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The use of fertilizers affects not only the soil fertility and crop yield, but also significantly changes the taxonomic structure of the soil microbiocenosis. Here, based on stationary field experiment, we studied the influence of organo-mineral fertilizer (ОМF), modified by bacteria Bacillus subtilis, H-13 in comparison with different fertilizer systems (organic, mineral, organo-mineral) on (i) crop yield, (ii) physical and chemical properties, and (iii) alpha and beta diversity of the microbial community Albic Retisol (Loamic, Aric, Cutanic, Differentic, Ochric). The studies were carried out against the background of liming (рНКCl - 5.9) and without it (рНКCl - 5.1). The use of only one cattle farmyard manure was less effective than its co-application with mineral fertilizers in half doses. A similar effect was obtained when applying ОМF. In addition, the use of OMF contributes to a significant increase in the reserves of soil organic carbon in the soil layer 0-20 cm by 18%-32%. Using high-throughput sequencing of the 16S rRNA variable V4 gene sequence libraries, 10.759 taxa from 456 genera were identified, assigned to 34 fila (31 bacterial and 3 archaeotic. Unilateral application of mineral fertilizers leads to a significant decrease in the alpha diversity of the structure of soil microbial communities (OTE (other things equal) and Shannon index). A clear clustering of the microbiota was found in the variants with and without the introduction of сattle farmyard manure. It is revealed that the taxonomic structure of the microbiocenosis is formed under the influence of two main factors: crop rotation culture and applied fertilizers. The type of cultivated crop determines the dynamics of the microbiota at the level of larger taxa, such as domains, and fertilizers affect the structure of the microbial community at a lower taxonomic level (phyla, orders, bloodlines). On the basis of the Deseq analysis, marker taxa were identified, according to the share participation of which it is possible to determine the type of cultivated crop and fertilizers used in the experiment. Understanding the dynamics of taxa association and other influential factors can lead to the creation of universal systems of metagenomic indication, where tracking the dynamics of microbial communities will allow for a comprehensive assessment of the agroecological state of soils and timely decisions to prevent their degradation.

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Ehrlichia chaffeensis is a bacterium belonging to the Anaplasmataceae family. In Mexico, only 2 species have been recorded in association with tick species and humans. The objective of the present study was to detect the presence of bacteria of the genus Ehrlichia in ticks collected from the Chamela-Cuixmala Biosphere Reserve, Jalisco, Mexico. The collected ticks were identified and analyzed individually by polymerase chain reaction to amplify a fragment of the Anaplasmataceae 16S rRNA gene and the Ehrlichia-specific dsb gene. A total of 204 ticks, corresponding to 5 species of Ixodidae and 1 of Argasidae, were collected from 147 mammals of 6 species and 4 orders; 57 ticks collected from vegetation were also included. Among the total ticks collected, 1.47% (3/204) was positive for Ehrlichia sp. DNA was obtained using the primers EHR 16SD and EHR 16SR for 16S rRNA and DSB-330 and DSB-728 for dsb. The positive samples corresponded to a larva (Amblyomma sp.) associated with Didelphis virginiana and 2 nymphs (Amblyomma cf. oblongoguttatum) infesting Nasua narica. None of the ticks collected from the vegetation tested positive for Ehrlichia sp. DNA on the basis of the 16S rRNA and dsb genes. The sequences from the larvae of Amblyomma sp. and the nymphs of A. cf. oblongoguttatum were similar to those of E. chaffeensis. The phylogenetic analysis inferred with maximum likelihood corroborated the identity as E. chaffeensis. Although the role of these tick species as vectors of E. chaffeensis is still undetermined, the presence of infected ticks in the area indicates a potential zoonotic risk.

