Characterization of a novel shrimp pathogen, Vibrio brasiliensis, isolated from Pacific white shrimp, Penaeus vannamei.

A novel pathogenic strain Vibrio 20190611023 was isolated from the hepatopancreas of moribund cultured Penaeus vannamei suffering from black gill disease. This strain was identified as V. brasiliensis based on the phylogenetic analyses of 16S rDNA gene and five other housekeeping genes (i.e., gapA, ftsZ, mreB, topA and gyrB). Some biochemical features of this strain were determined with an API 20NE system, and its haemolytic activity was determined using a sheep blood agar plate. The pathogenicity of this isolate 20190611023 was confirmed by the experimental challenge tests and histopathological examinations. P. vannamei were challenged via reverse gavage with different doses of bacterial suspensions. The calculated median lethal dose (LD50 ) was (3.16 ± 1.78) × 105  CFU/g (body weight). Moreover, antibiotic susceptibility tests were performed, the results of which showed that the strain 20190611023 was sensitive to chloramphenicol, compound sulphamethoxazole, ciprofloxacin, doxycycline and oxacillin, but resistant to erythromycin, kanamycin, gentamicin, cefoperazone, ceftriaxone, cefamezin and piperacillin. To our knowledge, this is the first report for demonstrating V. brasiliensis as a shrimp pathogen, which expands the host range of V. brasiliensis infection. The present study highlights that more attention should be paid to this novel pathogen in intensive shrimp aquaculture.

Molecular detection and characterization of Anaplasma platys and Ehrlichia canis in dogs from the Caribbean.

Anaplasma platys is a tick-transmitted rickettsial pathogen, which is known to be the etiologic agent for cyclic thrombocytopenia in its primary canine host. Infections with this pathogen are also reported in cats, cattle and people. Similarly, Ehrlichia canis is another tick-borne rickettsial pathogen responsible for canine monocytic ehrlichiosis and is also reported to cause infections in people. We describe infections in dogs with these two pathogens on the Caribbean island of Grenada, West Indies by detection using molecular methods. We utilized a 16S rRNA gene-based PCR assay to detect both Ehrlichia and Anaplasma species by screening 155 canine blood samples from asymptomatic dogs. We found 18.7 % of the dogs to be positive for A. platys and 16.8 % for E. canis. Samples that tested positive for A. platys were further assessed by sequence analysis targeting 16S rRNA, 23S rRNA, citrate synthase (gltA) and heat shock protein (groEL) genes. Phylogenetic analysis revealed high correlation of A. platys 16S rRNA and gltA gene sequences with the geographic origins, while 23S rRNA and groEL gene sequences clustered independent of the geographic origins. This study represents an important step in defining the widespread distribution of active rickettsial infections in Caribbean dogs with no apparent clinical signs, thus posing a high risk for canine health and to a lesser extent to humans, as most dogs in the Caribbean are free-roaming.

Alterations in the gut-associated microbiota of juvenile Caribbean spiny lobsters Panulirus argus (Latreille, 1804) infected with PaV1.

The spiny lobster Panulirus argus (Latreille, 1804) is currently affected by an unenveloped, icosahedral, DNA virus termed Panulirus argus virus 1 (PaV1), a virulent and pathogenic virus that produces a long-lasting infection that alters the physiology and behaviour of heavily infected lobsters. Gut-associated microbiota is crucial for lobster homeostasis and well-being, but pathogens could change microbiota composition affecting its function. In PaV1 infection, the changes of gut-associated microbiota are yet to be elucidated. In the present study, we used high-throughput 16S rRNA sequencing technology to compare the bacterial microbiota in intestines of healthy and heavily PaV1-infected male and female juveniles of spiny lobsters P. argus captured in Puerto Morelos Reef lagoon, Quintana Roo, Mexico. We found that basal gut-associated microbiota composition showed a sex-dependent bias, with females being enriched in amplicon sequence variants (ASVs) assigned to Sphingomonas, while males were enriched in the genus Candidatus Hepatoplasma and Aliiroseovarius genera. Moreover, the alpha diversity of microbiota decreased in PaV1-infected lobsters. A significant increase of the genus Candidatus Bacilloplasma was observed in infected lobsters, as well as a significant decrease in Nesterenkonia, Caldalkalibacillus, Pseudomonas, Cetobacterium and Phyllobacterium. We also observed an alteration in the abundances of Vibrio species. Results from this study suggest that PaV1 infection impacts intestinal microbiota composition in Panulirus argus in a sex-dependent manner.

