected root length and stem branching,indicating severe phytotoxic effects.Enzyme activity assays showed that at low Sr^(2+)concentration(10 mM),GST,CAT,POD,and SOD activities were similar to the control.At moderate concentrations(100 mM),GST and POD activities increased,suggesting enhanced detoxification.At high concentrations(1000 mM),all enzyme activities were significantly elevated,reflecting a robust antioxidative defense mechanism.This study provides valuable insights into the toxicological impacts and physiological responses of these wheat species to Sr^(2+)stress.展开更多
基金supported by a Collaborative Funding Grant from North Carolina Biotechnology Center and Syngenta Biotechnology (2016-CFG-8003)startup funds provided by East Carolina University and University of Maryland to Y.Q.a grant from the National Science Foundation (IOS-1339209)
文摘Breakthroughs in the generation of programmable sequence-specific nucleases (SSNs), such as zinc finger nucleases (ZFNs),TAL effector nucleases (TALENs) and the RNA-directed nuclease CRISPR-associated protein 9 (Cas9), have greatly increased the ease of plant genome engineering (Voytas, 2013; Malzahn et al.,2017). Programmable SSNs introduce a DNA double-strand break
基金The study was funded by grants from the Special R&D Program of Ministry of Science and Technology(No.2019YFC1316203)Ministry of Science and Technology(No.2020YFC0844700)Clinical Foundation of Tongji Hospital(No.XXGZBDYJ010).
文摘Summary:The COVID-19 pandemic caused by SARS-CoV2 is characterized by a remarkable variation in clinical severity ranging from a mild illness to a fatal multi-organ disease.Understanding the dysregulated human immune responses in the fatal subjects is critical for management of COVID-19 patients and the pandemic.In this study,we examined the immune cell compositions in the lung tissues and hilar lymph nodes using immunohistochemistry on 6 deceased COVID-19 patients and 4 focal organizing pneumonia(FOP)patients who underwent lung surgery and served as controls.We found a dominant presence of macrophages and a general deficiency of T cells and B cells in the lung tissues from deceased COVID-19 patients.In contrast to the FOP patients,Tfh cells and germinal center formation were largely absent in the draining hilar lymph nodes in the deceased COVID-19 patients.This was correlated with reduced IgM and IgG levels compared to convalescent COVID-19 patients.In summary,our data highlight a defect of germinal center structure in deceased COVID-19 patients leading to an impaired humoral immunity.Understanding the mechanisms of this deficiency will be one of the key points for the management of this epidemic.
基金supported by the National Key R&D Program of China(2017YFC1001901 and 2017YFA0102801)the National Natural Science Foundation of China (31671540)+3 种基金the National Transgenic Major Program (2016ZX08006003-006)the Natural Science Foundation of Guangdong Province (2015A020212005 and 2014A030312011)the Key R&D Program of Guangdong Province (2018B020203003)the Guangzhou Science and Technology Project (201803010020)
文摘Genetically modified pigs represent a great promise for generating models of human diseases and producing new breeds.Generation of genetically edited pigs using somatic cell nuclear transfer(SCNT)or zygote cytoplasmic microinjection is a tedious process due to the low developmental rate or mosaicism of the founder(FO).Herein,we developed a method termed germinal vesicle oocyte gene editing(GVGE)to produce non-mosaic porcine embryos by editing maternal alleles during the GV to MII transition.Injection of Cas9 mRNA and X-linked Dmd gene-specific gRNA into GV oocytes did not affect their developmental potential.The MII oocytes edited during in vitro maturation(IVM)could develop into blastocysts after parthenogenetic activation(PA)or in vitro fertilization(IVF).Genotyping results indicated that the maternal gene X-linked Dmd could be efficiently edited during oocyte maturation.Up to81.3% of the edited IVF embryos were non-mosaic Dmd gene mutant embryos.In conclusion,GVGE might be a valuable method for the generation of non-mosaic maternal allele edited FO embryos in a short simple step.
