The plastome of Melocactus glaucescens Buining & Brederoo reveals unique evolutionary features and loss of essential tRNA genes.

MAIN CONCLUSION: The plastome of Melocactus glaucescens shows unique rearrangements, IR expansion, and unprecedented gene losses in Cactaceae. Our data indicate tRNA import from the cytosol to the plastids in this species. Cactaceae represents one of the richest families in keystone species of arid and semiarid biomes. This family shows various specific features comprehending morphology, anatomy, and metabolism, which allow them to grow under unfavorable environmental conditions. The subfamily Cactoideae contains the most divergence of species, which are highly variable in growth habit and morphology. This subfamily includes the endangered species Melocactus glaucescens (tribe Cereeae), which is a cactus endemic to the biome Caatinga in Brazil. Aiming to analyze the plastid evolution and develop molecular markers, we sequenced and analyzed in detail the plastome of M. glaucescens. Our analyses revealed that the M. glaucescens plastome is the most divergent among the species of the family Cactaceae sequenced so far. We characterized here unique rearrangements, expanded IRs containing an unusual set of genes, and several gene losses. Some genes related to the ndh complex were lost during the plastome evolution, while others have lost their functionality. Additionally, the loss of three tRNA genes (trnA-UGC, trnV-UAC, and trnV-GAC) suggests tRNA import from the cytosol to the plastids in M. glaucescens. Moreover, we identified high gene divergence, several putative positive signatures, and possible unique RNA-editing sites. Furthermore, we mapped 169 SSRs in the plastome of M. glaucescens, which are helpful to access the genetic diversity of natural populations and conservation strategies. Finally, our data provide new insights into the evolution of plastids in Cactaceae, which is an outstanding lineage adapted to extreme environmental conditions and a notorious example of the atypical evolution of plastomes.

Plastid genome evolution in Amazonian açaí palm (Euterpe oleracea Mart.) and Atlantic forest açaí palm (Euterpe edulis Mart.).

KEY MESSAGE: The plastomes of E. edulis and E. oleracea revealed several molecular markers useful for genetic studies in natural populations and indicate specific evolutionary features determined by vicariant speciation. Arecaceae is a large and diverse family occurring in tropical and subtropical ecosystems worldwide. E. oleracea is a hyperdominant species of the Amazon forest, while E. edulis is a keystone species of the Atlantic forest. It has reported that E. edulis arose from vicariant speciation after the emergence of the belt barrier of dry environment (Cerrado and Caatinga biomes) between Amazon and Atlantic forests, isolating the E. edulis in the Atlantic forest. We sequenced the complete plastomes of E. edulis and E. oleracea and compared them concerning plastome structure, SSRs, tandem repeats, SNPs, indels, hotspots of nucleotide polymorphism, codon Ka/Ks ratios and RNA editing sites aiming to investigate evolutionary traits possibly affected by distinct environments. Our analyses revealed 303 SNPs, 91 indels, and 82 polymorphic SSRs among both species. Curiously, the narrow correlation among localization of repetitive sequences and indels strongly suggests that replication slippage is involved in plastid DNA mutations in Euterpe. Moreover, most non-synonymous substitutions represent amino acid variants in E. edulis that evolved specifically or in a convergent manner across the palm phylogeny. Amino acid variants observed in several plastid proteins in E. edulis were also identified as positive signatures across palm phylogeny. The higher incidence of specific amino acid changes in plastid genes of E. edulis in comparison with E. oleracea probably configures adaptive genetic variations determined by vicariant speciation. Our data indicate that the environment generates a selective pressure on the plastome making it more adapted to specific conditions.

Re-emergence of Gamma-like-II and emergence of Gamma-S:E661D SARS-CoV-2 lineages in the south of Brazil after the 2021 outbreak.