The apical root canal system microbial communities determined by next-generation sequencing.

The aim of this study was to explore the microbial communities of endodontic infections at their apical portion by 16S rRNA Illumina sequencing and delineate the core microbiome of root canal infections and that of their associated clinical symptomatology. Samples were collected from fifteen subjects presenting one tooth with a root canal infection, and their associated symptoms were recorded. Samples were collected from the apical third of roots using a #10 K file and then amplified using multiple displacement amplification and PCR-amplified with universal primers. Amplicons were sequenced (V3-V4 hypervariable region of the 16S rRNA gene) using MiSeq (Illumina, CA). The microbial composition of the samples was determined using QIIME and HOMINGS. Data were analyzed using t tests and ANOVA. A total of 1,038,656 good quality sequences were obtained, and OTUs were assigned to 10 bacterial phyla, led by Bacteroidetes (51.2%) and Firmicutes (27.1%), and 94 genera were represented primarily by Prevotella (17.9%) and Bacteroidaceae G-1 (14.3%). Symptomatic teeth were associated with higher levels of Porphyromonas (p < 0.05) and Prevotella. P. endodontalis and P. oris were present in both cores. The present study demonstrated the complexity of the root canal microbiome and the "common denominators" of root canal infections and identified taxa whose virulence properties should be further explored. The polymicrobial etiology of endodontic infections has long been established. However, few studies have focused on expanding the breadth and depth of coverage of microbiome-infected root canals at their apical portion.

Fish Skin and Gut Microbiomes Show Contrasting Signatures of Host Species and Habitat.

Teleost fish represent an invaluable repertoire of host species to study the factors shaping animal-associated microbiomes. Several studies have shown that the phylogenetic structure of the fish gut microbiome is driven by species-specific (e.g., host ancestry, genotype, or diet) and habitat-specific (e.g., hydrochemical parameters and bacterioplankton composition) factors. However, our understanding of other host-associated microbial niches, such as the skin mucus microbiome, remains limited. The goal of our study was to explore simultaneously the phylogenetic structure of the fish skin mucus and gut microbiome and compare the effect of species- and habitat-specific drivers on the structure of microbial communities in both tissues. We sampled 114 wild fish from 6 populations of 3 ecologically and phylogenetically contrasting Amazonian teleost species. Water samples were collected at each site, and 10 physicochemical parameters were characterized. The skin mucus, gut, and water microbial communities were characterized using a metabarcoding approach targeting the V3-V4 regions of the 16S rRNA. Our results showed a significant distinction between the phylogenetic profile and diversity of the microbiome from each microbial niche. Skin mucus and bacterioplankton communities were significantly closer in composition than gut and free-living communities. Species-specific factors mostly modulated gut bacterial communities, while the skin mucus microbiome was predominantly associated with environmental physicochemistry and bacterioplankton community structure. These results suggest that the variable skin mucus community is a relevant target for the development of microbial biomarkers of environmental status, while the more conserved gut microbiome is better suited to study long-term host-microbe interactions over evolutionary time scales.IMPORTANCE Whether host-associated microbiomes are mostly shaped by species-specific or environmental factors is still unresolved. In particular, it is unknown to what extent microbial communities from two different host tissues from the same host respond to these factors. Our study is one of the first to focus on the microbiome of teleost fish to shed a light on this topic as we investigate how the phylogenetic structure of microbial communities from two distinct fish tissues are shaped by species- and habitat-specific factors. Our study showed that in contrast to the teleost gut microbiome, skin mucus communities are highly environment dependent. This result has various implications: (i) the skin mucus microbiome should be used, rather than the gut, to investigate bacterial biomarkers of ecosystem perturbance in the wild, and (ii) the gut microbiome is better suited for studies of the drivers of phylosymbiosis, or the coevolution of fish and their symbionts.

