scholarly journals Local emergence and decline of a SARS-CoV-2 variant with mutations L452R and N501Y in the spike protein

2021 ◽  
Author(s):  
Jan-Philipp Mallm ◽  
Christian Bundschuh ◽  
Heeyoung Kim ◽  
Niklas Weidner ◽  
Simon Steiger ◽  
...  
Keyword(s):  
Amino Acid ◽  
Severe Acute Respiratory Syndrome ◽  
Type Strain ◽  
Wild Type Strain ◽  
Population Level ◽  
Spike Protein ◽  
Whole Genome ◽  
Wild Type ◽  
Spike Gene ◽  
Mutational Pattern

SummaryVariants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are replacing the initial wild-type strain, jeopardizing current efforts to contain the pandemic. Amino acid exchanges in the spike protein are of particular concern as they can render the virus more transmissible or reduce vaccine efficacy. Here, we conducted whole genome sequencing of SARS-CoV-2 positive samples from the Rhine-Neckar district in Germany during January-March 2021. We detected a total of 166 samples positive for a variant with a distinct mutational pattern in the spike gene comprising L18F, L452R, N501Y, A653V, H655Y, D796Y and G1219V with a later gain of A222V. This variant was designated A.27.RN according to its phylogenetic clade classification. It emerged in parallel with the B.1.1.7 variant, increased to >50% of all SARS-CoV-2 variants by week five. Subsequently it decreased to <10% of all variants by calendar week eight when B.1.1.7 had become the dominant strain. Antibodies induced by BNT162b2 vaccination neutralized A.27.RN but with a two-to-threefold reduced efficacy as compared to the wild-type and B.1.1.7 strains. These observations strongly argue for continuous and comprehensive monitoring of SARS-CoV-2 evolution on a population level.

scholarly journals Mechanism of PQQ and CoQ10 overproduction in Methylobacterium as revealed by comparative genomic analysis between mutant and wild-type strains

2020 ◽  
Author(s):  
Changle Zhao ◽  
Yinping Wan ◽  
Xiaojie Cao ◽  
Huili Zhang ◽  
Xin Bao
Keyword(s):  
Mutant Strain ◽  
Type Strain ◽  
Wild Type Strain ◽  
Genomic Analysis ◽  
Comparative Genomic Analysis ◽  
Comparative Genomic ◽  
Regulation Mechanism ◽  
Whole Genome ◽  
Wild Type ◽  
Coq10 Production

Abstract Background The microbial synthesis of pyrroloquinoline quinone (PQQ) and Coenzyme Q10 (CoQ10) remains the most promising industrial production route. Methylobacterium has been used to generate PQQ and other value-added chemicals from cheap carbon feedstocks.However, the low PQQ and CoQ10 production capacity of the Methylobacterium strains is a major limitation The regulation mechanism for PQQ and CoQ10 biosynthesis in this strain has also not been fully elucidated. Results Methylobacterium sp. CLZ strain was isolated from soil contaminated with chemical wastewater, which can simultaneously produce PQQ, CoQ10, and carotenoids by using cheap methanol as carbon source. We investigated a mutant strain NI91, which increased the PQQ and CoQ10 yield by 72.44% and 59.80%, respectively. Whole-genome sequencing of NI91 and wild-type strain CLZ revealed that both contain a 5.28 Mb chromosome. The comparative genomic analysis and validation study revealed that a significant increase in biomass and PQQ production was associated with the base mutations in the methanol dehydrogenase (MDH) synthesis genes, mxaD and mxaJ. The significant increase in CoQ10 production may be associated with the base mutations in dxs gene, a key gene in the MEP/DOXP pathway. Conclusions A PQQ producing strain that simultaneously produces CoQ10 and carotenoids was selected and after ANI analysis, named as Methylobacterium sp. CLZ. After random mutagenesis of this strain, we obtained NI91 strain, which showed increased production of PQQ and CoQ10. Based on comparative genomic analysis of the whole genome of mutant strain NI91 and wild-type strain CLZ, a total of 270 SNPs and InDels events were detected, which provided a reference for subsequent research. The mutations in mxaD, mxaJ and dxs genes may be related to the high yield of PQQ and CoQ10. These findings will enhance our understanding of the PQQ and CoQ10 over-production mechanism in Methylobacterium sp. NI91 at the genomic level. It will also provide useful clues for strain engineering in order to improve the PQQ and CoQ10 production.

