scholarly journals Degenerative Minimalism in the Genome of a Psyllid Endosymbiont

2001 ◽  
Vol 183 (6) ◽  
pp. 1853-1861 ◽  
Author(s):  
Marta A. Clark ◽  
Linda Baumann ◽  
MyLo Ly Thao ◽  
Nancy A. Moran ◽  
Paul Baumann

ABSTRACT Psyllids, like aphids, feed on plant phloem sap and are obligately associated with prokaryotic endosymbionts acquired through vertical transmission from an ancestral infection. We have sequenced 37 kb of DNA of the genome of Carsonella ruddii, the endosymbiont of psyllids, and found that it has a number of unusual properties revealing a more extreme case of degeneration than was previously reported from studies of eubacterial genomes, including that of the aphid endosymbiont Buchnera aphidicola. Among the unusual properties are an exceptionally low guanine-plus-cytosine content (19.9%), almost complete absence of intergenic spaces, operon fusion, and lack of the usual promoter sequences upstream of 16S rDNA. These features suggest the synthesis of long mRNAs and translational coupling. The most extreme instances of base compositional bias occur in the genes encoding proteins that have less highly conserved amino acid sequences; the guanine-plus-cytosine content of some protein-coding sequences is as low as 10%. The shift in base composition has a large effect on proteins: in polypeptides of C. ruddii, half of the residues consist of five amino acids with codons low in guanine plus cytosine. Furthermore, the proteins ofC. ruddii are reduced in size, with an average of about 9% fewer amino acids than in homologous proteins of related bacteria. These observations suggest that the C. ruddii genome is not subject to constraints that limit the evolution of other known eubacteria.

1986 ◽  
Vol 235 (3) ◽  
pp. 895-898 ◽  
Author(s):  
M S López de Haro ◽  
A Nieto

An almost full-length cDNA coding for pre-uteroglobin from hare lung was cloned and sequenced. The derived amino acid sequence indicated that hare pre-uteroglobin contained 91 amino acids, including a signal peptide of 21 residues. Comparison of the nucleotide sequence of hare pre-uteroglobin cDNA with that previously reported for the rabbit gene indicated five silent point substitutions and six others leading to amino acid changes in the coding region. The untranslated regions of both pre-uteroglobin mRNAs were very similar. The amino acid changes observed are discussed in relation to the different progesterone-binding abilities of both homologous proteins.


2016 ◽  
Author(s):  
Mei Fang Lin ◽  
Wen Hwa Chou ◽  
Marcelo V Kitahara ◽  
Chao Lun Allen Chen ◽  
David John Miller ◽  
...  

Calcification is one of the most distinctive traits of scleractinian corals. Their hard skeletons form the substratum of reef ecosystems and confer on corals their remarkable diversity of shapes. Corallimorpharians are non-calcifying, close relatives of scleractinian corals, and the evolutionary relationship between these two groups is key to understanding the evolution of calcification in the coral lineage. One pivotal question is whether scleractinians are a monophyletic group, paraphyly being an alternative possibility if corallimorpharians are corals that have lost their ability to calcify, as is implied by the “naked-coral” hypothesis. Despite major efforts, relationships between scleractinians and corallimorpharians remain equivocal and controversial. Although the complete mitochondrial genomes of a range of scleractinians and corallimorpharians have been obtained, heterogeneity in composition and evolutionary rates means that mitochondrial sequences are insufficient to understand the relationship between these two groups. To overcome these limitations, transcriptome data were generated for three representative corallimorpharians. These were used in combination with sequences available for a representative range of scleractinians to identify 291 orthologous single copy protein-coding nuclear markers. Unlike the mitochondrial sequences, these nuclear markers do not display any distinct compositional bias in their nucleotide or amino-acid sequences. A range of phylogenomic approaches congruently reveal a topology consistent with scleractinian monophyly and corallimorpharians as the sister clade of scleractinians.


