scholarly journals Isolation and Characterization of a Cyanophage Infecting the Toxic Cyanobacterium Microcystis aeruginosa

2006 ◽  
Vol 72 (2) ◽  
pp. 1239-1247 ◽  
Author(s):  
Takashi Yoshida ◽  
Yukari Takashima ◽  
Yuji Tomaru ◽  
Yoko Shirai ◽  
Yoshitake Takao ◽  
...  

ABSTRACT We isolated a cyanophage (Ma-LMM01) that specifically infects a toxic strain of the bloom-forming cyanobacterium Microcystis aeruginosa. Transmission electron microscopy showed that the virion is composed of anisometric head and a tail complex consisting of a central tube and a contractile sheath with helical symmetry. The morphological features and the host specificity suggest that Ma-LMM01 is a member of the cyanomyovirus group. Using semi-one-step growth experiments, the latent period and burst size were estimated to be 6 to 12 h and 50 to 120 infectious units per cell, respectively. The size of the phage genome was estimated to be ca. 160 kbp using pulse-field gel electrophoresis; the nucleic acid was sensitive to DNase I, Bal31, and all 14 restriction enzymes tested, suggesting that it is a linear double-stranded DNA having a low level of methylation. Phylogenetic analyses based on the deduced amino acid sequences of two open reading frames coding for ribonucleotide reductase alpha- and beta-subunits showed that Ma-LMM01 forms a sister group with marine and freshwater cyanobacteria and is apparently distinct from T4-like phages. Phylogenetic analysis of the deduced amino acid sequence of the putative sheath protein showed that Ma-LMM01 does not form a monophyletic group with either the T4-like phages or prophages, suggesting that Ma-LMM01 is distinct from other T4-like phages that have been described despite morphological similarity. The host-phage system which we studied is expected to contribute to our understanding of the ecology of Microcystis blooms and the genetics of cyanophages, and our results suggest the phages could be used to control toxic cyanobacterial blooms.

2018 ◽  
Vol 44 (1) ◽  
pp. 20
Author(s):  
Eloiza Teles Caldart ◽  
Helena Mata ◽  
Cláudio Wageck Canal ◽  
Ana Paula Ravazzolo

Background: Phylogenetic analyses are an essential part in the exploratory assessment of nucleic acid and amino acid sequences. Particularly in virology, they are able to delineate the evolution and epidemiology of disease etiologic agents and/or the evolutionary path of their hosts. The objective of this review is to help researchers who want to use phylogenetic analyses as a tool in virology and molecular epidemiology studies, presenting the most commonly used methodologies, describing the importance of the different techniques, their peculiar vocabulary and some examples of their use in virology.Review: This article starts presenting basic concepts of molecular epidemiology and molecular evolution, emphasizing their relevance in the context of viral infectious diseases. It presents a session on the vocabulary relevant to the subject, bringing readers to a minimum level of knowledge needed throughout this literature review. Within its main subject, the text explains what a molecular phylogenetic analysis is, starting from a multiple alignment of nucleotide or amino acid sequences. The different software used to perform multiple alignments may apply different algorithms. To build a phylogeny based on amino acid or nucleotide sequences it is necessary to produce a data matrix based on a model for nucleotide or amino acid replacement, also called evolutionary model. There are a number of evolutionary models available, varying in complexity according to the number of parameters (transition, transversion, GC content, nucleotide position in the codon, among others). Some papers presented herein provide techniques that can be used to choose evolutionary models. After the model is chosen, the next step is to opt for a phylogenetic reconstruction method that best fits the available data and the selected model. Here we present the most common reconstruction methods currently used, describing their principles, advantages and disadvantages. Distance methods, for example, are simpler and faster, however, they do not provide reliable estimations when the sequences are highly divergent. The accuracy of the analysis with probabilistic models (neighbour joining, maximum likelihood and bayesian inference) strongly depends on the adherence of the actual data to the chosen development model. Finally, we also explore topology confidence tests, especially the most used one, the bootstrap. To assist the reader, this review presents figures to explain specific situations discussed in the text and numerous examples of previously published scientific articles in virology that demonstrate the importance of the techniques discussed herein, as well as their judicious use.Conclusion: The DNA sequence is not only a record of phylogeny and divergence times, but also keeps signs of how the evolutionary process has shaped its history and also the elapsed time in the evolutionary process of the population. Analyses of genomic sequences by molecular phylogeny have demonstrated a broad spectrum of applications. It is important to note that for the different available data and different purposes of phylogenies, reconstruction methods and evolutionary models should be wisely chosen. This review provides theoretical basis for the choice of evolutionary models and phylogenetic reconstruction methods best suited to each situation. In addition, it presents examples of diverse applications of molecular phylogeny in virology.