文摘Germinal centers （GC） of secondary lymphoid tissues are critical to mounting a high-affinity humoral immune response. B cells within the GC undergo rapid clonal expansion and selection while diversifying their antibody genes. Although it is generally believed that GC B cells employ a unique proliferative program to accommodate these processes, little is known about how the GC-associated cell cycle is orchestrated. The D-type cyclins constitute an important component of the cell cycle engine that enables the cells to respond to physiological changes. Cell type- and developmental stage-specific roles of D-type cyclins have been described but the cyclin D requirement during GC reaction has not been addressed. In this study, we report that cyclin D3 is largely dispensable for proliferation and Ig class switching of in vitro activated B cells. In contrast, GC development in Ccnd3^-/- mice is markedly impaired, as is the T cell-dependent antibody response. Within the GC, although both switched and unswitched B cells are affected by cyclin D3 inactivation, the IgM^- pool is more severely reduced. Interestingly, despite a compensatory increase in cyclln D2 expression, a significant number of Ccnd3^-/- GC B cells accumulate in quiescent GO state. Lastly, although cyclin D3 inactivation did not disrupt BCL6 expression in GC B cells, it completely blocked the GC promoting effect of BCL6 overexpression, suggesting that cyclin D3 acts downstream of BCL6 to regulate GC formation. This is the first demonstration that cyclin D3 plays an important and unique role at the GC stage of B cell development.
基金Item supported by international coopera-tion programme of science and technology of Shanghai (No.015407005)
文摘The purpose of this study was to evaluate the viability and subsequent developmental ability of porcine germinal vesicle（GV） oocytes vitrified step-wise exposure to cryoprotectants. Oocytes were transferred to a vitrification solution composed of 10% ethylene glycol（EG）,10% dimethyl sulfoxide（DMSO）, 300 g/L-1 Ficoll and 0.5 mol/L-1 sucrose（EDFS40） in a direct manner （non-preequilibrium） or in step-wise manner（ single- and two-step preequilibrium）. After vitrification and storage in liquid nitrogen, the oocytes were thawed,washed and in vitro maturation, fertilization and culture. In the non-preequilibrium group, the rates of post-thawed oocytes surviving, maturing to metaphase-Ⅱ, cleavage rate and blastocysts rate was significantly lower than that of sigle- and two-step preequilubrium groups（P<0.05）. In the single- and two- step groups, the rates of metaphase-Ⅱ stage were 46.8%, 42.7% and 49.7%, respectively, the rates which developed to blastocysts were 10.5%,11.1% and 14.8%, respectivaly. In the non-vitrified control group,the rates of oocytes maturing to metaphase-Ⅱ, developing to blastocysts was significantly higher than that vitrified groups（P<0.05）. The present study shows that the vitrification of porcine GV oocytes by a step-wise method involving two-steps preequilibrium may have advantage in maintaining the viability and subsequent production of blastocysts.
文摘Monoclonal antibodies were used to label cutaneous germinal center cell-derived lymphomas <CGCCL) obtained from 10 patients. According to the Kiel classification, they were classified into 2 types. Eight patients had centroblastic/centrocytic <CB/CC) lymphomas while 2 patients and centrocytic (CC) lymphomas. After monoclonal antibody labelling, the results were consistent with those of the clinical and morphologic analyses. Of the 10 cases, 9 were B1 positive, 6 were K positive, and 4 were λ positive. In 8 cases labeled with immunoglobulin, 6 were IgGFab positive, 2 were IgM positive and 8 were IgA negative. Five cases (CB/CC 3, CC 2) were both Bl, K and IgG positive (γ K). Four cases CB/CC were both Bl and A positive. Only one case (CB/CC) was both K and IgM positive (μ K). Two cases (CB CC) were both A and IgG positive (γ λ). The results indicate that Bl, K and A are the most important markers to phenotype cutaneous B-cell lymphomas. Our findings also show a higher percentage of y K types in CGCCL as compared with Western countries.
