日粮添加复合饲用益生菌对肉牛生长性能及肠道微生物的影响

[目的]为研究添加饲用益生菌对肉牛生长性能、血液生理生化指标及肠道微生物区系的影响.[方法]在青海地区选取西门塔尔牛与荷斯坦牛的杂交1代18头,按每组平均体重相近的原则随机分为2组,每组9头,试验组饮食添加地衣芽孢杆菌、枯草芽孢杆菌和酿酒酵母的复合饲用益生菌.[结果]试验结果表明:试验组显著地提高了胸围日增长量(P=0...     

Biochemical properties of a native β-1,4-mannanase from Aspergillus aculeatus QH1 and partial characterization of its N-glycosylation

N-glycosylation plays critical roles in protein secretion, sorting, stability, activity modulation, and interactions to other molecules in the eukaryotic organisms. Fungal β-1,4-mannanases have been widely used in the agri-food industry and contribute to the pathogenesis on plants. However, the information on N-glycosylation of a specific fungal carbohydrate-active enzyme (CAZyme) is currently limited. Herein, a cDNA was cloned from Aspergillus aculeatus QH1, displaying a full length of 1302 bp with an open reading frame of 1134 bp encoding for a GH5 subfamily 7 β-1, 4-mannanase, namely AacMan5_7A. The enzyme was purified and exhibited an optimal activity at pH 4.6 and 60 °C, hydrolyzing glucomannan and galactomannan, but not yeast mannan. AacMan5_7A is an N-glycosylated protein decorated with a high-mannose type glycan. Further through UPLC-ESI-MS/MS analysis, one of the four predicted N-glycosylation sites at N255 position was experimentally verified. The present study expands the information of N-glycosylation in fungal CAZymes, providing scientific bases for enhancing the production of fungal enzymes and their applications in food, feed, and plant biomass conversions.     

Tsp2 Facilitates Tumor-associated Fibroblasts Formation and Promotes Tumor Progression in Retroperitoneal Liposarcoma

Retroperitoneal liposarcoma (RLPS) is the most common subtype of retroperitoneal soft tissue sarcoma, characterized by a high recurrence rate and insensitivity to radiotherapy and chemotherapy. The function of tumor microenvironmental components, especially tumor-associated fibroblasts (TAFs), remains unclear in RLPS. The crosstalk between tumor cells and stromal cells should be clarified for therapy target discovery in RLPS. In this study, we demonstrated that TAFs from dedifferentiated liposarcoma (DDLPS) could attract LPS cells and promote their proliferation and migration. However, although α-SMA is positively expressed in RLPS, its expression does not indicate prognosis. By screening differentially expressed genes, performing Oncomine visualization, TCGA gene expression correlation analysis and qPCR verification, we determined that thrombospondin-2 (THBS2) gene expression was related to TAFs. The expression of Tsp2 protein, which was encoded by THBS2, was correlated with α-SMA expression, and it was an independent predictive factor for disease-free survival and recurrence-free survival in patients with RLPS. In vitro, Tsp2 facilitated the transformation of bone marrow-derived fibroblasts (BMFs) to TAFs and promoted the malignant biological behaviors of LPS cells by activating the MAPK/MEK/ERK pathway. Therefore, suppression of Tsp2 is expected to be a promising treatment method for RLPS patients.     

Whole Genome Sequence Analysis of Lactiplantibacillus Plantarum Bacteriophage P2

Phage P2 was isolated from failed fermentation broth carried out by Lactiplantibacillus plantarum IMAU10120. A previous study in our laboratory showed that this phage belonged to the Siphoviridae family. In this study, this phage’s genomic characteristics were analyzed using whole-genome sequencing. It was revealed that phage P2 was 77.9 kb in length and had 39.28% G + C content. Its genome included 96 coding sequences (CDS) and two tRNA genes involved in the function of the structure, DNA replication, packaging, and regulation. Phage P2 had higher host specificity; many tested strains were not infected. Cell wall adsorption experiments showed that the adsorption receptor component of phage P2 might be a part of the cell wall peptidoglycan. This research might enrich the knowledge about genomic information of lactobacillus phages and provide some primary data to establish phage control measures.     

乳酸菌胆盐水解酶和共轭脂肪酸产生及对宿主脂代谢影响的研究进展

乳酸菌是一类影响宿主脂代谢的人体肠道益生菌。乳酸菌对脂代谢的影响作用与其产生胆盐水解酶(bile salt hydrolase,EC3.5.1.24,BSH)及共轭转化多不饱和脂肪酸(polyunsaturated fatty acids,PUFAs)关系密切。菌株差异、菌群分布和饮食差异是影响BSH及共轭脂肪酸产生的重要因素。本文重点阐述了两类物质对宿主脂代谢的影响机制,以期为后续研究提供借鉴。BSH能够降解肝脏分泌的胆汁酸(bile acids,BAs),降低脂类物质的吸收。BAs的降解产物胆汁酸脱氧胆酸(deoxycholic acid,DCA)和石胆酸(lithocholic acid,LCA)能够通过机体信号通路法尼类X受体(farnesoid X receptor,FXR)、小异二聚体伴侣(small heterodimer partner,SHP)及肝脏X受体(liver X receptor,LXR)等信号通路进行调控,促进胆固醇转运及向BAs转化。此外,BSH还能够通过下调固醇调节元件结合蛋白1c (sterol regulatory element binding protein 1c,SREBP-1c)、上调5ʹ-腺苷单磷酸激活蛋白激酶α(5ʹ-AMP activated protein kinase,AMPKα)和过氧化物酶体增殖物激活受体α (peroxisome proliferator-activated receptor α,PPARα)抑制脂质合成,促进脂质的分解。PUFAs可被乳酸菌转化产生共轭脂肪酸,如共轭亚油酸(conjugated linoleic acid,CLA)和共轭亚麻酸(conjugated linolenic acid,CLNA),CLA/CLNA能够促进机体产生瘦素(leptin,LP),抑制食欲、促进能量消耗;CLA/CLNA还可以通过激活PPARα进行调控,促进人体脂质的氧化分解。乳酸菌通过以上多种途径共同作用调节宿主的脂代谢,对深入理解乳酸菌调控脂代谢机制及临床应用有着重要意义。     

