102 resultados para Blast-furnace
Resumo:
Heat shock protein 90 (HSP90) is a highly conserved molecular chaperone contributing to the folding, maintenance of structural integrity and proper regulation of a subset of cytosolic proteins. The full-length cDNA of Zhikong scallop Chlamysfarreri HSP90 (designated CfHSP90) was cloned by EST and rapid RACE techniques. It was of 2710 bp, including an open reading frame (ORF) of 2181 bp encoding a polypeptide of 726 amino acids with all the five HSP90 family signatures. BLAST analysis revealed that the CfHSP90 gene shared high similarity with other known HSP90 genes. Fluorescent real-time quantitative RT-PCR was used to examine the expression pattern of CfHSP90 mRNA in haemocytes of scallops exposed to Cd2+, Pb2+ and Cu2+ for 10 and 20 days, respectively. All the three heavy metals could induce CfHSP90 expression. There was a clear dose-dependent expression pattern of CfHSP90 after heavy metals exposure for 10 days or 20 days. Different concentrations of the same metal resulted in different effects on CfHSP90 expression. The results indicated that CfHSP90 responded to various heavy metal stresses with a dose-dependent expression pattern as well as exposure time effect, and could be used as a molecular biomarker in a heavy metal polluted environment. (c) 2007 Elsevier Inc. All rights reserved.
Resumo:
Heat shock protein 90 (HSP90) is a highly conserved molecular chaperone that plays key roles in the folding, maintenance of structural integrity and regulation of a subset of cytosolic proteins. In the present study, the cDNA of Argopecten irradians HSP90 (designated AiHSP90) was cloned by the combination of homology cloning and rapid amplification of cDNA ends (RACE) approaches. The full-length cDNA of AiHSP90 was of 2669 bp, including an open reading frame (ORF) of 2175 bp encoding a polypeptide of 724 amino acids with predicted molecular weight of 83.08 kDa and theoretical isoelectric point of 4.81. BLAST analysis revealed that AiHSP90 shared high similarity with other known HSP90s, and the five conserved amino acid blocks defined as HSP90 protein family signatures were also identified in AiHSP90, which indicated that AiHSP90 should be a cytosolic member of the HSP90 family. Fluorescent real-time quantitative PCR was employed to examine the expression pattern of AiHSP90 mRNA in haemocytes of scallops challenged by Gram-negative bacteria Vibrio anguillarum and Gram-positive bacteria Micrococcus luteus. In both bacterial challenged groups, the relative expression level of AiHSP90 transcript was up-regulated and reached maximal. level at 9 h after injection, and then dropped progressively to the original level at about 48 h post challenge. The results indicated that AiHSP90 was potentially involved in the immune responses against bacteria challenge in scallop A. irradian. (c) 2007 Elsevier Ltd. All rights reserved.
Resumo:
The community structure and vertical distribution of prokaryotes in a deep-sea (ca. 3,191 m) cold sediment sample (ca. 43 cm long) collected at the East Pacific Rise (EPR) similar to 13 degrees N were studied with 16SrDNA-based molecular analyses. Total community DNA was extracted from each of four discrete layers EPRDS-1, -2, -3 and -4 (from top to bottom) and 16S rDNA were amplified by PCR. Cluster analysis of DGGE profiles revealed that the bacterial communities shifted sharply between EPRDS-1 and EPRDS-2 in similarity coefficient at merely 49%. Twenty-three sequences retrieved from DGGE bands fell into 11 groups based on BLAST and bootstrap analysis. The dominant groups in the bacterial communities were Chloroflexi, Gamma proteobacteria, Actinobacterium and unidentified bacteria, with their corresponding percentages varying along discrete layers. Pairwise Fst (F-statistics) values between the archaeal clone libraries indicated that the archaeal communities changed distinctly between EPRDS-2 and EPRDS-3. Sequences from the archaeal libraries were divided to eight groups. Crenarchaea Marine Group I (MGI) was prevalent in EPRDS-1 at 83%, while Uncultured Crenarchaea group II B (UCII B) abounded in EPRDS-4 at 61%. Our results revealed that the vertically stratified distribution of prokaryotic communities might be in response to the geochemical settings and suggested that the sampling area was influenced by hydrothermalism. The copresence of members related to hydrothermalism and cold deep-sea environments in the microbial community indicated that the area might be a transitional region from hydrothermal vents to cold deep-sea sediments.
