Microbial diversity and abundance of Hg related genes from water, sediment and soil the Colombian amazon ecosystems impacted by artisanal and small-scale gold mining.

The Amazon region abounds in precious mineral resources including gold, copper, iron, and coltan. Artisanal and small-scale gold mining (ASGM) poses a severe risk in this area due to considerable mercury release into the surrounding ecosystems. Nonetheless, the impact of mercury on both the overall microbiota and the microbial populations involved in mercury transformation is not well understood. In this study we evaluated microbial diversity in samples of soil, sediment and water potentially associated with mercury contamination in two localities (Taraira and Tarapacá) in the Colombian Amazon Forest. To this end, we characterized the bacterial community structure and mercury-related functions in samples from sites with a chronic history of mercury contamination which today have different levels of total mercury content. We also determined mercury bioavailability and mobility in the samples with the highest THg and MeHg levels (up to 43.34 and 0.049 mg kg-1, respectively, in Taraira). Our analysis of mercury speciation showed that the immobile form of mercury predominated in soils and sediments, probably rendering it unavailable to microorganisms. Despite its long-term presence, mercury did not appear to alter the microbial community structure or composition, which was primarily shaped by environmental and physicochemical factors. However, an increase in the relative abundance of merA genes was detected in polluted sediments from Taraira. Several Hg-responsive taxa in soil and sediments were detected in sites with high levels of THg, including members of the Proteobacteria, Acidobacteria, Actinobacteria, Firmicutes and Chloroflexi phyla. The results suggest that mercury contamination at the two locations sampled may select mercury-adapted bacteria carrying the merA gene that could be used in bioremediation processes for the region.

Building a genome-based understanding of bacterial pH preferences.

The environmental preferences of many microbes remain undetermined. This is the case for bacterial pH preferences, which can be difficult to predict a priori despite the importance of pH as a factor structuring bacterial communities in many systems. We compiled data on bacterial distributions from five datasets spanning pH gradients in soil and freshwater systems (1470 samples), quantified the pH preferences of bacterial taxa across these datasets, and compiled genomic data from representative bacterial taxa. While taxonomic and phylogenetic information were generally poor predictors of bacterial pH preferences, we identified genes consistently associated with pH preference across environments. We then developed and validated a machine learning model to estimate bacterial pH preferences from genomic information alone, a model that could aid in the selection of microbial inoculants, improve species distribution models, or help design effective cultivation strategies. More generally, we demonstrate the value of combining biogeographic and genomic data to infer and predict the environmental preferences of diverse bacterial taxa.

Satisfacción laboral de los académicos de la licenciatura de cirujano dentista de la Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México / ob satisfaction of the dental surgeon academics from the Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México

Objetivo : Conocer la satisfacción laboral en los académicos de la licenciatura de Cirujano Dentista del Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México en el período 2019. Material y métodos : Estudio observacional, prolectivo, transversal, descriptivo. La población de estudio estuvo conformada por 123 académicos, a los que se les aplicó un cuestionario de 20 ítems con respuestas en escala Likert (α de Cronbach 0.845). Resultados : Del total de encuestados, el 45% (55) del sexo masculino, 55% (68) del femenino, con una media de edad de 36.5 (± 9.6) años. El 48% (59) de los académicos se encuentran satisfechos con el trabajo docente que realizan, en contraste, el 25% (31) está muy insatisfechos. Entre los factores que influyen en la insatisfacción se encontró: La carga horaria, sobre todo los que tienen en turno mixto, el poco apoyo que la institución da para estudiar un posgrado, el estrés que conlleva la responsabilidad de supervisar a los estudiantes en el área clínica en la atención a pacientes. La insatisfacción se presenta en mayor proporción en académicos con una edad ≥ 50 años. Conclusiones : Los factores referidos que influyen en la insatisfacción son: el bajo salario, las inadecuadas instalaciones para impartir clase, la falta de apoyo para la capacitación por parte de la institución, el no reconocimiento al trabajo realizado. Llama la atención que, en la licenciatura de Cirujano Dentista donde el trabajo en equipo es de suma importancia, este no se dé o se dé muy pocas veces.