scholarly journals Whole-Genome Sequence of SARS-CoV-2 Isolate Siena-1/2020

2020 ◽  
Vol 9 (39) ◽  
Author(s):  
Maria Grazia Cusi ◽  
David Pinzauti ◽  
Claudia Gandolfo ◽  
Gabriele Anichini ◽  
Gianni Pozzi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Severe Acute Respiratory Syndrome ◽  
Genome Sequence ◽  
Amino Acid Change ◽  
Amplicon Sequencing ◽  
Spike Protein ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Nanopore Sequencing ◽  
Protein Coding

ABSTRACT The complete genome sequence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isolate Siena-1/2020 was obtained by Nanopore sequencing, combining the direct RNA sequencing and amplicon sequencing approaches. The isolate belongs to the B1.1 lineage, which is prevalent in Europe, and contains a mutation in the spike protein coding sequence leading to the D614G amino acid change.

scholarly journals A Single Amino Acid at Residue 188 of Hexon Protein is Responsible for the Pathogenicity of the Emerging Novel Fowl Adenovirus 4

2021 ◽  
Author(s):  
Yu Zhang ◽  
Aijing Liu ◽  
Yanan Wang ◽  
Hongyu Cui ◽  
Yulong Gao ◽  
...  
Keyword(s):  
Amino Acid ◽  
Mutant Strain ◽  
Molecular Basis ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Live Attenuated Vaccine ◽  
Hexon Protein

Since 2015, severe hydropericardium-hepatitis syndrome (HHS) associated with a novel fowl adenovirus 4 (FAdV-4) has emerged in China, representing a new challenge for the poultry industry. Although various highly pathogenic FAdV-4 strains have been isolated, the virulence factor and the pathogenesis of novel FAdV-4 are unclear. In our previous studies, we reported that a large genomic deletion (1966 bp) is not related to increased virulence. In this study, two recombinant chimeric viruses, rHN20 strain and rFB2 strain, were generated from a highly pathogenic FAdV-4 strain by replacing hexon or fiber-2 gene of a non-pathogenic FAdV-4, respectively. Both chimeric strains showed similar titers to the wild type strain in vitro . Notably, rFB2 and the wild type strain induced 100% mortality, while no mortality or clinical signs appeared in chickens inoculated with rHN20, indicating that hexon, but not fiber-2, determines the novel FAdV-4 virulence. Furthermore, an R188I mutation in the hexon protein identified residue 188 as the key amino acid for the reduced pathogenicity. The rR188I mutant strain was significantly neutralized by chicken serum in vitro and in vivo , whereas the wild type strain was able to replicate efficiently. Finally, the immunogenicity of the rescued rR188I was investigated. Non-pathogenic rR188I provided full protection against lethal FAdV-4 challenge. Collectively, these findings provide an in-depth understanding of the molecular basis of novel FAdV-4 pathogenicity and present rR188I as a potential live attenuated vaccine candidate or a novel vaccine vector for HHS vaccines. Importance HHS associated with a novel FAdV-4 infection in chickens has caused huge economic losses to the poultry industry in China since 2015. The molecular basis for the increased virulence remains largely unknown. Here, we demonstrate that the hexon gene is vital for FAdV-4 pathogenicity. Furthermore, we show that the amino acid residue at position 188 of the hexon protein is responsible for pathogenicity. Importantly, the rR188I mutant strain was neutralized by chicken serum in vitro and in vivo , whereas the wild type strain was not. Further, the rR188I mutant strain provided complete protection against FAdV-4 challenge. Our results provide a molecular basis of the increased virulence of novel FAdV-4. We propose that the rR188I mutant is a potential live attenuated vaccine against HHS and a new vaccine vector for HHS-combined vaccines.

scholarly journals Cloning and Inactivation of a Branched-Chain-Amino-Acid Aminotransferase Gene from Staphylococcus carnosus and Characterization of the Enzyme