BACKGROUND: We report a genomic surveillance of SARS-CoV-2 lineages circulating in Paraná, southern Brazil, from March 2020 to April 2021. Our analysis, based on 333 genomes, revealed that the first variants detected in the state of Paraná in March 2020 were the B.1.1.33 and B.1.1.28 variants. The variants B.1.1.28 and B.1.1.33 were predominant throughout 2020 until the introduction of the variant P.2 in August 2020 and a variant of concern (VOC), Gamma (P.1), in January 2021. The VOC Gamma, a ramification of the B.1.1.28 lineage first detected in Manaus (northern Brazil), has grown rapidly since December 2020 and was thought to be responsible for the deadly second wave of COVID-19 throughout Brazil. METHODS: The 333 genomic sequences of SARS-CoV-2 from March 2020 to April 2021 were generated as part of the genomic surveillance carried out by Fiocruz in Brazil Genomahcov Fiocruz. SARS-CoV-2 sequencing was performed using representative samples from all geographic areas of Paraná. Phylogenetic analyses were performed using the 333 genomes also included other SARS-CoV-2 genomes from the state of Paraná and other states in Brazil that were deposited in the GISAID. In addition, the time-scaled phylogenetic tree was constructed with up to 3 random sequences of the Gamma variant from each state in Brazil in each month of 2021. In this analysis we also added the sequences identified as the B.1.1.28 lineage of the Amazonas state and and the Gamma-like-II (P.1-like-II) lineage identified in different regions of Brazil. RESULTS: Phylogenetic analyses of the SARS-CoV-2 genomes that were previously classified as the VOC Gamma lineage by WHO/PANGO showed that some genomes from February to April 2021 branched in a monophyletic clade and that these samples grouped together with genomes recently described with the lineage Gamma-like-II. Additionally, a new mutation (E661D) in the spike (S) protein has been identified in nearly 10% of the genomes classified as the VOC Gamma from Paraná in March and April 2021.Finally, we analyzed the correlation between the lineage and the Gamma variant frequency, age group (patients younger or older than 60 years old) and the clinical data of 86 cases from the state of Paraná. CONCLUSIONS: Our results provided a reliable picture of the evolution of the SARS-CoV-2 pandemic in the state of Paraná characterized by the dominance of the Gamma strain, as well as a high frequencies of the Gamma-like-II lineage and the S:E661D mutation. Epidemiological and genomic surveillance efforts should be continued to unveil the biological relevance of the novel mutations detected in the VOC Gamma in Paraná.

The microbiome of a shell mound: ancient anthropogenic waste as a source of Streptomyces degrading recalcitrant polysaccharides.

Metagenome amplicon DNA sequencing and traditional cell culture techniques are helping to uncover the diversity and the biotechnological potential of prokaryotes in different habitats around the world. It has also had a profound impact on microbial taxonomy in the last decades. Here we used metagenome 16S rDNA amplicon sequencing to reveal the microbiome composition of different layers of an anthropogenic soil collected at a shell mound Sambaqui archeological site. The Samabaqui soil microbiome is mainly composed by phyla Acidobacteria, Rokubacteria, Proteobacteria and Thaumarchaeota. Using culture-dependent analysis we obtained few Streptomyces isolates from the Sambaqui soil. One of the isolates, named Streptomyces sp. S3, was able to grow in minimal medium containing recalcitrant polysaccharides including chitin, xylan, carboxymethylcellulose or microcrystalline cellulose as sole carbon sources. The activities of enzymes degrading these compounds were confirmed in cell free supernatants. The genome sequence revealed not only an arsenal of genes related to polysaccharides degradation but also biosynthetic gene clusters which may be involved in the production of biotechnologically interesting secondary metabolites.

Phylogenetic and evolutionary features of the plastome of Tropaeolum pentaphyllum Lam. (Tropaeolaceae).

MAIN CONCLUSION: Complete plastome sequence of Tropaeolum pentaphyllum revealed molecular markers, hotspots of nucleotide polymorphism, RNA editing sites and phylogenetic aspects Tropaeolaceae Juss. ex DC. comprises approximately 95 species across North and South Americas. Tropaeolum pentaphyllum Lam. is an unconventional and endangered species with occurrence in some countries of South America. Although this species presents nutritional, medicinal and ornamental uses, genetic studies involving natural populations or promising genotypes are practically non-existent. Here, we report the nucleotide sequence of T. pentaphyllum plastome. It represents the first complete plastome sequence of the family Tropaeolaceae to be fully sequenced and analyzed in detail. The sequencing data revealed that the T. pentaphyllum plastome is highly similar to the plastomes of other Brassicales. Notwithstanding, our analyses detected some specific features concerning events of IR expansion and structural changes in some genes such as matK, rpoA, and rpoC2. We also detected 251 SSR loci, nine hotspots of nucleotide polymorphism, and two specific RNA editing sites in the plastome of T. pentaphyllum. Moreover, plastid phylogenomic inference indicated a closed relationship between the families Tropaeolaceae and Akaniaceae, which formed a sister group to Moringaceae-Caricaceae. Finally, our data bring new molecular markers and evolutionary features to be applied in the natural population, germplasm collection, and genotype selection aiming conservation, genetic diversity evaluation, and exploitation of this endangered species.

