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bioRxiv2018

Protein Kinase A Negatively Regulates Ca2+ signalling in Toxoplasma gondii

The phylum Apicomplexa comprises a group of obligate intracellular parasites that alternate between intracellular replicating forms and actively motile extracellular forms that move through tissue. Parasite cytosolic Ca2+ signalling activates motility, but how this is switched off after invasion is not understood. Here we show that the cAMP-dependent Protein Kinase A catalytic subunit 1 (PKAc1) of Toxoplasma is responsible for suppression of Ca2+ signalling upon host cell invasion. We demonstrate that that PKAc1 is sequestered to the parasite periphery by dual acylation of its regulatory subunit PKAr1. Newly invaded PKAc1-deficient parasites exit host cells shortly thereafter in a perforin-like protein 1 (PLP-1)-dependent fashion. We demonstrate that loss of PKAc1 results in an inability to rapidly downregulate cytosolic Ca2+ levels shortly after invasion. Furthermore, we demonstrate that PKAc1 also specifically negatively regulates resting cytosolic Ca2+ in conditions that mimic intracellularity. We also show that cAMP and cGMP have opposing role in microneme secretion, further supporting evidence that cAMP signalling has a suppressive role during motility. Together, this work provides a new paradigm in understanding how Toxoplasma and related apicomplexan parasites regulate infectivity.

microbiology↗

bioRxiv2018

RD5-mediated lack of PE_PGRS and PPE-MPTR export in BCG vaccine strains results in strong reduction of antigenic repertoire but little impact on protection

Tuberculosis is the deadliest infectious disease worldwide. Although the BCG vaccine is widely used, it does not efficiently protect against pulmonary tuberculosis and an improved tuberculosis vaccine is therefore urgently needed. Mycobacterium tuberculosis uses different ESX/Type VII secretion (T7S) systems to transport proteins important for virulence and host immune responses. We recently reported that secretion of T7S substrates belonging to the mycobacteria-specific Pro-Glu (PE) and Pro-Pro-Glu (PPE) proteins of the PGRS (polymorphic GC-rich sequences) and MPTR (major polymorphic tandem repeat) subfamilies required both a functional ESX-5 system and a functional PPE38/71 protein for secretion. Inactivation of ppe38/71 and the resulting loss of PE_PGRS/PPE-MPTR secretion were linked to increased virulence of M. tuberculosis strains. Here, we show that a predicted total of 89 PE_PGRS/PPE-MPTR surface proteins are not exported by certain animal-adapted strains of the M. tuberculosis complex including M. bovis. This {Delta}ppe38/71-associated secretion defect therefore also occurs in the M. bovis-derived tuberculosis vaccine BCG and could be restored by introduction of the M. tuberculosis ppe38-locus. Epitope mapping of the PPE-MPTR protein PPE10, further allowed us to monitor T-cell responses in splenocytes from BCG/M. tuberculosis immunized mice, confirming the dependence of PPE10-specific immune-induction on ESX-5/PPE38-mediated secretion. Restoration of PE_PGRS/PPE-MPTR secretion in recombinant BCG neither altered global antigenic presentation or activation of innate immune cells, nor protective efficacy in two different mouse vaccination-infection models. This unexpected finding stimulates a reassessment of the immunomodulatory properties of PE_PGRS/PPE-MPTR proteins, some of which are contained in vaccine formulations currently in clinical evaluation.

microbiology↗

bioRxiv2018

Resistance to pentamidine is mediated by AdeAB, regulated by AdeRS, and influenced by growth conditions in Acinetobacter baumannii ATCC 17978

