Microcystin influence on soil-plant microbiota: Unraveling microbiota modulations and assembly processes in the rhizosphere of Vicia faba.

Microcystins (MCs) are frequently detected in cyanobacterial bloom-impacted waterbodies and introduced into agroecosystems via irrigation water. They are widely known as phytotoxic cyanotoxins, which impair the growth and physiological functions of crop plants. However, their impact on the plant-associated microbiota is scarcely tackled and poorly understood. Therefore, we aimed to investigate the effect of MCs on microbiota-inhabiting bulk soil (BS), root adhering soil (RAS), and root tissue (RT) of Vicia faba when exposed to 100 µg L-1 MCs in a greenhouse pot experiment. Under MC exposure, the structure, co-occurrence network, and assembly processes of the bacterial microbiota were modulated with the greatest impact on RT-inhabiting bacteria, followed by BS and, to a lesser extent, RAS. The analyses revealed a significant decrease in the abundances of several Actinobacteriota-related taxa within the RT microbiota, including the most abundant and known genus of Streptomyces. Furthermore, MCs significantly increased the abundance of methylotrophic bacteria (Methylobacillus, Methylotenera) and other Proteobacteria-affiliated genera (e.g., Paucibacter), which are supposed to degrade MCs. The co-occurrence network of the bacterial community in the presence of MCs was less complex than the control network. In MC-exposed RT, the turnover in community composition was more strongly driven by deterministic processes, as proven by the beta-nearest taxon index. Whereas in MC-treated BS and RAS, both deterministic and stochastic processes can influence community assembly to some extent, with a relative dominance of deterministic processes. Altogether, these results suggest that MCs may reshape the structure of the microbiota in the soil-plant system by reducing bacterial taxa with potential phytobeneficial traits and increasing other taxa with the potential capacity to degrade MCs.

Behavior and use of quaternary ammonium-based disinfectants in biosafety protocols against Fusarium oxysporum f.sp. cubense race 1 and tropical race 4.

The banana is one of Colombia's main export products. However, production is seriously affected by Fusarium wilt of Banana (FWB), which is the most destructive disease caused by the fungus Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4). Currently, management strategies focus on containment and biosecurity protocols to prevent its spread to territories that are free of this disease. This study aimed to evaluate 9 quaternary ammonium-based disinfectants (QAC) in vitro in Colombia on reproductive (microconidia and macroconidia) and resistance structures (chamydospores) of Foc Race 1 (R1) and Tropical Race 4 (TR4), with and without soil, to determine the influence of organic matter and soil texture on the action of QACs. A method for inhibiting the action of QACs was standardized and evaluated at 1,200 ppm with a contact time of ≤ 30 seconds, while evaluating the soil-inoculum and soil-disinfectant interaction. The efficacy of QACs was 100% in the reproductive and resistance structures of Foc R1 and TR4 without soil and in the soil-inoculum interaction. However, in the soil-disinfectant interaction, only QAC4 controlled the pathogen at 100%. The presence of organic matter influenced the biocidal action of the QACs, and fine textures had a greater reducing effect on the concentration. Soil decreased the efficacy of the QACs and, therefore, must be removed from contaminated boots before treatments are applied.

Genetic diversity and natural selection of Plasmodium vivax reticulocyte invasion genes in Ecuador.

