TL;DR: The taxonomic status of 14 strains of members of the genus Acinetobacter isolated from floral nectar of wild Mediterranean insect-pollinated plants, which did not belong to any previously described species within this genus, was investigated following a polyphasic approach and confirmed that these strains formed two separate lineages.
Abstract: The taxonomic status of 14 strains of members of the genus Acinetobacter isolated from floral nectar of wild Mediterranean insect-pollinated plants, which did not belong to any previously described species within this genus, was investigated following a polyphasic approach. Confirmation that these strains formed two separate lineages within the genus Acinetobacter was obtained from comparative analysis of the partial sequences of the 16S rRNA gene and the gene encoding the β-subunit of RNA polymerase (rpoB), DNA-DNA reassociation data, determination of the DNA G+C content and physiological tests. The names Acinetobacter nectaris sp. nov. and Acinetobacter boissieri sp. nov. are proposed. The type strain of A. nectaris sp. nov. is SAP 763.2(T) ( = LMG 26958(T) = CECT 8127(T)) and that of A. boissieri sp. nov. is SAP 284.1(T) ( = LMG 26959(T) = CECT 8128(T)).
TL;DR: Phylogenetic analyses based on 16S rRNA, rpoB and gyrB gene sequences, together with DNA-DNA hybridization values less than 70%, revealed that strain 1NM-4(T) belongs to the genus Acinetobacter and may represent a novel species.
Abstract: A Gram-stain-negative, non-motile bacterial strain designated 1NM-4T was isolated from an abandoned lead–zinc ore mine site in Mei County, Meizhou, Guangdong Province, southern China. The isolate was light yellow, strictly aerobic, oxidase-negative and catalase-positive. Phylogenetic analyses based on 16S rRNA, rpoB and gyrB gene sequences, together with DNA–DNA hybridization values less than 70 %, revealed that strain 1NM-4T belongs to the genus
Acinetobacter
and may represent a novel species. The major respiratory quinone was ubiquinone 9 (Q-9) and the major cellular fatty acids consisted of C18 : 1ω9c, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C12 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, an unidentified aminolipid and two unidentified phospholipids. The genomic DNA G+C content of strain 1NM-4T was 47.17±0.02 mol%. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strain 1NM-4T should be assigned to a novel species of the genus
Acinetobacter
, for which the name Acinetobacter guangdongensis sp. nov. is proposed. The type strain is 1NM-4T ( = GIMCC 1.656T = CCTCC AB 2014199T = KCTC 42012T).
TL;DR: The upregulation of cellular repair and metabolism genes, and the formation of different subpopulations of A.junii in both effluents provide insights into the mechanisms employed by A. junii to persist in the conditions of a WWTP.
Abstract: A membrane bioreactor (MBR)-based wastewater treatment plant (WWTP) in Saudi Arabia is assessed over a five-month period in 2015 and once in 2017 for bacterial diversity and transcriptional activity using metagenomics, metatranscriptomics and real time quantitative polymerase chain reaction (RT-qPCR). Acinetobacter spp. are shown to be enriched in the chlorinated effluent. Members of the Acinetobacter genus are the most abundant in the effluent and chlorinated effluent. At the species level, Acinetobacter junii have higher relative abundances post MBR and chlorination. RNA-seq analysis show that, in A. junii, 288 genes and 378 genes are significantly upregulated in the effluent and chlorinated effluent, respectively, with 98 genes being upregulated in both. RT-qPCR of samples in 2015 and 2017 confirm the upregulation observed in RNA-seq. Analysis of the 98 genes show that majority of the upregulated genes are involved in cellular repair and metabolism followed by resistance, virulence, and signaling. Additionally, two different subpopulations of A. junii are observed in the effluent and chlorinated effluent. The upregulation of cellular repair and metabolism genes, and the formation of different subpopulations of A. junii in both effluents provide insights into the mechanisms employed by A. junii to persist in the conditions of a WWTP.
TL;DR: The taxonomic position of six phenetically related strains of the genus Acinetobacter, which were recovered from hospital sewage in China and showed different patterns of resistance to clinically important antibiotics, are studied and it is concluded that the six strains represent a novel AcinetOBacter species.