Resumo:
Peptidoglycan recognition protein (PGRP) specifically binds to peptidoglycan and plays a crucial role in the innate immune responses as a pattern recognition receptor (PRR). The cDNA of a short type PGRP was cloned from scallop Chlamys farreri (named CfPGRP-SI) by homology cloning with degenerate primers, and confirmed by virtual Northern blots. The full length of CfPGRP-SI cDNA was 1073 bp in length, including a 5 ' untranslated region (UTR) of 59 bp, a 3 ' UTR of 255 bp, and an open reading frame (ORF) of 759 bp encoding a polypeptide of 252 amino acids with an estimated molecular mass of 27.88 kDa and a predicted isoelectric point of 8.69. BLAST analysis revealed that CfPGRP-S1 shared high identities with other known PGRPs. A conserved PGRP domain and three zinc-binding sites were present at its C-terminus. The temporal expression of QPGRP-S1 gene in healthy, Vibrio anguillarum-challenged and Micrococcus lysodeikticus-challenged scallops was measured by RT-PCR analysis. The expression of CfPGRP-S1 was upregulated initially in the first 12 h or 24 h either by M. lysodeikticus or V. anguillarum challenge and reached the maximum level at 24 h or 36 h, then dropped progressively, and recovered to the original level as the stimulation decreased at 72 h. There was no significant difference between V. anguillarum and M. lysodeikticus challenge. The results indicated that the CfPGRP-S1 was a constitutive and inducible acute-phase protein which was involved in the immune response against bacterial infection. (c) 2007 Elsevier Ltd. All rights reserved.
Resumo:
LPS-induced TNF-alpha factor (LITAF) is a novel transcriptional factor that was first discovered in LPS-stimulated human macrophage cell line THP-1. LITAF can bind to TNF-a promoter to regulate its expression. The first scallop LITAF (named as CfLITAF) was cloned from Zhikong scallop Chlamys farreri by Expressed Sequence Tag (EST) and Polymerase Chain Reaction (PCR) techniques. The cDNA of CfLITAF was of 1240 bp and consisted of a 5' untranslated region (UTR) of 112 bp, a 3' UTR of 678 bp and an open reading frame (ORF) of 450 bp encoding a polypeptide of 149 amino acids with an estimated molecular mass of 16.08 kDa and theoretical isoelectric point of 6.77. A typical conserved LITAF-domain was identified in CfLITAF by SMART analysis. Homology analysis of the deduced amino acid sequence of CfLITAF with other known sequences by using the BLAST program revealed that CfLITAF was homologous to the LITAF from human and rat (Identity = 46%), cattle, horse, mouse and chicken (Identity = 48%), western clawed frog (Identity = 42%), and zebrafish (Identity = 50%). The mRNA expression of CfLITAF in different tissues including haemocytes, muscle, mantle, heart, gill and gonad, and the temporal expression in haemocytes challenged by LPS or peptidoglycan (PGN) were measured by Real-time RT-PCR. CfLITAF mRNA transcripts could be detected in all tissues examined and be up-regulated in haemocytes after LPS challenge. No significant changes were observed after PGN stimulation. All these data indicated the existence of LITAF in scallop and also provided clue on the presence of TNF-alpha-like molecules in invertebrates. (C) 2007 Elsevier Ltd. All rights reserved.
Resumo:
The bay scallop, Argopecten irradians irradians, introduced from North America, has become one of the most important aquaculture species in China. Inan effort to identify scallop genes involved in host defense, a high-quality cDNA library was constructed from whole body tissues of the bay scallop. A total of 5828 successful sequencing reactions yielded 4995 expressed sequence tags (ESTs) longer than 100 bp. Cluster and assembly analyses of the ESTs identified 637 contigs (consisting of 2853 sequences) and 2142 singletons, totaling 2779 unique sequences. Basic Local Alignment Search Tool (BLAST) analysis showed that the majority (73%) of the unique sequences had no significant homology (E-value >= 0.005) to sequences in GenBank. Among the 748 sequences with significant GenBank matches, 160 (21.4%) were for genes related to metabolism, 131 (17.5%) for cell/organism defense, 124 (16.6%) for gene/protein expression, 83 (11.1%) for cell structure/motility, 70 (9.4%) for cell signaling/communication, 17 (2.3%) for cell division, and 163 (21.8%) matched to genes of unknown functions. The list of host-defense genes included many genes with known and important roles in innate defense such as lectins, defensins, proteases, protease inhibitors, heat shock proteins, antioxidants, and Toll-like receptors. The study provides a significant number of ESTs for gene discovery and candidate genes for studying host defense in scallops and other molluscs.