Nitrogen Fixation in Pozol, a Traditional Fermented Beverage.

Traditional fermentations have been widely studied from the microbiological point of view, but little is known from the functional perspective. In this work, nitrogen fixation by free-living nitrogen-fixing bacteria was conclusively demonstrated in pozol, a traditional Mayan beverage prepared with nixtamalized and fermented maize dough. Three aspects of nitrogen fixation were investigated to ensure that fixation actually happens in the dough: (i) the detection of acetylene reduction activity directly in the substrate, (ii) the presence of potential diazotrophs, and (iii) an in situ increase in acetylene reduction by inoculation with one of the microorganisms isolated from the dough. Three genera were identified by sequencing the 16S rRNA and nifH genes as Kosakonia, Klebsiella, and Enterobacter, and their ability to fix nitrogen was confirmed.IMPORTANCE Nitrogen-fixing bacteria are found in different niches, as symbionts in plants, in the intestinal microbiome of several insects, and as free-living microorganisms. Their use in agriculture for plant growth promotion via biological nitrogen fixation has been extensively reported. This work demonstrates the ecological and functional importance that these bacteria can have in food fermentations, reevaluating the presence of these genera as an element that enriches the nutritional value of the dough.

Microbial Community Structure Along a Horizontal Oxygen Gradient in a Costa Rican Volcanic Influenced Acid Rock Drainage System.

We describe the geochemistry and microbial diversity of a pristine environment that resembles an acid rock drainage (ARD) but it is actually the result of hydrothermal and volcanic influences. We designate this environment, and other comparable sites, as volcanic influenced acid rock drainage (VARD) systems. The metal content and sulfuric acid in this ecosystem stem from the volcanic milieu and not from the product of pyrite oxidation. Based on the analysis of 16S rRNA gene amplicons, we report the microbial community structure in the pristine San Cayetano Costa Rican VARD environment (pH = 2.94-3.06, sulfate ~ 0.87-1.19 g L-1, iron ~ 35-61 mg L-1 (waters), and ~ 8-293 g kg-1 (sediments)). San Cayetano was found to be dominated by microorganisms involved in the geochemical cycling of iron, sulfur, and nitrogen; however, the identity and abundance of the species changed with the oxygen content (0.40-6.06 mg L-1) along the river course. The hypoxic source of San Cayetano is dominated by a putative anaerobic sulfate-reducing Deltaproteobacterium. Sulfur-oxidizing bacteria such as Acidithiobacillus or Sulfobacillus are found in smaller proportions with respect to typical ARD. In the oxic downstream, we identified aerobic iron-oxidizers (Leptospirillum, Acidithrix, Ferrovum) and heterotrophic bacteria (Burkholderiaceae bacterium, Trichococcus, Acidocella). Thermoplasmatales archaea closely related to environmental phylotypes found in other ARD niches were also observed throughout the entire ecosystem. Overall, our study shows the differences and similarities in the diversity and distribution of the microbial communities between an ARD and a VARD system at the source and along the oxygen gradient that establishes on the course of the river.

First detection of "Candidatus Rickettsia wissemanii" in Ornithodoros hasei (Schulze, 1935) (Acari: Argasidae) from Argentina.

The aim of this study was to assess the presence of Rickettsia in soft ticks (Acari: Argasidae) collected from insectivorous bats (Chiroptera) in Santa Fe province, Argentina. First, a subset of ticks were mounted in Hoyer's medium to be determined by morphological characters and then confirmed by sequencing the mitochondrial 16S rRNA gene. Also ticks were processed by PCR assays using primers CS-78 and CS-323, which amplify a fragment of the Rickettsia spp. gltA gene. Positive ticks were subjected to a second PCR round with primers Rr190.70p and Rr190.701n of the spotted fever group rickettsiae ompA gene. A phylogenetic analysis was performed with Maximum-likelihood method, and the best fitting substitution models were determined with the Akaike Information Criterion. Five bats of the species Eptesicus diminutus Osgood, 1915, Eptesicus furinalis (d'Orbigny and Gervais, 1847), Eptesicus spp. (Vespertilionidae), and Molossops temminckii Burmeister, 1854 (Molossidae) were parasitized with Ornithodoros hasei (Schulze, 1935) larvae. One E. diminutus ticks' tested positive to "Candidatus Rickettsia wissemanii", a spotted fever group rickettsiae. The association O. hasei -"Ca. R. wissemanii" detected in this study represents the first evidence of a Rickettsia in Ornithodoros ticks in Argentina and the third report of this association in America. Also, this finding constitutes the first record of "Ca. R. wissemanii" in Argentina. Finally, we found for the first time the insectivorous bats E. diminutus and E. furinalis parasitized with O. hasei larvae. These findings add two new hosts and a new location, the southernmost recorded to date, for O. hasei.