Bradyrhizobium uaiense sp. nov., a new highly efficient cowpea symbiont.

This study describes two Bradyrhizobium strains, UFLA03-164T and UFLA03-153, which share more than 99% sequence similarity of the 16S rRNA with the type strains of 15 species in this genus. The concatenation of three housekeeping genes (recA, gyrB, and dnaK) indicated that both strains formed a single clade separate from known Bradyrhizobium species. B. viridifuturi, represented by SEMIA 690T, is the closest neighboring species (96.2%). Low (< 92%) average nucleotide identity (ANI) was observed between strain UFLA03-164T and any of the closest species on the phylogenetic trees based on concatenated housekeeping genes. The DNA G+C content of UFLA03-164T is 63.25%. Phenotypic characteristics were determined for both UFLA strains. Based on the data, the two strains represent a new species for which the name Bradyrhizobium uaiense is proposed, with UFLA03-164T (= LMG 31509T) as type strain.

Genome-based reclassification of Azospirillum brasilense Sp245 as the type strain of Azospirillum baldaniorum sp. nov.

Azospirillum sp. strain Sp245T, originally identified as belonging to Azospirillum brasilense, is recognized as a plant-growth-promoting rhizobacterium due to its ability to fix atmospheric nitrogen and to produce plant-beneficial compounds. Azospirillum sp. Sp245T and other related strains were isolated from the root surfaces of different plants in Brazil. Cells are Gram-negative, curved or slightly curved rods, and motile with polar and lateral flagella. Their growth temperature varies between 20 to 38 °C and their carbon source utilization is similar to other Azospirillum species. A preliminary 16S rRNA sequence analysis showed that the new species is closely related to A. brasilense Sp7T and A. formosense CC-Nfb-7T. Housekeeping genes revealed that Azospirillum sp. Sp245T, BR 12001 and Vi22 form a separate cluster from strain A. formosense CC-Nfb-7T, and a group of strains closely related to A. brasilense Sp7T. Overall genome relatedness index (OGRI) analyses estimated based on average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) between Azospirillum sp. Sp245T and its close relatives to other Azospirillum species type strains, such as A. brasilense Sp7T and A. formosense CC-Nfb-7T , revealed values lower than the limit of species circumscription. Moreover, core-proteome phylogeny including 1079 common shared proteins showed the independent clusterization of A. brasilense Sp7T, A. formosense CC-Nfb-7T and Azospirillum sp. Sp245T, a finding that was corroborated by the genome clustering of OGRI values and housekeeping phylogenies. The DNA G+C content of the cluster of Sp245T was 68.4-68.6 %. Based on the phylogenetic, genomic, phenotypical and physiological analysis, we propose that strain Sp245T together with the strains Vi22 and BR12001 represent a novel species of the genus Azospirillum, for which the name Azospirillum baldaniorum sp. nov. is proposed. The type strain is Sp245T (=BR 11005T=IBPPM 219T) (GCF_007827915.1, GCF_000237365.1, and GCF_003119195.2).

Efficient Nitrogen-Fixing Bacteria Isolated from Soybean Nodules in the Semi-arid Region of Northeast Brazil are Classified as Bradyrhizobium brasilense (Symbiovar Sojae).

