马铃薯StPSKRs基因的克隆及其亚细胞定位分析

该研究采用同源克隆与PCR扩增方法,从马铃薯品种‘Desiree’中克隆植物磺肽素受体基因StPSKR1和StPSKR2的全长cDNA,并对其进行生物信息学分析及亚细胞定位分析,为深入研究StPSKR1和StPSKR2基因在马铃薯生长发育和生物胁迫中的作用提供理论依据。结果发现:(1)通过同源克隆与PCR扩增获得StPSKR1和StPSKR2的全长cDNA片段,并将其克隆到pGWB5-GFP载体;测序结果显示这2个基因编码的蛋白质与数据库给定的蛋白质序列保持一致,表明成功克隆到StPSKR1和StPSKR2基因。(2)StPSKR1位于马铃薯1号染色体上,cDNA全长3 042 bp,编码1 013个氨基酸,预测蛋白相对分子质量为112.16 kD,理论等电点6.27;StPSKR2位于7号染色体,cDNA全长3 135 bp,编码1 044个氨基酸,相对分子量为114.99 kD,理论等电点6.19。(3)生物信息学分析显示,StPSKR1和StPSKR2都属于跨膜蛋白。(4)亚细胞定位结果显示,StPSKR1和StPSKR2均定位于细胞膜上。     

Expression and characteristics of vanilloid receptor 1 in the rabbit submandibular gland

Vanilloid receptor 1 (VR1) is a polymodal receptor originally found in sensory neurons of the central nervous system. Recent evidence indicates that VR1 is also expressed in non-neuronal tissues. We report here endogenous expression of VR1 in rabbit submandibular gland (SMG) and its possible role in regulating saliva secretion based on: (i) the expression of VR1 mRNA and protein detected in SMG; (ii) VR1 was mainly localized in the basolateral membrane of duct cells and the cytoplasm of acinar cells and also in cytoplasm of primary cultured neonatal rabbit SMG cells; (iii) stimulation of neonatal rabbit SMG cells with capsaicin induced a significant increase in intracellular calcium, and capsazepine, a VR1 antagonist, abolished this increase; (iv) infusion of capsaicin via the external carotid artery to isolated SMG increased saliva secretion of the gland. These findings indicated that VR1 was expressed in SMG and appeared to play an important role in regulating saliva secretion.     

蛋白质结构中卷曲螺旋的研究进展

卷曲螺旋 (coiledcoil)是存在于多种天然蛋白质中的结构模式 .近年来 ,通过对天然蛋白质中卷曲螺旋结构以及根据已有知识设计合成的卷曲螺旋结构的研究 ,已基本掌握了这类结构模式的特点 ,并将特异的卷曲螺旋结构应用于生化分析、工业、医药卫生等领域 .本文主要从天然蛋白质中卷曲螺旋的主要存在形式及其生物学功能、卷曲螺旋的主要结构特点、影响卷曲螺旋稳定性和结构特异性的因素、卷曲螺旋结构设计及其应用以及今后卷曲螺旋研究的主要发展方向等几个方面对近年来卷曲螺旋结构的研究进展情况进行了综述 .     

Chromosome‐level de novo genome assembly of Sarcophaga peregrina provides insights into the evolutionary adaptation of flesh flies

Sarcophaga peregrina is considered to be of great ecological, medical and forensic significance, and has unusual biological characteristics such as an ovoviviparous reproductive pattern and adaptation to feed on carrion. The availability of a high‐quality genome will help to further reveal the mechanisms underlying these charcateristics. Here we present a de novo‐assembled genome at chromosome scale for S. peregrina. The final assembled genome was 560.31 Mb with contig N50 of 3.84 Mb. Hi‐C scaffolding reliably anchored six pseudochromosomes, accounting for 97.76% of the assembled genome. Moreover, 45.70% of repeat elements were identified in the genome. A total of 14,476 protein‐coding genes were functionally annotated, accounting for 92.14% of all predicted genes. Phylogenetic analysis indicated that S. peregrina and S. bullata diverged ~ 7.14 million years ago. Comparative genomic analysis revealed expanded and positively selected genes related to biological features that aid in clarifying its ovoviviparous reproduction and carrion‐feeding adaptations, such as lipid metabolism, olfactory receptor activity, antioxidant enzymes, proteolysis and serine‐type endopeptidase activity. Protein‐coding genes associated with ovoviparity, such as yolk proteins, transferrin and acid sphingomyelinase, were identified. This study provides a valuable genomic resource for S. peregrina, and sheds insight into further revealing the underlying molecular mechanisms of adaptive evolution.     

