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1.
It was found that S-adenosylmethionine (SAM) could effectively improve avermectin titer with 30–60 μg/mL addition to FH medium. To clearly elucidate the mechanism of SAM on intracellular metabolites of Streptomyces avermitilis, a GC–MS-based comparative metabolomics approach was carried out. First, 230 intracellular metabolites were identified and 14 of them remarkably influenced avermectin biosynthesis were discriminative biomarkers between non-SAM groups and SAM-treated groups by principal components analysis (PCA) and partial least squares (PLS). Based on further key metabolic pathway analyses, these biomarkers, such as glucose, oxaloacetic acid, fatty acids (in soybean oil), threonine, valine, and leucine, were identified as potentially beneficial precursors and added in medium. Compared with single-precursor feeding, the combined feeding of the precursors and SAM markedly increased the avermectin titer. The co-feeding approach not only directly verified our hypothesis on the mechanism of SAM by comparative metabolomics, but also provided a novel strategy to increase avermectin production.  相似文献   
2.
Dissecting the genetic basis for the traits of northern-style Chinese steamed bread (NCSB) is of great significance for wheat quality breeding. Quantitative trait loci (QTLs) for the processing quality of NCSB were studied using a recombinant inbred line (RIL) consisting of 173 lines derived from a “Shannong01–35 × Gaocheng9411” cross. Twenty-four putative additive QTLs were detected on chromosomes 1A, 1B, 1D, 3A, 3B, 4A, 4B, 5B, 6B, and 7B. Of these QTLs, QTex1A.1-27, QHei5B.5-488, and QGum4B.4-17 had the highest contribution and accounted for 9.33, 10.9, and 12.0% of the phenotypic variations, respectively. Several co-located QTLs with additive effects were detected on chromosomes 1A, 1D, 4B, and 5B. Two clusters (RFL_CONTIG2160_524-WSNP_CAP12_C2438_1180601 and EX_C101685_705-RAC875_C27536_611) for height, total score, and texture and for chewiness, gumminess, and hardness were detected on chromosomes 1A and 4B, respectively. Two QTLs for chewiness and hardness (QCh1D-4, QHa1D-4) with additive effects were detected; these alleles could be good targets for improving the processing quality of steamed bread from common wheat (Triticum aestivum L.). In addition, QTLs for wheat flour quality and the associated correlations with NCSB were simultaneously analyzed. Negative correlations were detected between chewiness and the wet/dry gluten content (WGC/DGC) or protein content. Two QTLs (QCh4B.4-17 and QPr4B.4-17) and three QTLs (QCh4B.4-13, QWG4B.4-13, and QDG4B.4-13) clustered in the same chromosomal region. The detected QTL clusters should be further investigated during wheat breeding and could be used by breeders to improve wheat quality and especially the processing quality of NCSB.  相似文献   
3.
Kernel size and kernel weight are important factors possibly involved in the determination of grain yield in maize, so identifying the genetic basis of kernel-related traits provides insights into the breeding of high-yield maize varieties. Kernel length (KL), kernel width (KW) and hundred kernel weight (HKW) were evaluated in three various planting conditions for the 240 field-grown double haploid (DH) lines derived from the single-cross hybrid Xianyu335. Variations in KL, KW and HKW were observed among DH lines, and all three traits showed a broad sense heritability of 76%. A total of 964 single nucleotide polymorphisms (SNPs) from the MaizeSNP3072 chip was utilised to create a high-density genetic map of 1546.4 cM and to identify quantitative trait loci (QTLs). Using composite interval mapping, a total of five, seven and five QTLs have been mapped for KL, KW and HKW, respectively. qkl1-2 and qkl4-1 explained 17.8% and 14.2% of the phenotypic variation in KL, respectively, and the other three QTLs contributed 3.2–4.0%. The phenotypic variation explained (PVE) of seven QTLs responsible for KW ranged from 3.3 to 9.5%. Three QTLs for HKW, qhkw1, qhkw5 and qhkw10 each explained more than 10% of the phenotypic variation, and qhkw4 and qhkw9 accounted for 3.0% and 6.0%, respectively. Due to their detection in multiple planting environments, the loci mapped here appear to be potential targets for the improvement of maize grain yield.  相似文献   
4.