Resumo:
Heat shock protein 70 (HSP70) is an important member of the heat shock protein superfamily, and it plays a key role in the process of protecting cells, facilitating the folding of nascent peptides and responding to stress. The cDNA of bay scallop Argopecten irradians HSP70 (designated AIHSP70) was cloned by the techniques of homological cloning and rapid amplification of cDNA end (RACE). The full length of AIHSP70 cDNA was 2651 bp in length, having a 5' untranslated region (UTR) of 96 bp, a 3' UTR of 575 bp, and an open reading frame (ORF) of 1980 bp encoding a polypeptide of 659 amino acids with an estimated molecular mass of 71.80 kDa and an estimated isoelectric point of 5.26. BLAST analysis revealed that the AIHSP70 gene shared high identity with other known HSP70 genes. Three classical HSP signature motifs were detected in AIHSP70 by InterPro, analysis. 3-D structural prediction of AIHSP70 showed that its N terminal ATPase activity domain and,C terminal substrate-binding domain shared high similarity with that in human heat shock protein 70. The results indicated that the AIHSP70 was a member of the heat shock protein 70 family. A semi-quantitive RT-PCR method was used to analyse the expression of AIHSP70 gene after the treatment of naphthalin which is one kind of polycyclic aromatic hydrocarbon (PAH) and the challenge of bacteria. mRNA expression of AIHSP70 in scallop was up-regulated significantly after the stimulation of naphthalin and increased with increasing naphthalin concentration. A clearly time-dependent expression pattern of AIHSP70 was observed after the scallops were infected by Vibrio anguillarum, and the mRNA expression reached a maximum level at 8 h and lasted to 16 h, and then dropped progressively. The results indicated that AIHSP70 could play an important role in mediating the environmental stress and immune response in scallop. (c) 2006 Elsevier Ltd. All rights reserved.
