Screening and evaluation of the biocontrol efficacy of a Trichoderma brevicompactum strain and its metabolite trichodermin against banana Fusarium wilt / 生物工程学报

The banana Fusarium wilt (BFW) caused by Fusarium oxysporum f. sp. cubense tropical race4 (FocTR4) is difficult to control worldwide, which causes a huge economic losse to banana industry. The purpose of this study was to screen Trichoderma strains with antagonistic activity against FocTR4, to isolate and purify the active compound from the fermentation broth, so as to provide important biocontrol strains and active compound resources. In this work, Trichoderma strains were isolated and screened from the rhizosphere soil of crops, and the strains capable of efficiently inhibiting FocTR4 were screened by plate confrontation, and further confirmed by testing inhibition for the conidial germination and mycelial growth of FocTR4. The phylogenetic tree clarified the taxonomic status of the biocontrol strains. Moreover, the active components in the fermentation broth of the strains were separated and purified by column chromatography, the structure of the most active component was analyzed by nuclear magnetic resonance spectroscopy (NMR), the BFW control effect was tested by pot experiments. We obtained a strain JSHA-CD-1003 with antagonistic activity against FocTR4, and the inhibition rate from plate confrontation was 60.6%. The fermentation broth of JSHA-CD-1003 completely inhibited the germination of FocTR4 conidia within 24 hours. The inhibition rate of FocTR4 hyphae growth was 52.6% within 7 d. A phylogenetic tree was constructed based on the ITS and tef1-α gene tandem sequences, and JSHA-CD-1003 was identified as Trichoderma brevicompactum. Purification and NMR identification showed that the single active compound was trichodermin, and the minimum inhibitory concentration (MIC) was 25 μg/mL. Pot experiments showed that the fermentation broth of strain JSHA-CD-1003 was effective against BFW. The control rate of leaf yellowing was 47.4%, and the rate of bulb browning was 52.0%. Therefore, JSHA-CD-1003 effectively inhibited FocTR4 conidial germination and mycelium growth through producing trichodermin, and showed biocontrol effect on banana wilt caused by FocTR4, thus is a potential biocontrol strain.

RGS16 regulated by let-7c-5p promotes glioma progression by activating PI3K-AKT pathway / 医学前沿

Gliomas are the most common central nervous system tumours; they are highly aggressive and have a poor prognosis. RGS16 belongs to the regulator of G-protein signalling (RGS) protein family, which plays an important role in promoting various cancers, such as breast cancer, pancreatic cancer, and colorectal cancer. Moreover, previous studies confirmed that let-7c-5p, a well-known microRNA, can act as a tumour suppressor to regulate the progression of various tumours by inhibiting the expression of its target genes. However, whether RGS16 can promote the progression of glioma and whether it is regulated by miR let-7c-5p are still unknown. Here, we confirmed that RGS16 is upregulated in glioma tissues and that high expression of RGS16 is associated with poor survival. Ectopic deletion of RGS16 significantly suppressed glioma cell proliferation and migration both in vitro and in vivo. Moreover, RGS16 was validated as a direct target gene of miR let-7c-5p. The overexpression of miR let-7c-5p obviously downregulated the expression of RGS16, and knocking down miR let-7c-5p had the opposite effect. Thus, we suggest that the suppression of RGS16 by miR let-7c-5p can promote glioma progression and may serve as a potential prognostic biomarker and therapeutic target in glioma.

Identification of a mimotope of an infectious bronchitis virus S1 protein

The S1 protein of the infectious bronchitis virus (IBV) is a major structural protein that induces the production of the virus-neutralization antibodies. The monoclonal antibody against the IBV M41 S1 protein was used as a target for biopanning. After three rounds of biopanning, randomly selected phages bound to the monoclonal antibody. Sequence analysis showed that the dominant sequence was SFYDFEMQGFFI. Indirect competitive enzymelinked immunosorbent assay showed that SFYDFEMQGFFI is a mimotope of the S1 protein that was predicted by PepSurf. The mimotope may provide information for further structural and functional analyses of the S1 protein.