Objective : To know the job satisfaction in the Dental Surgeon academics from the Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, during 2019. Methods : Observational, prolective, cross-sectional, descriptive study. The study population consisted of 123 academics, to whom a 20-item questionnaire was applied with responses on the Likert scale (Cronbach's α 0.845). Results : Of the total number of respondents, 45% (55) were male, 55% (68) were female, with a mean age of 36.5 (± 9.6) years. 48% (59) of the academics are satisfied with the teaching work they do, in contrast, 25% (31) are very dissatisfied. Among the factors that influence dissatisfaction, the following was found: The workload, especially those who have a mixed shift, the little support that the institution gives to study a postgraduate course, the stress that comes with the responsibility of supervising students in the area clinic in patient care. Dissatisfaction occurs in a higher proportion in academics aged ≥ 50 years. Conclusions : The referred factors that influence dissatisfaction are: low salary, inadequate facilities to teach classes, lack of support for training by the institution, non-recognition of the work done. It is striking that, in the Dental Surgeon degree where teamwork is of the utmost importance, this does not occur or occurs very rarely.

Dinámica funcional de la comunidad bacteriana del lodo activado de una planta de tratamiento de agua residual y su relación con variables ambientales y de operación / Funcional dynamics of the bacterial community from activated sludge wastewater treatment plant and its relationship with environmental and operational variables

RESUMEN El proceso de lodos activados es comúnmente utilizado en plantas de tratamiento de aguas residuales (PTAR) para reducir la concentración de materia orgánica disuelta que llega en el afluente. A pesar de los avances en el estudio de las comunidades microbianas de los lodos activados, falta mucho para entender su potencial funcional y su variabilidad ante las fluctuaciones temporales del afluente y los cambios en la operación de las PTAR. En consecuencia, en este trabajo se analizó la variación del potencial metabólico de la comunidad bacteriana del lodo activado a lo largo de un ciclo anual y se relacionó esa dinámica con variables ambientales y operacionales de una PTAR con alcantarillado combinado. La predicción del metagenoma de la comunidad bacteriana se realizó con PICRUSt2. Esta aproximación permitió evidenciar el fenómeno de redundancia funcional en la comunidad. También, se logró analizar la fluctuación temporal de los genes asociados a procesos relacionados con los ciclos del nitrógeno y azufre y su relación con variables ambientales y operacionales de la PTAR. Se encontró que dichos procesos están relacionados diferencialmente con la precipitación y los cambios en la edad de lodo observados para el periodo estudiado. Estos resultados contribuyen al entendimiento de las dinámicas de la comunidad bacteriana con relación al funcionamiento de este tipo de sistemas biotecnológicos.

ABSTRACT Activated sludge process is commonly used in wastewater treatment plants (WWTP) where a microbial community removes the organic matter from the influent. Despite the advances in the study of this community, there is still a gap of knowledge about its functional potential and its variability due to temporary fluctuations of the influent and the WWTP operation. Therefore, this work analyzed the metabolic potential variation of the activated sludge bacterial community throughout an annual cycle. Furthermore, the dynamics of the bacterial community was related to environmental and operating variables of a WWTP with combined sewerage. The metagenome prediction of the bacterial community was carried out with PICRUSt2. This approach allowed to demonstrate the phenomenon of functional redundancy in the community. Moreover, the temporal fluctuation of genes associated with the nitrogen and sulfur cycles and their relationship with environmental and the operating variables of the WWTP were analyzed. It was found that those processes were differentially related to precipitation events and variations in the sludge age observed during the studied period. These results contribute to the understanding of the bacterial community dynamics in relation to the functioning of this type of biotechnological systems.