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The Sierra Nevada de Santa Marta (SNSM), located in northern Colombia, is considered a geographical island with high levels of biodiversity and endemism. However, little is known about tick species and their associated microorganisms at the SNSM. In this study we sampled host-seeking ticks in areas of the town of Minca within the SNSM. We collected 47 ticks identified as Amblyomma pacae, Amblyomma longirostre, Amblyomma ovale, Amblyomma mixtum, Haemaphysalis juxtakochi, Ixodes sp. cf. Ixodes affinis and Ixodes sp. Of these ticks, we tested for Rickettsia spp. by amplifying the gltA, SCA1, and 16S rRNA genes via PCR. Rickettsia amblyommatis was detected in one pool of 3 larvae and in a female of A. pacae. Additonally, we isolated Rickettsia sp. belonging to the group of spotted fevers in larvae of A. longirostre. This study reports new findings of six species of ticks and two species of Rickettsia within the SNSM.

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Highly anthropophilic and adapted to urban environments, Aedes aegypti mosquitoes are the main vectors of arboviruses that cause human diseases such as dengue, zika, and chikungunya fever, especially in countries with tropical and subtropical climates. Microorganisms with mosquitocidal and larvicidal activities have been suggested as environmentally safe alternatives to chemical or mechanical mosquito control methods. Here, we analyzed cultivable bacteria isolated from all stages of the mosquito life cycle for their larvicidal activity against Ae. aegypti. A total of 424 bacterial strains isolated from eggs, larvae, pupae, or adult Ae. aegypti were analyzed for the pathogenic potential of their crude cultures against larvae of this same mosquito species. Nine strains displayed larvicidal activity comparable to the strain AM65-52, reisolated from commercial BTi-based product VectoBac® WG. 16S rRNA gene sequencing revealed that the set of larvicidal strains contains two representatives of the genus Bacillus, five Enterobacter, and two Stenotrophomonas. This study demonstrates that some bacteria isolated from Ae. aegypti are pathogenic for the mosquito from which they were isolated. The data are promising for developing novel bioinsecticides for the control of these medically important mosquitoes.

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Fastidious endosymbiotic Rickettsiales-like organisms (RLOs) have been observed in the digestive diverticula of the cultured pleasure oyster (Crassostrea corteziensis) from Nayarit, Mexico since 2007. In a few mollusk species, these bacteria have been associated with mortality events and production losses. The type of relationship between the RLOs and the pleasure oyster is largely unknown and further investigations are needed to determine if these bacteria warrant management concern in C. corteziensis. In this study, the morphological characteristics of the RLOs were studied by histology and SEM, and the taxonomic affiliations of the bacteria were evaluated by 16S rRNA amplicon sequencing. In addition, the prevalence and intensity of the RLOs was recorded from 2007 to 2017 by histology. The RLOs were observed inside circular basophilic cytoplasmic membrane bound vacuoles (MBVs) that had an average length and width of 15.70 ± 15.24 µm and 15.42 ± 14.95 µm respectively. Apart from cellular hypertrophy, no tissue alterations were observed in the areas adjacent to the RLOs. Individual bacteria within the MBVs were coccoid in shape with an average length of 0.65 ± 0.12 µm and an average width of 0.38 ± 0.09 µm. The bacterial microbiota of a selected number of samples (one sample without RLOs and two samples with RLOs) showed the presence of intracellular parasite OTUs corresponding to the families Rickettsiaceae and Anaplasmataceae, suggesting that the RLOs from the pleasure oyster is associated with the order Rickettsiales. A mean prevalence of 5 % was observed throughout the study period and the majority of the organisms (89 %) presented low intensity of Grade 1 (30-61 RLOs) of the MBVs. A higher prevalence of the RLOs was observed during warmer months. The lack of tissue alterations, the low prevalence and the low intensity of the MBVs suggest that the RLOs from C. corteziensis is a commensal endosymbiont that presents little risk for oyster production in Nayarit, México. However, regular monitoring is needed to detect if any variation in this relationship occurs, mainly in a scenario where extreme environmental fluctuations may occur.