2013 ◽  
Vol 35 (4) ◽  
pp. 20-24
Author(s):  
Sandy J. Macdonald ◽  
Gavin H. Thomas ◽  
Angela E. Douglas

A combined computational and experimental analysis of metabolism in the symbiosis between the pea aphid and its obligate endosymbiont Buchnera aphidicola redefines existing notions of symbiotic nitrogen recycling. As a consequence of metabolic pathways shared between the partners, the insect recycles waste ammonia into essential amino acids (EAAs) that are lacking in its diet of sugar-rich but nitrogen-poor plant phloem sap.


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2463 ◽  
Author(s):  
Mei Fang Lin ◽  
Wen Hwa Chou ◽  
Marcelo V. Kitahara ◽  
Chao Lun Allen Chen ◽  
David John Miller ◽  
...  

Calcification is one of the most distinctive traits of scleractinian corals. Their hard skeletons form the substratum of reef ecosystems and confer on corals their remarkable diversity of shapes. Corallimorpharians are non-calcifying, close relatives of scleractinian corals, and the evolutionary relationship between these two groups is key to understanding the evolution of calcification in the coral lineage. One pivotal question is whether scleractinians are a monophyletic group, paraphyly being an alternative possibility if corallimorpharians are corals that have lost their ability to calcify, as is implied by the “naked-coral” hypothesis. Despite major efforts, relationships between scleractinians and corallimorpharians remain equivocal and controversial. Although the complete mitochondrial genomes of a range of scleractinians and corallimorpharians have been obtained, heterogeneity in composition and evolutionary rates means that mitochondrial sequences are insufficient to understand the relationship between these two groups. To overcome these limitations, transcriptome data were generated for three representative corallimorpharians. These were used in combination with sequences available for a representative range of scleractinians to identify 291 orthologous single copy protein-coding nuclear markers. Unlike the mitochondrial sequences, these nuclear markers do not display any distinct compositional bias in their nucleotide or amino-acid sequences. A range of phylogenomic approaches congruently reveal a topology consistent with scleractinian monophyly and corallimorpharians as the sister clade of scleractinians.


Author(s):  
Mei Fang Lin ◽  
Wen Hwa Chou ◽  
Marcelo V Kitahara ◽  
Chao Lun Allen Chen ◽  
David John Miller ◽  
...  

Calcification is one of the most distinctive traits of scleractinian corals. Their hard skeletons form the substratum of reef ecosystems and confer on corals their remarkable diversity of shapes. Corallimorpharians are non-calcifying, close relatives of scleractinian corals, and the evolutionary relationship between these two groups is key to understanding the evolution of calcification in the coral lineage. One pivotal question is whether scleractinians are a monophyletic group, paraphyly being an alternative possibility if corallimorpharians are corals that have lost their ability to calcify, as is implied by the “naked-coral” hypothesis. Despite major efforts, relationships between scleractinians and corallimorpharians remain equivocal and controversial. Although the complete mitochondrial genomes of a range of scleractinians and corallimorpharians have been obtained, heterogeneity in composition and evolutionary rates means that mitochondrial sequences are insufficient to understand the relationship between these two groups. To overcome these limitations, transcriptome data were generated for three representative corallimorpharians. These were used in combination with sequences available for a representative range of scleractinians to identify 291 orthologous single copy protein-coding nuclear markers. Unlike the mitochondrial sequences, these nuclear markers do not display any distinct compositional bias in their nucleotide or amino-acid sequences. A range of phylogenomic approaches congruently reveal a topology consistent with scleractinian monophyly and corallimorpharians as the sister clade of scleractinians.