BACKGROUND: Knowledge of the diversity of invasion ligands in malaria parasites in endemic regions is essential to understand how natural selection influences genetic diversity of these ligands and their feasibility as possible targets for future vaccine development. In this study the diversity of four genes for merozoite invasion ligands was studied in Ecuadorian isolates of Plasmodium vivax. METHODS: Eighty-eight samples from P. vivax infected individuals from the Coast and Amazon region of Ecuador were obtained between 2012 and 2015. The merozoite invasion genes pvmsp-1-19, pvdbpII, pvrbp1a-2 and pvama1 were amplified, sequenced, and compared to the Sal-1 strain. Polymorphisms were mapped and genetic relationships between haplotypes were determined. RESULTS: Only one nonsynonymous polymorphism was detected in pvmsp-1-19, while 44 nonsynonymous polymorphisms were detected in pvdbpII, 56 in pvrbp1a-2 and 33 in pvama1. While haplotypes appeared to be more related within each area of study and there was less relationship between parasites of the coastal and Amazon regions of the country, diversification processes were observed in the two Amazon regions. The highest haplotypic diversity for most genes occurred in the East Amazon of the country. The high diversity observed in Ecuadorian samples is closer to Brazilian and Venezuelan isolates, but lower than reported in other endemic regions. In addition, departure from neutrality was observed in Ecuadorian pvama1. Polymorphisms for pvdbpII and pvama1 were associated to B-cell epitopes. CONCLUSIONS: pvdbpII and pvama1 genetic diversity found in Ecuadorian P. vivax was very similar to that encountered in other malaria endemic countries with varying transmission levels and segregated by geographic region. The highest diversity of P. vivax invasion genes in Ecuador was found in the Amazonian region. Although selection appeared to have small effect on pvdbpII and pvrbp1a-2, pvama1 was influenced by significant balancing selection.

Comorbidities & burden of disease in atopic dermatitis.

BACKGROUND: Atopic dermatitis is associated with an increased frequency of other atopic & allergic manifestations, including asthma in 10% to 30% of cases depending on age, allergic rhinitis, food allergies, eosinophilic diseases, and allergic conjunctivitis. The comorbidities outside the atopic march are overall less frequent than in psoriasis. OBJECTIVE: This review aims to demonstrate the intense, broad burden of this disease, comorbidities and its multidimensional involvement as a complex, heterogeneous disease. METHODS: Methods: The present narrative review summarizes the findings from the world's largest epidemiological studies and smaller, AD-specific studies on the comorbidities and burdens of this disease. RESULTS: Results: The risk of asthma, specifically, and other atopic manifestations and skin infections, generally, is clearly increased among patients with AD. Of the other skin diseases, there is an undeniable risk of alopecia areata, vitiligo, and contact eczema and a lower risk of developing other autoimmune diseases. While comorbidities exist, their frequency seems to be modified by lifestyle, particularly by smoking. There is a link with overweight, obesity, and metabolic syndrome, especially in severe AD. This is also the case for cardiovascular diseases; however, with OR/HRs below 1.5. There is no link to type II diabetes but, rather, to type I in children. In all other areas, the data are often inconsistent, and any increase in risk is low. Eye diseases seem to be the only exception. AD also has psychiatric consequences, including attention-hyperactivity disorder, anxiety, depression, and sometimes suicidality, especially when severe. CONCLUSIONS: Conclusions: The recently published work largely confirms our existing understanding of AD.

Microbiologically influenced corrosion on naval carbon steel inside the hull of tugboats: a case study of prevention and control.

Microbiologically influenced corrosion (MIC) has a significant cost to many industries, including naval engineering. In this case-of-study, three tugboats developed pitting corrosion in the carbon steel of the inner hulls. Grade A naval steel was used for the hull sheets but the inner side (corroded) showed only two protective layers of paint. The maintenance employed seawater, which ended up in the bilge and made MIC possible. Bilge's waters were submitted to physicochemical, biological and molecular tests. DNA analyses confirmed the presence of Pseudomonas spp. and Desulfovibrio spp. in water samples and, consequently, a MIC mechanism was proposed to explain the corrosion process. In addition, a biocide treatment was evaluated and a new maintenance protocol was recommended. This work highlights the importance of the engineering design to prevent MIC in marine transports and provides some guidelines to treat it.