2002 ◽  
Vol 68 (8) ◽  
pp. 4007-4014 ◽  
Author(s):  
Søren M. Madsen ◽  
Hans Christian Beck ◽  
Peter Ravn ◽  
Astrid Vrang ◽  
Anne Maria Hansen ◽  
...  
Keyword(s):  
Growth Rate ◽  
Amino Acid ◽  
Mutant Strain ◽  
Type Strain ◽  
Wild Type Strain ◽  
Biomass Yield ◽  
Degradation Products ◽  
Wild Type ◽  
Staphylococcus Carnosus ◽  
Branched Chain

ABSTRACT Staphylococcus carnosus and Staphylococcus xylosus are widely used as aroma producers in the manufacture of dried fermented sausages. Catabolism of branched-chain amino acids (BCAAs) by these strains contributes to aroma formation by production of methyl-branched aldehydes and carboxy acids. The first step in the catabolism is most likely a transamination reaction catalyzed by BCAA aminotransferases (IlvE proteins). In this study, we cloned the ilvE gene from S. carnosus by using degenerate oligonucleotides and PCR. We found that the deduced amino acid sequence was 80% identical to that of the corresponding enzyme in Staphylococcus aureus and that the ilvE gene was constitutively expressed as a monocistronic transcript. To study the influence of ilvE on BCAA catabolism, we constructed an ilvE deletion mutant by gene replacement. The IlvE protein from S. carnosus was shown mainly to catalyze the transamination of isoleucine, valine, leucine, and, to some extent, methionine using pyridoxal 5′-phosphate as a coenzyme. The ilvE mutant degraded less than 5% of the BCAAs, while the wild-type strain degraded 75 to 95%. Furthermore, the mutant strain produced approximately 100-fold less of the methyl-branched carboxy acids, 2-methylpropanoic acid, 2-methylbutanoic acid, and 3-methylbutanoic acid, which derived from the BCAA catabolism, clearly emphasizing the role of IlvE in aroma formation. In contrast to previous reports, we found that IlvE was the only enzyme that catalyzed the deamination of BCAAs in S. carnosus. The ilvE mutant strain showed remarkably lower growth rate and biomass yield compared to those of the wild-type strain when grown in rich medium. Normal growth rate and biomass yield were restored by addition of the three BCAA-derived α-keto acids, showing that degradation products of BCAAs were essential for optimal cell growth.

Growth inhibition by alpha-aminoadipate and reversal of the effect by specific amino acid supplements in Saccharomyces cerevisiae

1982 ◽  
Vol 152 (2) ◽  
pp. 874-879
Author(s):  
M K Winston ◽  
J K Bhattacharjee
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Type Strain ◽  
Wild Type Strain ◽  
Reductase Activity ◽  
Inhibitory Effect ◽  
Single Amino Acid ◽  
Amino Acid Supplementation ◽  
Wild Type ◽  
Multiple Buds

The growth of Saccharomyces cerevisiae wild-type strain X2180 in minimal medium was inhibited by the addition of higher-than-supplementary levels of alpha-aminoadipate. This inhibitory effect was reversed by the addition of arginine, asparagine, aspartate, glutamine, homoserine, methionine, or serine as single amino acid supplements. Mutants belonging to the lys2 and lys14 loci were able to grow in lysine-supplemented alpha-aminoadipate medium, although not as well as when selected amino acids were added. Growth in alpha-aminoadipate medium by all strains was accompanied by an accumulation of alpha-ketoadipate. Glutamate:keto-adipate transaminase levels were derepressed two- to fivefold in lys2 mutants using alpha-aminoadipate as a nitrogen source. Wild-type strain X2180 growing in amino acid-supplemented AA medium exhibited higher levels of alpha-aminoadipate reductase. Mutants unable to use alpha-aminoadipate without amino acid supplementation were obtained by treatment of lys2 strain MW5-64 and were shown to have glutamate: ketoadipate transaminase activity and to lack alpha-aminoadipate reductase activity. Altered cell morphologies, including increased size, multiple buds, pseudohyphae, and germ tubes, evidenced by cells grown in alpha-aminoadipate medium suggest that higher-than-supplementary levels of alpha-aminoadipate result in an impairment of cell division.