In recent years, effective treatment of infections caused by Acinetobacter baumannii has become challenging due to the ability of the bacterium to acquire or up-regulate antimicrobial resistance determinants. Two component signal transduction systems are known to regulate expression of virulence factors including multidrug efflux pumps. Here, we investigated the role of the AdeRS two component signal transduction system in regulating the AdeAB efflux system, determined whether AdeA and/or AdeB can individually confer antimicrobial resistance, and explored the interplay between pentamidine resistance and growth conditions in A. baumannii ATCC 17978. Results identified that deletion of adeRS affected resistance towards chlorhexidine and 4,6-diamidino-2-phenylindole dihydrochloride, two previously defined AdeABC substrates, and also identified an 8-fold decrease in resistance to pentamidine. Examination of {Delta}adeA, {Delta}adeB and {Delta}adeAB cells augmented results seen for {Delta}adeRS and identified a set of dicationic AdeAB substrates. RNA-sequencing of {Delta}adeRS revealed transcription of 290 genes were [≥]2-fold altered compared to the wildtype. Pentamidine shock significantly increased adeA expression in the wildtype, but decreased it in {Delta}adeRS, implying that AdeRS activates adeAB transcription in ATCC 17978. Investigation under multiple growth conditions, including the use of Biolog phenotypic microarrays, revealed resistance to pentamidine in ATCC 17978 and mutants could be altered by bioavailability of iron or utilization of different carbon sources. In conclusion, the results of this study provide evidence that AdeAB in ATCC 17978 can confer intrinsic resistance to a subset of dicationic compounds and in particular, resistance to pentamidine can be significantly altered depending on the growth conditions.

microbiology↗

bioRxiv2018

Yellow Fever, Dengue Fever And West Nile Viruses Co-Circulation In Ogbomoso

Arboviruses are an emerging threat of significant impact on human health and well-being. With increasing proportion of the world living in urban environments, inadvertently, there is the creation of better habitats for vector species. This study is aimed at establishing the occurrence of arboviruses within Ogbomoso, with a view to providing baseline data for further study. Ninety-three plasma samples from consenting individuals in the age range 1-75 years were collected and screened for IgM to dengue fever (DENV), West Nile (WNV) and yellow fever (YFV) viruses using third generation Enzyme Linked Immuno-Sorbent Assay (WKEA Med Supplies Corp, China) kits. An overall prevalence of 52.7% (49/93) were recorded from the recruited individuals. IgM antibodies to Dengue, Yellow fever and West Nile viruses were found in 16/49 (17.2%), 16/49 (17.2%) and 17/49 (18.3%), respectively. High prevalence were recorded in the age groups 16-30, 31-45 and 61-75 years. Gender analysis of the positive samples showed higher prevalence among females than males. The result also showed high prevalence in urban settings than rural settings for DENV and WNV, however, for YNF, higher prevalence was found in the rural area. The prevalence of dual and trio arboviral infection showed 17.2% and 11.8% respectively. This study confirms the circulation of Dengue fever, Yellow fever and West Nile viruses in Ogbomoso and therefore suggest the need for public awareness on vector control.

microbiology↗

bioRxiv2018

The proteome of the malaria plastid organelle, a key anti-parasitic target

Malaria parasites (Plasmodium spp.) and related apicomplexan pathogens contain a non-photosynthetic plastid called the apicoplast. Derived from an unusual secondary eukaryote-eukaryote endosymbiosis, the apicoplast is a fascinating organelle whose function and biogenesis rely on a complex amalgamation of bacterial and algal pathways. Because these pathways are distinct from the human host, the apicoplast is an excellent source of novel antimalarial targets. Despite its biomedical importance and evolutionary significance, the absence of a reliable apicoplast proteome has limited most studies to the handful of pathways identified by homology to bacteria or primary chloroplasts, precluding our ability to study the most novel apicoplast pathways. Here we combine proximity biotinylation-based proteomics (BioID) and a new machine learning algorithm to generate a high-confidence apicoplast proteome consisting of 346 proteins. Critically, the high accuracy of this proteome significantly outperforms previous prediction-based methods and extends beyond other BioID studies of unique parasite compartments. Half of identified proteins have unknown function, and 77% are predicted to be important for normal blood-stage growth. We validate the apicoplast localization of a subset of novel proteins and show that an ATP-binding cassette protein ABCF1 is essential for blood-stage survival and plays a previously unknown role in apicoplast biogenesis. These findings indicate critical organellar functions for newly discovered apicoplast proteins. The apicoplast proteome will be an important resource for elucidating unique pathways derived from secondary endosymbiosis and prioritizing antimalarial drug targets.