A georeferenced rRNA amplicon database of aquatic microbiomes from South America.

The biogeography of bacterial communities is a key topic in Microbial Ecology. Regarding continental water, most studies are carried out in the northern hemisphere, leaving a gap on microorganism's diversity patterns on a global scale. South America harbours approximately one third of the world's total freshwater resources, and is one of these understudied regions. To fill this gap, we compiled 16S rRNA amplicon sequencing data of microbial communities across South America continental water ecosystems, presenting the first database µSudAqua[db]. The database contains over 866 georeferenced samples from 9 different ecoregions with contextual environmental information. For its integration and validation we constructed a curated database (µSudAqua[db.sp]) using samples sequenced by Illumina MiSeq platform with commonly used prokaryote universal primers. This comprised ~60% of the total georeferenced samples of the µSudAqua[db]. This compilation was carried out in the scope of the µSudAqua collaborative network and represents one of the most complete databases of continental water microbial communities from South America.

Síndrome de Guillain-Barré postinfección por SARS-CoV-2 y postvacunación contra covid-19: una revisión sistemática de casos / Guillain-Barré syndrome post-SARS-CoV-2 infection and post-vaccination against COVID-19: a systematic review of cases

RESUMEN INTRODUCCIÓN: El síndrome de Guillain-Barré (SGB) se ha asociado recientemente con la infección por SARS-CoV-2 y su vacunación. El objetivo de esta revisión es describir los datos sociodemográficos y la presentación clínica del SGB asociado con la infección y la vacunación contra covid--19. MATERIALES Y MÉTODOS: Se realizó una búsqueda sistemática en las bases de datos Medline, Embase y LILACS. Se incluyeron reportes de casos publicados entre los años 2021 y 2022. De los artículos seleccionados se extrajo edad, sexo, comorbilidades, laboratorio de la vacuna, tiempo de inicio de síntomas, manifestaciones clínicas, método diagnóstico, tratamiento recibido y desenlace. RESULTADOS: Se seleccionaron 93 artículos, en los que se reporta un total de 131 casos: 82 asociados con la infección por SARS-CoV-2 y 49 asociados con la vacunación contra el covid-19. La población más afectada fue el sexo masculino y se encontró entre los 31 y los 65 años. Las principales manifestaciones descritas fueron: paresia de extremidades, compromiso de la sensibilidad, arreflexia, compromiso de los pares craneales. DISCUSIÓN: El cuadro clínico del SGB presentó características similares a la presentación clásica. La disautonomía y la falla respiratoria son las principales complicaciones mortales de esta entidad. CONCLUSIÓN: El SGB se puede presentar de manera postinfecciosa o parainfecciosa. Se debe sospechar cuando se consulta por cuadro clínico de neuropatía desmielinizante con antecedentes de inmunización o síntomas concomitantes sugestivos de covid-19. Se necesitan más estudios para establecer una asociación entre el virus y el SGB.

ABSTRACT INTRODUCTION: Guillain-Barre syndrome (GBS) has recently been associated with SARS-CoV-2 infection and vaccination. The objective of this review is to describe the sociodemographic data and the clinical presentation of GBS associated with infection and vaccination against COVID-19. MATERIALS AND METHODS: A systematic search was performed in the Medline, Embase and LILACS databases. Case reports published in 2021-2022 are included. From the selected articles, age, sex, comorbidi-ties, vaccine brand, symptom onset time, clinical manifestations, diagnostic method, treatment received and outcome were extracted. RESULTS: 93 articles were selected, reporting a total of 131 cases: 82 associated with SARS-CoV-2 infection and 49 associated with vaccination against COVID-19. The most affected population was the male sex and was between 31 and 65 years old. The main manifestations described were: limb paresis, compromised sensitivity, areflexia, compromised cranial nerves. DISCUSSION: The clinical picture of GBS presented characteristics similar to the classic presentation. Dys-autonomia and respiratory failure are the main fatal complications of this entity. CONCLUSION: GBS can present in a postinfectious, parainfectious manner. It should be suspected when consulting for a clinical picture of demyelinating neuropathy with a history of immunization or concomitant symptoms suggestive of COVID-19. More studies are needed to establish an association between the virus and GBS.