TL;DR: A detailed evaluation of eight bacterial isolates from floral nectar and animal visitors to flowers shows evidence that they represent three novel species in the genus Acinetobacter as discussed by the authors, for which the names Acinetebacter pollinis sp. nov., Acinetabacter baretiae sp.nov. and Acinetibacter rathckeae sp.Nov. are proposed.
Abstract: A detailed evaluation of eight bacterial isolates from floral nectar and animal visitors to flowers shows evidence that they represent three novel species in the genus Acinetobacter. Phylogenomic analysis shows the closest relatives of these new isolates are Acinetobacter apis, Acinetobacter boissieri and Acinetobacter nectaris, previously described species associated with floral nectar and bees, but high genome-wide sequence divergence defines these isolates as novel species. Pairwise comparisons of the average nucleotide identity of the new isolates compared to known species is extremely low (<83 %), thus confirming that these samples are representative of three novel Acinetobacter species, for which the names Acinetobacter pollinis sp. nov., Acinetobacter baretiae sp. nov. and Acinetobacter rathckeae sp. nov. are proposed. The respective type strains are SCC477T (=TSD-214T=LMG 31655T), B10AT (=TSD-213T=LMG 31702T) and EC24T (=TSD-215T=LMG 31703T=DSM 111781T).
TL;DR: It is concluded that both geographical distance and local environmental abiotic conditions affect and shape the composition and diversity of nectar inhabiting bacterial communities.
TL;DR: The newest addition in MEGA5 is a collection of maximum likelihood (ML) analyses for inferring evolutionary trees, selecting best-fit substitution models, inferring ancestral states and sequences, and estimating evolutionary rates site-by-site.
Abstract: Comparative analysis of molecular sequence data is essential for reconstructing the evolutionary histories of species and inferring the nature and extent of selective forces shaping the evolution of genes and species. Here, we announce the release of Molecular Evolutionary Genetics Analysis version 5 (MEGA5), which is a user-friendly software for mining online databases, building sequence alignments and phylogenetic trees, and using methods of evolutionary bioinformatics in basic biology, biomedicine, and evolution. The newest addition in MEGA5 is a collection of maximum likelihood (ML) analyses for inferring evolutionary trees, selecting best-fit substitution models (nucleotide or amino acid), inferring ancestral states and sequences (along with probabilities), and estimating evolutionary rates site-by-site. In computer simulation analyses, ML tree inference algorithms in MEGA5 compared favorably with other software packages in terms of computational efficiency and the accuracy of the estimates of phylogenetic trees, substitution parameters, and rate variation among sites. The MEGA user interface has now been enhanced to be activity driven to make it easier for the use of both beginners and experienced scientists. This version of MEGA is intended for the Windows platform, and it has been configured for effective use on Mac OS X and Linux desktops. It is available free of charge from http://www.megasoftware.net.
39,110 citations
"Acinetobacter nectaris sp. nov. and..." refers methods in this paper
...Following these procedures, 1320 nt positions (98 % of the original alignment) remained for subsequent phylogenetic analysis using the neighbour-joining (NJ) method as implemented in the MEGA 5 software package (Tamura et al., 2011)....
TL;DR: A computerized method is presented that reduces to a certain extent the necessity of manually editing multiple alignments, makes the automation of phylogenetic analysis of large data sets feasible, and facilitates the reproduction of the final alignment by other researchers.
Abstract: The use of some multiple-sequence alignments in phylogenetic analysis, particularly those that are not very well conserved, requires the elimination of poorly aligned positions and divergent regions, since they may not be homologous or may have been saturated by multiple substitutions. A computerized method that eliminates such positions and at the same time tries to minimize the loss of informative sites is presented here. The method is based on the selection of blocks of positions that fulfill a simple set of requirements with respect to the number of contiguous conserved positions, lack of gaps, and high conservation of flanking positions, making the final alignment more suitable for phylogenetic analysis. To illustrate the efficiency of this method, alignments of 10 mitochondrial proteins from several completely sequenced mitochondrial genomes belonging to diverse eukaryotes were used as examples. The percentages of removed positions were higher in the most divergent alignments. After removing divergent segments, the amino acid composition of the different sequences was more uniform, and pairwise distances became much smaller. Phylogenetic trees show that topologies can be different after removing conserved blocks, particularly when there are several poorly resolved nodes. Strong support was found for the grouping of animals and fungi but not for the position of more basal eukaryotes. The use of a computerized method such as the one presented here reduces to a certain extent the necessity of manually editing multiple alignments, makes the automation of phylogenetic analysis of large data sets feasible, and facilitates the reproduction of the final alignment by other researchers.