microbiology↗

bioRxiv2018

Real-time in vivo Global Transcriptional Dynamics During Plasmodium falciparum Blood-stage Development

Genome-wide analysis of transcription in the human malaria parasite Plasmodium falciparum has revealed robust variation in steady-state mRNA abundance throughout the 48-hour intraerythrocytic developmental cycle (IDC) suggesting that this process is highly dynamic and tightly regulated. However, the precise timing of mRNA transcription and decay remains poorly understood due to the utilization of methods that only measure total RNA and cannot differentiate between newly transcribed, decaying and stable cellular RNAs. Here we utilize rapid 4-thiouracil (4-TU) incorporation via pyrimidine salvage to specifically label, capture and quantify newly-synthesized P. falciparum RNA transcripts at every hour throughout the IDC following erythrocyte invasion. This high resolution global analysis of the transcriptome captures the timing and rate of transcription for each newly synthesized mRNA in vivo, revealing active transcription throughout all stages of the IDC. To determine the fraction of active transcription and/or transcript stabilization contributing to the total mRNA abundance at each timepoint we have generated a statistical model to fit the data for each gene which reveals varying degrees of transcription and stabilization for each mRNA corresponding to developmental transitions and independent of abundance profile. Finally, our results provide new insight into co-regulation of mRNAs throughout the IDC through regulatory DNA sequence motifs associated with these processes, thereby expanding our understanding of P. falciparum mRNA dynamics.

microbiology↗

bioRxiv2018

Drosophila melanogaster establishes a species-specific mutualistic interaction with stable gut-colonizing bacteria

Animals live together with diverse bacteria that can impact their biology. In Drosophila melanogaster, gut-associated bacterial communities are relatively simple in composition but also have a strong impact on host development and physiology. However, it is still unknown if bacteria can proliferate and stably associate with the gut of D. melanogaster. In fact, it is generally assumed that bacteria are transient and their constant ingestion with food is required to maintain their presence in the gut. Here, we identify bacterial species from wild-caught D. melanogaster that stably associate with the host independently of continuous inoculation. Moreover, we show that specific Acetobacter wild isolates can proliferate in the gut. We further demonstrate that the interaction between D. melanogaster and the wild isolated Acetobacter thailandicus is mutually beneficial and that the stability of the gut association is key to this mutualism. The stable population in the gut of D. melanogaster allows continuous bacterial spreading into the environment, which is advantageous to the bacterium itself. The bacterial dissemination is in turn advantageous to the host since the next generation of flies develops in the presence of this particularly beneficial bacterium. Ac. thailandicus leads to a faster host development and higher fertility of emerging adults, when compared to other bacteria isolated from wild-caught flies. Furthermore, Ac. thailandicus is sufficient and advantageous when D. melanogaster develops in axenic or freshly collected figs, respectively. This isolate of Ac. thailandicus colonizes several genotypes of D. melanogaster but not of the closely related Drosophila simulans, indicating that the stable association is host specific. This work establishes a new conceptual model to understand D. melanogaster- gut microbiota interactions in an ecological context; stable interactions can be mutualistic through microbial farming, a common strategy in insects. Moreover, these results develop the use of D. melanogaster as a model to study gut microbiota proliferation and colonization.\n\nAuthor summaryAnimals, including humans, live together with complex bacterial communities in their gut that influence their physiology and health. The fruit fly Drosophila melanogaster has been an excellent model organism to study host-microbe interactions and harbours a relative simple gut bacterial community. However, it is not known which of these bacteria can proliferate and form stable communities in the gut, and the current hypothesis is that these bacteria are only transiently associated with the gut. Here, we show that in D. melanogaster collected from a natural population stable gut bacteria do exist. We isolated specific species that can proliferate in the gut and form a stable association. This is beneficial to the bacteria since they can be constantly spread by the flies as they move around. On the other hand, this is a form of farming as the next generation of flies benefit from the association with these particular bacteria during development. They become adults faster and are more fertile than if they develop with other bacteria encountered in nature. These advantages are also observed when flies develop in figs, a natural food source. Our findings show that D. melanogaster has stable colonizing bacteria in the gut and establish a new framework to study host-gut bacteria interactions.