1999 ◽  
Vol 65 (8) ◽  
pp. 3341-3346 ◽  
Author(s):  
Do-Young Yum ◽  
Bong-Yong Lee ◽  
Jae-Gu Pan

ABSTRACT The identification of a gene (yiaE) encoding 2-ketoaldonate reductase (2KR) in our previous work led to the hypothesis that Escherichia coli has other ketogluconate reductases including 2,5-diketo-d-gluconate reductase (25DKGR) and to study of the related ketogluconate metabolism. By using the deduced amino acid sequences of 5-diketo-d-gluconate reductase (5KDGR) of Gluconobacter oxydans and 25DKGR ofCorynebacterium sp., protein databases were screened to detect homologous proteins. Among the proteins of E. coli, an oxidoreductase encoded by yjgU and having 56% similarity to 5KDGR of G. oxydans and two hypothetical oxidoreductases encoded by yqhE and yafB and having 49.8 and 42% similarity, respectively, to 25DKGR ofCorynebacterium sp. were detected. Recently, theyjgU gene was identified as encoding 5KDGR and renamedidnO (C. Bausch, N. Peekhaus, C. Utz, T. Blais, E. Murray, T. Lowary, and T. Conway, J. Bacteriol. 180:3704–3710, 1998). The pathways involved in the metabolism of ketogluconate by E. coli have been predicted by biochemical analysis of purified enzymes and chemical analysis of the pathway intermediates. The gene products of yqhE and yafB were identified as 25DKGR-A, and 25DKGR-B, respectively, catalyzing the reduction of 25KDG to 2-keto-l-gulonate (2KLG). The native 25DKGR-A, 25DKGR-B, and 5KDGR had apparent molecular weights of about 30,000, 30,000, and 54,000, respectively. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels, all three enzymes showed protein bands with a molecular weight of about 29,000, which indicated that 25DKGR-A, 25DKGR-B, and 5KDGR may exist as monomeric, monomeric, and dimeric proteins, respectively. The optimum pHs for reduction were 7.5, 7.0, and 8.0, respectively. The 5KDGR was active with NADH, whereas 25DKGR-A and 25DKGR-B were active with NADPH as a preferred electron donor. 25DKG can be converted to 5KDG by 2KR, which is then reduced tod-gluconate by 5KDGR. The pathways were compared with those of Erwinia sp. and Corynebacterium sp. A BLAST search of published and incomplete microbial genome sequences revealed that the ketogluconate reductases and their related metabolism may be widespread in many species.


2021 ◽  
pp. 895-901
Author(s):  
Kebao Song ◽  
Congtian Wang ◽  
Zhongbo Li ◽  
Peng Ning

The complete chloroplast (cp) genome of Oryza sativa L.(B810S) was 134546 bp in length in the study, which contains 149 genes including 99 coding protein genes, 41 transfer RNA genes, 8 ribosomal RNA genes and 1 non-coding region by gene annotation. A total of 20879 amino acids were encoded by this cp genome, TTT (Phe) and TTG (Leu) codon were the most frequent amino acids, whereas the ACC (Thr), GCC (Ala), CTC (Leu), and AAC (Asn) codon were the least frequent ones. The content of the four bases on the cp genome were 30.6% for A, 30.4% for T, 19.4% for C and 19.6% for G, respectively. Obviously, the A+T (61.0%) content is more higher than G+C (39.0%). The gene order and content are the same as those of previously reported cp genome of Rice. Phylogenetic analysis was implemented based on concatenated amino acid sequences of 99 protein-coding genes using Neighbor-Joining method (NJ) method. Therefore, the complete B810S cp genome provides interesting insights and valuable information that can be used to identify related species and reconstruct its phylogeny. Bangladesh J. Bot. 50(3): 895-901, 2021 (September) Special


1998 ◽  
Vol 64 (5) ◽  
pp. 1919-1923 ◽  
Author(s):  
Kwi S. Kim ◽  
Timothy G. Lilburn ◽  
Michael J. Renner ◽  
John A. Breznak

ABSTRACT arfI encoded the 57.7-kDa subunit of Cytophaga xylanolytica arabinofuranosidase I (ArfI). arfIIencoded a 59.2-kDa subunit of ArfII. Products of both cloned genes liberated arabinose from arabinan and arabinoxylan. The deduced amino acid sequences of ArfI and ArfII revealed numerous regions that were identical to each other and to regions of homologous proteins fromBacteroides ovatus, Bacillus subtilis, andClostridium stercorarium.