8,757 citations
"Acinetobacter nectaris sp. nov. and..." refers methods in this paper
...0 (Hall, 1999) to ensure that all sequences had the same start and end point, and analysed with Gblocks (Castresana, 2000) to eliminate ambiguously aligned regions, using ‘allow gap positions5with half’, ‘minimum length of a block559 and default settings for all other options....
[...]
...…alignment was trimmed with BioEdit v. 7.0.9.0 (Hall, 1999) to ensure that all sequences had the same start and end point, and analysed with Gblocks (Castresana, 2000) to eliminate ambiguously aligned regions, using ‘allow gap positions5with half’, ‘minimum length of a block559 and default settings…...
[...]
...As with the 16S rRNA gene sequence, concatenated sequences of rpoB zones 1 and 2 of the nectar strains and type strains of other species of the genus Acinetobacter were included in a multiple alignment and analysed with Gblocks, which resulted in the selection of 843 nucleotide positions (99 % of the original alignment)....
[...]
...The resulting alignment was trimmed with BioEdit v. 7.0.9.0 (Hall, 1999) to ensure that all sequences had the same start and end point, and analysed with Gblocks (Castresana, 2000) to eliminate ambiguously aligned regions, using ‘allow gap positions5with half’, ‘minimum length of a block559 and default settings for all other options....
TL;DR: The Clustal series of programs, widely used in molecular biology for the multiple alignment of both nucleic acid and protein sequences and for preparing phylogenetic trees, are extended.
Abstract: The Clustal series of programs are widely used in molecular biology for the multiple alignment of both nucleic acid and protein sequences and for preparing phylogenetic trees. The popularity of the programs depends on a number of factors, including not only the accuracy of the results, but also the robustness, portability and user-friendliness of the programs. New features include NEXUS and FASTA format output, printing range numbers and faster tree calculation. Although, Clustal was originally developed to run on a local computer, numerous Web servers have been set up, notably at the EBI (European Bioinformatics Institute) (http://www.ebi.
5,300 citations
"Acinetobacter nectaris sp. nov. and..." refers methods in this paper
...The 16S rRNA gene sequences of the novel nectar strains and reference strains of members of the genus Acinetobacter and the family Moraxellaceae were included in a multiple alignment generated by CLUSTAL W (Chenna et al., 2003)....
TL;DR: High-performance liquid chromatography is a promising alternative for determining the G+C content of bacterial deoxyribonucleic acid (DNA) and may also be more accurate than indirect methods, such as the buoyant density and thermal denaturation methods.
Abstract: High-performance liquid chromatography is a promising alternative for determining the G+C content of bacterial deoxyribonucleic acid (DNA). The method which we evaluated involves enzymatic degradation of the DNA to nucleosides by P1 nuclease and bovine intestinal mucosa alkaline phosphatase, separation of the nucleosides by high-performance liquid chromatography, and calculation of the G+C content from the apparent ratios of deoxyguanosine and thymidine. Because the nucleosides are released from the DNA at different rates, incomplete degradation produces large errors in the apparent G+C content. For partially purified DNA, salts are a major source of interference in degradation. However, when the salts are carefully removed, the preparation and degradation of DNA contribute little error to the determination of G+C content. This method also requires careful selection of the chromatographic conditions to ensure separation of the major nucleosides from the nucleosides of modified bases and precise control of the flow rates. Both of these conditions are achievable with standard equipment and C18 reversed-phase columns. Then the method is precise, and the relative standard deviations of replicate measurements are close to 0.1%. It is also rapid, and a single measurement requires about 15 min. It requires small amounts of sample, and the G+C content can be determined from DNA isolated from a single bacterial colony. It is not affected by contamination with ribonucleic acid. Because this method yields a direct measurement, it may also be more accurate than indirect methods, such as the buoyant density and thermal denaturation methods. In addition, for highly purified DNA, the extent of modification can be determined.
4,685 citations
"Acinetobacter nectaris sp. nov. and..." refers methods in this paper
...The DNA was enzymically degraded into nucleosides and the nucleotidic base composition was determined by HPLC, according to the method of Mesbah et al. (1989)....