Bacteremia after Bacillus clausii administration for the treatment of acute diarrhea: A case report. / Bacteriemia tras la administración de Bacillus clausii para el tratamiento de la diarrea aguda: reporte de un caso

Bacillus clausii is a gram-positive rod used as a probiotic to treat diarrhea and the side effects of antibiotics such as pseudomembranous colitis. We report a case of B. clausii bacteremia in a non-immunocompromised patient with active peptic ulcer disease and acute diarrhea. The probiotic was administered during the patient´s hospitalization due to diarrhea of infectious origin. B. clausii was identified in the bloodstream of the patient through Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) days after her discharge. Given the wide use of probiotics, we alert clinicians to consider this microorganism as a causative agent when signs of systemic infection, metabolic compromise, and hemodynamic instability establish after its administration and no pathogens have been identified that could explain the clinical course.

Bacillus clausii es un bacilo grampositivo que se utiliza como probiótico para tratar la diarrea y los efectos secundarios de los antibióticos como la colitis pseudomembranosa. Presentamos un caso de bacteriemia por B. clausii en un paciente no inmunodeprimido con enfermedad ulcerosa péptica activa y diarrea aguda. El probiótico se administró durante la hospitalización del paciente por diarrea de origen infeccioso. B. clausii se identificó en el torrente sanguíneo de la paciente a través del tiempo de vuelo por ionización por desorción láser asistida por matriz (MALDI-TOF) días después de su alta. Dado el amplio uso de probióticos, alertamos a los médicos para que consideren este microorganismo como agente causal cuando se establezcan signos de infección sistémica, compromiso metabólico e inestabilidad hemodinámica después de su administración y no se hayan identificado patógenos que puedan explicar el curso clínico.

Bacteremia after Bacillus clausii administration for the treatment of acute diarrhea: A case report / Bacteriemia tras la administración de Bacillus clausii para el tratamiento de la diarrea aguda: reporte de un caso

Abstract | Bacillus clausii is a gram-positive rod used as a probiotic to treat diarrhea and the side effects of antibiotics such as pseudomembranous colitis. We report a case of B. clausii bacteremia in a non-immunocompromised patient with active peptic ulcer disease and acute diarrhea. The probiotic was administered during the patient's hospitalization due to diarrhea of infectious origin. B. clausii was identified in the bloodstream of the patient through Matrix- Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) days after her discharge. Given the wide use of probiotics, we alert clinicians to consider this microorganism as a causative agent when signs of systemic infection, metabolic compromise, and hemodynamic instability establish after its administration and no pathogens have been identified that could explain the clinical course.

Resumen | Bacillus clausii es un bacilo Gram positivo usado como probiótico para tratar la diarrea y efectos adversos de los antibióticos, como la colitis pseudomembranosa. Se reporta un caso de bacteriemia por B. clausii en una paciente inmunocompetente con enfermedad ulcerosa péptica activa y diarrea aguda. El probiótico le fue administrado durante la hospitalización debido al origen infeccioso de la diarrea. B. clausii se identificó en el torrente sanguíneo de la paciente, utilizando espectrometría de desorción/ionización mediante láser asistido por matriz (Matrix-Assisted Laser Desorption/Ionization, MALDI), acoplada a un detector de iones (Time of Flight, TOF) (MALDI-TOF), días después de haber sido dada de alta. Dado el amplio uso de los probióticos, alertamos a los clínicos para que consideren este microorganismo como agente causal cuando se detecten signos de infección sistémica, compromiso metabólico, e inestabilidad hemodinámica tras su administración, y no se haya identificado ningún patógeno que pueda explicar el cuadro clínico.