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Bacterial communities in the mammalian reproductive system can be rich and diverse, differing in structure and quantity depending on location. In addition, its microbiome is associated with the state of health of this tract and reproductive success. This study evaluated the microbiome composition of the uterine body (UB) and uterine horn mucosa (UH) samples using 16S rRNA sequencing of samples extracted from cows in the Amazon region. It was observed that four main phyla were shared between the uterine sites: Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Linear discriminant analysis effect size and heat tree analysis showed that members of Lachnospiraceae (NK3A20 group) and Oscillospiraceae were significantly more abundant in the UB than in UH. In addition, there are more unique genera in the UB than in the UH. A higher bacterial load in UB than in UH is expected because of the exposure to external factors of UB. However, comparing the site's communities through beta diversity did not generate well-defined clustering. Thus, it can be attributed to the closeness of the sites, which would make the niches similar ecologically and microbiologically. Therefore, this research provides knowledge to understand biomarkers in the prior reproduction period.

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A large number of tick species are proven vectors for the transmission of bacteria, protozoa, and viruses. Soft ticks (Acari: Argasidae) in South America have been found to be the most frequent carriers of borreliae of the relapsing fever group (RFG); however, there are several information gaps specially on the taxonomy and distribution of some tick species. Here, we used light microscopy, scanning electron microscopy, and PCR amplification of a fragment of the mitochondrial 16S rRNA gene to evaluate 174 larvae of Ornithodoros (Argasidae) collected from three bat species (Eptesicus orinocensis, Molossus rufus and Noctilio albiventris) in the Orinoquia Region of Colombia. The morphological and molecular results confirmed that all the analyzed larvae corresponded to Ornithodoros hasei. Comparisons of mitochondrial 16S rDNA sequences showed low genetic divergence (0% - 0.3%) between larvae of the Department of Arauca in the Orinoquia Region and higher genetic divergence (3.4 - 4.7%) in sequences from other American countries. Our work represents the most recent collection of this species in Colombia and provides a molecular evaluation for the first time. Moreover, a new association of O. hasei with bats such as E. orinocensis is documented. Considering the wide distribution of O. hasei in the American Continent, and its putative role as vector for Borrelia, integrative studies that involve morphological, morphometric, molecular data and experimental crosses are needed to determine if the higher genetic distances are associated with cryptic speciation, as detected in other tick complexes, or represent genetic divergences among geographically different populations of O. hasei.

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Hemoplasmas are non-cultivable bacterial parasites of erythrocytes that infect domestic and wild animals, as well as humans. Their means of transmission and pathogenesis remain contentious issues and difficult to evaluate in wild animals. Procyon cancrivorus is a South American carnivore and occurs in all Brazilian biomes. In this study, we aimed to investigate occurrences of hemoplasmas infecting P. cancrivorus and to identify their 16S rRNA gene, in southern Brazil. DNA was extracted from spleen and blood samples of P. cancrivorus (n = 9) from different locations. Hemoplasma DNA was detected in six samples, based on 16S rRNA gene amplification and phylogenetic analysis. Four of the six sequences belonged to the "Mycoplasma haemofelis group", which is closely related to genotypes detected in Procyon lotor from the USA; one was within the "Mycoplasma suis group", closely related to "Candidatus Mycoplasma haemominutum"; and one was within the intermediate group between these clusters. Thus, these sequences showed that the molecular identity of hemoplasmas in the population studied was very variable. In five positive animals, Amblyomma aureolatum ticks and a flea (Ctenocephalides felis felis) were collected. The present study describes the first molecular detection of mycoplasmas in P. cancrivorus.(AU)