文摘The germinal matrix being an accumulation of immature blood vessels in the premature infant brain is known to be the main cause of the intracranial hemorrhage. To investigate the injuring mechanism to the blood vessels of the germinal matrix, a modeling scenario that consists of three basic steps is proposed. First, the cerebral blood flow that depends on autoregulation, CO2 reactivity, and variations of intracranial pressure is modeled. Second, the chaotic blood vessel network of the germinal matrix is generated, and blood pressures in the vessels of this network are computed dependent on the outcome of the first step. In the third step, the pressures computed on the second step are used in finite element simulations of separate blood vessels of the germinal matrix to detect critical values for vessels impairment.
基金supported by the Research Center for Brain Cognition and Human Development,Guangdong,China(2024B0303390003)Special Funds for the Cultivation of Guangdong College Students’Scientific and Technological Innovation(“Climbing Program”Special Funds pdjh2024b118)+2 种基金Autism Research Special Fund of Zhejiang Foundation For Disabled Persons(2023003)Scientific Research Innovation Project of Graduate School of South China Normal University(43204021)Startup Fund for Talented Scholars of South China Normal University.
文摘B cells,a pivotal constituent of the lymphatic system,undergo differentiation into plasma cells and memory B cells upon antigen stimulation,thereby primarily facilitating humoral immunity(Zhang et al.,2024).Most B cells necessitate transit through germinal centers(GCs)to achieve complete differentiation and maturation.Abnormal transformation of GC B cells represents a fundamental etiological factor in the development of diffuse large B-cell lymphoma(DLBCL)(Mlynarczyk et al.,2019)and multiple myeloma(MM)(Rizq et al.,2023).
基金supported by the German Research Foundation(DFG),project ID 509546995supported by DFG grants HU 1294/8-1,HU 1294/8-2,and SFB 1526-A08(project ID 454193335)+2 种基金funded by the Federal Ministry of Education and Research(BMBF)as part of the German Center for Child and Adolescent Health(DZKJ)under funding codes 01GL2401C,CONAN and TreATgrants from the Leibniz Association(Leibniz Collaborative Excellence,TargArt and ImpACt)supported by Germany’s Excellence Strategy grants EXC2151 and EXC2047.
文摘Pulmonary T and B cells are important for protection of this mucosal barrier site.While viral infections lead to the development of ectopic lymphoid structures highly similar to those in germinal centers in secondary lymphoid organs,little is known about how T/B cooperation occurs in the unstructured,diffuse tissue infiltrates characteristic of autoimmune diseases and nonviral infections.Using a mouse model of interstitial lung inflammation,we found that naive B cells are directly activated in lung tissue.Despite the absence of any germinal center-like structures,the interaction of B cells with peripheral T helper cells results in efficient somatic hypermutation and class switching.As antigen-presenting cells,macrophages are critical for this process.Unique B-cell repertoires indicated that the lung response was autonomous from the lung-draining lymph node.Only lung GC-like B cells were switched to IgA and had a broader repertoire,making them ideal candidates for producing broadly neutralizing immunoglobulins against respiratory pathogens.
基金supported by the Deutsche Krebshilfe,Nr.70113859 to U.Z.-S.and H.A.,the Wilhelm-Sander-Stiftung Nr.2022.128.1 to A.Ö.Y and U.Z.-S.and the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under award number R01AI170965。
文摘Initially,identified as a Hodgkin lymphoma marker,CD30 was subsequently detected on a subset of human B cells within and around germinal centers(GCs).While CD30 expression is typically restricted to a few B cells,expansion of CD30-expressing B cells occurs in certain immune disorders and during viral infections.The role of CD30 in B cells remains largely unclear.To address this gap in knowledge,we established a conditional CD30-knockin mouse strain.In these mice,B-cell-specific CD30 expression led to a normal B-cell phenotype in young mice,but most aged mice exhibited significant expansion of B cells,T cells and myeloid cells and increased percentages of GC B cells and IgG1-switched cells.This may be driven by the expansion of CD4+senescence-associated T cells and T follicular helper cells,which partially express CD30-L(CD153)and may stimulate CD30-expressing B cells.Inducing CD30 expression in antigen-activated B cells accelerates the GC reaction and augments plasma cell differentiation,possibly through the posttranscriptional upregulation of CXCR4.Furthermore,CD30 expression in GC B cells promoted the expansion of IgG1-switched cells,which displayed either a GC or memory-like B-cell phenotype,with abnormally high IgG1 levels compared with those in controls.These findings shed light on the role of CD30 signaling in GC B cells and suggest that elevated CD30+B-cell numbers lead to pathological lymphocyte activation and proliferation.