microbiology↗

bioRxiv2018

Yellow fever virus is susceptible to sofosbuvir both in vitro and in vivo

Yellow fever virus (YFV) is a member of the Flaviviridae family, that causes major mortality. In Brazil, YFV activity increased in the last years. It has been registered that sylvatic, instead of urban, yellow fever (YF) leads our contemporary public health concern. Low vaccinal coverage leaves the human population near the jangle vulnerable to the outbreak, making it necessary to identify therapeutic options. Repurposing of clinically approved antiviral drugs represents an alternative for such identification. Other Flaviviruses, such Zika (ZIKV) and dengue (DENV) viruses, are susceptible to Sofosbuvir, a clinically approved drug against hepatitis C virus (HCV). Moreover, sofosbuvir has a safety record on critically ill hepatic patients, making it an attractive option. Our data show that YFV RNA polymerase uses conserved amino acid resides for nucleotide binding to dock sofosbuvir. This drug inhibited YFV replication in different lineages of human hepatoma cells, Huh-7 and HepG2, with EC50 value of 4.8 {micro}M. Sofosbuvir protected YFV-infected neonatal Swiss mice from mortality and weight loss. Our pre-clinical results indicate that sofosbuvir could represent an option against YFV.

microbiology↗

bioRxiv2018

Metagenomic analysis with strain-level resolution reveals fine-scale variation in the human pregnancy microbiome

Recent studies suggest that the microbiome has an impact on gestational health and outcome. However, characterization of the pregnancy-associated microbiome has largely relied on 16S rRNA gene amplicon-based surveys. Here, we describe an assembly-driven, metagenomics-based, longitudinal study of the vaginal, gut, and oral microbiomes in 292 samples from ten subjects sampled every three weeks throughout pregnancy. 1.53 Gb of non-human sequence was assembled into scaffolds, and functional genes were predicted for gene-and pathway-based analyses. Vaginal assemblies were binned into 97 draft quality genomes. Redundancy analysis (RDA) of microbial community composition at all three body sites revealed gestational age to be a significant source of variation in patterns of gene abundance. In addition, health complications were associated with variation in community functional gene composition in the mouth and gut. The diversity of Lactobacillus iners-dominated communities in the vagina, unlike most other vaginal community types, significantly increased with gestational age. The genomes of co-occurring Gardnerella vaginalis strains with predicted distinct functions were recovered in samples from two subjects. In seven subjects, gut samples contained strains of the same Lactobacillus species that dominated the vaginal community of that same subject, and not other Lactobacillus species; however, these within-host strains were divergent. CRISPR spacer analysis suggested shared phage and plasmid populations across body sites and individuals. This work underscores the dynamic behavior of the microbiome during pregnancy and suggests the potential importance of understanding the sources of this behavior for fetal development and gestational outcome.

microbiology↗

bioRxiv2018

Microbial diversity and toxin risk in tropical freshwater reservoirs of Cape Verde

The Cape Verde islands are part of the African Sahelian arid belt that possesses an irregular rainy season between August and October. This erratic rain pattern has prompted the need for water reservoirs, now critical for the countrys sustainability. Worldwide, freshwater cyanobacterial blooms are increasing in frequency due to global climate change and eutrophication of water bodies, particularly in reservoirs. To date there have been no risk assessments of cyanobacterial toxin production in these man-made structures. We evaluated this potential risk using 16S rRNA gene amplicon sequencing and full metagenome sequencing in freshwater reservoirs of Cape Verde.\n\nOur analysis revealed the presence of several potentially toxic cyanobacterial genera in all sampled reservoirs (Poilao, Saquinho and Faveta). In Faveta Microcystis sp., a genus well known for toxin production and bloom-formation, dominated our samples, while a green algae of the genus Cryptomonas and Gammaproteobacteria dominated Saquinho and Poilao.\n\nTaking advantage of the dominance of Microcystis in the Faveta reservoir, we were able to reconstruct and assemble its genome, extracted from a metagenome of bulk DNA from Faveta water. We named it Microcystis cf. aeruginosa CV01, for which a phylogenetic analysis revealed to have a close relationship with other genomes from those taxa, as well as other continental African strains, suggesting geographical coherency. In addition, it revealed several clusters of known toxin-producing genes. This assessment of Cape Verdean freshwater microbial diversity and potential for toxin production reinforces the need to better understand the microbial ecology as a whole of water reservoirs on the rise.