Manejo higiénico de los alimentos y enfermedades de transmisión alimentaria / Hygienic handling of food and foodborne diseases

Las enfermedades transmitidas por alimentos (ETA) constituyen un importante problema de salud pública debido a su alta incidencia a nivel mundial, las directrices para la higiene de los alimentos deben ser aplicadas, no solo por la población en general, sino también por los servicios médicos y sistemas hospitalarios. Por tal razón, esta investigación tiene como objetivo conocer las condiciones de higiene de los alimentos y determinar enfermedades de transmisión alimentaria en una clínica de especialidades médicas en la ciudad de Ambato, Ecuador. La investigación fue observacional, descriptivo, de corte transversal, con una muestra de 117 personas de tres turnos de trabajo, a quienes se le aplicó un cuestionario de higiene alimentaria compuesto por 24 ítems distribuido en cinco (5) categorías, el análisis de los datos fue mediante la estadística descriptiva, aplicando el cálculo porcentual y análisis de distribución de frecuencias. Como resultado se evindeció mayor existencia de protocolo/norma para el lavado de manos (76,65%) y menor para la prohibición de uso de joyas y accesorios (29,91%), a pesar de esto, el cumplimiento de protocolo fue 100,00% en equipo de protección personal, prohibición de uso de joyas y accesorios, uso de uñas cortas, limpias y sin esmalte, accidentes cortopunzantes y manejo higiénico de personal con enfermedades dermatológicas, respiratorias y diarreicas. Por otra parte, se encontró un (1) caso de una intoxicación alimentaria causada por una cepa de la bacteria Scherichia coli enterotoxigénica (ETEC) sin identificación de nexo epidemiológico. Concluyendo, la higiene correcta de alimentos podría evitar la propagación de múltiplies enfermedades(AU)

Foodborne illnessare a major public health problem due to their high incidence worldwide, the guidelines for food hygiene must be applied, not only by the general population, but also by medical services and hospital systems. For this reason, this research aims to know the hygiene conditions of food and determine foodborne illness in a medical specialty clinic in the city of Ambato, Ecuador. The research was observational, descriptive, cross-sectional, with a sample of 117 people from three work shifts, to whom a food hygiene questionnaire composed of 24 items distributed in five (5) categories was applied, the data analysis was through descriptive statistics, applying the percentage calculation and frequency distribution analysis. As a result, there was a greater existence of protocol/norm for hand washing (76.65%) and less for the prohibition of the use of jewelry and accessories (29.91%), despite this, compliance with the protocol was 100.00% in personal protection equipment, prohibition of the use of jewelry and accessories, use of short, clean nails without polish, sharps accidents and hygienic handling of personal with dermatological, respiratory and diarrheal diseases. On the other hand, one (1) case of food poisoning caused by a strain of enterotoxigenic Scherichia coli (ETEC) bacteria without identification of an epidemiological link was found. In conclusion, correct food hygiene could prevent the spread of multiple diseases(AU)

Estrategia de intervención sobre educación sexual en estudiantes universitarios / Intervention strategy on sexual education in university students

Las estrategias preventivas para la salud sexual y reproductiva se han convertido en una prioridad de salud pública, gran cantidad de jóvenes tienen comportamientos sexuales que comprometen su vida, de ahí que no solo los sistemas de salud deben dar respuesta a esta situación, sino también las distintas organizaciones comunitarias, que además de los problemas de salud que pueden derivarse de esas conductas inadecuadas, se encarecen considerablemente los costos de la atención sanitaria. Luego de la intervención, en todos los ítems explorados se obtuvo mayor puntuación en el grupo de estudio que en el grupo control, con significancia estadística p<0,005. Asimismo, el grupo de estudio, después de la intervención mejoró significativamente sus puntajes de media (calificación general: 131,7; IC 95%: 128,9-134,5), p<0,001. Se demostró asociaciones positivas entre recibir educación sexual y la mejor comprensión de varios comportamientos de riesgo sexual, conocimiento, motivación y habilidades, otorgándoles a los jóvenes información para que tomen de manera responsables decisiones acerca de su vida sexual(AU)