基金supported by the Major Scientific and Technological Project of the Henan Province,China(221100110600)the Beijing Life Science Academy,China(2024500CA0010)+1 种基金the Major Program of National Natural Science Foundation of China(32192452)the Chinese Postdoctoral Science Foundation(2023M743209)。
文摘Porcine epidemic diarrhea virus(PEDV),an enteric coronavirus,is widely spread worldwide and causes huge economic losses.The effective measure to control the viral infection is to develop ideal vaccines.Here,the collagenase equivalent domain(COE)of PEDV was displayed on the surface of nanoparticles(NPs)in order to develop a newer,safer and more effective subunit vaccine against PEDV.The monomeric COE was displayed on the mi3 protein,which self-assembles into nanoparticles composed of 60 subunits,using the SpyTag/SpyCatcher system.The size,zeta potential,microstructure of the COE-mi3 virus-like particles(VLPs)were investigated.The COE-mi3 VLPs that possessed good security,stability and better retention can be more efficiently taken up by antigen-presenting cells(APCs)and help promote dendritic cells(DCs)maturation.Moreover,COE-mi3 VLPs could prominently improve specifc antibody levels including neutralizing antibodies(NAbs),and serum IgG,mucosal IgA.Moreover,COE-mi3 VLPs elicited more activation of CD4^(+)and CD8^(+)T cells and production of IFN-γand IL-4 cytokines.In particular,COE-mi3 VLPs is an effectual antigen-delivery platform to enhance germinal center(GC)B cell responses.This structure-based self-assembly of NP gives great potential to be developed as a new subunit vaccines attractive platform,and may also provide new ideas for the development of other enteric coronavirus vaccines.
文摘The transcriptional repressor B cell lymphoma 6(BCL6) controls a large transcriptional network that is required for the formation and maintenance of germinal centers(GC). GC B cells represent the normal counterpart of most human B-cell lymphomas, which are often characterized by deregulated BCL6 expression or BCL6-mediated pathways. BCL6 suppresses gene transcription largely through recruitment of its co-repressors through its distinct repression domain. Understanding the precise biological roles of each repression domain in normal and malignant B cells is helpful for development of targeted inhibition of BCL6 functions that is emerging as the basis for design of anti-lymphoma therapies. This review focuses on recent progress in the molecular mechanisms of action of BCL6 in B cells and discusses remaining unresolved questions related to how these mechanisms are linked to normal and malignant B cell development.
基金supported by the National Key R&D Program of China (2017YFC1001901 and 2017YFA0102801)the National Natural Science Foundation (31671540)+3 种基金the National Transgenic Major Program (2016ZX08006003-006)the Natural Science Foundation of Guangdong Province (2015A020212005 and 2014A030312011)the Key R&D Program of Guangdong Province (2018B020203003)the Guangzhou Science and Technology Project (201803010020)。
文摘Cytosine and adenine base editors are promising new tools for introducing precise genetic modifications that are required to generate disease models and to improve traits in pigs. Base editors can catalyze the conversion of C→T(C>T) or A→G(A>G) in the target site through a single guide RNA. Injection of base editors into the zygote cytoplasm can result in the production of offspring with precise point mutations, but most F0 are mosaic, and breeding of F1 heterozygous pigs is time-intensive. Here, we developed a method called germinal vesicle oocyte base editing(GVBE) to produce point mutant F0 porcine embryos by editing the maternal alleles during the GV to MⅡ transition. Injection of cytosine base editor 3(BE3) mRNA and X-linked Dmdspecific guide RNAs into GVoocytes efficiently edited maternal Dmd during in vitro maturation and did not affect the maturation potential of the oocytes. The edited MⅡ oocytes developed into blastocysts after parthenogenetic activation(PA) or in vitro fertilization(IVF). However, BE3 may reduce the developmental potential of IVF blastocysts from 31.5%±0.8% to 20.4%±2.1%. There 40%–78.3% diploid PA blastocysts had no more than two different alleles, including up to 10% embryos that had only C>T mutation alleles. Genotyping of IVF blastocysts indicated that over 70% of the edited embryos had one allele or two different alleles of Dmd. Since the male embryos had only a copy of Dmd allele, all five(5/19) F0 male embryos are homozygous and three of them were Dmd precise C>T mutation. Nine(9/19) female IVF embryos had two different alleles including a WT and a C>T mutation. DNA sequencing showed that some of them might be heterozygous embryos. In conclusion, the GVBE method is a valuable method for generating F0 embryos with maternal point mutated alleles in a single step.