microbiology↗

bioRxiv2018

Non-antibiotic antimicrobial triclosan induces multiple antibiotic resistance through genetic mutation

Antibiotic resistance poses a major threat to public health. Overuse and misuse of antibiotics are generally recognised as the key factors contributing to antibiotic resistance. However, whether non-antibiotic, anti-microbial (NAAM) chemicals can directly induce antibiotic resistance is unclear. We aim to investigate whether the exposure to a NAAM chemical triclosan (TCS) has an impact on inducing antibiotic resistance on Escherichia coli. Here, we report that at a concentration of 0.2 mg/L TCS induces multi-drug resistance in wild-type Escherichia coli after 30-day TCS exposure. The oxidative stress induced by TCS caused genetic mutations in genes such as fabI, frdD, marR, acrR and soxR, and subsequent up-regulation of the transcription of genes encoding beta-lactamase and multi-drug efflux pump, together with down-regulation of genes related to membrane permeability. The findings advance our understanding of the potential role of NAAM chemicals in the dissemination of antibiotic resistance in microbes, and highlights the need for controlling biocide applications.

microbiology↗

bioRxiv2018

Serum-mediated cleavage of Bacillus anthracis Protective Antigen is a two-step process that involves a serum carboxypeptidase

Much our understanding of the activity of anthrax toxin is based on in-vitro systems, which delineate the interaction between B. anthracis toxins and the cell surface. These systems however, fail to account for the intimate association of B. anthracis with the circulatory system, including the contribution of serum proteins to the host response and processing of anthrax toxins. Using variety immunologic techniques to inhibit serum processing of B. anthracis Protective Antigen (PA) along with mass spectrometry analysis, we demonstrate that serum digests PA via 2 distinct reactions. In the first reaction, serum cleaves PA83 into 2 fragments to produce PA63 and PA20 fragments, similar to that observed following furin digestion. This is followed by carboxypeptidase-mediated removal of the carboxy-terminal arginine and lysine residues from PA20.

microbiology↗

bioRxiv2018

Microbial Engraftment and Efficacy of Fecal Microbiota Transplant for Clostridium difficile Patients With and Without IBD

Background & AimsRecurrent and refractory Clostridium difficile infections (CDI) are effectively treated with fecal microbiota transplant (FMT). Uncertainty exists regarding the effectiveness of FMT for CDI with underlying inflammatory bowel disease (IBD), its effects on disease activity and its effectiveness transferring the donor microbiome to patients with and without IBD. This study aims to determine FMTs effectiveness in subjects with and without IBD, its impact on IBD activity, the level of microbiome engraftment, and predictors of CDI recurrence.\n\nMethodsSubjects with and without IBD who underwent FMT for recurrent or refractory CDI between 2013 and 2016 at The Mount Sinai Hospital were followed for up to 6 months. The primary outcome was CDI recurrence 6 months after FMT. Secondary outcomes were (1) CDI recurrence 2 months after FMT; (2) Frequency of IBD flare after FMT; (3) Microbiome engraftment after FMT; (4) Predictors of CDI recurrence.\n\nResultsOverall, 134 patients, 46 with IBD, were treated with FMT. There was no difference in recurrence in patients with and without IBD at 2 months (22.5% vs 17.9%; p=0.63) and 6 months (38.7% vs 36.5%; p>0.99). Proton pump inhibitor use, severe CDI, and comorbid conditions were predictors of recurrence. The pre-FMT microbiome was not predictive of CDI recurrence. Subjects with active disease requiring medication escalation had reduced engraftment. There was no difference in engraftment based on IBD endoscopic severity at FMT.\n\nConclusionsIBD did not affect CDI recurrence rates 6 months after FMT. Pre-FMT microbiome was not predictive of recurrence, and microbial engraftment was dependent on IBD treatment escalation but not on underlying disease severity.