Resumo:
本论文报道从海洋中分离到的一株聚磷菌的分离、鉴定、在系统发育中的地位、除磷特性、菌体内多磷酸盐颗粒的研究、D-海因酶和核苷二磷酸激酶基因的克隆及序列分析,为海水系统的生物除磷提供部分基础资料。 从黄海海域分离到聚磷菌Halomonas sp. YSR-3,菌体呈杆状,大小为3.5 μm×1 μm,革兰氏阴性,好氧生长,能运动。透射电镜观察发现,菌体内有致密颗粒。经DAPI染色确定该致密颗粒是多磷酸盐,亦可称为异染粒、迂回体。16S rDNA鉴定结果表明,YSR-3与Halomonas属中的marine bacterium B5-7有较高的同源性,相似值99%。YSR-3的生理生化特性:对氯霉素和卡那霉素敏感;淀粉水解呈阳性;反硝化和几丁质降解呈阴性;能将葡萄糖作为唯一碳源和能源。 对YSR-3的培养条件进行优化。以海水2216培养基、24 ℃、180 rpm、pH 6.5的条件培养,更利于菌体生长和菌体内多磷酸盐的形成。 对YSR-3的除磷特性进行研究。无磷培养时,菌体不能生长;用磷酸钾盐作为磷源时,菌体生长较好,形成多磷酸盐的菌体比例较高;较适合YSR-3菌体生长和多磷酸盐形成的磷源是KH2PO4,较适磷浓度为1.5 mmol/L。pH的变化影响菌株的生长、多磷酸盐形成和除磷效果。pH值为5时,菌体的数量几乎不增加,体内多磷酸盐和培养基中磷含量变化不大;pH值为6、7和8时,菌体生长良好,95%以上的菌体内形成多磷酸盐,培养基中磷含量明显下降。YSR-3在不同培养基中除磷量和除磷率不同。在高磷培养基中除磷量为0.7 mmol/L(磷含量由1.84 mmol/L降到1.14 mmol/L),除磷率为37.5%;在低磷培养基中除磷量为0.02 mmol/L(磷含量由0.028 mmol/L降到0.008 mmol/L),除磷率为72.2%。 以海洋聚磷菌Halomonas sp. YSR-3的总DNA为模板,用PCR法扩增D-海因酶基因和核苷二磷酸激酶基因,将扩增片段克隆到pGM-T载体,转化E.coli TOP10菌株,经蓝白斑筛选、菌落PCR得到阳性克隆,测序后对序列进行Blast比对分析。得到的D-海因酶基因序列长度为1510 bp,与Pseudomonas entomophila L48的海因酶基因序列的相似性为77%。翻译后的序列与Pseudomonas fluorescens Pf-5,Marinomonas sp. MED121,Burkholderia vietnamiensis G4的海因酶蛋白序列相似性分别为75%,73%,70%。得到的核苷二磷酸激酶基因序列长度为420bp,翻译后的序列与Loktanella vestfoldensis SKA53,Jannaschia sp. CCS1,Roseobacter sp. CCS2的核苷二磷酸激酶蛋白序列相似性分别为89%,86%,85%。 聚磷菌能将外界环境中的磷吸收到体内,并以多磷酸盐的形式储存。多磷酸盐对于细胞的生存和生长有很重要的作用,但目前对于多磷酸盐的形成过程以及过程调控还不是很清楚。在今后可以通过构建高效表达的重组菌,提高与除磷相关的酶的纯度及活性。同时可以将相关酶的基因进行突变,对基因表达的调控以及酶的代谢以及功能结构等多方面进行基础研究,使聚磷菌在生物除磷中得到广泛应用。
Resumo:
扇贝是我国海水养殖的重要品种,但自1994年以来,养殖扇贝陆续爆发的大规模死亡,不但造成了巨大的经济损失,而且直接威胁到现有产业的生存和发展。引起扇贝大规模死亡原因是多方面的,其主要原因是养殖环境恶化、扇贝种质衰退和抗病力下降。因此,深入研究扇贝免疫防御机制,探讨提高机体抗病力的有效途径和方法,改良种质和培育抗病品系,无疑是解决目前困扰扇贝养殖业健康可持续发展的必经之路。 Toll样受体(TLRs)家族是新近发现的模式识别受体(PRRs),参与识别病原体相关的分子模式(PAMPs),在天然免疫系统中起着非常重要的作用。哺乳动物中Toll样受体信号通路还参与诱导树枝状细胞成熟、参与免疫耐受、参与凋亡发生发展、介导非感染性因素的识别等,被视为联系天然免疫和获得性免疫的桥梁。同时果蝇的Toll信号通路也是不具备获得性免疫的果蝇赖以抵御病毒、细菌和真菌感染,介导天然免疫反应的重要信号通路。 