Horizontal transmission of Piscirickettsia salmonis from the wild sub-Antarctic notothenioid fish Eleginops maclovinus to rainbow trout (Oncorhynchus mykiss) under experimental conditions.

Piscirickettsia salmonis is the aetiological agent of piscirickettsiosis, a bacterial disease that affects farmed salmonids, causing high mortalities and significant economic losses in the Chilean salmon farm industry. Given the Chilean native fish species Patagonian blenny, Eleginops maclovinus, lives in the vicinity of salmon farms, it is relevant to clarify the epidemiological role that this species could play in the transmission and/or dissemination of this pathogen. This study aimed to evaluate the bidirectional transmission of P. salmonis between the Patagonian blenny and Oncorhynchus mykiss (rainbow trout), via a cohabitation challenge model. The results of this study demonstrated the transmission of the bacteria from Patagonian blennies to rainbow trout, considering the specific mortality in cohabitant rainbow trout, reaching 46%: the necropsy of these specimens, evidencing the characteristic pathological lesions of the disease and the positive results of the qPCR analysis for P. salmonis, in the same individuals. In contrast, no mortalities of Patagonian blenny specimens were recorded in the challenged experimental groups. This study is the first report showing the horizontal transmission of P. salmonis from a native non-salmonid species, such as the Patagonian blenny, to a salmonid species, generating the disease and specific mortality in rainbow trout, using a cohabitation challenge.

Fractura avulsion bilateral de tuberosidad anterior de la tibia / Bilateral anterior tibial tubercle fracture-avulsion

La fractura por avulsión de la tuberosidad tibial es una patología poco común. Es una lesión característica de la infancia, con afección directa a la fisis, que amerita un diagnóstico oportuno y un tratamiento óptimo a fin de evitar complicaciones en el crecimiento, la mayoría de ellas graves. Para este tipo de lesión la reducción abierta y fijación interna es el tratamiento de elección; sin embargo, el procedimiento quirúrgico es un riesgo agregado al daño de la lesión per se. Suelen tener una evolución satisfactoria con un adecuado tratamiento y rehabilitación. Tomando en cuenta la baja incidencia de esta patología, en el siguiente artículo reportamos el caso de un paciente de 14 años con avulsión de tuberosidad tibial bilateal tipo II de Watson-Jones y tipo III de Watson-Jones, el abordaje diagnóstico-terapéutico y el éxito obtenido a seis meses de seguimiento; asimismo, realizamos una revisión de la literatura

Globalización, inequidades sociales y financierización de la salud, debate a partir del caso Colombia / Globalization, social inequalities and financialization of health: debate on the Colombian case

Este artículo tiene el objetivo de exponer la esencia, las fuerzas y el motor capitalista de la globalización como fenómeno histórico, mostrando las esferas de su intervención y sus efectos sobre la vida humana en general. Luego, se adentra en la relación globalización-mercados financieros y se enlazan sus impactos con las inequidades sociales y su expresión en el caso del sector de la salud en Colombia. Se cuestiona el rol de las Empresas Promotoras de Salud en este país y se ilustra cómo se han convertido en grupos empresariales como palanca financiera de negocios impensables del orden nacional y trasnacional. Uno a uno se fueron configurando entramados irreconocibles y difíciles de auditar que, junto a la falta de voluntad política por una reforma estructural al sistema de salud y seguridad social en Colombia mantiene al país en un escenario complejo, aun cuando luego de muchas disputas sociales, se declarara en el año 2015 que la salud es un derecho humano fundamental(AU)

This article has the aim of presenting the essence and capitalist forces of globalization as a historical phenomenon by showing the scopes of its intervention and its effects on human life in general terms. The article deepens in the globalization- financial markets relation and how its impacts link with social inequalities and its expression in the case of the health sector in Colombia. It is questionned the role of Health Promotion companies in that country and it is showed how they have become bussiness groups with financial leverage of inconceivable bussinesses in the national and transnational fields. There was step by step a configuration of unrecognizable structures and hard to audit which along together to the lack of political will for an structural reformation fo the health and the social wellfare systems in Colombia make the country to remain in a complex scenario; even after many social disputes it was declared in 2015 that health care is a fundamental human right(AU)

Taxonomic differences shape the responses of freshwater aerobic anoxygenic phototrophic bacterial communities to light and predation.