2011 ◽  
Vol 6 (4) ◽  
pp. 545-557 ◽  
Author(s):  
Malay Choudhury ◽  
Takahiro Oku ◽  
Shoji Yamada ◽  
Masaharu Komatsu ◽  
Keita Kudoh ◽  
...  

AbstractApolipoproteins such as apolipoprotein (apo) A-I, apoA-IV, and apoE are lipid binding proteins synthesized mainly in the liver and the intestine and play an important role in the transfer of exogenous or endogenous lipids through the circulatory system. To investigate the mechanism of lipid transport in fish, we have isolated some novel genes of the apoA-I family, apoIA-I (apoA-I isoform) 1–11, from Japanese eel by PCR amplification. Some of the isolated genes of apoIA-I corresponded to 28kDa-1 cDNAs which had already been deposited into the database and encoded an apolipoprotein with molecular weight of 28 kDa in the LDL, whereas others seemed to be novel genes. The structural organization of all apoIA-Is consisted of four exons separated by three introns. ApoIA-I10 had a total length of 3232 bp, whereas other genes except for apoIA-I9 ranged from 1280 to 1441 bp. The sequences of apoIA-Is at the exon-intron junctions were mostly consistent with the consensus sequence (GT/AG) at exon-intron boundaries, whereas the sequences of 3′ splice acceptor in intron 1 of apoIA-I1-7 were (AC) but not (AG). The deduced amino acid sequences of all apoIA-Is contained a putative signal peptide and a propeptide of 17 and 5 amino acid residues, respectively. The mature proteins of apoIA-I1-3, 7, and 8 consisted of 237 amino acids, whereas those of apoIA-I4-6 consisted of 239 amino acids. The mature apoIA-I10 sequence showed 65% identity to amino acid sequence of apoIA-I11 which was associated with an apolipoprotein with molecular weight of 23 kDa in the VLDL. All these mature apoIA-I sequences satisfied the common structural features depicted for the exchangeable apolipoproteins such as apoA-I, apoA-IV, and apoE but apoIA-I11 lacked internal repeats 7, 8, and 9 when compared with other members of apoA-I family. Phylogenetic analysis showed that these novel apoIA-Is isolated from Japanese eel were much closer to apoA-I than apoA-IV and apoE, suggesting new members of the apoA-I family.


Viruses ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1304
Author(s):  
Amélie Chastagner ◽  
Séverine Hervé ◽  
Stéphane Quéguiner ◽  
Edouard Hirchaud ◽  
Pierrick Lucas ◽  
...  

This study evaluated the genetic and antigenic evolution of swine influenza A viruses (swIAV) of the two main enzootic H1 lineages, i.e., HA-1C (H1av) and -1B (H1hu), circulating in France between 2000 and 2018. SwIAV RNAs extracted from 1220 swine nasal swabs were hemagglutinin/neuraminidase (HA/NA) subtyped by RT-qPCRs, and 293 virus isolates were sequenced. In addition, 146 H1avNy and 105 H1huNy strains were submitted to hemagglutination inhibition tests. H1avN1 (66.5%) and H1huN2 (25.4%) subtypes were predominant. Most H1 strains belonged to HA-1C.2.1 or -1B.1.2.3 clades, but HA-1C.2, -1C.2.2, -1C.2.3, -1B.1.1, and -1B.1.2.1 clades were also detected sporadically. Within HA-1B.1.2.3 clade, a group of strains named “Δ146-147” harbored several amino acid mutations and a double deletion in HA, that led to a marked antigenic drift. Phylogenetic analyses revealed that internal segments belonged mainly to the “Eurasian avian-like lineage”, with two distinct genogroups for the M segment. In total, 17 distinct genotypes were identified within the study period. Reassortments of H1av/H1hu strains with H1N1pdm virus were rarely evidenced until 2018. Analysis of amino acid sequences predicted a variability in length of PB1-F2 and PA-X proteins and identified the appearance of several mutations in PB1, PB1-F2, PA, NP and NS1 proteins that could be linked to virulence, while markers for antiviral resistance were identified in N1 and N2. Altogether, diversity and evolution of swIAV recall the importance of disrupting the spreading of swIAV within and between pig herds, as well as IAV inter-species transmissions.