Preventive strategies for sexual and reproductive health have become a public health priority, a large number of young people have sexual behaviors that compromise their lives, hence not only health systems must respond to this situation, but also different community organizations, which in addition to the health problems that may arise from these inappropriate behaviors, considerably increase the cost of health care. After the intervention, in all the items explored, a higher score was obtained in the study group than in the control group, with statistical significance p<0.005. Likewise, the study group, after the intervention, significantly improved their mean scores (general score: 131.7; 95% CI: 128.9-134.5), p<0.001. Positive associations were shown between receiving sex education and better understanding of various sexual risk behaviors, knowledge, motivation and skills, giving young people information to make responsible decisions about their sexual lives(AU)

Carinacuma umesi, a new genus and species of bodotriid cumacean (Crustacea: Malacostraca: Peracarida) from shallow waters of the Maryland Coastal Bays, Mid-Atlantic region, USA.

Carinacuma, a new bodotriid cumacean genus, is diagnosed to receive Spilocuma watlingi Omholt & Heard as its type species and C. umesi sp. nov., described from shallow waters (0.8 to 2.8 m) on the Mid-Atlantic coast of North America. Carinacuma gen. nov. has its closest affinities to the North American genera Spilocuma and Mancocuma, but can be distinguished from them and the other genera within the subfamily Vaunthompsoniinae by a combination of characters, including the presence of a dorsal carina or keel on pereonite 3 of the female, morphology of the antenna, absence of pleopods in the male, and the setation and segmentation of the uropods. Carinacuma umesi sp. nov., can be differentiated from its northern Gulf of Mexico cognate, C. watlingi comb. nov. by several characters, including: (1) maxilliped 3 carpus of female with inner margin bearing four to five simple setae, (2) uropod peduncle of female with inner margin bearing one sub-distal micro-serrate seta with single sub-terminal medial setule, (3) male antennule peduncle articles 1-2 sub-equal length, and (4) male antennule accessory flagellum slightly longer than basal article of main flagellum. A key to the five known males lacking pleopods within Vaunthompsoniinae is provided.

Seasonal changes dominate long-term variability of the urban air microbiome across space and time.

Compared to soil or aquatic ecosystems, the atmosphere is still an underexplored environment for microbial diversity. In this study, we surveyed the composition, variability and sources of microbes (bacteria and fungi) in the near surface atmosphere of a highly populated area, spanning ~ 4,000 Km2 around the city center of Madrid (Spain), in different seasonal periods along two years. We found a core of abundant bacterial genera robust across space and time, most of soil origin, while fungi were more sensitive to environmental conditions. Microbial communities showed clear seasonal patterns driven by variability of environmental factors, mainly temperature and accumulated rain, while local sources played a minor role. We also identified taxa in both groups characteristic of seasonal periods, but not of specific sampling sites or plant coverage. The present study suggests that the near surface atmosphere of urban environments contains an ecosystem stable across relatively large spatial and temporal scales, with a rather homogenous composition, modulated by climatic variations. As such, it contributes to our understanding of the long-term changes associated to the human exposome in the air of highly populated areas.

Assessment and statistical modelling of airborne microorganisms in Madrid.

The limited evidence available suggests that the interaction between chemical pollutants and biological particles may intensify respiratory diseases caused by air pollution in urban areas. Unlike air pollutants, which are routinely measured, records of biotic component are scarce. While pollen concentrations are daily surveyed in most cities, data related to airborne bacteria or fungi are not usually available. This work presents the first effort to understand atmospheric pollution integrating both biotic and abiotic agents, trying to identify relationships among the Proteobacteria, Actinobacteria and Ascomycota phyla with palynological, meteorological and air quality variables using all biological historical records available in the Madrid Greater Region. The tools employed involve statistical hypothesis contrast tests such as Kruskal-Wallis and machine learning algorithms. A cluster analysis was performed to analyse which abiotic variables were able to separate the biotic variables into groups. Significant relationships were found for temperature and relative humidity. In addition, the relative abundance of the biological phyla studied was affected by PM10 and O3 ambient concentration. Preliminary Generalized Additive Models (GAMs) to predict the biotic relative abundances based on these atmospheric variables were developed. The results (r = 0.70) were acceptable taking into account the scarcity of the available data. These models can be used as an indication of the biotic composition when no measurements are available. They are also a good starting point to continue working in the development of more accurate models and to investigate causal relationships.