本研究采用大规模EST测序方法,结合Genome Walker库的构建和cDNA末端快速扩增技术,从栉孔扇贝克隆得到CfToll-1、CfMyd88、CfTRAF6和CfCactus这四个Toll样受体信号通路基因的全长cDNA,同时用荧光实时定量PCR技术检测了这些基因的组织分布及在脂多糖(LPS)和肽聚糖(PGN)刺激下的表达规律。 栉孔扇贝Toll样受体(CfToll-1)的cDNA序列全长4308 bp,包含5’非翻译区(UTR)211 bp,3597 bp的开放阅读框,500 bp的3’UTR,最后为18个腺嘌呤的ploy A 尾巴。开放阅读框编码1198个氨基酸的多肽,该多肽的估计分子量为137.41kd,估计的等电点为5.62,该多肽有信号肽,具有一个预测的跨膜区,因此是一种跨膜蛋白。经BLAST比对,CfToll-1基因与节肢动物多种Toll蛋白高度的相似性。SMART(Simple Modular Architecture Research Tool)软件分析,CfToll-1包含典型的Toll样受体的结构:富含亮氨酸的重复序列的胞外区(leucine-rich repeats, LRR),一段跨膜结构域,以及胞内区的TIR结构域(Toll/IL-1 receptor homologous region)。利用Real-time RT-PCR发现CfToll-1mRNA在扇贝体内普遍存在于血细胞、肌肉、外套膜、心、性腺和鳃组织中。利用体外培养的原代血细胞系研究不同浓度LPS刺激后CfToll-1的表达变化,结果显示低剂量(100ng.mL-1 )LPS 使CfToll-1 mRNA表达量减小,该变化在1.5h、3h 和9h组差异显著,虽然在6h组表达量稍有恢复,但尚未达到对照水平;用1μg.mL-1LPS处理细胞时, 6h组CfToll-1表达量明显上调,约为对照水平的2倍。证实细菌结构脂多糖对CfToll-1基因的表达有影响,且这种影响有剂量依赖效应。 栉孔扇贝Myd88同源基因(CfMyd88)的cDNA序列全长1554bp,包含5’UTR 427 bp,1101bp的开放阅读框,最后为18个腺嘌呤的ploy A 尾。CfMyd88的开放阅读框可编码367个氨基酸的多肽,该多肽的估计分子量为42.37kD,估计的等电点为5.71。利用SMART程序分析发现CfMyd88编码了Death和TIR结构域, 这两个结构域是Myd88特征结构。BLAST程序发现扇贝的序列与数据库哺乳动物的Myd88基因高度同源。原代培养的扇贝血细胞在受到PGN刺激后,CfMyd88 mRNA表达在1.5小时开始下调,直到9小时下调至对照表达量的1/10,证实肽聚糖结构对CfMyd88基因的表达有影响。 栉孔扇贝TRAF6同源基因(CfTRAF6)的cDNA序列全长2510bp,包含5’UTR 337 bp,1965bp的开放阅读框,3’UTR 208bp,最后为21 个腺嘌呤的ploy A 尾巴。CfTRAF6开放阅读框编码655个氨基酸的多肽,该多肽的估计分子量为74.09kD,估计的等电点为6.01。InterPro Scan在线分析发现CfTRAF6有典型的TRAF蛋白家族的特征结构,包括的一个指环结构,两个锌指结构,一个MATH (the meprin and TRAF homology)结构域以及Coiled-coil区域。CfTRAF6的序列与数据库多物种的TRAF6高度同源,同源性最高的是乌贼序列(Identity=68)和鼠类(Identity=45%)。利用Real-time RT-PCR,发现CfTRAF6在各组织普遍存在,在性腺中的表达最高。原代培养的扇贝血细胞在受到不同浓度PGN刺激后,与CfMyd88的情况一样,CfTRAF6的表达量变化减少,且这种变化随剂量的增加更加明显。 栉孔扇贝Cactus同源基因(CfCactus)的cDNA序列全长2488bp,包含5’UTR 181 bp,840bp的开放阅读框, 3’UTR 1467bp,最后为19个腺嘌呤的ploy A 尾巴。CfCactus的开放阅读框编码279个氨基酸的多肽,该多肽的估计分子量为31.37 kD;估计的等电点为4.74,与果蝇的Cactus基因的等电点相近(4.5)。利用SMART程序分析发现CfCactus主要编码了ANK结构域(ankyrin repeats)。