基金We acknowledge all members of the Milpied and Vivier laboratories at CIML for fruitful discussionsEP is supported by a fellowship funded by Innate Pharma and the RHU PIONeeR project(ANR-17-RHUS-00XX-08)This work was supported by grants from ITMO Cancer and the RHU PIONeeR project.
文摘B cells play essential roles in immunity,mainly through the production of high affinity plasma cells(PCs)and memory B(Bmem)cells.The affinity maturation and differentiation of B cells rely on the integration of B-cell receptor(BCR)intrinsic and extrinsic signals provided by antigen binding and the microenvironment,respectively.In recent years,tumor infiltrating B(TIL-B)cells and PCs(TIL-PCs)have been revealed as important players in antitumor responses in human cancers,but their interplay and dynamics remain largely unknown.In lymphoid organs,B-cell responses involve both germinal center(GC)-dependent and GC-independent pathways for Bmem cell and PC production.Affinity maturation of BCR repertoires occurs in GC reactions with specific spatiotemporal dynamics of signal integration by B cells.In general,the reactivation of high-affinity Bmem cells by antigens triggers GC-independent production of large numbers of PC without BCR rediversification.Understanding B-cell dynamics in immune responses requires the integration of multiple tools and readouts such as single-cell phenotyping and RNA-seq,in situ analyses,BCR repertoire analysis,BCR specificity and affinity assays,and functional tests.Here,we review how those tools have recently been applied to study TIL-B cells and TIL-PC in different types of solid tumors.We assessed the published evidence for different models of TIL-B-cell dynamics involving GC-dependent or GC-independent local responses and the resulting production of antigen-specific PCs.Altogether,we highlight the need for more integrative B-cell immunology studies to rationally investigate TIL-B cells as a leverage for antitumor therapies.
基金We thank all personnel from the Toulouse animal facility CREFRE and from the flow cytometry,imaging,transcriptomics and bioinformatics technical platforms of INFINITy.M.D.D-M.is supported by ATIP-Avenir-Plan Cancer(C18003BS),ANR(ANR-20-CE15-0007)foundation ARSEP R19201BB,foundation ARC,La Ligue Contre Le Cancer and INSPIRE(Region Occitanie,Inserm and CHU Toulouse)M.T.is supported with a BBSRC core funding grant and a Wellcome Investigator award(200823/Z/16/Z).D.C.-S.is supported by Boehringer Ingelheim Fonds.
文摘Germinal centers(GCs)are essential for the establishment of long-lasting antibody responses.GC B cells rely on post-transcriptional RNA mechanisms to translate activation-associated transcriptional programs into functional changes in the cell proteome.However,the critical proteins driving these key mechanisms are still unknown.Here,we show that the RNA binding proteins TIA1 and TIAL1 are required for the generation of long-lasting GC responses.TIA1-and TIAL1-deficient GC B cells fail to undergo antigen-mediated positive selection,expansion and differentiation into B-cell clones producing high-affinity antibodies.Mechanistically,TIA1 and TIAL1 control the transcriptional identity of dark-and light-zone GC B cells and enable timely expression of the prosurvival molecule MCL1.Thus,we demonstrate here that TIA1 and TIAL1 are key players in the post-transcriptional program that selects high-affinity antigen-specific GC B cells.