[Lung cancer diagnosed by transesophageal ecoendoscopy and fine needle aspiration biopsy]. / Cáncer de pulmón diagnosticado mediante ecoendoscopía transesofágica y biopsia por punción con aguja fina.

Lung cancer is one of the leading causes of death worldwide. Pulmonary nodules located in the vicinity of the mediastinum, retrocardiac, near the aorta or pulmonary vessels, and in front of the spine, may be difficult to access through a percutaneous or bronchoscopic approach. Fine needle aspiration/biopsy guided by transesophageal echoendoscopy (EUS-FNA/FNB) is a minimally invasive method with low morbidity that could allow access to lesions in these places. We present the case of a patient with a solitary pulmonary nodule, in which the diagnosis of lung cancer was obtained by EUS-FNA/FNB.

El cáncer de pulmón es la principal causa de muerte por cáncer en todo el mundo. Los nódulos pulmonares ubicados en proximidad al mediastino, retrocardíacos, cercanos a grandes vasos o por delante de la columna vertebral pueden resultar de difícil acceso por vía percutánea o broncoscópica. La punción aspiración/biopsia con aguja fina guiada por ecoendoscopía transesofágica (EUS-FNA/FNB) es un método mini invasivo con baja morbilidad que permitiría acceder a estas localizaciones. Presentamos el caso de un paciente con nódulo pulmonar solitario, en el que se obtuvo el diagnóstico de cáncer de pulmón mediante EUS-FNA/FNB.

Cáncer de pulmón diagnosticado mediante ecoendoscopia transesofágica y biopsia por punción con aguja fina / Lung cancer diagnosed by transesophageal ecoendoscopy and fine needle aspiration biopsy

El cáncer de pulmón es la principal causa de muerte por cáncer en todo el mundo. Los nódulos pulmonares ubicados en proximidad al mediastino, retrocardíacos, cercanos a grandes vasos o por delante de la columna vertebral pueden resultar de difícil acceso por vía percutánea o broncoscópica. La punción aspiración/biopsia con aguja fina guiada por ecoendoscopía transesofágica (EUS-FNA/FNB) es un método mini invasivo con baja morbilidad que permitiría acceder a estas localizaciones. Presentamos el caso de un paciente con nódulo pulmonar solitario, en el que se obtuvo el diagnóstico de cáncer de pulmón mediante EUS-FNA/FNB.

Lung cancer is one of the leading causes of death worldwide. Pulmonary nodules located in the vicinity of the mediastinum, retrocardiac, near the aorta or pulmonary vessels, and in front of the spine, may be difficult to access through a percutaneous or bronchoscopic approach. Fine needle aspiration/biopsy guided by transesophageal echoendoscopy (EUS-FNA/FNB) is a minimally invasive method with low morbidity that could allow access to lesions in these places. We present the case of a patient with a solitary pulmonary nodule, in which the diagnosis of lung cancer was obtained by EUS-FNA/FNB.

The Differential Vertical Distribution of the Airborne Biological Particles Reveals an Atmospheric Reservoir of Microbial Pathogens and Aeroallergens.

The most abundant biological particles present in the air are bacteria, fungal propagules and pollen grains. Many of them are proved allergens or even responsible for airborne infectious diseases, which supports the increase of studies in recent years on their composition, diversity, and factors involved in their variability. However, most studies in urban areas are conducted close to ground level and a factor such as height is rarely taken into account. Thus, the information about how the composition of biological particles changes with this variable is scarce. Here, we examined the differential distribution of bacteria, fungi, and plants at four altitudes (up to ∼ 250 m) in a metropolitan area using high-throughput DNA sequencing. Most taxa were present at all levels (common taxa). However, a transitional layer between 80 and 150 m seemed to affect the scattering of these bioaerosols. Taxa not present at all altitudes (non-common) showed an upward tendency of diversity for bacteria and plants with height, while the opposite trend was observed for fungi. Certain patterns were observed for fungi and specific plant genera, while bacterial taxa showed a more arbitrary distribution and no patterns were found. We detected a wide variety of aeroallergens and potential pathogens at all heights, which summed a substantial portion of the total abundance for fungi and plants. We also identified potential connections between the biological particles based on their abundances across the vertical section.