Cactus基因为哺乳动物NF-κB抑制蛋白IκB的同源分子,BLAST 程序发现扇贝的序列与数据库多物种的Cactus或IκB基因高度同源。同源性最高的是太平洋牡蛎(Identity=35%)和圆尾鲎(Identities = 44%)。对CfTCactus mRNA在扇贝的血细胞、性腺、 肠的组织表达进行分析,并同时与CfTRAF6和CfMyd88的表达量进行了对比,发现CfCactus的表达水平明显高于这两个基因,而且CfTRAF6的基因表达量也高于CfMyd88,表现出级联放大效应。正常情况下,三个基因在性腺的表达量最高,推测这条通路可能和发育等功能密切相关。 通过本研究我们首次在双壳类软体动物找得到与果蝇Toll蛋白家族高度同源的CfToll-1基因,同时发现其他三个在Toll样受体信号传递过程中起重要作用的基因,其中包括在软体动物中获得的第一个Toll样受体的接头分子-CfMyd88基因,该结果直接证明软体动物具有与哺乳动物和节肢动物高度类似Myd88依赖的Toll样受体信号通路。同时通过这些基因组织分布的研究以及细菌结构LPS和PGN对这条通路上基因表达的影响,证明扇贝Toll信号通路可能与在果蝇中一样,参与扇贝的发育和免疫防御等多种功能。
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对虾病害在世界范围内肆虐,给水产养殖和沿海农村经济造成了重大损失。在水产养殖的实践中快速检测水产动物的病害并及时采取隔离等措施对于控制病害尤为重要,其中关键的环节就是快速检测出病害,并在对虾免疫机制上寻找对虾疾病防治的有效方法。研究表明当对虾等甲壳动物受到外界病原刺激时,极微量的微生物多糖就可以激活proPO系统。激活过程中涉及和产生一系列活性物质,如黑色素、酚氧化酶原激活因子(PPA)、模式识别蛋白(BGBP、PGBP、LGBP、LBP)及其膜上受体和A2巨球蛋白等,它们可通过多种方式参与防御反应,包括提供调理素,促进血细胞吞噬作用,形成结节或包囊以及介导凝集和凝固,产生杀菌物质并且黑色素化。黑色素常常在节肢动物的体表形成黑色斑点,形成的色素沉着对机体起到保护作用。所以,酚氧化酶原激活的级联反应是节肢动物免疫的关键因素。本论文研究开发了以环等温介导技术(LAMP)为基础的检测对虾白斑病毒(WSSV)和鳗弧菌(V. anguillarum)的快速检测方法。并从对虾对病害的免疫机制为切入点,从中国明对虾体内克隆了酚氧化酶原(PrpPO)和丝氨酸蛋白酶FcSP3这两个免疫系统中重要的基因,分析了它们的分子结构特征,组织分布及应答鳗弧菌病原刺激的表达变化模式。 建立的对虾常见病害对虾白班病毒(WSSV)和鳗弧菌(V. anguillarum)的LAMP检测方法,经过实验比对和Blast检索,发现本研究中使用的引物,比已经报导的LAMP方法或者PCR方法具有更宽的检测范围(更低的假阴性)。检测WSSV的LAMP方法使用病毒的VP28基因设计引物,而鳗弧菌的检测方法使用empA基因设计引物。在方法中,首次提出加入UNG酶和dUTP的措施来预防污染,在实际检测中非常有效。LAMP方法与PCR检测方法的灵敏性比较也进行了研究,二者灵敏性相当。 依据中国明对虾血液cDNA文库提供的部分片段信息,结合SMART-RACE技术,克隆了酚氧化酶原(PrpPO)基因,通过序列比对分析发现,PrpPO基因cDNA全长为3040 bp,其中开放阅读框2061 bp,编码686个氨基酸,其中推测的信号肽为12个氨基酸。推测的序列与斑节对虾(P. monodon)同源性为93%,与短钩对虾(P. semisulcatus.)同源性为92%。real time RT-PCR实验结果表明, ProPO在血细胞中的相对表达量最高,肝胰脏中表达量最低。弧菌刺激实验中注射弧菌,刺激了血细胞和淋巴器官中的ProPO mRNA显著增加,说明在血细胞和淋巴器官中存在快速反应的ProPO通路。而ProPO mRNA量在淋巴器官中在时间上早于血液中升至最高,说明该动物在在病原刚开始入侵的时候先有淋巴器官发挥主要的免疫作用,随着时间推移血细胞便变成主要的免疫器官。 根据中国明对虾肝胰脏cDNA文库提供EST信息,经过SMART-RACE克隆了一个丝氨酸蛋白酶FcSP3基因,通过序列比对分析发现,该丝氨酸蛋白酶基因cDNA全长为1622 bp,其中开放阅读框1431 bp,编码477个氨基酸,其中推测的信号肽为22个氨基酸。