Os micoplasmas hemotrópicos (hemoplasmas) são parasitas bacterianos não-cultiváveis de eritrócitos que infectam tanto animais domésticos e selvagens, como seres humanos. A transmissão e a patogênese são discutíveis e difíceis de avaliar em animais selvagens. O mão pelada (Procyon cancrivorus) é um carnívoro Sul-americano, que ocorre em todos os biomas brasileiros. O objetivo do presente estudo é o de investigar a ocorrência de hemoplasmas infectando P. cancrivorus e identificar seu gene 16S rRNA no Sul do Brasil. O DNA foi extraído do baço e amostras de sangue de P. cancrivorus (n= 9). O DNA de hemoplasma foi detectado em seis amostras, com base na amplificação do gene 16S rRNA e na análise filogenética. Quatro das seis sequências pertencem ao "Grupo Mycoplasma haemofelis", que estão intimamente relacionadas aos genótipos detectados no Procyon lotor dos EUA; uma dentro do "Grupo Mycoplasma suis", que está intimamente relacionado ao "Candidatus Mycoplasma haemominutum", e uma dentro do grupo intermediário entre esses clusters, mostrando assim que há uma diversidade genética de hemoplasmas na população estudada. Em cinco animais positivos, foram coletados carrapatos Amblyomma aureolatum e uma pulga Ctenocephalides felis. O presente estudo traz a primeira detecção molecular de micoplasmas em P. cancrivorus.(AU)

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Microbial biodiversity of an environment can contribute to plant growth and increase crop yield. Plant extracts from soybean (Glycine max (L.) Merrill) were investigated on soybean plants grown after inoculation with these extracts. Soil samples were collected from two important Brazilian soybean-growing regions to produce the extracts used in the experiments. The extracts were produced with material collected from aboveground biomass and rhizosphere of soybean plants cultivated in a controlled greenhouse (phase 1). The extracts produced in phase 1 were applied in a sequential experiment (phase 2). Phase 2 was conducted to examine the plant microbiome after the microbial alteration process in the greenhouse through seed inoculation with the extracts produced previously. Samples of aboveground biomass were collected to determine root dry matter and crop yield. Bacterial 16S rRNA sequences were processed to determine the final microbial content of soybean. The inoculated treatments had lower species diversity; however, the phyla Firmicutes and Bacteroidetes were more abundant in the treatments than in the non-inoculated treatment. The soybean plant stem in the inoculated treatment also had a positive response to enrichment of the bacterial classes Betaproteobacteria, Bacilli and Flavobacteria. Inoculation affected the microbial composition of soybean plants. The alteration of microbiome changes revealed differences for crop yield between the inoculated and non-inoculated treatments, with up to 93.5 % higher crop yields per plant according to the extract applied.

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Polymerase chain reaction (PCR) assays targeting 16S rRNA genes followed by DNA sequencing are still important tools to characterize microbial communities present in environmental samples. However, despite the crescent number of deposited archaeal DNA sequences in databases, until now we do not have a clear picture of the effectiveness and specificity of the universal primers widely used to describe archaeal communities from different natural habitats. Therefore, in this study, we compared the phylogenetic profile obtained when Cerrado lake sediment DNA samples were submitted to 16S rDNA PCR employing three Archaea-specific primer sets commonly used. Our findings reveal that specificity of primers differed depending on the source of the analyzed DNA. Furthermore, archaeal communities revealed by each primer pair varied greatly, indicating that 16S rRNA gene primer choice affects the community profile obtained, with differences in both taxon detection and operational taxonomic unit (OTU) estimates.(AU)

A amplificação de genes que codificam o rRNA 16S por reação em cadeia da polimerase (PCR) e o seu sub sequentesequenciamento consistem em uma ferramenta importante na caracterização de comunidades microbianas presentes em amostras ambientais. No entanto, apesar do crescente número de sequências de DNA de Archaea depositadas em bancos de dados, a especificidade e efetividade dos iniciadores de PCR descritos como universais e amplamente utilizados na descrição desse grupo ainda não está clara. Neste estudo foram comparados os perfis filogenéticos de comunidades de arqueias obtidos a partir amostras de DNA de sedimentos lacustres do Cerrado submetidas a ensaios de PCR empregando três pares de iniciadores específicos para Archaea, comumente utilizados neste tipo de estudo. Nossos resultados indicam que as comunidades de arqueias detectadas com cada par de iniciadores apresentaram grande variação filogenética, sugerindo que a escolha de iniciadores dirigidos ao gene de rRNA 16S tem efeito significativo no perfil da comunidade descrita, com diferenças tanto em relação aos táxons detectados, como nas estimativas de unidades taxonômicas operacionais (OTU).(AU)

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