Soybean (Glycine max L.) is an important legume that greatly benefits from inoculation with nitrogen-fixing bacteria. In a previous study, five efficient nitrogen-fixing bacterial strains, isolated from nodules of soybean inoculated with soil from semi-arid region, Northeast Brazil, were identified as a new group within the genus Bradyrhizobium. The taxonomic status of these strains was evaluated in this study. The phylogenetic analysis of the 16S rRNA gene showed the high similarity of the five strains to Bradyrhizobium brasilense UFLA03-321T (100%), B. pachyrhizi PAC48T (100%), B. ripae WR4T (100%), B. elkanii USDA 76T (99.91%), and B. macuxiense BR 10303T (99.91%). However, multilocus sequence analysis of the housekeeping genes atpD, dnaK, gyrB, recA, and rpoB, average nucleotide identity, and digital DNA-DNA hybridization analyses supported the classification of the group as B. brasilense. Some phenotypic characteristics allowed differentiating the five strains and the type strain of B. brasilense from the two neighboring species (B. pachyrhizi PAC48T and B. elkanii USDA 76T). The nodC and nifH genes' analyses showed that these strains belong to symbiovar sojae, together with B. elkanii (USDA 76T) and B. ferriligni (CCBAU 51502T). The present results support the classification of these five strains as Bradyrhizobium brasilense (symbiovar sojae).

Metagenomic analysis of the bacterial microbiota associated with cultured oysters (Crassostrea sp.) in estuarine environments.

In this work, we identified the bacterial microbiota associated with farmed oystersin estuarine regions of four states in the north eastern region of Brazil. During the drought and rainy seasons, for eight months, twenty oysters were sampled seasonally from seven different marine farms. In the laboratory, DNA extraction, amplification, and sequencing of the 16S rRNA gene were performed to establish the taxonomic units. We identified 106 genera of bacteria belonging to 103 families, 70 orders, 39 classes, and 21 phyla. Out of the total, 40 of the genera represented bacteria potentially pathogenic to humans; of these, nine are known to cause foodborne diseases and six are potentially pathogenic to oysters. The most prevalent genera were Mycoplasma, Propionigenium, Psychrilyobacter, and Arcobacter. The results indicate the need for more systematic monitoring of bacteria of the genus Mycoplasma in oyster farming operations in the Brazilian north eastern region. Currently, Mycoplasma is not one of the microorganisms analysed and monitored by order of Brazilian legislation during the oyster production and/or commercialization process, even though this genus was the most prevalent at all sampling points and presents pathogenic potential both for oysters and for consumers.

Genome comparison between clinical and environmental strains of Herbaspirillum seropedicae reveals a potential new emerging bacterium adapted to human hosts.

BACKGROUND: Herbaspirillum seropedicae is an environmental ß-proteobacterium that is capable of promoting the growth of economically relevant plants through biological nitrogen fixation and phytohormone production. However, strains of H. seropedicae have been isolated from immunocompromised patients and associated with human infections and deaths. In this work, we sequenced the genomes of two clinical strains of H. seropedicae, AU14040 and AU13965, and compared them with the genomes of strains described as having an environmental origin. RESULTS: Both genomes were closed, indicating a single circular chromosome; however, strain AU13965 also carried a plasmid of 42,977 bp, the first described in the genus Herbaspirillum. Genome comparison revealed that the clinical strains lost the gene sets related to biological nitrogen fixation (nif) and the type 3 secretion system (T3SS), which has been described to be essential for interactions with plants. Comparison of the pan-genomes of clinical and environmental strains revealed different sets of accessorial genes. However, antimicrobial resistance genes were found in the same proportion in all analyzed genomes. The clinical strains also acquired new genes and genomic islands that may be related to host interactions. Among the acquired islands was a cluster of genes related to lipopolysaccharide (LPS) biosynthesis. Although highly conserved in environmental strains, the LPS biosynthesis genes in the two clinical strains presented unique and non-orthologous genes within the genus Herbaspirillum. Furthermore, the AU14040 strain cluster contained the neuABC genes, which are responsible for sialic acid (Neu5Ac) biosynthesis, indicating that this bacterium could add it to its lipopolysaccharide. The Neu5Ac-linked LPS could increase the bacterial resilience in the host aiding in the evasion of the immune system. CONCLUSIONS: Our findings suggest that the lifestyle transition from environment to opportunist led to the loss and acquisition of specific genes allowing adaptations to colonize and survive in new hosts. It is possible that these substitutions may be the starting point for interactions with new hosts.

The plastomes of Astrocaryum aculeatum G. Mey. and A. murumuru Mart. show a flip-flop recombination between two short inverted repeats.