Polyomavirus BK (BKV) infection is an important cause of renal allograft failure. Viral microRNAs are known to play a crucial role in viral replication. This study investigated the expression of BKV-encoded microRNAs (miR-B1) in patients with polyomavirus-associated nephropathy (PVAN) and their role in viral replication. Following BKV infection in renal proximal tubular cells, the 3p and 5p miR-B1 levels were significantly increased. Cells transfected with the vector containing the miR-B1 precursor (the miR-B1 vector) showed a significant increase in expression of 3p and 5p miR-B1 and decrease in luciferase activity of a reporter containing the 3p and 5p miR-B1 binding sites, compared to cells transfected with the miR-B1-mutated vector. Transfection of the miR-B1 expression vector or the 3p and 5p miR-B1 oligonucleotides inhibited expression of TAg. TAg-enhanced promoter activity and BKV replication were inhibited by miR-B1. In contrast, inhibition of miR-B1 expression by addition of miR-B1 antagomirs or silencing of Dicer upregulated the expression of TAg and VP1 proteins in BKV-infected cells. Importantly, patients with PVAN had significantly higher levels of 3p and 5p miR-B1 compared to renal transplant patients without PVAN. In conclusion, we demonstrated that (1) miR-B1 expression was upregulated during BKV infection and (2) miR-B1 suppressed TAg-mediated autoregulation of BKV replication. Use of miR-B1 can be evaluated as a potential treatment strategy against BKV infection.  相似文献   
5.
Extramedullary hematopoiesis has been shown to contribute to the pathogenesis of a variety of diseases including cardiovascular diseases. In this process, the spleen is seeded with mobilized bone marrow cells that augment its hematopoietic ability. It is unclear whether these immigrant cells that are produced/reprogrammed in spleen are similar or different from those found in the bone marrow. To begin to understand this, we investigated the relative potency of adult splenocytes per se to repopulate bone marrow of lethally-irradiated mice and its functional consequences in atherosclerosis. The splenocytes were harvested from GFP donor mice and transplanted into myeloablated wild type recipient mice without the inclusion of any bone marrow helper cells. We found that adult splenocytes repopulated bone marrow of myeloablated mice and the transplanted cells differentiated into a full repertoire of myeloid cell lineages. The level of monocytes/macrophages in the bone marrow of recipient mice was dependent on the cell origin, i.e., the donor splenocytes gave rise to significantly more monocytes/macrophages than the donor bone marrow cells. This occurred despite a significantly lower number of hematopoietic stem cells being present in the donor splenocytes when compared with donor bone marrow cells. Atherosclerosis studies revealed that donor splenocytes displayed a similar level of atherogenic and atheroprotective activities to those of donor bone marrow cells. Cell culture studies showed that the phenotype of macrophages derived from spleen is different from those of bone marrow. Together, these results demonstrate that splenocytes can seed bone marrow of myeloablated mice and modulate atherosclerosis. In addition, our study shows the potential of splenocytes for therapeutic interventions in inflammatory disease.  相似文献   
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Increasing reports have verified that miRNAs had an important effect on the growth and development in farm animals. To evaluate the possible effect of miR-1596 polymorphisms on chicken economic traits, directly sequencing and polymerase chain reaction–restriction fragment length polymorphism, association analysis as well as online software were used. The results showed that a C > T polymorphism existed in the miR-1596 gene of the Gushi × Anka F2 resource population. The association analysis showed that it was significantly relevant with the potential of hydrogen of leg muscle, fat content of dry sample and fat content of fresh sample, shank length at 0 day and 4 weeks of age; leg weight, leg muscle weight, and breast muscle weight (P < 0.05); and highly significant association with shank girth at 8 weeks of age and abdominal fat weight (P < 0.01). We predicted the secondary structure of Gallus gallus-miR-1596 (gga-miR-1596) and the free energy by using M-fold, which were not altered. MiR-1596 is conserved between chicken and turkey. Our data implied that miR-1596 might participate in regulating the muscle development and adipogenesis.  相似文献   
9.
Abstract  The present paper deals with a new species Habrophlebiodes zijinensis sp. nov. collected in Nanjing, Jiangsu Povince, China.  相似文献   
10.
气候变化和人类活动是对陆地生态系统碳循环产生重要影响的两个因素,定量评估气候变化与人类活动对植被净初级生产力(NPP)的相对影响,对深入理解其驱动机制和控制荒漠化发展具有重要意义。以疏勒河流域为研究区,利用遥感和气象数据计算潜在NPP(PNPP)及其与实际NPP(ANPP)之间的差值,分别衡量了气候变化和人类活动对流域NPP的相对影响。研究结果表明:(1)2001—2015年疏勒河流域年ANPP整体呈缓慢增加趋势,与全国和西北地区相比,普遍较低,流域植被整体生产力水平不高。流域年ANPP空间分布呈现上游祁连山区和中下游绿洲区ANPP较高,而中下游荒漠戈壁区ANPP较低的分布格局。(2)2001—2015年流域年PNPP的变化趋势表明,降水量的变化是导致疏勒河流域植被退化加剧或缓解的主要气候驱动因素,但气温的变化对植被的影响较为复杂。(3)2001—2015年流域大部分地区植被退化系人类活动造成的,但人类活动的负向影响力在减弱。(4)气候变化和人类活动对植被NPP的相对影响均表现出明显的空间异质性,其中人类活动是疏勒河流域植被变化的主要驱动因素。  相似文献   
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