1987 ◽  
Author(s):  
A Ichinose ◽  
R E Bottenus ◽  
K R Loeb ◽  
E W Davie

Factor XIII (plasma transglutaminase, fibrin stabilizing factor) is a plasma protein that plays an important role in the final stages of blood coagulation and fibrinolysis. The molecule occurs in blood as a tetramer (a2b2) consisting of two a. subunits and two b subunits. Recently, we have determined the amino acid sequences for both the a. and b subunits of human factor XIII by a combination of cDNA cloning and amino acid sequence analysis. cDNAs coding for the a (3.8 Kb) and b (2.2 Kb) subunits were used for the screening of human genomic DNA libraries. Among 12 × 106 recombinant phage, ∼30 have been shown to contain the sequences for the a subunit and ∼10 have been shown to contain the gene for the b subunit of factor XIII. The clones coding for the a. subunit span ∼90 Kb and have been characterized by restriction mapping. Southern blotting, and DNA sequencing. Both 5’ and 3’ ends of the genomic clones correspond to the 5’ and 3’portions of the cDNA for the a.subunit of factor XIII. The DNA sequence revealed that the activation peptide released ^thrombin (amino acid residues 137), the first putative Ca2+ binding region (around residue 251), the active Site Cys (amino acid residue 314), and the second putative Ca2+ binding region (around residue 473) are encoded by separate exons. Accordingly, the intervening sequences may separate the a subunit into functional and structural domains. The gene organization for the b subunit will also be presented. (Supported by NIH Grant HL 16919.)


2006 ◽  
Vol 87 (4) ◽  
pp. 909-919 ◽  
Author(s):  
Grant S. Hansman ◽  
Katsuro Natori ◽  
Haruko Shirato-Horikoshi ◽  
Satoko Ogawa ◽  
Tomoichiro Oka ◽  
...  

Human norovirus (NoV) strains cause a considerable number of outbreaks of gastroenteritis worldwide. Based on their capsid gene (VP1) sequence, human NoV strains can be grouped into two genogroups (GI and GII) and at least 14 GI and 17 GII genotypes (GI/1–14 and GII/1–17). Human NoV strains cannot be propagated in cell-culture systems, but expression of recombinant VP1 in insect cells results in the formation of virus-like particles (VLPs). In order to understand NoV antigenic relationships better, cross-reactivity among 26 different NoV VLPs was analysed. Phylogenetic analyses grouped these NoV strains into six GI and 12 GII genotypes. An antibody ELISA using polyclonal antisera raised against these VLPs was used to determine cross-reactivity. Antisera reacted strongly with homologous VLPs; however, a number of novel cross-reactivities among different genotypes was observed. For example, GI/11 antiserum showed a broad-range cross-reactivity, detecting two GI and 10 GII genotypes. Likewise, GII/1, GII/10 and GII/12 antisera showed a broad-range cross-reactivity, detecting several other distinct GII genotypes. Alignment of VP1 amino acid sequences suggested that these broad-range cross-reactivities were due to conserved amino acid residues located within the shell and/or P1-1 domains. However, unusual cross-reactivities among different GII/3 antisera were found, with the results indicating that both conserved amino acid residues and VP1 secondary structures influence antigenicity.


2001 ◽  
Vol 183 (15) ◽  
pp. 4468-4476 ◽  
Author(s):  
Franz Kaufmann ◽  
Derek R. Lovley