MAIN CONCLUSION: The plastomes of Astrocaryum murumuru and A. aculeatum revealed a lineage-specific structural feature originated by flip-flop recombination, non-synonymous substitutions in conserved genes and several molecular markers. Astrocaryum murumuru Mart. and A. aculeatum G.Mey. are two palm species of Amazon forest that are economically important as source of food, oil and raw material for several applications. Genetic studies aiming to establish strategies for conservation and domestication of both species are still in the beginning given that the exploitation is mostly by extractive activity. The identification and characterization of molecular markers are essential to assess the genetic diversity of natural populations of both species. Therefore, we sequenced and characterized in detail the plastome of both species. We compared both species and identified 32 polymorphic SSR loci, 150 SNPs, 46 indels and eight hotspots of nucleotide diversity. Additionally, we reported a specific RNA editing site found in the ccsA gene, which is exclusive to A. murumuru. Moreover, the structural analysis in the plastomes of both species revealed a 4.6-kb inversion encompassing a set of genes involved in chlororespiration and plastid translation. This 4.6-kb inversion is a lineage-specific structural feature of the genus Astrocaryum originated by flip-flop recombination between two short inverted repeats. Furthermore, our phylogenetic analysis using whole plastomes of 39 Arecaceae species placed the Astrocaryum species sister to Acrocomia within the tribe Cocoseae. Finally, our data indicated substantial changes in the plastome structure and sequence of both species of the genus Astrocaryum, bringing new molecular markers, several structural and evolving features, which can be applied in several areas such as genetic, evolution, breeding, phylogeny and conservation strategies for both species.

The genomes of three Bradyrhizobium sp. isolated from root nodules of Lupinus albescens grown in extremely poor soils display important genes for resistance to environmental stress.

Lupinus albescens is a resistant cover plant that establishes symbiotic relationships with bacteria belonging to the Bradyrhizobium genus. This symbiosis helps the development of these plants in adverse environmental conditions, such as the ones found in arenized areas of Southern Brazil. This work studied three Bradyrhizobium sp. (AS23, NAS80 and NAS96) isolated from L. albescens plants that grow in extremely poor soils (arenized areas and adjacent grasslands). The genomes of these three strains were sequenced in the Ion Torrent platform using the IonXpress library preparation kit, and presented a total number of bases of 1,230,460,823 for AS23, 1,320,104,022 for NAS80, and 1,236,105,093 for NAS96. The genome comparison with closest strains Bradyrhizobium japonicum USDA6 and Bradyrhizobium diazoefficiens USDA110 showed important variable regions (with less than 80% of similarity). Genes encoding for factors for resistance/tolerance to heavy metal, flagellar motility, response to osmotic and oxidative stresses, heat shock proteins (present only in the three sequenced genomes) could be responsible for the ability of these microorganisms to survive in inhospitable environments. Knowledge about these genomes will provide a foundation for future development of an inoculant bioproduct that should optimize the recovery of degraded soils using cover crops.

Bradyrhizobium brasilense sp. nov., a symbiotic nitrogen-fixing bacterium isolated from Brazilian tropical soils.

Four strains of rhizobia isolated from nodules of Vigna unguiculata (UFLA03-321T, UFLA03-320 and UFLA03-290) and Macroptilium atropurpureum (UFLA04-0212) in Brazilian soils were previously reported as a new group within the genus Bradyrhizobium. To determine their taxonomic position, these strains were characterized in this study using a polyphasic approach. The analysis of the 16S rRNA gene grouped the four strains with Bradyrhizobium pachyrhizi PAC48T. However, the concatenated sequence analysis of the two (recA and glnII) or three (atpD, gyrB and recA) housekeeping genes indicated that these strains represent a novel species of Bradyrhizobium, which is very closely related to B. pachyrhizi PAC48T and B. elkanii USDA 76T. Genomic relatedness analyses between the UFLA03-321T strain and B. elkanii USDA 76T and B. pachyrhizi PAC48T revealed an average nucleotide identity below 96% and values of estimated DNA-DNA hybridization below 70%, confirming that they represent genomically distinct species. Analysis of MALDI-TOF MS (Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry) profiles and phenotypic characteristics also allowed differentiation of the novel species from its two neighboring species. In phylogenetic analysis of nodC and nifH genes, UFLA03-321T exhibited maximum similarity with B. tropiciagri CNPSo 1112T. The data suggest that these four UFLA strains represent a novel species, for which the name Bradyrhizobium brasilense sp. nov. is proposed, with UFLA03-321T (=LMG 29353 =CBAS645) as type strain. G + C content in the DNA of UFLA03-321T is 63.9 mol %.