Aerobic anoxygenic phototrophic (AAP) bacteria are a phylogenetically diverse and ubiquitous group of prokaryotes that use organic matter but can harvest light using bacteriochlorophyll a. Although the factors regulating AAP ecology have long been investigated through field surveys, the few available experimental studies have considered AAPs as a group, thus disregarding the potential differential responses between taxonomically distinct AAP assemblages. Here, we used sequencing of the pufM gene to describe the diversity of AAPs in 10 environmentally distinct temperate lakes, and to investigate the taxonomic responses of AAP communities in these lakes when subjected to similar experimental manipulations of light and predator removal. The studied communities were clearly dominated by Limnohabitans AAP but presented a clear taxonomic segregation between lakes presumably driven by local conditions, which was maintained after experimental manipulations. Predation reduction (but not light exposure) caused significant compositional shifts across most assemblages, but the magnitude of these changes could not be clearly related to changes in bulk AAP abundances or taxonomic richness of AAP assemblages during experiments. Only a few operational taxonomic units, which differed taxonomically between lakes, were found to respond positively during experimental treatments. Our results highlight that different freshwater AAP communities respond differently to similar control mechanisms, highlighting that in-depth knowledge on AAP diversity is essential to understand the ecology and potential role of these photoheterotrophs.

Influencia de la lengua dispar (tutunakú y español) en los mensajes e instrucciones que emite el personal de salud y la de las receptoras de la información / Influence of disparate language (Tutunakú and Spanish) in messages and instructions issued by health personnel and those receiving the information

Resumen OBJETIVO: Identificar la influencia de la lengua dispar (tutunakú y español) entre los mensajes e instrucciones que emite el personal de salud y la de las receptoras de esa información, en particular la dirigida a la práctica de la autoexploración con fines de prevención del cáncer de mama. MATERIALES Y MÉTODOS: Estudio descriptivo, transversal, efectuado en mujeres indígenas, mayores de 20 años, a quienes se aplicó un instrumento semiestructurado para la identificación de factores de riesgo y protección de cáncer de mama. Para determinar la asociación de las variables de hablantes de totonakú con el nivel de conocimiento, prevención y riesgo de cáncer de mama se utilizó la prueba de χ2. RESULTADOS: Se estudiaron 187 mujeres; de las que 109 (58.5%) solo hablaban tutunakú y 78 (41.5%) eran bilingües (tutunakú y español). La edad promedio de las participantes fue de 43.4 años (DE ± 14.8), con límites de 20 y 80 años. En relación con la escolaridad: 93 de 109 (85.5%) de las monolingües eran analfabetas y solo 44 de las 78 (57.1%) mujeres bilingües habían concluido la educación básica. Por lo que se refiere al conocimiento del cáncer de mama, las mujeres monolingües tuvieron menor nivel de conocimiento y menor práctica de la autoexploración; solo 34 de las 78 bilingües practicaban la autoexploración. CONCLUSIÓN: Si bien el riesgo de cáncer de mama no muestra asociación con el hecho de hablar una lengua sí lo tiene, directamente, con la escolaridad, con la capacidad necesaria para comprender instrucciones que permitan la práctica de la autoexploración.

