高强度Poly(AM-co-IA)/Al_2O_3纳米复合水凝胶的制备及形状记忆行为

以氧化铝(Al_2O_3)纳米粒子作为无机交联剂,丙烯酰胺(AM)和衣康酸(IA)为单体,原位自由基聚合制备了高强度PAI/Al_2O_3纳米复合水凝胶,并提出了水凝胶的交联机理。对纳米复合水凝胶的力学性质、微观结构和溶胀性质进行了表征。结果表明,制备的水凝胶具有优异力学性能,拉伸和压缩强度分别可达477 k Pa和13.45 MPa。此外,PAI/Al_2O_3纳米复合水凝胶还表现出透明的外观,规整的网络结构,较低的溶胀率以及水驱动的形状记忆行为。因此,这种水凝胶在生物医学领域有广阔的应用前景。

Research progress in physiological and molecular biology mechanism of drought resistance in rice

Rice is one of the most important crops, providing staple food for about half population of the world. Drought stress affects plant growth and development seriously. This article reviewed the research progress of the physiological and molecular biology mechanism including osmotic adjustment, scavenging oxidative radicals, endogenous hormones, drought-resistance genes and epigenetic modification, it may be afford interrelated reference for increasing rice drought resistance and breeding drought resistance rice varieties.

A predicted NEDD8 conjugating enzyme gene identified as a Capsicum candidate Rf gene using bulk segregant RNA sequencing

Cytoplasmic male sterility(CMS)is an important tool for producing F1 hybrids,which can exhibit heterosis.The companion system,restorer-of-fertility(Rf),is poorly understood at the molecular level and would be valuable in producing restorer lines for hybrid seed production.The identity of the Rf gene in Capsicum(pepper)is currently unclear.In this study,using bulked segregant RNA sequencing(BSR-seq),a strong candidate Rf gene,Capana06g002866,which is annotated as a NEDD8 conjugating enzyme E2,was identified.Capana06g002866 has an ORF of 555 bp in length encoding 184 amino acids;it can be cloned from F1 plants from the hybridization of the CMS line 8A and restorer line R1 but is not found in CMS line 8A.With qRT-PCR validation,Capana06g002866 was found to be upregulated in restorer accessions compared to sterile accessions.The relative expression in flower buds increased with the developmental stage in F1 plants,while the expression was very low in all flower bud stages of the CMS lines.These results provide new insights into the Rf gene in pepper and will be useful for other crops utilizing the CMS system.

Research of total levels on DNA methylation in plant based on HPLC analysis

HPLC analysis is important for determination of total level on DNA methylation in plants. It can be used to help characterise epigenetic changes during growth, development and stress. HPLC methods have been optimised for mammalian and microbial DNA, but not for plants. This article examines several important factors in the HPLC analysis of plant DNA methylation including extraction and purification of DNA and HPLC conditions choice by using leaves of rice seedling. The experimental results showed that RNA of nucleic acid was removed by using RNase A. This study also identified critical components of HPLC analysis. With the optimized method of HPLC conditions, the better result was achieved in the chromatogram of cytosine and 5-methylcytosine in genomic DNA acid hydrolysis. The study would offer a comprehensive guide for the stringent analysis of DNA methylation in plants.

The OsBZR1-OsSPX1/2 module fine-tunes the growth-immunity trade-off in adaptation to phosphate availability in rice

The growth-promoting hormones brassinosteroids(BRs)and their key signaling component BZR1 play a vital role in balancing normal growth and defense reactions.Here,we discovered that BRs and OsBZR1 up-regulated sakuranetin accumulation and conferred basal defense against Magnaporthe oryzae infection under normal conditions.Resource shortages,including phosphate(Pi)deficiency,potentially disrupt this growth-defense balance.OsSPX1 and OsSPX2 have been reported to sense Pi concentration and interact with the Pi signal mediator OsPHR2,thus regulating Pi starvation responses.In this study,we discovered that OsSPX1/2 interacts with OsBZR1 in both Pi-sufficient and Pi-deficient conditions,inhibit-ing BR-responsive genes.When Pi is sufficient,OsSPX1/2 is captured by OsPHR2,enabling most of OsBzR1 to promote plant growth and maintain basal resistance.In response to Pi starvation,more OsSPX1/2 is released from OsPHR2 to inhibit OsBZR1 activity,resulting in slower growth.Collectively,our study reveals that the OsBZR1-SPX1/2 module balances the plant growth-immunity trade-off in responsetoPiavailability.He Y.,Zhao Y.,Hu J.,Wang L.,Li L.,Zhang X.,Zhou Z.,Chen L.,Wang H.,Wang J.,and Hong G.(2024).The OsBZR1-OsSPX1/2 module fine-tunes the growth-immunity trade-off in adaptation to phosphate availability in esponse to Pi availability.

Construction of single-chromosome DNA library from Lilium regale Wilson

A protocol of simple rapid microdissection of single-chromosome, amplification and cloning of its DNA from Lilium regale Wilson is described. Single-chromosome, microdissected by micromanipulator, was put into a 0 5 mL Eppendorf tube and digested with Sau3A, and then the Sau3A linker adaptors were ligated to the ends of DNA fragments. After 2 rounds of PCR amplification with one chain of linker adaptor as primer, the PCR products thus obtained have a length of 300-2 500 base pairs (bp) with predominant fragments at about 1 000 bp. Southern blot analysis confirmed that the PCR products originated from the genome of Lilium regale Wilson. By cloning the amplification products from the second round of PCR, single-chromosome DNA library was constructed, in which about as many as 100 000 recombinant clones were produced. A total number of 84 clones were analysed, and it was revealed that the inserts ranged in size from 300 to 1 800 bp, with an average of 780 bp. Compared with the methods described in other literature, this protocol, eliminating the need for enzymatic digestion and ligating micromanipulation of chromosomal DNA in nanoliter volumes, permits the efficient amplification of single chromosome (not tens of chromosomes as reported before) and the fragments (780 bp in average) cloned in this study are longer than those reported before (650 bp in average).

Chromosome microdissection by laser microbeam, chromosomal fragment isolation and amplification in vitro in barley (Hordeum vulgare L.)

A method for microdissection, isolation and amplification of plant chromosomal fragments using laser microbeam and a glass microneedle was established. Firstly, 7H chromosome of barley (Hordeum vulgare L.) was dissected by Nd: YAG laserbeam with suitable parameters and the fragment comprising a satellite was isolated with a glass microneedle which was fixed on a micromanipulator. Then, the chromosomal fragment DNA was amplified by LA_PCR (linker adaptor PCR) for two rounds. The size of the DNA fragments of PCR products varied from 500-3 000 bp and the PCR products originated from the genome of barley were verified by Southern hybridization. Compared with previous reports, there are some advantages in this research. The performance is easier, the dissection is more precise and the cost is low. It also permits efficient amplification with only one single chromosome fragment. Laser microbeam_glass microneedle method may be useful in the microdissection of special chromosome regions, especially in plants with middle or small chromosomes.