A Culture-Independent Approach to Enrich Endophytic Bacterial Cells from Sugarcane Stems for Community Characterization.

Bacterial endophytes constitute a very diverse community and they confer important benefits which help to improve agricultural yield. Some of these benefits remain underexplored or little understood, mainly due to the bottlenecks associated with the plant feature, a low number of endophytic bacterial cells in relation to the plant, and difficulties in accessing these bacteria using cultivation-independent methods. Enriching endophytic bacterial cells from plant tissues, based on a non-biased, cultivation-independent physical enrichment method, may help to circumvent those problems, especially in the case of sugarcane stems, which have a high degree of interfering factors, such as polysaccharides, phenolic compounds, nucleases, and fibers. In the present study, an enrichment approach for endophytic bacterial cells from sugarcane lower stems is described. The results demonstrate that the enriched bacterial cells are suitable for endophytic community characterization. A community analysis revealed the presence of previously well-described but also novel endophytic bacteria in sugarcane tissues which may exert functions such as plant growth promotion and biological control, with a predominance of the Proteobacterial phylum, but also Actinobacteria, Bacteroidetes, and Firmicutes, among others. In addition, by comparing the present and literature data, it was possible to list the most frequently detected bacterial endophyte genera in sugarcane tissues. The presented enrichment approach paves the way for improved future research toward the assessment of endophytic bacterial community in sugarcane and other biofuel crops.

Molecular adaptations of Herbaspirillum seropedicae during colonization of the maize rhizosphere.

Molecular mechanisms of plant recognition and colonization by diazotrophic bacteria are barely understood. Herbaspirillum seropedicae is a Betaproteobacterium capable of colonizing epiphytically and endophytically commercial grasses, to promote plant growth. In this study, we utilized RNA-seq to compare the transcriptional profiles of planktonic and maize root-attached H. seropedicae SmR1 recovered 1 and 3 days after inoculation. The results indicated that nitrogen metabolism was strongly activated in the rhizosphere and polyhydroxybutyrate storage was mobilized in order to assist the survival of H. seropedicae during the early stages of colonization. Epiphytic cells showed altered transcription levels of several genes associated with polysaccharide biosynthesis, peptidoglycan turnover and outer membrane protein biosynthesis, suggesting reorganization of cell wall envelope components. Specific methyl-accepting chemotaxis proteins and two-component systems were differentially expressed between populations over time, suggesting deployment of an extensive bacterial sensory system for adaptation to the plant environment. An insertion mutation inactivating a methyl-accepting chemosensor induced in planktonic bacteria, decreased chemotaxis towards the plant and attachment to roots. In summary, analysis of mutant strains combined with transcript profiling revealed several molecular adaptations that enable H. seropedicae to sense the plant environment, attach to the root surface and survive during the early stages of maize colonization.

Genome of Herbaspirillum seropedicae strain SmR1, a specialized diazotrophic endophyte of tropical grasses.

The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazotrophic endophytes and plants are scarcely known. Herbaspirillum seropedicae is an endophytic bacterium capable of colonizing intercellular spaces of grasses such as rice and sugar cane. The genome of H. seropedicae strain SmR1 was sequenced and annotated by The Paraná State Genome Programme--GENOPAR. The genome is composed of a circular chromosome of 5,513,887 bp and contains a total of 4,804 genes. The genome sequence revealed that H. seropedicae is a highly versatile microorganism with capacity to metabolize a wide range of carbon and nitrogen sources and with possession of four distinct terminal oxidases. The genome contains a multitude of protein secretion systems, including type I, type II, type III, type V, and type VI secretion systems, and type IV pili, suggesting a high potential to interact with host plants. H. seropedicae is able to synthesize indole acetic acid as reflected by the four IAA biosynthetic pathways present. A gene coding for ACC deaminase, which may be involved in modulating the associated plant ethylene-signaling pathway, is also present. Genes for hemagglutinins/hemolysins/adhesins were found and may play a role in plant cell surface adhesion. These features may endow H. seropedicae with the ability to establish an endophytic life-style in a large number of plant species.

