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51.
52.
Hongyan Han Qiang Ao Guoqiang Chen Shijie Wang Huancong Zuo 《Biotechnology letters》2010,32(4):585-591
Autologous nerve grafts are widely used in bridging critical gaps of peripheral nerves, but they remain associated with high
morbidity of the donor site and lack of full recovery. As an alternative, we have focused on chitosan nerve conduits filled
with a heparin-incorporated fibrin–fibronectin matrix serving as delivery systems for basic fibroblast growth factor (bFGF). The artificial nerve conduits were
used for repairing sciatic nerve defects of 10 mm in adult rats. Three months post-operation, the conduction velocity recovery
index (CVRI) and the muscle restoration rate (MRR) in animals of the experimental group were 32 ± 4.1 and 77.4 ± 7.9%, respectively,
which were significantly higher than those of the PBS control group (17.8 ± 1.9 and 66.7 ± 6.5%), and similar to those of
the autograft group (38.4 ± 3.9 and 81.3 ± 7.8%). These results were also consistent with the densities of regenerated axons
in the three groups, which were demonstrated by histomorphological analysis. 相似文献
53.
Liu WB Ao L Zhou ZY Cui ZH Zhou YH Yuan XY Xiang YL Cao J Liu JY 《Biochemical and biophysical research communications》2010,402(3):507-514
The epigenetic mechanisms underlying the tumorigenesis caused by polycyclic aromatic hydrocarbons and nitrosamine compounds such as 3-methylcholanthrene (MCA) and diethylnitrosamine (DEN) are currently unknown. We reported previously that dynamic changes in DNA methylation occurred during MCA/DEN-induced rat lung carcinogenesis. Here, we used the same animal model to further study the evolution of methylation alterations in tumor suppressor genes (TSGs) DAPK1, FHIT, RASSF1A, and SOCS-3. We found that none of these genes were methylated in either normal or hyperplasia tissue. However, as the severity of the cancer progressed through squamous metaplasia and dysplasia to carcinoma in situ (CIS) and infiltrating carcinoma, so methylation became more prevalent. Particularly dramatic increases in the level of methylation, the average number of methylated genes, and the incidence of concurrent methylation in three genes were observed in CIS and infiltrating carcinoma. Similar but less profound changes were seen in squamous metaplasia and dysplasia. Furthermore, methylation status was closely correlated to loss of protein expression for these genes, with protein levels markedly declining along the continuum of carcinogenesis. These results suggest that progressive CpG island hypermethylation leading to inactivation of TSGs might be a vital molecular mechanism in the pathogenesis of MCA/DEN-induced multistep rat lung carcinogenesis. 相似文献
54.
Gaoneng Shao Shaoqing Tang Ju Luo Guiai Jiao Xiangjin Wei Ao Tang Jianli Wu Jieyun Zhuang Peisong Hu 《遗传学报》2010,37(8):523-531
A residual heterozygous line(RHL)carrying a heterozygous segment between two SSR loci RM11 and RM134 on the rice chromosome 7 was selected from a set of recombinant inbred lines from the cross D50(javanica)/HB277(indica).The former parent produces much longer grains than the latter.Selfed progenies of this selection were analyzed genotypically(SSRs)and phenotypically(grain length).Grain length was discontinuously variable in the mapping populations,allowing for the placement of this QTL qGL7-2 within a~4.8 cM interval defined by RM351 and RM234.A set of new markers within this region were developed,which narrowed the QTL to a 278 kb region defined by the markers Indel1 and RM21945.This region contains 49 predicted genes.The results also suggest that the novel allele for grain length will be used for the application of marker assisted selection for the improvement of grain length. 相似文献
55.
Sheng Lin Hua Chen Zimin Chen Fanli Yang Fei Ye Yue Zheng Jing Yang Xi Lin Honglu Sun Lingling Wang Ao Wen Haohao Dong Qingjie Xiao Dong Deng Yu Cao Guangwen Lu 《Nucleic acids research》2021,49(9):5382
The emergence of SARS-CoV-2 infection has posed unprecedented threat to global public health. The virus-encoded non-structural protein 14 (nsp14) is a bi-functional enzyme consisting of an exoribonuclease (ExoN) domain and a methyltransferase (MTase) domain and plays a pivotal role in viral replication. Here, we report the structure of SARS-CoV-2 nsp14-ExoN domain bound to its co-factor nsp10 and show that, compared to the SARS-CoV nsp10/nsp14-full-length complex, SARS-CoV-2 nsp14-ExoN retains an integral exoribonuclease fold and preserves an active configuration in the catalytic center. Analysis of the nsp10/nsp14-ExoN interface reveals a footprint in nsp10 extensively overlapping with that observed in the nsp10/nsp16 structure. A marked difference in the co-factor when engaging nsp14 and nsp16 lies in helix-α1′, which is further experimentally ascertained to be involved in nsp14-binding but not in nsp16-engagement. Finally, we also show that nsp10/nsp14-ExoN is enzymatically active despite the absence of nsp14-MTase domain. These data demonstrate that SARS-CoV-2 nsp10/nsp14-ExoN functions as an exoribonuclease with both structural and functional integrity. 相似文献
56.
57.
