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1.
A phylogenetic tree was constructed on the basis of the amino acid sequences of the known cyclodextrin glucanotransferases (CDGTs), including those deduced from the nucleotide sequences ofBacillus sp. strain 6.6.3 andPaenibacillus macerans IB-7 genes encoding α- and β-CDGTs. The tree clearly demonstrates the existence of distinct phylogenetic groups of CDGT-producing microorganisms and the divergence of the α-, β-, and γ-CDGT produced by microorganisms from the generaBacillus, Paenibacillus, Brevibacillus, andThermoanaerobacter from a common ancestor, whereas the CDGT ofKlebsiella pneumoniae is independent and results from the convergence of different ancestors. The degree of homology of the leader peptide sequences of CDGTs may serve as a criterion of intraspecies relatedness between CDGT-producing microorganisms.  相似文献   

2.
天山北坡甜菜内生菌分离鉴定及其动态变化   总被引:3,自引:0,他引:3  
史应武  娄恺  李春 《生态学报》2009,29(5):2374-2382
对新疆昌吉和石河子两地种植的甜菜内生菌进行了分离、鉴定和分析,结果表明甜菜内生菌多属于细菌,其中假单胞菌 (Pseudomonas sp. )和芽孢菌类(Bacillus sp.)的分离频率分别在33.2%~59.2%和12.7%~28.1%,是甜菜植株中的优势内生菌群.16S rDNA 和 ITS 序列同源性比较和系统发育分析表明内生菌具有丰富的多样性.根中内生菌的多样性高于茎、叶,昌吉地区种植的甜菜中分离出的内生菌种类较多.从感病品种及生长不良甜菜植株中分离出的内生菌种类比较丰富.通过回接分离及利用扫描电镜观察内生菌在植物体内分布发现,内生菌能够定殖于甜菜块根.  相似文献   

3.
We have built phylogenetic tree of alpha-, beta- and gamma-tubulins of plant kingdom, alpha- and beta-tubulins of pig, and all epsilon- and delta-tubulins with known primary sequences and analyzed the levels of homology of tubulin sequences for repersentatives of different groups of organisms. It has been established low heterogeneity of alpha-, gamma-tubulin families and more than two fold higher heterogeneity of beta-tubulins, based on the sequence speciality of alga tubulins. We have showed that sequences of animal tubulins do not fit any cluster formed by on the plant tubulins. Presence in primary tubulin sequences of three major families of insignificant specific differences which are specific for such phylogenetic items of plant kingdom as alga and angiosperms has been also demostrated. The cladogramm shows clear clasterization of investigated sequences according to their belonging to the tubulin families.  相似文献   

4.
一株高效纤维素降解菌株的分离鉴定及其酶学性质   总被引:16,自引:2,他引:14  
从黄浦江淀山湖的水底沉积物中筛选分离得到一株产纤维素酶的菌株。经细菌形态观察,生理生化实验并结合16SrRNA序列分析,鉴定该菌为蜡状芽孢杆菌(Bacillus cereus),同时发现其在系统发育树中处于一个独立的分支,推测该菌为Bacillus属中一个新的亚种。对该菌株产酶及酶活特性进行了初步研究,发现纤维素酶的产生与细菌的生长密切相关。该菌株在37°C,pH7.0的条件下,发酵66h后纤维素酶活达到最高值4.58U/mL。  相似文献   

5.
The field of microbial phylogenetics has questioned the feasibility of using a tree‐like structure to the describe microbial evolution. This debate centres on two main points. First, because microorganisms are able to transfer genes from one to another in zero generations (horizontal gene transfer, or HGT), the use of molecular characters to perform phylogenetic analyses will yield an erroneous topology and HGT clearly makes the evolution of microorganisms non tree‐like. Second, the use of concatenated gene sequences in a total evidence approach to phylogenetic systematics is a verificationist endeavour, the aim of which is to bolster support. However, the goal of the total evidence approach to phylogenetic research is based in the idea of increasing explanatory power over background knowledge through test and corroboration, rather than to bolster support for nodes in a tree. In this context, the testing of phylogenetic data is a falsificationist endeavour that includes the possibility of not rejecting the null hypothesis that there is no tree‐like structure in molecular phylogenetic data. We discuss several tests that aim to test rigorously the hypothesis that a tree of life exists for microorganisms. We also discuss the philosophical ramifications of background knowledge and corroboration in microbial studies that need to be considered when suggesting that HGT confounds the tree of life. © The Willi Hennig Society 2009.  相似文献   

