Amplicon-Based Analysis of the Fungal Diversity Across Kenyan Soda Lakes

BackgroundMicroorganisms have been able colonize and thrive in environments characterized by low/high pH, temperature, salt or pressure. Examples of extreme environments are the soda lakes and soda deserts. The objective of this study was to explore the fungal diversity across soda lakes Magadi, Elmenteita, Sonachi and Bogoria in Kenya. A new set of primers was designed to amplify a fragment long enough for the 454-pyrosequencing technology. Results Analysis of the amplicons generated showed that the new primers amplified for eukaryotic groups. A total of 153,634 quality-filtered, non-chimeric sequences were used for community diversity analysis. The sequence reads were clustered into 502 operational taxonomic Units (OTUs) at 97% similarity using BLASTn analysis of which 432 were affiliated to known fungal phylotypes and the rest to other eukaryotes. Fungal OTUs were distributed across 107 genera affiliated to the phylum Ascomycota, Basidiomycota, Glomeromycotina and Incertae Sedis. The Phylum Ascomycota was the most abundant phylotype. Overall, fifteen (15) genera (Chaetomium, Monodictys, Arthrinium, Cladosporium, Fusarium, Myrothecium, Phyllosticta, Coniochaeta, Diatrype, Sarocladium, Sclerotinia, Aspergillus, Preussia and Eutypa) accounted for 65.3% of all the reads. The Genus Cladosporium was detected across all the samples at varying percentages with the highest being water from Lake Bogoria (51.4%). Good’s coverage estimator values ranged between 97 and 100%, an indication that the dominant phylotypes were represented in the data. ConclusionThese results provide useful insights that can guide cultivation dependent studies in order to understand the physiology and biochemistry of the as yet uncultured taxa.

Impact of Nosema Disease and American Foulbrood on Gut Bacterial Communities of Honeybees Apis mellifera

Honeybees, Apis mellifera, are important pollinators of many economically important crops. However, one of the reasons for their decline is pathogenic infection. Nosema disease and American foulbrood (AFB) disease are the most common bee pathogens that propagate in the gut of honeybees. This study investigated the impact of gut-propagating pathogens, including Nosema ceranae and Paenibacillus larvae, on bacterial communities in the gut of A. mellifera using 454-pyrosequencing. Pyrosequencing results showed that N. ceranae was implicated in the elimination of Serratia and the dramatic increase in Snodgrassella and Bartonella in adult bees’ guts, while bacterial communities of P. larvae-infected larvae were not affected by the infection. The results indicated that only N. ceranae had an impact on some core bacteria in the gut of A. mellifera through increasing core gut bacteria, therefore leading to the induction of dysbiosis in the bees’ gut.

Bacterial Community of Neutral Mine Drainage of Elizabeth’s Shaft (Slovinky, Slovakia)

Neutral mine drainage is the less frequent subject of the interest than acid mine drainage but it can have adverse environmental eff ects caused mainly by precipitation of dissolved Fe. Th e aim of the study was to characterize the composition of bacterial population in environment with high concentration of iron and sulfur compounds represented by neutral mine drainage water of Elizabeth’s shaft , Slovinky (Slovakia). Th e pH value of drainage water decreased from 7.1 to 6.5 during the years 2008–2014. Direct microscopic observations, cultivation methods, and 454 pyrosequencing of the 16S rRNA gene amplicons were used to examine the bacterial population. Microscopic observations identifi ed iron–oxidizing Proteobacteria of the genera Gallionella and Leptothrix which occurrence was not changed during the years 2008–2014. Using 454 pyrosequencing, there were identifi ed members of 204 bacterial genera that belonged to 25 phyla. Proteobacteria (69.55%), followed by Chlorofl exi (10.31%) and Actinobacteria (4.24%) dominated the bacterial community. Genera Azotobacter (24.52%) and Pseudomonas (14.15%), followed by iron–oxidizing Proteobacteria Dechloromonas (11%) and Methyloversatilis (8.53%) were most abundant within bacterial community. Typical sulfur bacteria were detected with lower frequency, e.g., Desulfobacteraceae (0.25%), Desulfovibrionaceae (0.16%), or Desulfobulbaceae (0.11%). Our data indicate that the composition of bacterial community of the Elizabeth’s shaft drainage water refl ects observed neutral pH, high level of iron and sulfur ions in this aquatic habitat.

Insights from the revised complete genome sequences of Acinetobacter baumannii strains AB307-0294 and ACICU belonging to global clone 1 and 2

2.AbstractThe Acinetobacter baumannii global clone 1 (GC1) isolate AB307-0294, recovered in the USA in 1994, and the global clone 2 (GC2) isolate ACICU, isolated in 2005 in Italy, were among the first A. baumannii isolates to be completely sequenced. AB307-0294 is susceptible to most antibiotics and has been used in many genetic studies and ACICU belongs to a rare GC2 lineage. The complete genome sequences, originally determined using 454 pyrosequencing technology which is known to generate sequencing errors, were re-determined using Illumina MiSeq and MinION (ONT) technologies and a hybrid assembly generated using Unicycler. Comparison of the resulting new high-quality genomes to the earlier 454-sequenced version identified a large number of nucleotide differences affecting protein coding features, and allowed the sequence of the long and highly-repetitive bap and blp1 genes to be properly resolved for the first time in ACICU. Comparisons of the annotations of the original and revised genomes revealed a large number of differences in the protein coding features (CDSs), underlining the impact of sequence errors on protein sequence predictions and core gene determination. On average, 400 predicted CDSs were longer or shorter in the revised genomes and about 200 CDS features were no longer present.3.Impact statementThe genomes of the first 10 A. baumannii strains to be completely sequenced underpin a large amount of published genetic and genomic analysis. However, most of their genome sequences contain substantial numbers of errors as they were sequenced using 454 pyrosequencing, which is known to generate errors particularly in homopolymer regions; and employed manual PCR and capillary sequencing steps to bridge contig gaps and repetitive regions in order to finish the genomes. Assembly of the very large and internally repetitive gene for the biofilm-associated proteins Bap and BLP1 was a recurring problem. As these strains continue to be used for genetic studies and their genomes continue to be used as references in phylogenomics studies including core gene determination, there is value in improving the quality of their genome sequences. To this end, we re-sequenced two such strains that belong to the two major globally distributed clones of A. baumannii, using a combination of highly-accurate short-read and gap-spanning long-read technologies. Annotation of the revised genome sequences eliminated hundreds of incorrect CDS feature annotations and corrected hundreds more. Given that these revisions affected hundreds of non-existent or incorrect CDS features currently cluttering GenBank protein databases, it can be envisaged that similar revision of other early bacterial genomes that were sequenced using error-prone technologies will affect thousands of CDS currently listed in GenBank and other databases. These corrections will impact the quality of predicted protein sequence data stored in public databases. The revised genomes will also improve the accuracy of future genetic and comparative genomic analyses incorporating these clinically important strains.4.Data summaryThe corrected complete genome sequence of A. baumannii AB307-0294 has been deposited in GenBank; GenBank accession number CP001172.2 (chromosome url - https://www.ncbi.nlm.nih.gov/nuccore/CP001172.2).The corrected complete genome sequence of ACICU has been deposited in GenBank under the GenBank accession numbers CP031380 (chromosome; url - https://www.ncbi.nlm.nih.gov/nuccore/CP031380), CP031381 (pACICU1; url - https://www.ncbi.nlm.nih.gov/nuccore/CP031381) and CP031382 (pACICU2; url - https://www.ncbi.nlm.nih.gov/nuccore/CP031382).The authors confirm all supporting data, code and protocols have been provided within the article or through supplementary data files.