Identification of a mimotope of an infectious bronchitis virus S1 protein

The S1 protein of the infectious bronchitis virus (IBV) is a major structural protein that induces the production of the virus-neutralization antibodies. The monoclonal antibody against the IBV M41 S1 protein was used as a target for biopanning. After three rounds of biopanning, randomly selected phages bound to the monoclonal antibody. Sequence analysis showed that the dominant sequence was SFYDFEMQGFFI. Indirect competitive enzymelinked immunosorbent assay showed that SFYDFEMQGFFI is a mimotope of the S1 protein that was predicted by PepSurf. The mimotope may provide information for further structural and functional analyses of the S1 protein.

Clinical characteristics, plasma levels of hydrogen sulfide and gene analysis of cardiovascular involvement in children with methylmalonic acidemia and homocystinemia / 中华实用儿科临床杂志

Objective:To explore the clinical characteristics, plasma levels of hydrogen sulfide(H 2S) and the relationship between the genotype and phenotype of cardiovascular involvement in children with methylmalonic acidemia and homocystinemia. Methods:The clinical and laboratory data of 66 outpatients diagnosed with methylmalonic acidemia combined with homocystinemia in Department of Pediatrics, Peking University First Hospital from January 2014 to July 2014 were collected and analyzed respectively, and the patients were divided into 2 groups: cardiovascular involvement group (10 cases) and non-cardiovascular involvement group(56 cases). The differences in the clinical characteristics, plasma levels of H 2S and genotypes were compared between 2 groups. Results:(1) There were 45 cases of early-onset children under 1 year old, including 4 cases of cardiovascular system involvement and 41 cases of non-cardiovascular system involvement.Twenty-one cases had onset above 1 year old, including 6 cases of cardiovascular system involvement and 15 cases of non-cardiovascular system involvement. There were 44 male children, including 8 cases with cardiovascular system involvement and 36 cases without cardiovascular system involvement; 22 cases female children, including 2 cases with cardiovascular system involvement and 20 cases without cardiovascular system involvement. There was no significant difference in onset age and gender distribution between the 2 groups ( χ2=2.910, 0.368, all P>0.05). (2)In the 10 cases with cardiovascular involvement, there were 3 cases with hypertension, 2 cases with hypertension combined with pulmonary hypertension, 2 cases with mild myocardial hypertrophy, 1 case with atrial septal defect combined with pulmonary hypertension, 1 case with pulmonary hypertension, 1 case with myocardial noncompaction.Compared with the non-cardiovascular involvement group, the proportion of kidney involvement was increased and that of nervous system was decreased in cardiovascular system involvement group( χ2=20.34, 5.79, all P<0.05), the proportion of hematological system involvement between the 2 groups had no significant differences ( χ2=1.28, P>0.05). The plasma levels of hydrogen sulfide of children with cardiovascular involvement was significantly lower than that of non-cardiovascular involvement[(33.8±3.6) μmol/L vs.(39.3±5.2) μmol/L, t=-3.22, P<0.01]. (3) MMACHC gene mutation (cblC type) was identified in all 46 patients.It was found that the most common type of gene mutation was c. 80A>G in cardiovascular involvement group, while c. 609G>A was the most common type of gene mutation in non-cardiovascular involvement group. Conclusions:The clinical manifestations of children with methylmalonic acidemia and homocystinemia involving cardiovascular system are multiple and prone to multiple system involvement, especially renal involvement.A decrease in plasma hydrogen sulfide levels may be involved in the involvement of its cardiovascular system.The MMACHC gene c. 80A>G mutation is the most common genetic mutation site in children with cardiovascular involvement with methylmalonic acidemia and homocystinemia.

A novel missense mutation in MIP gene resulted in polymorphic cataract / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To map the disease locus for a congenital cataract family, and detect the disease-causing gene.</p><p><b>METHODS</b>An autosomal dominant congenital cataract family was genotyped by genome wide scan using 382 autosomal microsatellite markers from ABI-MD10. Two-point linkage analysis was carried out by the MLINK program.</p><p><b>RESULTS</b>The disease locus of this family was mapped at 12p11.2-q15. Sequence analysis of a candidate gene-major intrinsic protein (MIP) revealed a novel missense mutation G-->A at the nucleotide 702 in exon 4, which resulted in a substitution of arginine to lysine at codon 233 (p.R233K).</p><p><b>CONCLUSION</b>The mutation G-->A at nt702 in MIP gene was associated with the binocular polymorphic congenital cataract in the family. This transition occurring at the C-terminus of MIP might decrease the stability of the C-end of the protein and impact the function of the protein.</p>