scholarly journals Functional Analysis of Fructosyl-Amino Acid Oxidases of Aspergillus oryzae

2004 ◽  
Vol 70 (10) ◽  
pp. 5882-5890 ◽  
Author(s):  
Shin-ichi Akazawa ◽  
Tetsuya Karino ◽  
Nobuyuki Yoshida ◽  
Tohoru Katsuragi ◽  
Yoshiki Tani
Keyword(s):  
Amino Acid ◽  
Aspergillus Oryzae ◽  
Type Strain ◽  
Wild Type Strain ◽  
Nitrogen Sources ◽  
Amino Acid Sequences ◽  
Wild Type ◽  
Amino Acid Oxidase ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen

ABSTRACT Three active fractions of fructosyl-amino acid oxidase (FAOD-Ao1, -Ao2a, and -Ao2b) were isolated from Aspergillus oryzae strain RIB40. N-terminal and internal amino acid sequences of FAOD-Ao2a corresponded to those of FAOD-Ao2b, suggesting that these two isozymes were derived from the same protein. FAOD-Ao1 and -Ao2 were different in substrate specificity and subunit assembly; FAOD-Ao2 was active toward N ε-fructosyl N α-Z-lysine and fructosyl valine (Fru-Val), whereas FAOD-Ao1 was not active toward Fru-Val. The genes encoding the FAOD isozymes (i.e., FAOAo1 and FAOAo2) were cloned by PCR with an FAOD-specific primer set. The deduced amino acid sequences revealed that FAOD-Ao1 was 50% identical to FAOD-Ao2, and each isozyme had a peroxisome-targeting signal-1, indicating their localization in peroxisomes. The genes was expressed in Escherichia coli and rFaoAo2 showed the same characteristics as FAOD-Ao2, whereas rFaoAo1 was not active. FAOAo2 disruptant was obtained by using ptrA as a selective marker. Wild-type strain grew on the medium containing Fru-Val as the sole carbon and nitrogen sources, but strain ΔfaoAo2 did not grow. Addition of glucose or (NH4)2SO4 to the Fru-Val medium did not affect the assimilation of Fru-Val by wild-type, indicating glucose and ammonium repressions did not occur in the expression of the FAOAo2 gene. Furthermore, conidia of the wild-type strain did not germinate on the medium containing Fru-Val and NaNO2 as the sole carbon and nitrogen sources, respectively, suggesting that Fru-Val may also repress gene expression of nitrite reductase. These results indicated that FAOD is needed for utilization of fructosyl-amino acids as nitrogen sources in A. oryzae.

scholarly journals Long-Chain Aldehyde Dehydrogenase That Participates in n-Alkane Utilization and Wax Ester Synthesis in Acinetobacter sp. Strain M-1

2000 ◽  
Vol 66 (8) ◽  
pp. 3481-3486 ◽  
Author(s):  
Takeru Ishige ◽  
Akio Tani ◽  
Yasuyoshi Sakai ◽  
Nobuo Kato
Keyword(s):  
Amino Acid ◽  
Aldehyde Dehydrogenase ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wax Ester ◽  
Wild Type ◽  
Chromosomal Dna ◽  
Ester Formation ◽  
Long Chain ◽  
Chain Aldehyde

ABSTRACT A long-chain aldehyde dehydrogenase, Ald1, was found in a soluble fraction of Acinetobacter sp. strain M-1 cells grown onn-hexadecane as a sole carbon source. The gene (ald1) was cloned from the chromosomal DNA of the bacterium. The open reading frame of ald1 was 1,512 bp long, corresponding to a protein of 503 amino acid residues (molecular mass, 55,496 Da), and the deduced amino acid sequence showed high similarity to those of various aldehyde dehydrogenases. Theald1 gene was stably expressed in Escherichia coli, and the gene product (recombinant Ald1 [rAld1]) was purified to apparent homogeneity by gel electrophoresis. rAld1 showed enzyme activity toward n-alkanals (C4 to C14), with a preference for longer carbon chains within the tested range; the highest activity was obtained with tetradecanal. Theald1 gene was disrupted by homologous recombination on theAcinetobacter genome. Although the ald1disruptant (ald1Δ) strain still had the ability to grow on n-hexadecane to some extent, its aldehyde dehydrogenase activity toward n-tetradecanal was reduced to half the level of the wild-type strain. Under nitrogen-limiting conditions, the accumulation of intracellular wax esters in the ald1Δ strain became much lower than that in the wild-type strain. These and other results imply that a soluble long-chain aldehyde dehydrogenase indeed plays important roles both in growth on n-alkane and in wax ester formation in Acinetobacter sp. strain M-1.