6.
Three mutanase (alpha-1,3-glucanase)-producing microorganisms isolated from soil samples were identified as a relatives of Paenibacillus. A mutanase was purified to homogeneity from cultures of each, and the molecular masses of the purified enzymes were approximately 132, 141, and 141kDa, respectively. The corresponding three genes for mutanases were cloned by PCR using primers designed from each N-terminal amino acid sequence. Another mutanase-like gene from one strain was also cloned by PCR using primers designed from conserved amino acid sequences among known mutanases. Consequently, four mutanase-like genes were sequenced. The genes contained long open reading frames of 3411 to 3915bp encoding 1136 to 1304 amino acids. The deduced amino acid sequences of the mutanases showed relatively high similarity to those of a mutanase (E16590) from Bacillus sp. RM1 with 46.9% to 73.2% identity and an alpha-1,3-glucanase (AB248056) from Bacillus circulans KA-304 with 46.7% to 70.4% identity. Phylogenetic analysis based on the amino acid sequences of the enzymes showed bacterial mutanases form a new family between fungal mutanases (GH family 71) and Streptomycetes mycodextranases (GH family 87).  相似文献   

7.
本文对33株枯草芽孢杆菌群菌株进行β-甘露聚糖酶活性筛选,其中的32株具有β-甘露聚糖酶活性,只有1株无β-甘露聚糖酶活性.通过基因克隆测序的方法获得33株枯草芽孢杆菌群菌株β-甘露聚糖酶基因编码区全序列,对酶基因进行同源性分析并构建系统发育树;在β-甘露聚糖酶基因系统发育树中,33株枯草芽孢杆菌群菌株聚为3个分支,分别是枯草芽孢杆菌分支、地衣芽孢杆菌分支和解淀粉芽孢杆菌分支;枯草芽孢杆菌、地衣芽孢杆菌和解淀粉芽孢杆菌β-甘露聚糖酶基因种内同源性大于91%,而种间同源性为60%69%.  相似文献   

8.
With the development of genome sequencing more whole genomes of microorganisms were completed, many methods wereintroduced to reconstruct the phylogenetic tree of those microorganismswith the information extracted from the whole genomes through variousways of transforming or mapping the whole genome sequences into otherforms which can describe the evolutionary distance in a new way. We thinkit might be possible that there exists information buried in the wholegenome transferred along lineage, which remains stable and is moreessential than sequence conservation of individual genes or the arrangementof some genes of a selected set. We need to find one measurement that caninvolve as many phylogenetic features as possible that are beyond thegenome sequence itself. We converted each genome sequence of themicroorganisms into another linear sequence to represent the functionalstructure of the sequence, and we used a new information function tocalculate the discrepancy of sequences and to get one distance matrix of thegenomes, and built one phylogenetic tree with a neighbor joining method.The resulting tree shows that the major lineages are consistent with theresult based on their 16srRNA sequences. Our method discovered onephylogenetic feature derived from the genome sequences and the encodedgenes that can rebuild the phylogenetic tree correctly. The mapping of onegenome sequence to its new form representing the relative positions of thefunctional genes provides a new way to measure the phylogeneticrelationships, and with the more specific classification of gene functions theresult could be more sensitive.  相似文献   