基金This work was supported by the 973 Program of the Ministry of Science and Technology of China （2010CB529700 and 2012CB910204）, the National Natural Science Foundation of China （NSFC10979005 and NSFC30970566） and the Science and Technology Commission of Shanghai Municipality （11JC14140000）. Dr ZZ is a scholar of the Hundred Talents Program of the Chinese Academy of Sciences. Dr Greene is supported by grants from the NIH, NCI, the Abramson Family Research Institute and the BCRF.
文摘Germinal center kinases （GCKs） participate in a variety of signaling pathways needed to regulate cellular functions including apoptosis, cell proliferation, polarity and migration. Recent studies have shown that GCKs are participants in both adaptive and innate immune regulation. However, the differential activation and regulatory mechanisms of GCKs, as well as upstream and downstream signaling molecules, remain to be fully defined. It remains unresolved whether and how GCKs may cross-talk with existing signaling pathways. This review stresses the progresses in research of GCKs relevant to the immune system.
基金funded by the Natural Science Foundation of Shandong Province(ZR2020MC144)the Scientific Research Training Program for Undergraduates of Qufu Normal University(XJ2024016).
文摘Strontium has similar chemical properties to calcium and has recently been recognized as a non-essential beneficial element for plants.In order to compare the effects of strontium and calcium on improving salt tolerance of Chinese cabbage during the germination stage,2,4,and 8 mmol/L of SrCl_(2),CaCl_(2) or an equimolar mixture of both were added separately to a 150 mmol/L NaCl solution.The results showed that Ca-Sr addition significantly increased seed viability,seed vigor,seed germination rate and seed germination uniformity of Chinese cabbage compared with the salt-control group.The differences in germination percentage(GP)and germination energy(GE)among the Ca-addition and Sr-addition groups were not significant,and the differences in coefficient of rate of germination(CRG),index of rate of germination(IRG)and coefficient of variation of the germination time(CVT)were relatively small,but clear differences were observed in germination index(GI),vigor index(VI)and coefficient of uniformity of germination(CUG).The results of GI and VI indicated that the higher the concentration of Ca-addition or Sr-addition,the more significant the enhancement of seed vigor.Under saline stress(150 mmol/L NaCl),the Ca-Sr co-addition outperformed Sr-treatment alone,and Ca-addition achieved the highest seed vigor at equivalent concentrations.Furthermore,all Ca-Sr treatments significantly enhanced the uniformity of Chinese cabbage sprouts exposed to 150 mM NaCl,with the best uniformity improved by the addition of 2 and 4 mmol/L SrCl_(2).Ca-Sr treatments increased the salt tolerance of Chinese cabbage sprouts during the germination stage mainly because the Ca2+and Sr2+significantly enhanced plasma membrane stability and reduced oxidative stress(as indicated by decreased contents of malondialdehyde and O2⋅-contents)in sprouts.The decrease of soluble sugar and proline content caused by Ca-Sr addition implies that elevated levels of these osmolytes were not the primary contributors to improved seed germinability in Chinese cabbage.These findings demonstrate that Sr is a beneficial element for enhancing salt tolerance in plants,laying a theoretical foundation for the development and application of strontium in agriculture.