Densely Populated Water Droplets in Heavy-Oil Seeps.

Most of the microbial degradation in oil reservoirs is believed to take place at the oil-water transition zone (OWTZ). However, a recent study indicates that there is microbial life enclosed in microliter-sized water droplets dispersed in heavy oil of Pitch Lake in Trinidad and Tobago. This life in oil suggests that microbial degradation of oil also takes place in water pockets in the oil-bearing rock of an oil leg independent of the OWTZ. However, it is unknown whether microbial life in water droplets dispersed in oil is a generic property of oil reservoirs rather than an exotic exception. Hence, we took samples from three heavy-oil seeps, Pitch Lake (Trinidad and Tobago), the La Brea Tar Pits (California, USA), and an oil seep on the McKittrick oil field (California, USA). All three tested oil seeps contained dispersed water droplets. Larger droplets between 1 and 10 µl revealed high cell densities of up to 109 cells ml-1 Testing for ATP content and LIVE/DEAD staining showed that these populations consist of active and viable microbial cells with an average of 60% membrane-intact cells and ATP concentrations comparable to those of other subsurface ecosystems. Microbial community analyses based on 16S rRNA gene amplicon sequencing revealed the presence of known anaerobic oil-degrading microorganisms. Surprisingly, the community analyses showed similarities between all three oil seeps, revealing common OTUs, although the sampling sites were thousands of kilometers apart. Our results indicate that small water inclusions are densely populated microhabitats in heavy oil and possibly a generic trait of degraded-oil reservoirs.IMPORTANCE Our results confirmed that small water droplets in oil are densely populated microhabitats containing active microbial communities. Since these microhabitats occurred in three tested oil seeps which are located thousands of kilometers away from each other, such populated water droplets might be a generic trait of biodegraded oil reservoirs and might be involved in the overall oil degradation process. Microbial degradation might thus also take place in water pockets in the oil-bearing oil legs of the reservoir rock rather than only at the oil-water transition zone.

Ehrlichia canis TRP36 diversity in naturally infected-dogs from an urban area of Colombia.

Ehrlichia canis is the etiologic agent of a highly prevalent tick-borne disease, canine monocytic ehrlichiosis (CME). Four defined E. canis genotypes based on the trp36 gene sequences have been reported, three of them identified in North or South America. The diversity of E. canis has been investigated using genetic and serologic approaches based on distinct 36 kDa tandem repeat protein (trp36) gene sequences that have been reported. The main objectives of this study were to determine the prevalence of E. canis infection in dogs from Medellín, Colombia by PCR and determine the E. canis diversity using molecular and serologic approaches. Blood was collected from dogs (n = 300) with clinical signs of CME for PCR detection of E. canis 16S rRNA, dsb and trp36 DNA. Phylogenetic analysis of trp36 gene sequences was performed using MEGA. A serological evaluation was performed using immunofluorescence microscopy and ELISA with species-specific peptides from E. canis TRP19 and TRP36 (3 genotypes) and E. chaffeensis (TRP32). E. canis DNA (16S rRNA and/or dsb) was detected in 18 % (53/300) of dogs by PCR amplification. The trp36 gene was amplified and sequenced from 35/53 16S rRNA/dsb PCR positive samples revealing three genotypes: United States (US; n = 21), Costa Rica (CR; n = 11), and Brazil (BR; n = 3). Most dogs (33/35) with detectable trp36 DNA had anti-E. canis TRP19 and TRP36 peptide antibodies that corresponded to the genotype detected by PCR. Dogs that had antibodies to the TRP19 peptide (82/300; 38 %), also had antibodies to one or more genotype-specific TRP36 peptides. Based on TRP36 serology, the dogs exhibited highest frequency of infection with the US genogroup (US = 26), followed by the CR genogroup (CR = 19) and the BR genogroup (BR = 11). Notably, 26/53 trp36 PCR positive dogs had detectable antibodies to multiple E. canis genotypes (US/BR/CR = 8, BR/CR = 7, US/CR = 6 and US/BR = 5) suggesting coinfection or multiple sequential infections with different genotypes. Colombian dogs did not have antibodies to E. chaffeensis as determined by a TRP32 species-specific ELISA. Our results demonstrate the presence of three previously defined genotypes in North and South America in Colombian dogs (US, BR, CR). These results also demonstrate that TRP19 and TRP36 serology can provide valuable information regarding E. canis exposure and the potential genotype(s) involved in infection.