Abstract OBJECTIVE: To identify the influence of the disparate language (tutunaku and Spanish) between the messages and instructions issued by health personnel and those of the recipients of this information, in particular that directed at the practice of self-examination for the purpose of breast cancer prevention. MATERIALS AND METHODS: Descriptive, cross-sectional study, carried out on indigenous women over 20 years of age, to whom a semi-structured instrument was applied for the identification of risk factors and protection from breast cancer. To determine the association of Totonaku speakers' variables with the level of knowledge, prevention and risk of breast cancer, the test of 2 was used. RESULTS: A total of 187 women were studied; 109 (58.5%) spoke only tutunaku and 78 (41.5%) were bilingual (tutunaku and Spanish). The average age of participants was 43.4 years (SD 14.8), with limits of 20 and 80 years. With regard to schooling: 93 of 109 (85.5%) of the monolingual women were illiterate and only 44 of 78 (57.1%) of the bilingual women had completed basic education. With regard to knowledge of breast cancer, monolingual women had a lower level of knowledge and less practice of self-examination; only 34 of the 78 bilingual women practiced self-examination. CONCLUSION: Although the risk of breast cancer is not associated with speaking a language, it is directly associated with schooling, with the ability to understand instructions that allow the practice of self-examination.

Deterministic and stochastic processes driving the shift in the prokaryotic community composition in wastewater treatment plants of a coastal Chinese city.

Wastewater treatment plants (WWTPs) rely mainly on the microbial assemblages to contribute significantly for the removal of organic pollutants and nutrients. However, limited information is available on the ecological driving forces underlying the turnover of prokaryotic communities across wastewater treatment processes (i.e., from influents (IFs) and effluents (EFs)) within WWTPs. Here, we used a combination of the 16S rRNA gene amplicon sequencing and a quantitative ecological null model analysis to explore the ecological processes governing the turnover of the prokaryotic communities and the dominant taxonomic taxa across wastewater treatment processes of five full-scale WWTPs in China. Our results indicated that a significant variation in the composition of prokaryotic communities and the dominant taxa between IFs and EFs. The analysis of the environmental sources of indicator OTUs showed that a relatively lower abundance of the sludge/sewage and human guts associated OTUs in EFs than in IFs. Ecological null models revealed that among the ecological processes, deterministic processes were dominant in controlling the turnover of the overall communities from IFs to EFs, whereas the relative importance of deterministic processes varied among the dominant taxa (i.e., Bacteroidetes > Proteobacteria > Gammaproteobacteria > Firmicutes > Betaproteobacteria). However, the assembly of IF and EF communities was influenced mainly by the deterministic and stochastic processes, respectively. In addition, our results indicated that EF communities have a higher phylogenetic diversity than those of the IF communities, but the abundance of prokaryotic 16S rRNA genes was lower in EFs than in IFs. Overall, our study provides a novel insight of the assembly mechanisms underlying the turnover of prokaryotic communities during wastewater treatment processes.

CLAME: a new alignment-based binning algorithm allows the genomic description of a novel Xanthomonadaceae from the Colombian Andes.

BACKGROUND: Hot spring bacteria have unique biological adaptations to survive the extreme conditions of these environments; these bacteria produce thermostable enzymes that can be used in biotechnological and industrial applications. However, sequencing these bacteria is complex, since it is not possible to culture them. As an alternative, genome shotgun sequencing of whole microbial communities can be used. The problem is that the classification of sequences within a metagenomic dataset is very challenging particularly when they include unknown microorganisms since they lack genomic reference. We failed to recover a bacterium genome from a hot spring metagenome using the available software tools, so we develop a new tool that allowed us to recover most of this genome. RESULTS: We present a proteobacteria draft genome reconstructed from a Colombian's Andes hot spring metagenome. The genome seems to be from a new lineage within the family Rhodanobacteraceae of the class Gammaproteobacteria, closely related to the genus Dokdonella. We were able to generate this genome thanks to CLAME. CLAME, from Spanish "CLAsificador MEtagenomico", is a tool to group reads in bins. We show that most reads from each bin belong to a single chromosome. CLAME is very effective recovering most of the reads belonging to the predominant species within a metagenome. CONCLUSIONS: We developed a tool that can be used to extract genomes (or parts of them) from a complex metagenome.