9.
赵庆新  谭远德 《遗传》2002,24(4):447-454
肠道微生物与寄主具有复杂的、多方面的相互依存效应,这种依存效应所产生的共生关系或协同进化关系既可反映寄主间的系统演化关系,也可显示肠道微生物间的系统演化关系,共生关系或协同进化关系是由于寄主与肠道微生物两者之间存在着相互自然选择作用所形成的,在长期的进化历程中逐步发生的共生关系信息很可能被记录在DNA序列中。本文通过检测鱼鲤鱼科8种鱼中9种肠道菌群的分布含量对这9种菌群进行分析,且利用从GenBank调取这9种肠道细菌菌属的43个种或亚种的16S DNA序列的构建NJ树和MP树,将这6个科9个属43个种或亚种分为革兰氏阴性和革兰氏阳性两大类群(一级分枝)。在这两类群中,又以科为单位分为6个亚类群(二级分枝),而肠杆菌科中则以属为单位分为4个小类群(三级分枝),此外球状菌与杆状菌也能截然分开。将16S DNA的NJ树隐去所有的种,以属为单位所得到的以分枝形式的无根树在拓扑结构上与菌群分布含量(寄主范围)所构建的无根树相近,但芽孢杆菌在两种无根树的位置中有较大的差异。如果提高检测水平,扩大所检测的寄主对象,这种差异有可能消除。  相似文献   

10.
Novel members of the subfamily Gammaherpesvirinae, hosted by eight mammalian species from six orders (Primates, Artiodactyla, Perissodactyla, Carnivora, Scandentia, and Eulipotyphla), were discovered using PCR with pan-herpesvirus DNA polymerase (DPOL) gene primers and genus-specific glycoprotein B (gB) gene primers. The gB and DPOL sequences of each virus species were connected by long-distance PCR, and contiguous sequences of approximately 3.4 kbp were compiled. Six additional gammaherpesviruses from four mammalian host orders (Artiodactyla, Perissodactyla, Primates, and Proboscidea), for which only short DPOL sequences were known, were analyzed in the same manner. Together with available corresponding sequences for 31 other gammaherpesviruses, alignments of encoded amino acid sequences were made and used for phylogenetic analyses by maximum-likelihood and Bayesian Monte Carlo Markov chain methods to derive a tree which contained two major loci of unresolved branching details. The tree was rooted by parallel analyses that included alpha- and betaherpesvirus sequences. This gammaherpesvirus tree contains 11 major lineages and presents the widest view to date of phylogenetic relationships in any subfamily of the Herpesviridae, as well as the most complex in the number of deep lineages. The tree's branching pattern can be interpreted only in part in terms of the cospeciation of virus and host lineages, and a substantial incidence of the interspecies transfer of viruses must also be invoked.  相似文献   

11.
Summary: The intent of this article is to provide a critical assessment of our current understanding of life''s phylogenetic diversity. Phylogenetic comparison of gene sequences is a natural way to identify microorganisms and can also be used to infer the course of evolution. Three decades of molecular phylogenetic studies with various molecular markers have provided the outlines of a universal tree of life (ToL), the three-domain pattern of archaea, bacteria, and eucarya. The sequence-based perspective on microbial identification additionally opened the way to the identification of environmental microbes without the requirement for culture, particularly through analysis of rRNA gene sequences. Environmental rRNA sequences, which now far outnumber those from cultivars, expand our knowledge of the extent of microbial diversity and contribute increasingly heavily to the emerging ToL. Although the three-domain structure of the ToL is established, the deep phylogenetic structure of each of the domains remains murky and sometimes controversial. Obstacles to accurate inference of deep phylogenetic relationships are both systematic, in molecular phylogenetic calculations, and practical, due to a paucity of sequence representation for many groups of organisms.  相似文献   

12.
华重楼内生菌SS02的分离与抗菌活性的初步研究   总被引:1,自引:0,他引:1  
从华重楼(Paris polyphylla var.Chinensis Franch)的地下块茎中分离到一株内生细菌(SS02),试验表明其发酵液对13种作物致病菌的生长有抑制作用。形态和生理生化特征表明SS02属于芽孢杆菌属(Bacillus sp.)细菌。扩增、测序得到SS02的部分16SrDNA序列,GenBank接收号AY842144。用Blastn调出与菌株16SrDNA同源的序列,用Clustalw进行多重序列对比,用Phylip按Neighbor—Joining法构建16SrDNA系统发育树。菌株SS02与Paenibacillus daejeonensis处于同一分支,相似性为97.7%,将其鉴定为Paenibacillus daejeonensisSS02。  相似文献   