Dynamics of Abundant and Rare Bacteria During Degradation of Lignocellulose from Sugarcane Biomass.

Microorganisms play a crucial role in lignocellulosic degradation. Many enriched microbial communities have demonstrated to reach functional and structural stability with effective degrading capacities of industrial interest. These microbial communities are typically composed by only few dominant species and a high number of usually overlooked rare species. Here, we used two sources of lignocellulose (sugarcane bagasse and straw) in order to obtain lignocellulose-degrading bacteria through an enriched process, followed the selective trajectory of both abundant and rare bacterial communities by 16S rRNA gene amplification and analyzed the outcomes of selection in terms of capacities and specialization. We verified the importance of pre-selection by using two sources of microbial inoculum: soil samples from a sugarcane field with history of straw addition (St15) and control samples, from the same field, without amendments (St0). We found similitudes in terms of stabilization between the abundant and rare fractions. We also found positive correlations of both abundant and rare taxa (like Caulobacteraceae and Alcaligenaceae) and the degradation of lignocellulosic fractions. Differences in the inocula's initial diversity rapidly decreased during the enrichment resulting in comparable richness levels at the end of the process; however, the legacy of the St15 inoculum and its specialization positively influenced the degradation capacities of the community. Analysis of specialization of the final communities revealed increased straw degradation capacity in the communities enriched in bagasse, which could be potentially used as a strategy for improving lignocellulose waste degradation on the sugarcane fields. This work highlights the importance of including the rare fraction of bacterial communities during investigations involving the screening and assessment of effective degrading communities.

The Gut Microbiota Composition of the Moth Brithys crini Reflects Insect Metamorphosis.

Lepidoptera is a highly diverse insect order with major importance in agriculture as many species are considered pests. The role of the gut microbiota in insect physiology is still poorly understood, despite the research undertaken in recent years. Furthermore, Lepidoptera are holometabolous insects and few studies have addressed the influence of the changes taking place on the gut microbiome composition and diversity during metamorphosis, especially in monophagous species. The V3-V4 region of the 16S rRNA gene was sequenced to investigate the microbiota composition and diversity of the monophagous moth Brithys crini during three different life stages: egg, larvae (midgut and hindgut), and adult (gut). Our results showed that the microbiota composition of B. crini was stage specific, indicating that the developmental stage is a main factor affecting the gut microbiome in composition and potential functions. Moreover, the diversity of the gut microbiome reflected the developmental process, since a drop in diversity occurred between the larval and the adult phase, when the intestine is completely renewed. In spite of the changes in the gut microbiota during metamorphosis, 29 genera were conserved throughout the three developmental stages, mainly belonging to the Proteobacteria phylum, which define the core microbiome of B. crini. These genera seem to contribute to host physiology by participating in food digestion, nutrition, and detoxification mechanisms.

Histophilus somni myocarditis and leptomeningitis in feedlot cattle: case report and occurrence in South America.

We investigated deaths in a group of feedlot steers in Argentina. The main findings in 3 steers autopsied were pulmonary congestion and edema, necrotizing myocarditis, pericarditis, suppurative leptomeningitis, and bronchopneumonia. Histophilus somni was detected by bacterial culture and immunohistochemistry in the hearts of the 3 animals. Partial sequences of the 16S rRNA gene of a H. somni isolate had 99% similarity with other H. somni sequences in GenBank. Most reports of H. somni septicemia in cattle originate from North America and western Europe. There is scant information about cardiac histophilosis in South America. A survey of diagnostic laboratory personnel in 7 South American countries documented various forms of bovine histophilosis in Argentina, Brazil, Uruguay, and Venezuela.