scholarly journals A Point Mutation in the 14α-Sterol Demethylase Gene cyp51A Contributes to Itraconazole Resistance in Aspergillus fumigatus

2003 ◽  
Vol 47 (3) ◽  
pp. 1120-1124 ◽  
Author(s):  
T. M. Diaz-Guerra ◽  
E. Mellado ◽  
M. Cuenca-Estrella ◽  
J. L. Rodriguez-Tudela
Keyword(s):  
Amino Acid ◽  
Aspergillus Fumigatus ◽  
Point Mutation ◽  
Resistant Strain ◽  
Type Strain ◽  
Wild Type Strain ◽  
Gene Copy ◽  
Wild Type ◽  
Genes Encoding ◽  
Resistant Strains

ABSTRACT The genes encoding 14α-sterol demethylases (cyp51A and cyp51B) were analyzed in 12 itraconazole (ITC)-resistant and three ITC-susceptible clinical isolates of Aspergillus fumigatus. Six ITC-resistant strains exhibited a substitution of another amino acid for glycine at position 54, which is located at a very conserved region of the Cyp51A protein. The cyp51A gene from the A. fumigatus wild-type strain (CM-237) was replaced with the mutated cyp51A gene copy of an ITC-resistant strain (AF-72). Two transformants exhibited resistance to ITC, both of which had incorporated the mutated copy of the cyp51A gene.

scholarly journals Sequencing and analysis of four new Enterobacter ampD Alleles.

1996 ◽  
Vol 40 (8) ◽  
pp. 1953-1956 ◽  
Author(s):  
A F Ehrhardt ◽  
C C Sanders ◽  
J R Romero ◽  
J S Leser
Keyword(s):  
Amino Acid ◽  
Type Strain ◽  
Wild Type Strain ◽  
Enterobacter Cloacae ◽  
Temperature Sensitive ◽  
Beta Lactamase ◽  
Wild Type ◽  
The Family

Sequences of ampD genes from wild-type, temperature-sensitive, and stably derepressed mutants of the wild-type strain of Enterobacter cloacae 029 and the hyperinducible strain E. cloacae 1194E were determined and compared with the ampD gene of the wild-type strain E. cloacae 14. Seventy nucleotide differences were found between the wild-type sequences, resulting in 13 amino acid changes. The deduced amino acid changes do not correspond to published AmpC regulation mutations and expand the number of known mutations leading to altered AmpC beta-lactamase expression in members of the family Enterobacteriaceae.

scholarly journals Studies towards the production of candicidin by Streptomyces sp. CBMAI 2043

2019 ◽  
Author(s):  
Rodrigo Silva de Oliveira ◽  
Luciana Gonzaga de Oliveira
Keyword(s):  
Gene Cluster ◽  
Genome Sequencing ◽  
Type Strain ◽  
Wild Type Strain ◽  
Gene Clusters ◽  
Whole Genome ◽  
Biosynthetic Pathways ◽  
Wild Type ◽  
Streptomyces Sp ◽  
Cluster A

The aim of this study was to explore two gene clusters from Streptomyces sp. CBMAI 2043. One of them was the candicidin gene cluster, a polyketide annotated form the strain whole genome sequencing. By deleting important genes it is possible to have clues about the biosynthetic pathways and released intermediates. The second gene is a unknown non ribosomal. Using the same approach we expected to ,correlate the gene cluster to the chemical entity. These studies will help to have a better understanding of the whole matabolite profile of the wild type strain.

Sign in / Sign up

Export Citation Format

Share Document