推测的序列与疟蚊的丝氨酸蛋白酶(A. gambiae)同源性为33%,与丽蝇蛹集金小蜂的酚氧化酶原激活因子(N. vitripennis)同源性为32%,与东北大黑鳃金龟的酚氧化酶原激活因子(H. diomphalia)同源性为34%。淋巴器官中PPAⅡ表达量约为血液中表达量的47560倍,肝胰脏中的FCSP3表达量为血细胞表达量的6226倍。鳗弧菌注射对虾后,淋巴器官中刺激组和对照组FcSP3的mRNA量在刺激后6小时显著降低,但是刺激组的表达量明显高于对照组。刺激组的血细胞与肝胰脏中FcSP3 mRNA的相对表达量增高。而病原刺激后的血液与肝胰脏中的FcSP3 mRNA的增长趋势也在时间上先与ProPO mRNA。这说明FcSP3对ProPO有正调控的作用,但这个调控有一个时间差,并且在不同组织中有不同的调控效率。
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介绍了一种新型的固定式烧毁炉系统,该系统主要用于装药量100gTNT当量以下的非金属外壳防步兵地雷以及火工品的烧毁处理。通过PLC的自动控制,实现了烧毁处理过程的自动协调控制;同时,配备了视频监控系统,使烧毁工作更安全可靠。本设计完全满足工艺要求,实际应用中提高了工作效率。
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铊是一种有毒有害的重金属元素,已经引起了广泛的关注。本论文通过对黔西南铊矿区土壤和沉积物样品的菌株分离、铊高耐受性菌株的筛选、胞外吸附、富集、亚细胞水平区系分布、絮凝实验及ITS序列等实验研究分析,并结合铊的地球化学相关研究,较系统地阐述了真菌--铊的生物地球化学过程机理,得出以下结论: 1、与环境背景区相比,黔西南滥木厂铊矿区内的河流、土壤中铊的已有不同程度的积累,直接导致了当地微生物生物量在很大程度上的降低,微生物生物量与铊含量间有显著的负相关关系。研究区内的沉积物、土壤中的微生物区系结构和数量发生了明显变化,细菌、真菌及放线菌数量均出现显著降低,而且三大微生物对重金属污染的敏感性大小也不一样,即放线菌>细菌>真菌。从土壤样品中分离到的主要菌群仍为常见种属,如青霉属(Penicillium)、木霉属(Trichoderma)、拟青霉(Paecilomyces)等。 2、经过初筛菌株的铊耐受性实验,在1000 mg/L水平筛选得到九株高耐受性菌株。吸附实验表明:微生物菌株对铊的吸附效率在4.63~16.89%,且随着环境中铊浓度的上升而降低,这可能是因为铊浓度的升高加大了对微生物生长的抑制作用,所形成的菌丝体(或菌丝球)减少,表面积也相应减少,从而导致了吸附效率的下降。各种常量元素和铊的关系呈显著相关性,钙、钾和钠等常量元素也是微生物赖以维持生存的因子,可能由于微生物细胞对钙、钾的吸附方式与对铊的吸附方式类似。因此,随着铊处理浓度的上升,钙和钾的吸附量也随之减少,而钠则呈现相反的趋势。 3、富集实验表明,九株菌株对铊的富集量随着铊处理浓度上升而降低,其影响趋势与对生物量的影响趋势基本一致,最高可达到7189 mg/kg,最大富集系数为7.2。九株菌株对常量元素的富集与对铊的富集并无明显的相关性,但在考察铊处理浓度对常量元素的富集影响时发现,铊处理浓度的上升与对钙的富集量表现出较强的正相关;而对钾、钠、镁的富集影响并不明显。 4、亚细胞水平上的铊分布研究表明,铊的富集优先顺序为:细胞质>细胞壁>细胞器。亚细胞水平的区隔化作用是微生物对铊的主要耐受机制,细胞质是赋存铊的主要场所(53.83~79.45 %)。结合各亚细胞组分中常量元素与铊之间的相关性,并联系前人的研究,Tl+主要是通过细胞壁的Na+ -K+ ATPase和K+ -电位门通道进入细胞内的从而影响细胞的正常代谢的,而Ca2+的活化更有助于这一过程。 5、絮凝实验表明,培养三天后的发酵液对矿区废水中铊的去除率最高可达到70.49 %,最佳影响因子组合为:pH=8,温度为16℃,搅拌时间为4分钟。菌株的絮凝活性最高可达到57.32%,最佳影响因子组合为:pH=8,温度为14℃,搅拌时间为4分钟。 6、通过对九株铊高耐受性菌株的ITS序列分析及其在Gene Bank中的BLAST比对结果表明,五株菌株同属于木霉属(Trichoderma),两株菌株同属于青霉属(Penicillium)。这表明这两类真菌对铊的适应性较强,为以后寻找铊高耐受性菌株及其资源化利用提供了理论基础。