Novel artificial intelligence machine learning approaches to precisely predict survival and site-specific recurrence in cervical cancer: A multi-institutional study

BackgroundMachine learning (ML) has been gradually integrated into oncologic research but seldom applied to predict cervical cancer (CC), and no model has been reported to predict survival and site-specific recurrence simultaneously. Thus, we aimed to develop ML models to predict survival and site-specific recurrence in CC and to guide individual surveillance.MethodsWe retrospectively collected data on CC patients from 2006 to 2017 in four hospitals. The survival or recurrence predictive value of the variables was analyzed using multivariate Cox, principal component, and K-means clustering analyses. The predictive performances of eight ML models were compared with logistic or Cox models. A novel web-based predictive calculator was developed based on the ML algorithms.ResultsThis study included 5112 women for analysis (268 deaths, 343 recurrences): (1) For site-specific recurrence, larger tumor size was associated with local recurrence, while positive lymph nodes were associated with distant recurrence. (2) The ML models exhibited better prognostic predictive performance than traditional models. (3) The ML models were superior to traditional models when multiple variables were used. (4) A novel predictive web-based calculator was developed and externally validated to predict survival and site-specific recurrence.ConclusionML models might be a better analytic approach in CC prognostic prediction than traditional models as they can predict survival and site-specific recurrence simultaneously, especially when using multiple variables. Moreover, our novel web-based calculator may provide clinicians with useful information and help them make individual postoperative follow-up plans and further treatment strategies.     

Comparative chloroplast genomes of <Emphasis Type="Italic">Paris</Emphasis> Sect. <Emphasis Type="Italic">Marmorata</Emphasis>: insights into repeat regions and evolutionary implications

Background

Species of Paris Sect. Marmorata are valuable medicinal plants to synthesize steroidal saponins with effective pharmacological therapy. However, the wild resources of the species are threatened by plundering exploitation before the molecular genetics studies uncover the genomes and evolutionary significance. Thus, the availability of complete chloroplast genome sequences of Sect. Marmorata is necessary and crucial to the understanding the plastome evolution of this section and facilitating future population genetics studies. Here, we determined chloroplast genomes of Sect. Marmorata, and conducted the whole chloroplast genome comparison.

Results

This study presented detailed sequences and structural variations of chloroplast genomes of Sect. Marmorata. Over 40 large repeats and approximately 130 simple sequence repeats as well as a group of genomic hotspots were detected. Inverted repeat contraction of this section was inferred via comparing the chloroplast genomes with the one of P. verticillata. Additionally, almost all the plastid protein coding genes were found to prefer ending with A/U. Mutation bias and selection pressure predominately shaped the codon bias of most genes. And most of the genes underwent purifying selection, whereas photosynthetic genes experienced a relatively relaxed purifying selection.

Conclusions

Repeat sequences and hotspot regions can be scanned to detect the intraspecific and interspecific variability, and selected to infer the phylogenetic relationships of Sect. Marmorata and other species in subgenus Daiswa. Mutation and natural selection were the main forces to drive the codon bias pattern of most plastid protein coding genes. Therefore, this study enhances the understanding about evolution of Sect. Marmorata from the chloroplast genome, and provide genomic insights into genetic analyses of Sect. Marmorata.

     

结核杆菌抗原85A与小鼠白细胞介素21共表达DNA疫苗的构建及其免疫效应研究

目的:利用真核表达质粒pRSC,构建结核杆菌抗原85A(Ag85A)与小鼠白细胞介素21(mIL21)共表达重组体pRSC-mIL21-Ag85A,为研究新型结核杆菌DNA疫苗提供新的策略。方法:从质粒pcDNA3.1-mIL21中经PCR扩增出mIL21基因,并插入质粒pRSC中构成pRSC-mIL21;再从pIRES-Ag85A质粒中经PCR扩增出Ag85A基因,构建于pRSC-mIL21重组质粒上,成为共表达DNA疫苗pRSC-mIL21-Ag85A。结果:经酶切、基因测序证实,该疫苗构建正确并能成功表达目的基因。共表达DNA疫苗免疫小鼠后,CTL活性、特异性淋巴细胞增殖水平及小鼠血清特异性抗体均呈有意义的提高。结论:结核杆菌Ag85A与mIL21共表达DNA疫苗能诱导小鼠免疫反应,为进一步研究DNA疫苗抗结核杆菌攻击的免疫防护效应奠定了基础。