13.
Strains of species in the Bacillus cereus group are potentially enterotoxic. Thus, the detection of all B. cereus group strains is important. As 16S ribosomal DNA sequence analysis cannot adequately differentiate species of the B. cereus group, we explored the potential of the groEL gene as a phylogenetic marker. A phylogenetic analysis of the groEL sequences of 78 B. cereus group strains revealed that the B. cereus group strains were split into two major clusters, one including six B. mycoides and one B. pseudomycoides (cluster II) and the other including two B. mycoides and the rest of the B. cereus group strains (cluster I). Cluster I was further differentiated into two subclusters, Ia and Ib. The sodA gene sequences of representative strains from different clusters were also compared. The phylogenetic tree constructed from the sodA sequences showed substantial similarity to the tree constructed from the groEL sequences. Based on the groEL sequences, a PCR assay for detection and identification of B. cereus group strains was developed. Subsequent restriction fragment length polymorphism (RFLP) analysis verified the PCR amplicons and the differentiation of the B. cereus group strains. RFLP with MboI was identical for all the B. cereus group strains analyzed, while RFLP with MfeI or PstI classified all B. cereus and B. thuringiensis strains into two groups. All cluster II B. mycoides and B. pseudomycoides strains could be discriminated from other B. cereus group bacteria by restriction analysis with TspRI.  相似文献   

14.
The increasing number of whole genomic sequences of microorganisms has led to the complexity of genome-wide annotation and gene sequence comparison among multiple microorganisms. To address this problem, we have developed nWayComp software that compares DNA and protein sequences of phylogenetically-related microorganisms. This package integrates a series of bioinformatics tools such as BLAST, ClustalW, ALIGN, PHYLIP and PRIMER3 for sequence comparison. It searches for homologous sequences among multiple organisms and identifies genes that are unique to a particular organism. The homologous gene sets are then ranked in the descending order of the sequence similarity. For each set of homologous sequences, a table of sequence identity among homologous genes along with sequence variations such as SNPs and INDELS is developed, and a phylogenetic tree is constructed. In addition, a common set of primers that can amplify all the homologous sequences are generated. The nWayComp package provides users with a quick and convenient tool to compare genomic sequences among multiple organisms at the whole-genome level.  相似文献   

15.
Twenty-five Bacillus strains capable of producing gamma-polyglutamic acid (PGA) were isolated from fermented locust bean products manufactured in the savanna area of Ghana. To clarify the phylogeny of these PGA-producing strains, phylogenetic analyses based on sequences of 16S rDNA, rpoB (RNA polymerase beta-subunit) and fus (elongation factor G) genes were performed. A phylogenetic tree based on 16S rDNA indicated that ten isolates were clustered in the same group of Bacillus subtilis. Another ten isolates were located in the cluster of B. amyloliquefaciens, and the remaining isolates were identified as B. pumilus (three isolates) and B. licheniformis (two isolates), respectively. Phylogenetic trees based on the partial sequences of rpoB and fus genes were similar to the phylogeny based on 16S rDNA sequences. Thirty-four strains in 27 species belonging to the genus Bacillus and its neighbors were also investigated for PGA production. It was found that PGA was produced by B. amyloliquefaciens NBRC 14141 and NBRC 15535(T), B. atrophaeus NBRC 15539(T), B. licheniformis NBRC 12107, B. mojavensis NBRC 15718(T), B. pumilus NBRC 12094, B. subtilis NBRC 16449, and Lysinibacillus sphaericus NBRC 3525. Except for L. sphaericus, the above Bacillus species are very closely related in phylogeny, indicating that PGA-producing Bacillus strains constitute a cluster.  相似文献   

16.
We have recently reported a method to identify the shortest possible phylogenetic tree for a set of protein sequences [Foulds Hendy & Penny (1979) J. Mol. Evol. 13. 127--150; Foulds, Penny & Hendy (1979) J. Mol. Evol. 13, 151--166]. The present paper discusses issues that arise during the construction of minimal phylogenetic trees from protein-sequence data. The conversion of the data from amino acid sequences into nucleotide sequences is shown to be advantageous. A new variation of a method for constructing a minimal tree is presented. Our previous methods have involved first constructing a tree and then either proving that it is minimal or transforming it into a minimal tree. The approach presented in the present paper progressively builds up a tree, taxon by taxon. We illustrate this approach by using it to construct a minimal tree for ten mammalian haemoglobin alpha-chain sequences. Finally we define a measure of the complexity of the data and illustrate a method to derive a directed phylogenetic tree from the minimal tree.  相似文献   