Novel Ehrlichia sp. detected in Magellanic penguins (Sphenicus magellanicus) and in the seabird tick Ixodes uriae from Magdalena Island, southern Chile.

Ehrlichia spp. are obligatory intracellular microorganisms that infect hematopoietic, endothelial or blood cells of mammals. Ticks are the only vectors of these agents in nature. To date, the role of birds and their associated ticks as reservoirs of ehrlichiae remains almost unexplored. In this study, we performed a molecular screening for bacteria of Anaplasmataceae family in samples of spleen (n = 72) and lung (n = 17), recovered from 72 carcasses of Magellanic penguins (Spheniscus magellanicus) in Brazil and Chile. One apparently unengorged tick (Ixodes uriae) was also collected while wandering upon one of the carcasses and submitted to molecular analyses as well. Through conventional and nested PCR protocols three genes (16S rRNA, dsb and groEL) of a new Ehrlichia sp. were partially characterized upon organs of three penguins and in the tick coming from Magdalena Island (Chile). First matches after BLASTn comparisons showed that our sequences share 99.4% (16S rRNA), 94.6% (groEL) and 79.3% (dsb) of identity with "Candidatus Ehrlichia ornithorhynchi", Ehrlichia sp. NS101 and Ehrlichia canis CCZ, respectively. Matrixes of genetic distance including other representatives of the Ehrlichia genus point a 99.4%, 94.0%, and 80.0% of identity with 16S rRNA, groEL and dsb genes from Ehrlichia sp. It25, Ehrlichia sp. NS101, and Ehrlichia chaffeensis San Louis, respectively. A Bayesian phylogenetic analysis of Anaplasmataceae 16S rRNA gene places the detected Ehrlichia sp. into a group with Ehrlichia sp. BAT and Ehrlichia sp. Natal. Although depicting different topologies, Bayesian unrooted phylogenetic trees constructed for groEL and dsb genes position this Ehrlichia sp. into well-supported branches, which reinforces the finding of a new taxon. For the moment, any pathogenic effect of this new Ehrlichia sp. on penguins is still unknown. However, this fact becomes important to assess from a conservation point of view since populations of Magellanic penguins are currently threatened and in an ongoing decrease.

Characterization of Bacterial Communities in Breeding Waters of Anopheles darlingi in Manaus in the Amazon Basin Malaria-Endemic Area.

The microbiota in mosquito breeding waters can affect ovipositing mosquitoes, have effects on larval development, and can modify adult mosquito-gut bacterial composition. This, in turn, can affect transmission of human pathogens such as malaria parasites. Here, we explore the microbiota of four breeding sites for Anopheles darlingi, the most important malaria vector in Latin America. The sites are located in Manaus in the Amazon basin in Brazil, an area of active malaria transmission. Using 16S rRNA gene sequencing by MiSeq, we found that all sites were dominated by Proteobacteria and Firmicutes and that 94% of the total number of reads belonged to 36 operational taxonomic units (OTUs) identified in all sites. Of these, the most common OTUs belonged to Escherichia/Shigella, Staphylococcus, and Pseudomonas. Of the remaining 6% of the reads, the OTUs found to differentiate between the four sites belonged to the orders Burkholderiales, Actinomycetales, and Clostridiales. We conclude that An. darlingi can develop in breeding waters with different surface-water bacteria, but that the common microbiota found in all breeding sites might indicate or contribute to a suitable habitat for this important malaria vector.

Short term changes in the abundance of nitrifying microorganisms in a soil-plant system simultaneously exposed to copper nanoparticles and atrazine.