基金the Genetics and Agricultural Biotechnology Institute of Tabarestan (GABIT) Sari Agricultural Sciences and Natural Resources University (SANRU) for the use of the services and financial supports of this research
文摘The oilseed crop Camelina sativa exhibits salinity tolerance,but the effects on early growth stages across a range of different salts and in combination with salicylic acid(SA)have not been thoroughly evaluated.In this study,seeds were germinated in varying concentrations of six salts(NaCl,CaCl_(2),ZnCl_(2),KCl,MgSO_(4),and Na2SO_(4))with or without 0.5 mM SA.Using the halotime model,we estimated salt thresholds for germination and parameters of seedling growth.Germination and seedling growth parameters of camelina significantly decreased with increasing salt concentration across all salt types.Salts containing Zn and SO_(4) were most detrimental to germination and seedling growth.Except for KCl,0.5 mM SA generally reduced the salinity tolerance threshold(Saltb(50))of camelina.Specifically,Saltb(50)was 21.5%higher for KCl and 16.1%,25.0%,54.9%,21.0%,and 5.6%lower for CaCl_(2),NaCl,MgSO_(4),Na2SO_(4),and ZnCl_(2),respectively,when 0.5 mM SA was compared to 0 mM SA.Furthermore,camelina seedling growth was consistently more sensitive than germination across all salt types.SA did not significantly enhance germination or seedling growth and was harmful when combined with certain salts or at the germination stage.It can be concluded that both the type of salt and the concentration of SA are as critical as the salt concentration in saline irrigation water.
基金Supported by National Wheat Industry Technology System"Linyi Integrated Experimental Station"(CARS-03-66)Shandong Provincial Modern Agricultural Industry Technology System"Linyi Integrated Experimental Station"(SDATT-01-18).
文摘[Objectives]To identify the drought resistance of main wheat varieties in Shandong Province and screen suitable cultivars for dryland cultivation.[Methods]Employing eight varieties including Jimai 60 as test materials,this study simulated drought stress using 20%PEG-6000 and measured changes in germination-stage indicators.A comprehensive evaluation was conducted using the membership function method,incorporating relative coleoptile length,relative germ length,relative radicle length,relative germination rate,relative germination potential,and stress germination index.[Results]Drought stress not only reduced wheat seed germination rate but also inhibited the growth of the germ,coleoptile,and radicle.The D values of the eight varieties were ranked as follows:Jimai 60>Linmai 9>Yannong 999>Shannong 30>Shannong 28>Luyuan 502>Yannong 1212>Jimai 22.Based on D values,the eight dominant wheat varieties were classified into three categories:highly drought-resistant varieties(Linmai 9 and Jimai 60),moderately drought-resistant varieties(Yannong 999 and Shannong 30),and sensitive varieties(the others).Linmai 9 and Jimai 60 are recommended as suitable wheat varieties for dryland cultivation in Shandong Province.[Conclusions]Drought stress induced by 20%PEG-6000 reduced germination rate,germination potential,and germination index of wheat varieties while inhibiting the growth of coleoptiles and radicles.These indicators can provide a preliminary assessment of drought resistance in wheat cultivars.However,since filter paper was selected as the growth medium,root length measurement errors were introduced during root washing,leading to variations in final experimental results.Futuer studies could attempt using sterilized sand as an alternative growth medium.
文摘The present study examines the toxicological effects and bioaccumulation of strontium(Sr^(2+))in two Moroccan wheat species,Triticum durum(Nachit)and Triticum aestivum(Ibtissam).Germination rates and seedling growth parameters were evaluated under Sr^(2+)concentrations of 0,10,100,and 1000 mM.Results revealed a significant decline in germination rates as Sr^(2+)concentrations increased,with T.aestivum showing higher sensitivity compared to T.durum.Low Sr^(2+)concentrations(10 mM)initially promoted stem growth in T.aestivum,but growth declined sharply at higher concentrations.Both species sustained growth at moderate Sr^(2+)concentrations(100 mM),but experienced a substantial reduction at 1000 mM,with T.durum demonstrating slightly better tolerance.Elevated Sr^(2+)concentrations notably affected root length and stem branching,indicating severe phytotoxic effects.Enzyme activity assays showed that at low Sr^(2+)concentration(10 mM),GST,CAT,POD,and SOD activities were similar to the control.At moderate concentrations(100 mM),GST and POD activities increased,suggesting enhanced detoxification.At high concentrations(1000 mM),all enzyme activities were significantly elevated,reflecting a robust antioxidative defense mechanism.This study provides valuable insights into the toxicological impacts and physiological responses of these wheat species to Sr^(2+)stress.