Factors shaping the gut bacterial community assembly in two main Colombian malaria vectors.

BACKGROUND: The understanding of the roles of gut bacteria in the fitness and vectorial capacity of mosquitoes that transmit malaria, is improving; however, the factors shaping the composition and structure of such bacterial communities remain elusive. In this study, a high-throughput 16S rRNA gene sequencing was conducted to understand the effect of developmental stage, feeding status, species, and geography on the composition of the gut bacterial microbiota of two main Colombian malaria vectors, Anopheles nuneztovari and Anopheles darlingi. RESULTS: The results revealed that mosquito developmental stage, followed by geographical location, are more important determinants of the gut bacterial composition than mosquito species or adult feeding status. Further, they showed that mosquito gut is a major filter for environmental bacteria colonization. CONCLUSIONS: The sampling design and analytical approach of this study allowed to untangle the influence of factors that are simultaneously shaping the microbiota composition of two Latin-American malaria vectors, essential aspect for the design of vector biocontrol strategies.

Identifying the core seed bank of a complex boreal bacterial metacommunity.

Seed banks are believed to contribute to compositional changes within and across microbial assemblages, but the application of this concept to natural communities remains challenging. Here we describe the core seed bank of a bacterial metacommunity from a boreal watershed, using the spatial distribution of bacterial operational taxonomic units (OTUs) across 223 heterogeneous terrestrial, aquatic and phyllosphere bacterial assemblages. Taxa were considered potential seeds if they transitioned from rare to abundant somewhere within the metacommunity and if they were ubiquitous and able to persist under unfavorable conditions, the latter assessed by checking their presence in three deeply sequenced samples (one soil, one river and one lake, 2.2-3 million reads per sample). We show that only a small fraction (13%) of all detected OTUs constitute a metacommunity seed bank that is shared between all terrestrial and aquatic communities, but not by phyllosphere assemblages, which seem to recruit from a different taxa pool. Our results suggest directional recruitment driven by the flow of water in the landscape, since most aquatic sequences were associated to OTUs found in a single deeply-sequenced soil sample, but only 45% of terrestrial sequences belonged to OTUs found in the two deeply-sequenced aquatic communities. Finally, we hypothesize that extreme rarity, and its interplay with water residence time and growth rates, may further constrain the size of the potential seed bank.

Exploring the Ecological Coherence between the Spatial and Temporal Patterns of Bacterioplankton in Boreal Lakes.

One of the major contemporary challenges in microbial ecology has been to discriminate the reactive core from the random, unreactive components of bacterial communities. In previous work we used the spatial abundance distributions of bacterioplankton across boreal lakes of Québec to group taxa into four distinct categories that reflect either hydrology-mediated dispersal along the aquatic network or environmental selection mechanisms within lakes. Here, we test whether this categorization derived from the spatial distribution of taxa is maintained over time, by analyzing the temporal dynamics of the operational taxonomic units (OTUs) within those spatially derived categories along an annual cycle in the oligotrophic lake Croche (Québec, Canada), and assessing the coherence in the patterns of abundance, occurrence, and environmental range of these OTUs over space and time. We report that the temporal dynamics of most taxa within a single lake are largely coherent with those derived from their spatial distribution over large spatial scales, suggesting that these properties must be intrinsic of particular taxa. We also identified a set of rare taxa cataloged as having a random occupancy based on their spatial distribution, but which showed clear seasonality and abundance peaks along the year, yet these comprised a very small fraction of the total rare OTUs. We conclude that the presence of most rare bacterioplankton taxa in boreal lakes is random, since both their temporal and spatial dynamics suggest links to passive downstream transport and persistence in freshwater networks, rather than environmental selection.