Two new apseudomorphan species (Crustacea: Tanaidacea: Metapseudidae) from Mo'orea Island (Society Islands, French Polynesia) with taxonomic keys.

Previous information on the taxonomy and distribution of the crustacean order Tanaidacea occurring within the widely-dispersed Polynesian Archipelago has been limited to four nominal species, Apseudes rikiteanus Nobili, Apseudes seurati Nobili, Zeuxo seurati (Nobili) and Tanzanapseudes polynesiensis Müller. Based on specimens collected between 2009 and 2011 from coastal waters of Mo'orea Island (Society Islands, French Polynesia), two new metapseudid tanaidaceans, Apseudomorpha drummi and Cryptapseudes mamua, are described. Keys to the identification of species currently placed within the genera Apseudomorpha Gutu and Cryptapseudes Bacescu are provided.

Tanaella quintanai, a new deep-water tanaellid (Crustacea: Peracarida: Tanaidacea) from the Colombian Caribbean Coast, with a key to the species of the genus Tanaella Norman & Stebbing, 1886.

A new tanaidacean, Tanaella quintanai sp. nov., is described based on specimens collected from depths of 1,598 to 2,853 m during 2014-2015. The new species appears to be most closely related to the western Atlantic species, T. kroyeri and T. mclellandi. Tanaella quintanai can be separated from the two former, as well as from the other members of the genus by a combination of characters, including (1) a labium with apical lobe bearing one blunt seta (2) a cheliped with the inner margin of the dactylus bearing a sub-proximal bipinnate seta, (3) pereopods 1-3 with basis having sub-dorsoproximal and sub-ventroproximal margins setulose, (4) pereopods 4-6 with basis having ventroproximal margin setulose, (5) pereopods 4-6 with unguis bearing two parallel rows of small setules, and (6) a pleotelson as long as pleonites 1-5 combined. A key separating the currently recognized species of Tanaella is presented.

Comprehensive analysis of different adhesives in aerobiological sampling using optical microscopy and high-throughput DNA sequencing.

The standardization and unification of the procedures to analyze and quantify the airborne pollen concentrations are very important topics. In this work, the effectiveness of the two most used adhesives in aerobiological sampling, silicone prepared with cyclohexane solvent (Silicone) and petroleum jelly (Vaseline), was compared under outdoor conditions. This comparison was carried out using the traditional method based on the identification and quantification by optical microscopy (OM) of the airborne pollen and the novel methodology by high-throughput sequencing analysis (HTS). Globally, the results from both methods of analysis (OM and HTS) showed a good agreement between the two adhesives tested regarding the abundance of the main pollen types present in the samples: Cupressaceae, Olea, Poaceae, Platanus, Quercus. We concluded that the results from both adhesives are comparable data. Furthermore, the comparisons between methodologies, OM vs. HTS, showed that both techniques can accurately identify the most abundant pollen types in the atmosphere for the studied periods, with a good agreement of their relative abundances especially when the airborne pollen diversity is low but showing some divergences as the number of pollen types increases.

Characterization of Soybean yellow shoot virus, a New Member of the Family Potyviridae Infecting Soybean Plants in Brazil.