Involvement of antioxidant defense system in chill hardening-induced chilling tolerance in Jatropha curcas seedlings 总被引:1,自引:0,他引:1
Jatropha curcas L. is a sustainable energy plant with great potential for biodiesel production, and low temperature is an important limiting factor for its distribution and production. In this present work, chill hardening-induced chilling tolerance and involvement of antioxidant defense system were investigated in J. curcas seedlings. The results showed that chill hardening at 10 or 12 °C for 1 and 2 days greatly lowered death rate and alleviated electrolyte leakage as well as accumulation of the lipid peroxidation product malondialdehyde (MDA) of J. curcas seedlings under severe chilling stress at 1 °C for 1–7 days, indicating that the chill hardening significantly improved chilling tolerance of J. curcas seedlings. Measurement of activities of the antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), and glutathione reductase (GR), and the levels of the antioxidants ascorbic acid (AsA) and glutathione (GSH) showed the chill hardening at 12 °C for 2 days could obviously increase the activities of these antioxidant enzymes and AsA and GSH contents in the hardened seedlings. When the hardened and non-hardening (control) seedlings were subjected to severe chilling stress at 1 °C for 1–7 days, the chill-hardened seedlings generally maintained significantly higher activities of the antioxidant enzymes SOD, APX, CAT, POD, and GR, and content of the antioxidants AsA and GSH as well as ratio of the reduced antioxidants to total antioxidants [AsA/(AsA + DHA) and GSH/(GSH + GSSG)], when compared with the control without chill hardening. All above-mentioned results indicated that the chill hardening could enhance the chilling tolerance, and the antioxidant defense system plays an important role in the chill hardening-induced chilling tolerance in J. curcas seedlings. 相似文献
58.
A CXCL13-like chemokine cDNA was isolated from large yellow croaker (Pseudosciaena crocea) by expressed sequence tag (EST) analysis (LycCXCL13). The full-length cDNA of LycCXCL13 is 796 nucleotides (nt) encoding a protein of 97 amino acids (aa), with a putative molecular weight of 10.7 kDa. The deduced LycCXCL13 contains a 24-aa signal peptide and a 73-aa mature polypeptide, which possesses the typical arrangement of four cysteines as found in other known CXC chemokines (C25, C27, C52 and C68). It shares 35, 36 and 39% aa sequence identities to green puffer CXCL13-like, Atlantic salmon CXCL13 and Japanese flounder CXCL13 chemokines, and 24–29% identities to CXCL13 chemokines in mammals, respectively. Phylogenetic analysis showed that LycCXCL13 is more closely related to the CXCL13 subgroup than to any other CXC chemokine subgroups. LycCXCL13 gene was constitutively expressed in all tissues examined, except for intestine. Upon induction with poly(I:C) or inactivated trivalent bacterial vaccine, LycCXCL13 gene expression was significantly up-regulated in spleen, head kidney, heart and gills at 24 h post-injection. Real-time PCR results showed that LycCXCL13 gene expression reached peak level in spleen and head kidney at 12 h after induction by poly(I:C), while its expression increased to the highest level in head kidney at 24 h or in spleen at 48 h by bacterial vaccine. Recombinant LycCXCL13 protein produced in E. coli BL21 exhibited obvious chemotaxis to the peripheral blood leucocytes (PBLs) from large yellow croaker. These results suggest that LycCXCL13 may be involved in inflammatory responses as well as homeostatic processes in large yellow croaker. 相似文献
59.
Porous fiber-reinforced chitosan nerve conduits were fabricated from chitosan yarns and a chitosan solution by combining an
industrial braiding method with a mold casting/lyophilization technique. The conduits were permeable to molecules ranging
in molecular size from 180 Da (glucose) to 66,200 Da (BSA). The compressive load of the reinforced conduits was significantly
higher than that of a non-reinforced control conduit at equal levels of strain. The tensile strength of the reinforced conduits
was also increased from 0.41 ± 0.17 to 3.69 ± 0.64 MPa. An in vitro cytotoxicity test showed the conduits were not cytotoxic
to Neuro-2a cells. Preliminary in vivo implantation testing indicated that the conduits were compatible with the surrounding
tissue.
Aijun Wang and Qiang Ao contributed equally to this work. 相似文献
60.
Mutations in HOXD13 underlie syndactyly type V and a novel brachydactyly-syndactyly syndrome 下载免费PDF全文
Zhao X Sun M Zhao J Leyva JA Zhu H Yang W Zeng X Ao Y Liu Q Liu G Lo WH Jabs EW Amzel LM Shan X Zhang X 《American journal of human genetics》2007,80(2):361-371
HOXD13, the homeobox-containing gene located at the most 5' end of the HOXD cluster, plays a critical role in limb development. It has been shown that mutations in human HOXD13 can give rise to limb malformations, with variable expressivity and a wide spectrum of clinical manifestations. Polyalanine expansions in HOXD13 cause synpolydactyly, whereas amino acid substitutions in the homeodomain are associated with brachydactyly types D and E. We describe two large Han Chinese families with different limb malformations, one with syndactyly type V and the other with limb features overlapping brachydactyly types A4, D, and E and mild syndactyly of toes 2 and 3. Two-point linkage analysis showed LOD scores >3 (theta =0) for markers within and/or flanking the HOXD13 locus in both families. In the family with syndactyly type V, we identified a missense mutation in the HOXD13 homeodomain, c.950A-->G (p.Q317R), which leads to substitution of the highly conserved glutamine that is important for DNA-binding specificity and affinity. In the family with complex brachydactyly and syndactyly, we detected a deletion of 21 bp in the imperfect GCN (where N denotes A, C, G, or T) triplet-containing exon 1 of HOXD13, which results in a polyalanine contraction of seven residues. Moreover, we found that the mutant HOXD13 with the p.Q317R substitution was unable to transactivate the human EPHA7 promoter. Molecular modeling data supported these experimental results. The calculated interactions energies were in agreement with the measured changes of the activity. Our data established the link between HOXD13 and two additional limb phenotypes--syndactyly type V and brachydactyly type A4--and demonstrated that a polyalanine contraction in HOXD13, most likely, led to other digital anomalies but not to synpolydactyly. We suggest the term "HOXD13 limb morphopathies" for the spectrum of limb disorders caused by HOXD13 mutations. 相似文献