Copper nanoparticles (NCu) may co-exist with other pollutants in agricultural soils, such as pesticides. However, this has been little evaluated yet. Thus, possible effects of the simultaneous applications of pesticides and NCu on biogeochemical cycles are expected, for example on the nitrogen cycle. Therefore, the aim of this work was to evaluate the effect of simultaneous application of the herbicide atrazine (ATZ) and NCu on the abundance of total bacteria and nitrifying communities: ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Moreover, the ATZ dissipation was evaluated. A soil-plant system containing ATZ at field dose (3 mg a.i. kg-1) was mixed with two doses of NCu (0.05% or 0.15% w/w). Changes in the abundance of 16S rRNA and ammonia monooxygenase (amoA) genes of AOA and AOB were evaluated by real-time quantitative PCR (qPCR) at three sampling times (1, 15 and 30 days). The residual ATZ and nitrate production were also measured. The results showed significant differences in microbial composition and abundance over the 30 days of the experiment. Particularly, an initial decrease was observed in total bacterial abundance due to the presence of ATZ and NCu respect to ATZ alone (~60%). The abundance of AOA was also remarkably reduced (~85%), but these communities gradually recovered towards the end of the experiment. Conversely, AOB abundance initially increased (>100%) and remained mainly unaltered in soil exposed to ATZ and NCu 0.15% w/w, where nitrate formation was also constant. Moreover, NCu decreased the ATZ dissipation, which was translated in a 2-fold increase on the ATZ half-life values (T1/2). This study demonstrates that the simultaneous presence of NCu and ATZ may represent a risk for the total bacteria present in soil and sensitive microorganisms such as nitrifying communities, and changes in the dissipation of the pesticide could influence this process.

A high gene flow in populations of Amblyomma ovale ticks found in distinct fragments of Brazilian Atlantic rainforest.

The genetic structure of populations of the tick Amblyomma ovale from five distinct areas of the Brazilian Atlantic rainforest was evaluated via DNA sequencing and associated with the presence of domestic dogs acting as hosts at the edge of forest fragments. Ticks were collected from domestic dogs and from the environment between 2015 and 2017. Four collection areas were located in the surroundings and within the Serra do Mar State Park, São Paulo State (23°37'21"S, 45°24'43"W), where dogs were bimonthly monitored along 2 years using camera traps and GSM trackers. To determine the spatial limits of genetic structure, ticks collected upon dogs living near the Serra do Baturié, Ceará State (4°15'40"S, 38°55'54"W) were included as well. A total of 39 haplotypes of 16S rRNA and Cox 1 mitochondrial genes sequences were observed, with 27 of them coming from areas within the Serra do Mar State Park. No haplotype was shared between the Serra do Mar and the Serra do Baturié indicating isolation of tick populations at the scale of 2000 km. Although three different haplotype lineages of A. ovale occurred within the Serra do Mar State Park, no genetic structure was found across the study sites within this park, suggesting high tick gene flow across a range of 45 km. Monitoring data from domestic dogs and wild carnivores showed that these species share the same habitats at the forest edge, with dogs playing a likely limited role in tick dispersal. Our findings have important implications for understanding the genetic structure of wide spread A. ovale along Brazilian rainforest remnants, which can further be associated to tick-borne infectious agents, such as Rickettsia parkeri, and used for predicting future patterns of tick diversity in the Brazilian Atlantic rainforest.

Impact of phosphate solubilizing bacteria on wheat (Triticum aestivum ) in the presence of pesticides.

Three phosphate solubilizing bacteria were isolated and identified by 16S rRNA sequencing as Pseudomonas putida, Pseudomonas sp and Pseudomonas fulva . The strains were subjected to plant biochemical testing and all the PGPR attributes were checked in the presence of pesticides (chlorpyrifos and pyriproxyfen). The phosphate solubilizing index of strain Ros2 was highest in NBRIP medium i.e 2.23 mm. All the strains showed acidic pH (ranges from 2.5-5) on both medium i.e PVK and NBRIP. Strain Ros2 was highly positive for ammonia production as well as siderophore production while strain Rad2 was positive for HCN production. The results obtained by the strains Rad1, Rad2 and Ros2 for auxin production were 33.1, 30.67 and 15.38 µg ml-1, respectively. Strain Rad1 showed 16% increase in percentage germination in comparison to control in the presence of pesticide stress. Most promising results for chlorophyll content estimation were obtained in the presence of carotenoids upto 6 mgg-1 without stress by both strains Rad1 and Rad2. Study suggests that especially strain Ros2 can enhance plant growth parameters in the pesticide stress.