ABSTRACT NADPH is an intermediate in the oxidation of organic compounds coupled to Fe(III) reduction in Geobacter species, but Fe(III) reduction with NADPH as the electron donor has not been studied in these organisms. Crude extracts of Geobacter sulfurreducens catalyzed the NADPH-dependent reduction of Fe(III)-nitrilotriacetic acid (NTA). The responsible enzyme, which was recovered in the soluble protein fraction, was purified to apparent homogeneity in a four-step procedure. Its specific activity for Fe(III) reduction was 65 μmol · min−1 · mg−1. The soluble Fe(III) reductase was specific for NADPH and did not utilize NADH as an electron donor. Although the enzyme reduced several forms of Fe(III), Fe(III)-NTA was the preferred electron acceptor. The protein possessed methyl viologen:NADP+ oxidoreductase activity and catalyzed the reduction of NADP+ with reduced methyl viologen as electron donor at a rate of 385 U/mg. The enzyme consisted of two subunits with molecular masses of 87 and 78 kDa and had a native molecular mass of 320 kDa, as determined by gel filtration. The purified enzyme contained 28.9 mol of Fe, 17.4 mol of acid-labile sulfur, and 0.7 mol of flavin adenine dinucleotide per mol of protein. The genes encoding the two subunits were identified in the complete sequence of the G. sulfurreducens genome from the N-terminal amino acid sequences derived from the subunits of the purified protein. The sequences of the two subunits had about 30% amino acid identity to the respective subunits of the formate dehydrogenase from Moorella thermoacetica, but the soluble Fe(III) reductase did not possess formate dehydrogenase activity. This soluble Fe(III) reductase differs significantly from previously characterized dissimilatory and assimilatory Fe(III) reductases in its molecular composition and cofactor content.


Author(s):  
Zhilong Tian ◽  
Yuqin Wang ◽  
Huibin Shi ◽  
Zhibo Wu ◽  
Xiaohui Zhang ◽  
...  

To further to understand the structure and function of the TAC1 gene, we cloned the full-length cDNAs of the TAC1 genes from goat by rapid amplification of cDNA ends-PCR and the qRT-PCR was used to analyze the TAC1 mRNA expression patterns of goat various tissues. The full-length cDNA of goat TAC1 was 1176 bp, with a 339 bp open reading frame encoding 112 amino acids. The amino acid sequence analysis revealed that goat TAC1 gene encoded a water-drain protein and its relative molecular weight and isoelectric point was 13,012.86 Da and 6.29 respectively. Alignment and phylogenetic analyses revealed that their amino acid sequences were highly similar to those of other vertebrates. TAC1 expression of the goat of the brain, cerebellum, medulla oblongata, heart, liver, spleen, lung, kidney, uterus, ovaries. These results serve as a foundation for further study on the Capra hircus TAC1 gene.


Genome ◽  
2006 ◽  
Vol 49 (11) ◽  
pp. 1481-1489 ◽  
Author(s):  
Nakao Kubo ◽  
Shin-ichi Arimura ◽  
Nobuhiro Tsutsumi ◽  
Koh-ichi Kadowaki ◽  
Masashi Hirai

Three copies of the gene that encodes cytochrome c oxidase subunit Vb were isolated from the pea (PscoxVb-1, PscoxVb-2, and PscoxVb-3). Northern Blot and reverse transcriptase-PCR analyses suggest that all 3 genes are transcribed in the pea. Each pea coxVb gene has an N-terminal extended sequence that can encode a mitochondrial targeting signal, called a presequence. The localization of green fluorescent proteins fused with the presequence strongly suggests the targeting of pea COXVb proteins to mitochondria. Each pea coxVb gene has 5 intron sites within the coding region. These are similar to Arabidopsis and rice, although the intron lengths vary greatly. A phylogenetic analysis of coxVb suggests the occurrence of gene duplication events during angiosperm evolution. In particular, 2 duplication events might have occurred in legumes, grasses, and Solanaceae. A comparison of amino acid sequences in COXVb or its counterpart shows the conservation of several amino acids within a zinc finger motif. Interestingly, a homology search analysis showed that bacterial protein COG4391 and a mitochondrial complex I 13 kDa subunit also have similar amino acid compositions around this motif. Such similarity might reflect evolutionary relationships among the 3 proteins.


1976 ◽  
Vol 54 (10) ◽  
pp. 872-884 ◽  
Author(s):  
Alexander Kurosky ◽  
Theo Hofmann

The amino acid sequences of 48 peptides obtained from a chymotryptic digest of the mould acid protease, penicillopepsin (EC 3.4.23.7), have been determined. These peptides established the sequences of 26 unique fragments of up to 28 residues in length. The 28-residue fragment was identified as the N-terminal region. The C-terminal region is represented by a 13-residue fragment. The amino acids contained in these fragments account for some 85% of the residues of the enzyme.


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