17.
Bacillus DNA in fossil bees: an ancient symbiosis?   总被引:3,自引:0,他引:3       下载免费PDF全文
We report here the isolation of DNA from abdominal tissue of four extinct stingless bees (Proplebeia dominicana) in Dominican amber, PCR amplification of a 546-bp fragment of the 16S rRNA gene from Bacillus spp., and their corresponding nucleotide sequences. These sequences were used in basic local alignment search tool searches of nonredundant nucleic acid data bases, and the highest scores were obtained with 16S rRNA sequences from Bacillus spp. Phylogenetic inference analysis by the maximum-likelihood method revealed close phylogenetic relationships of the four presumed ancient Bacillus sequences with Bacillus pumilus, B. firmus, B. subtilis, and B. circulans. These four extant Bacillus spp. are commonly isolated from abdominal tissue of stingless bees. The close phylogenetic association of the extracted DNA sequences with these bee colonizers suggests that a similar bee-Bacillus association existed in the extinct species P. dominicana.  相似文献   

18.
【目的】分析大熊猫肠道中芽孢杆菌的种类、纤维素分解能力、抗微生物作用和常用抗生素药物敏感性。【方法】利用芽孢耐高温特性分离菌株,基于16S r RNA基因序列构建系统发育树,通过测量芽孢杆菌在刚果红纤维素培养基上的分解圈分析其纤维素分解能力,采用牛津杯法测定芽孢杆菌的抑菌能力,结合软件分析抑菌能力和进化树之间的关系,通过PCR调查芽孢杆菌的抗菌肽分布规律,最后通过药敏试验检测芽孢杆菌是否对常用抗生素敏感。【结果】共分离得到21株芽孢杆菌;进化树显示,这些芽孢杆菌分为6个类别(Category);羧甲基纤维素钠水解结果显示,所有菌株均能分解纤维素;大部分芽孢杆菌菌株对3种肠道病原菌有较强的抑制能力,聚类分析表明,菌株的抗菌能力与基于16S r RNA基因的分类有一定的关联性;66.67%(14/21)的菌株中可以检测到2个或3个抗菌肽基因;药敏试验结果显示,菌株整体药物耐受率低,仅为7.54%(19/264),但仍有少数菌株对抗生素耐受。【结论】分离菌株种类丰富,分布平均,且均具有纤维素分解能力。21株菌株都含有抗菌肽基因,代谢产物对3种肠道病原菌具有明显抑制作用。常用抗生素耐受性低,对规范临床用药具有指导性。  相似文献   

19.
In this report we present phylogenetic tree based on the sequences of FtsZ-proteins of Archaea, Bacteria and Eukaryota. We have analyzed the relative positions of separate sequences and their clusters and their distance to the hypothetical root of phylogenetic tree as well. It has been demonstrated that most of procaryotic and eucaryotic FtsZ-protein sequences are located at the distance of 0.3-0.8 substitutions per site from the hypothetical root of phylogenetic tree. The tubulins are outlined from the root at 7-8 fold larger distances in comparison with the separate sequences. This confirms the slight aminoacid homology between these two groups of cytoskeletal proteins. At the same time the significant similarity between FtsZ-proteins of cyanobacteria and of plant plastids has been shown.  相似文献   

20.
We study distorted metrics on binary trees in the context of phylogenetic reconstruction. Given a binary tree T on n leaves with a path metric d, consider the pairwise distances {d(u,v)} between leaves. It is well known that these determine the tree and the d length of all edges. Here, we consider distortions d of d such that, for all leaves u and v, it holds that |d(u,v)-dmacr(u,v)|1.....T0 such that the true tree T may be obtained from that forest by adding alpha-1 edges and alpha-1les2-Omega(M/g)n. Our distorted metric result implies a reconstruction algorithm of phylogenetic forests with a small number of trees from sequences of length logarithmic in the number of species. The reconstruction algorithm is applicable for the general Markov model. Both the distorted metric result and its applications to phylogeny are almost tight  相似文献   

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