Cloning and molecular characterization of a novel rolling-circle replicating plasmid, pK1S-1, from Bacillus thuringiensis subsp. kurstaki K1

Bacillus thuringiensis, an entomopathogenic bacterium belonging to the B. cereus group, harbors numerous extra-chromosomal DNA molecules whose sizes range from 2 to 250 kb. In this study, we used a plasmid capture system (PCS) to clone three small plasmids from B. thuringiensis subsp. kurstaki Kl which were not found in B. thuringiensis subsp. kurstaki HD-1, and determined the complete nucleotide sequence of plasmid pKlS-1 (5.5 kb). Of the six putative open reading frames (ORF2-ORF7) in pKlS-1, ORF2 (MobKl) showed approximately 90% aa identity with the Mob-proteins of pGI2 and pTX14-2, which are rolling circle replicating group VII (RCR group VII) plasmids from B. thuringiensis. In addition, a putative origin of transfer (oriT) showed 95.8% identity with those of pGI2 and pTX14-2. ORF3 (RepK1) showed relatively low aa identity (17.8～25.2%) with the Rep protein coded by RCR plasmids, however. The putative double-strand origin of replication (dso) and single-strand origin of replication (sso) of pKlS-1 exhibited approximately 70% and 64% identities with those of pGI2 and pTX14-2. ORF6 and 7 showed greater than 50% similarities with alkaline serine protease, which belongs to the subtilase family. The other 2 ORFs were identified as hypothetical proteins. To determine the replicon of pKlS-1, seven subclones were contructed in the B. thuringiensis ori-negative pHTIK vector and were electroporated into a plasmid cured B. thuringiensis strain. The 1.6 kb region that included the putative ORF3 (ReplK), dso and ORF4, exhibited replication ability. These findings identified pKlS-1 as a new RCR group VII plasmid, and determined its replication region.     

Retracted: Upregulated microRNA-15b alleviates ovarian cancer through inhitbition of the PI3K/Akt pathway by targeting LPAR3

Ovarian cancer characterizes as the fourth leading consequence of death associated with cancer for women. Accumulating evidence underscores the vital roles of microRNAs (miRNAs) in preventing ovarian cancer development. Besides, induction of the phosphatidylinositol-3 kinase/serine/threonine kinase (PI3K/Akt) pathway associated with the ovarian cancer cell migration and invasion. The study aims to examine the effects of miR-15b on the proliferation, apoptosis, and senescence of human ovarian cancer cells by binding to lysophosphatidic acid receptor 3 (LPAR3) with the involvement of the PI3K/Akt pathway. The positive expression of LPAR3 protein was detected by immunohistochemistry. Then the interaction between miR-15b and LPAR3 was examined. The possible role of miR-15b in ovarian cancer was explored using gain- and loss-of-function experiments. Subsequently, the functions of miR-15b on PI3K/Akt pathway, proliferation, migration, invasion, senescence and apoptosis of ovarian cancer cells were assessed. Furthermore, in vivo tumorigenicity assay in nude mice was performed. LPAR3 was overexpressed, whereas miR-15b was poorly expressed in ovarian cancer tissues. LPAR3 is a direct target of miR-15b. Restored miR-15b promoted Bax expression, apoptosis, and senescence, inhibited expression of LPAR3 and Bcl-2, the extent of PI3K and Akt phosphorylation, as well as ovarian cancer cell proliferation, migration, and invasion. Further, tumor growth was observed to be prevented by miR-15b overexpression. Collectively, our study demonstrates that miR-15b represses the proliferation and drives the senescence and apoptosis of ovarian cancer cells through the suppression of LPAR3 and the PI3K/Akt pathway, highlighting an antitumorigenic role of miR-15b.     

Splenocytes Seed Bone Marrow of Myeloablated Mice: Implication for Atherosclerosis

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.     

南方红壤旱坡地花生植株对施用氮肥的响应

选用多年夏花生-冬蔬菜种植制度下的典型红壤旱坡地,通过田间试验,研究了5种氮肥水平下花生根系的形态特征、固氮能力、植株生物量以及荚果产量。结果表明:不同氮肥施用量对花生植株生物量及荚果产量影响均不显著(P=0.091);而不同处理的土壤固氮酶活性与氮肥施用量间呈极显著的负相关(R2=0.88,P=0.005);单株花生根系总长度、总表面积、总分叉数及根尖条数均随氮肥施用量的增加而减小,且与单株花生根瘤生物量呈极显著(P<0.001)正相关。     

类胡萝卜素产生菌深红酵母(Rhodotorula rubra)的培养条件的优化研究

本文研究深红酵母及其产生的类胡萝卜素的培养优化条件,并对其进行了小型发酵试验,结果表明pH值对深红酵母和类胡萝卜素有影响,初始pH值越低,色素的积累量越高,发酵过程中控制pH值能有效地增加色素积累的速度和初始色素积累量,但随着发酵时间的延长,色素积累量逐渐下降。