A new virus species, belonging to the family Potyviridae and capable of infecting most of the soybean cultivars grown in Brazil, was collected in Lavras, Minas Gerais, Brazil, and named Soybean yellow shoot virus (SoyYSV). In this study, the complete 9,052-nucleotide genome of SoyYSV was determined and the structural, biological, and molecular properties of the virus were investigated. The SoyYSV genome encoded a single polyprotein that could be subsequently cleaved, generating 11 proteins. The SoyYSV genome shared 49% nucleotide and 36% amino acid sequence identity with Blackberry virus Y. However, the P1 protein of SoyYSV was much smaller and lacked the ALK1 domain characteristic of the genus Brambyvirus. Electron microscopy revealed flexuous filamentous virus particles, 760 to 780 nm in length, and cytoplasmic inclusions typical of those found in plant cells infected with Potyviridae species. In addition to soybean, SoyYSV infected species in the Amaranthaceae, Caricaceae, Fabaceae, and Solanaceae families. Among the most common potyviruses present in Brazil, only SoyYSV induced local necrotic lesions in Carica papaya L. SoyYSV was transmissible by Myzus persicae and Aphis gossypii but lacked the HC-Pro domain required for aphid transmission in other potyviruses. No seed transmission in soybean was observed.

Preventing legionellosis outbreaks by a quick detection of airborne Legionella pneumophila.

Legionellosis is a severe pneumonic infection caused by inhaling bacteria of the genus Legionella. Most cases reported in the USA and Europe are associated with the species Legionella pneumophila. This Gram-negative bacterium can survive within a wide spectrum of temperatures, and be transmitted via aerosols from multiple aquatic sources: fountains, thermal spas and other water systems. Although the PCR is one of the most popular methods to verify its presence in environmental or clinical samples, the direct application of this technique to ambient air samples is unusual because of the scarce material in the specimens. Here, we have developed a two-PCR assay, carried out over the V3 and V5 hypervariable regions of the 16S rRNA gene, to detect specifically the pathogenic bacteria Legionella pneumophila in outdoor air samples with low concentration of DNA. The application of this protocol does not require culture and retrieves quick results to activate the corresponding public alerts to prevent legionellosis outbreaks.

Artemisia pollen is the main vector for airborne endotoxin.

BACKGROUND: Endotoxin (LPS) released from gram-negative bacteria causes strong immunologic and inflammatory effects and, when airborne, can contribute to respiratory conditions, such as allergic asthma. OBJECTIVES: We sought to identify the source of airborne endotoxin and the effect of this endotoxin on allergic sensitization. METHODS: We determined LPS levels in outdoor air on a daily basis for 4 consecutive years in Munich (Germany) and Davos (Switzerland). Air was sampled as particulate matter (PM) greater than 10 µm (PM > 10) and PM between 2.5 and 10 µm. LPS levels were determined by using the recombinant Factor C assay. RESULTS: More than 60% of the annual endotoxin exposure was detected in the PM > 10 fraction, showing that bacteria do not aerosolize as independent units or aggregates but adhered to large particles. In Munich 70% of annual exposure was detected between June 12th and August 28th. Multivariate modeling showed that endotoxin levels could be explained by phenological parameters (ie, plant growth). Indeed, days with high airborne endotoxin levels correlated well with the amount of Artemisia pollen in the air. Pollen collected from plants across Europe (100 locations) showed that the highest levels of endotoxin were detected on Artemisia vulgaris (mugwort) pollen, with little on other pollen. Microbiome analysis showed that LPS concentrations on mugwort pollen were related to the presence of Pseudomonas species and Pantoea species communities. In a mouse model of allergic disease, the presence of LPS on mugwort pollen was needed for allergic sensitization. CONCLUSIONS: The majority of airborne endotoxin stems from bacteria dispersed with pollen of only one plant: mugwort. This LPS was essential for inducing inflammation of the lung and allergic sensitization.

A New Putative Caulimoviridae Genus Discovered through Air Metagenomics.

Members of the Caulimoviridae family are important plant pathogens. These circular double-stranded DNA viruses may integrate into the host genome, although this integration is not required for the viral replication cycle. Here, we describe three complete genomes belonging to a new putative Caulimoviridae genus discovered through air metagenomics.