Hepatic transcriptome, transcriptional effects and antioxidant responses in Poecilia vivipara exposed to sanitary sewage.

Aquatic environments are subject to threats from multiple human activities, particularly through the release of untreated sanitary sewage into the coastal environments. These effluents contain a large group of natural or synthetic compounds referred to as emerging contaminants. Monitoring the types and quantities of toxic substances in the environment, especially complex mixtures, is an exhausting and challenging task. Integrative effect-based tools, such as biomarkers, are recommended for environmental quality monitoring programs. In this study, fish Poecilia vivipara were exposed for 24 and 96 h to raw untreated sewage diluted 33 % (v/v) in order to identify hepatic genes to be used as molecular biomarkers. Through a de novo hepatic transcriptome assembly, using Illumina MiSeq, 54,285 sequences were assembled creating a reference transcriptome for this guppy species. Transcripts involved in biotransformation systems, antioxidant defenses, ABC transporters, nuclear and xenobiotic receptors were identified and evaluated by qPCR. Sanitary sewage induced transcriptional changes in AhR, PXR, CYP2K1, CYP3A30, NQO1, UGT1A1, GSTa3, GSTmu, ST1C1, SOD, ABCC1 and SOX9 genes from liver of fish, particularly after 96 h of exposure. Changes in hepatic enzyme activities were also observed. The enzymes showed differences in fish exposed to both periods, while in the gills there was a prevalence of significant results after 96 h. The observed differences were associated to gender and/or to sewage exposure. The obtained results support the use of P. vivipara as sentinel and model organism for ecotoxicological studies and evidence the importance of understanding the differential responses associated to gender.

Dissemination of NDM-producing bacteria in Southern Brazil.

BACKGROUND: The dissemination of NDM-1 carbapenemases (New Delhi Metallo-ß-lactamase) is a global public health problem, mainly in developing countries. The aim of this study was to characterize the spread of NDM-producing bacteria in the Southern Brazilian states analyzing epidemiological, molecular, and antimicrobial susceptibility aspects. METHODS: A total of 10,684 carbapenem-resistant isolates of Enterobacterales, Pseudomonas spp. and Acinetobacter spp. obtained from several hospitals in eight cities in Southern Brazil were screened, and 486 NDM-producing bacteria were selected. RESULTS: The incidence varied from 0.5 to 77 cases/100.000 habitants. ST11, ST15, ST340 and ST674 were the most common in K. pneumoniae. A total of 5 plasmids were identified in one K. pneumoniae strain: Col440I, Col440II, IncFIA(HI1), IncFIB(K), IncFIB(pQil)/ IncFII(K), and IncR. CONCLUSIONS: The number of patients with NDM-producing bacteria has increased in Southern Brazil, whose gene is present in different plasmids, explaining the expansion of this enzyme.

The type III secretion system is necessary for the development of a pathogenic and endophytic interaction between Herbaspirillum rubrisubalbicans and Poaceae.

BACKGROUND: Herbaspirillum rubrisubalbicans was first identified as a bacterial plant pathogen, causing the mottled stripe disease in sugarcane. H. rubrisubalbicans can also associate with various plants of economic interest in a non pathogenic manner. RESULTS: A 21 kb DNA region of the H. rubrisubalbicans genome contains a cluster of 26 hrp/hrc genes encoding for the type three secretion system (T3SS) proteins. To investigate the contribution of T3SS to the plant-bacterial interaction process we generated mutant strains of H. rubrisubalbicans M1 carrying a Tn5 insertion in both the hrcN and hrpE genes. H. rubrisulbalbicans hrpE and hrcN mutant strains of the T3SS system failed to cause the mottled stripe disease in the sugarcane susceptible variety B-4362. These mutant strains also did not produce lesions on Vigna unguiculata leaves. Oryza sativa and Zea mays colonization experiments showed that mutations in hrpE and hrcN genes reduced the capacity of H. rubrisulbalbicans to colonize these plants, suggesting that hrpE and hrcN genes are involved in the endophytic colonization. CONCLUSIONS: Our results indicate that the T3SS of H. rubrisubalbicans is necessary for the development of the mottled stripe disease and endophytic colonization of rice.