2000 ◽  
Vol 74 (11) ◽  
pp. 5123-5132 ◽  
Author(s):  
Karyn N. Johnson ◽  
Jean-Louis Zeddam ◽  
L. Andrew Ball

ABSTRACT Pariacoto virus (PaV) was recently isolated in Peru from the Southern armyworm (Spodoptera eridania). PaV particles are isometric, nonenveloped, and about 30 nm in diameter. The virus has a bipartite RNA genome and a single major capsid protein with a molecular mass of 39.0 kDa, features that support its classification as aNodavirus. As such, PaV is the firstAlphanodavirus to have been isolated from outside Australasia. Here we report that PaV replicates in wax moth larvae and that PaV genomic RNAs replicate when transfected into cultured baby hamster kidney cells. The complete nucleotide sequences of both segments of the bipartite RNA genome were determined. The larger genome segment, RNA1, is 3,011 nucleotides long and contains a 973-amino-acid open reading frame (ORF) encoding protein A, the viral contribution to the RNA replicase. During replication, a 414-nucleotide long subgenomic RNA (RNA3) is synthesized which is coterminal with the 3′ end of RNA1. RNA3 contains a small ORF which could encode a protein of 90 amino acids similar to the B2 protein of other alphanodaviruses. RNA2 contains 1,311 nucleotides and encodes the 401 amino acids of the capsid protein precursor α. The amino acid sequences of the PaV capsid protein and the replicase subunit share 41 and 26% identity with homologous proteins of Flock house virus, the best characterized of the alphanodaviruses. These and other sequence comparisons indicate that PaV is evolutionarily the most distant of the alphanodaviruses described to date, consistent with its novel geographic origin. Although the PaV capsid precursor is cleaved into the two mature capsid proteins β and γ, the amino acid sequence at the cleavage site, which is Asn/Ala in all other alphanodaviruses, is Asn/Ser in PaV. To facilitate the investigation of PaV replication in cultured cells, we constructed plasmids that transcribed full-length PaV RNAs with authentic 5′ and 3′ termini. Transcription of these plasmids in cells recreated the replication of PaV RNA1 and RNA2, synthesis of subgenomic RNA3, and translation of viral proteins A and α.


2020 ◽  
Vol 21 (23) ◽  
pp. 9184
Author(s):  
Pierpaolo Di Nocera ◽  
Eliana De Gregorio

We have identified a variety of proteins in species of the Legionella, Aeromonas, Pseudomonas, Vibrio, Nitrosomonas, Nitrosospira, Variovorax, Halomonas, and Rhizobia genera, which feature repetitive modules of different length and composition, invariably ending at the COOH side with Asp–Asp–x–Pro (DDxP) motifs. DDxP proteins range in size from 900 to 6200 aa (amino acids), and contain 1 to 5 different module types, present in one or multiple copies. We hypothesize that DDxP proteins were modeled by the action of specific endonucleases inserting DNA segments into genes encoding DDxP motifs. Target site duplications (TSDs) formed upon repair of staggered ends generated by endonuclease cleavage would explain the DDxP motifs at repeat ends. TSDs acted eventually as targets for the insertion of more modules of the same or different types. Repeat clusters plausibly resulted from amplification of both repeat and flanking TSDs. The proposed growth shown by the insertion model is supported by the identification of homologous proteins lacking repeats in Pseudomonas and Rhizobium. The 85 DDxP repeats identified in this work vary in length, and can be sorted into short (136–215 aa) and long (243–304 aa) types. Conserved Asp–Gly–Asp–Gly–Asp motifs are located 11–19 aa from the terminal DDxP motifs in all repeats, and far upstream in most long repeats.


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