Impact of phosphate solubilizing bacteria on wheat (Triticum aestivum ) in the presence of pesticides / Impacto das bactérias solubilizantes de fosfato no trigo (Triticum aestivum ) na presença de pesticidas

Abstract Three phosphate solubilizing bacteria were isolated and identified by 16S rRNA sequencing as Pseudomonas putida, Pseudomonas sp and Pseudomonas fulva . The strains were subjected to plant biochemical testing and all the PGPR attributes were checked in the presence of pesticides (chlorpyrifos and pyriproxyfen). The phosphate solubilizing index of strain Ros2 was highest in NBRIP medium i.e 2.23 mm. All the strains showed acidic pH (ranges from 2.5-5) on both medium i.e PVK and NBRIP. Strain Ros2 was highly positive for ammonia production as well as siderophore production while strain Rad2 was positive for HCN production. The results obtained by the strains Rad1, Rad2 and Ros2 for auxin production were 33.1, 30.67 and 15.38 µg ml-1, respectively. Strain Rad1 showed 16% increase in percentage germination in comparison to control in the presence of pesticide stress. Most promising results for chlorophyll content estimation were obtained in the presence of carotenoids upto 6 mgg-1 without stress by both strains Rad1 and Rad2. Study suggests that especially strain Ros2 can enhance plant growth parameters in the pesticide stress.

Resumo Três bactérias solubilizantes de fosfato foram isoladas e identificadas por seqüenciamento de rRNA 16S como Pseudomonas putida, Pseudomonas sp e Pseudomonas fulva. As estirpes foram submetidas a testes bioquímicos de plantas e todos os atributos PGPR foram verificados na presença de pesticidas (clorpirifos e piriproxifeno). O índice de solubilização de fosfato da estirpe Ros2 foi mais elevado no meio NBRIP, isto é, 2,23 mm. Todas as estirpes apresentaram um pH ácido (varia de 2,5-5) em ambos os meios, isto é PVK e NBRIP. A estirpe Ros2 foi altamente positiva para a produção de amoníaco, bem como a produção de sideróforos enquanto a estirpe Rad2 foi positiva para a produção de HCN. Os resultados obtidos pelas estirpes Rad1, Rad2 e Ros2 para a produção de auxina foram 33,1, 30,67 e 15,38 μg ml-1 , respectivamente. A deformação Rad1 mostrou aumento de 16% na germinação percentual em comparação com o controlo na presença de stress de pesticida. Os resultados mais promissores para a estimativa do teor de clorofila foram obtidos na presença de carotenóides até 6 mgg-1 sem estresse por ambas as cepas Rad1 e Rad2. Estudo sugere que especialmente a estirpe Ros2 pode melhorar parâmetros de crescimento de plantas no estresse de pesticidas.

Dangerous passengers: multidrug-resistant bacteria on hands and mobile phones.

INTRODUCTION: It is recognized that mobile phones may play a role in microorganism transmission and that hand hygiene, is considered the most important action for preventing infections and the spread of pathogens. The objective of this study was to determine presence and circulation bacteria on hands and mobile phones capable of causing infections in people and also determine if disinfection with gel-alcohol is useful to reduce the bacterial colonization. METHODS: The bacterial evaluation included 596 hands of participants and 256 mobile phones. Isolated colonies were identified by biochemical test and confirmed by gene 16S rRNA sequencing. Antimicrobial susceptibility was performed using the automated instrument Vitek®2-Compact and disk-diffusionmethod. RESULTS: In total, 92.9% of mobile phones and 98.3% of participants in study demonstrated evidence of bacterial contamination with different types of bacteria. Surprisingly, we observed that 18.6% plaques inoculated with disinfected fingers showed bacterial growth. In general, Gram negative isolates showed resistance to a higher number of antibiotics tested than Gram positive isolates. CONCLUSIONS: Our results could help to raise awareness in our society about the importance of hand hygiene, as well as frequently used devices, reducing bacterial contamination and limiting the possibility of transmission of resistant multi-drug bacteria.