microbiology↗

bioRxiv2018

A molecular rack and pinion actuates a cell-surface adhesin and enables bacterial gliding motility

The mechanism for bacterial gliding is not understood. The gliding bacterium Flavobacterium johnsoniae is known to have an adhesin, SprB, that moves along the cell surface on a spiral track. When cells are sheared by passage of a suspension through thin tubing, they stop gliding but can be tethered by addition of an anti-SprB antibody. Tethered cells spin about 3 Hz. We labeled the Type 9 secretion system (T9SS) with a yellow-fluorescent-protein (YFP) fusion of GldL. When labeled cells were tethered, a yellow fluorescent spot was found near the rotation axis, which shows that the motor that drives the rotation localizes with the T9SS. The spiral track was labeled by following the motion of Cy3 attached to SprB via an antibody. The distance between the rotation axis and the track was determined by a measurement involving both labels, YFP and Cy3, yielding 90 nm. If a rotary motor spins a pinion of radius 90 nm 3 Hz, a spot on its periphery will move 1.5 m/s, the speed at which cells glide. We suggest that the pinion drives a flexible tread that carries SprB along a track fixed to the cell surface. Cells glide when such an adhesin adheres to the solid substratum.

microbiology↗

bioRxiv2018

Evolution of subgenomic RNA shapes dengue virus adaptation and epidemiological fitness

Genetic changes in the dengue virus (DENV) genome affects viral fitness both clinically and epidemiologically. Even in the 3 untranslated region (3UTR), mutations could impact the formation of subgenomic flaviviral RNA (sfRNA) and the specificity of sfRNA in inhibiting host proteins necessary for successful viral replication. Indeed, we have recently shown that mutations in the 3UTR of DENV2 affected its ability to inhibit TRIM25 E3 ligase activity to reduce interferon (IFN) expression, which potentially contributed to the emergence of a new viral clade during the 1994 dengue epidemic in Puerto Rico. However, whether differences in 3UTRs shaped DENV evolution on a larger scale remains incompletely understood. Herein, we combined RNA phylogeny with phylogenetics to gain insights on sfRNA evolution. We found that sfRNA structures are under purifying selection and highly conserved despite sequence divergence. Interestingly, only the second flaviviral Nuclease-resistant RNA (fNR2) structure of DENV-2 has undergone strong positive selection. Epidemiological reports also suggest that nucleotide substitutions in fNR2 may drive DENV-2 epidemiological fitness, possibly through sfRNA-protein interactions. Collectively, our findings indicate that 3UTRs are important determinants of DENV fitness in human-mosquito cycles.\n\nHighlightsO_LIDengue viruses (DENV) preserve RNA elements in their 3 untranslated region (UTR).\nC_LIO_LISite-specific quantification of natural selection revealed positive selection on DENV2 sfRNA.\nC_LIO_LIFlaviviral nuclease-resistant RNA (fNR) structures in DENV 3UTRs contribute to DENV speciation.\nC_LIO_LIA highly evolving fNR structure appears to increase DENV-2 epidemiological fitness.\nC_LI

microbiology↗

bioRxiv2018

Microbial Treatment of Soil Contaminated with Spent engine Oil / Biotreatment of Soil Contaminated with Spent Engine by Microorganisms

The potential of six microorganisms (Pseudomonas aeruginosa, Micrococcus sp, Flavobacterium sp, Rhizopus sp, Penicillium sp and Fusarium sp) isolated from hydrocarbon contaminated site were evaluated for their biodegradation ability. The soil samples were contaminated with 5% (w/v) of spent engine oil and the rate of biodegradation of the oil was studied for a period of 10weeks under greenhouse experiment. The total heterotrophic bacteria count (THBC), total hydrocarbon degrading bacteria count (THDBC), physicochemical and heavy metals properties of the soil samples and Total Petroleum Hydrocarbon (TPH) were determined after treatment with test organisms. THBC and THDBC ranged from 0.175 to 0.280 CFUg-1 and 0.47 CFUg-1 respectively for the control plot, while THBC is ranging from 0.197 to 0.275 CFUg-1 and THDBC was 0.180 to 0. 473 CFUg-1 for the contaminated plot. There was a slight increase in the pH value of the contaminated soil sample and the treated soil samples as the experimental weeks increased. The results obtained showed a significant decrease (at p [≤] 0.05) in the nutrients content of the soil samples. There was an increase from 1.09 in the control to 15.5% in the content of organic matter after contamination and from 1.88% to 26.8% in the % of organic matter too. There was a significant reduction (at p [≤] 0.05) in the concentration of Fe, Zn, Pb, Cd, Cu, Cr and Ni after 10 weeks of incubation with the tested organisms. Plant growth in the treated contaminated soil samples ranged from 32.6cm to 38.6cm, while that of the control 1 (Uncontaminated soil) was 51.2cm and 19.7cm high was observed in the Control 2 (contaminated untreated soil) after 22 days of the experiment. The TPH degradation (% loss) ranged from 79.7 to 89. 2% after 10 weeks of treatment. P. aeruginosa had the highest level of degradation (89.2%), while Micrococcus sp and Rhizopus sp had the least degradation at 79.9%.\n\nAll the microorganisms used in this study had the abilities to remediating soil contaminated with spent engine oil and the remediated soil samples were able to support the growth of Zea mays at 5% (w/v) level of contamination.

microbiology↗

bioRxiv2018

Whole-genome sequencing of parvoviruses from wild and domestic animals in Brazil provides new insights into parvovirus distribution and diversity

AbstractParvoviruses (family Parvoviridae) are small, single-stranded DNA viruses. Many parvoviral pathogens of medical, veterinary and ecological importance have been identified. In this study, we used high-throughput sequencing (HTS) to investigate the diversity of parvoviruses infecting wild and domestic animals in Brazil. We identified 21 parvovirus sequences (including twelve nearly complete genomes and nine partial genomes) in samples derived from rodents, bats, opossums, birds and cattle in Pernambuco, Sao Paulo, Parana and Rio Grande do Sul states. These sequences were investigated using phylogenetic and distance-based approaches, and were thereby classified into eight parvovirus species (six of which have not been described previously), representing six distinct genera in the subfamily Parvovirinae. Our findings extend the known biogeographic range of previously characterized parvovirus species, and the known host range of three parvovirus genera (Dependovirus, Aveparvovirus, and Tetraparvovirus). Moreover, our investigation provides a window into the ecological dynamics of parvovirus infections in vertebrates, revealing that many parvovirus genera contain well-defined sub-lineages that circulate widely throughout the world within particular taxonomic groups of hosts.

microbiology↗

bioRxiv2018

Influenza A virus environmental persistence is driven by the hemagglutinin and the neuraminidase

The transmission routes of Influenza A viruses (IAVs) submit virus particles to a wide range of environmental conditions that affect their transmission. In water, temperature, salinity and pH are important factors modulating viral persistence in a strain-dependant manner, and the viral factors driving IAV persistence remained to be described. We used an innovative method based on a real-time cell system analysis to quantify viral decay in an environmental model. Thus, we identified the viral hemagglutinin (HA) and neuraminidase (NA) as the main proteins driving the environmental persistence by comparing the inactivation slopes of several reassortant viruses. We also introduced synonymous and non-synonymous mutations in the HA or in the NA that modulated IAV persistence. Our results demonstrate that HA stability and expression level, as well as calcium-binding sites of the NA protein are molecular determinants of viral persistence.\n\nFinally, IAV particles could not trigger membrane fusion after environmental exposure, stressing the importance of the HA and the NA for environmental persistence.

microbiology↗