Comparative Analyses of Bacteriophage Genomes.

Bacterial viruses (bacteriophages or phages) are the most abundant and diverse biological entities on Earth. There is a renewed worldwide interest in phage-centered research motivated by their enormous potential as antimicrobials to cope with multidrug-resistant pathogens. An ever-growing number of complete phage genomes are becoming available, derived either from newly isolated phages (cultivated phages) or recovered from metagenomic sequencing data (uncultivated phages). Robust comparative analysis is crucial for a comprehensive understanding of genotypic variations of phages and their related evolutionary processes, and to investigate the interaction mechanisms between phages and their hosts. In this chapter, we present a protocol for phage comparative genomics employing tools selected out of the many currently available, focusing on complete genomes of phages classified in the class Caudoviricetes. This protocol provides accurate identification of similarities, differences, and patterns among new and previously known complete phage genomes as well as phage clustering and taxonomic classification.

Dynamics of major environmental disasters involving fire in the Brazilian Pantanal.

The 2020 environmental catastrophe in Pantanal has highlighted the fragility of environmental policies and practices for managing and fighting fires in this biome. Therefore, it is essential to know the causes and circumstances that potentiate these fires. This study aimed to: (I) assess the relationship between fire foci and carbon absorption (GPP), precipitation, and carbon dioxide (CO2) flux; (ii) analyze vegetation recovery using the differenced normalized burn ratio (ΔNBR) in Brazilian Pantanal between 2001 and 2022; and (iii) identify priority areas, where the highest intensities of fire foci have occurred, in order to guide public policies in Brazil to maintain local conservation. To this purpose, fire foci were detected using data from the MODIS MOD14/MYD14 algorithm, annual precipitation with CHIRPS (Climate Hazards Group InfraRed Precipitation with Station data), and CO2 flux using the MODIS/MODO9A1 product, and Gross Primary Production (GPP) with the MODIS/MOD17A2 product. The severity of the burned area was also assessed using the ΔNBR index and the risk areas were determined using the averages of these images. During the time series studied, a total of 300,127 fire foci were detected throughout the Pantanal, where 2020 had the highest number of foci and the lowest accumulated precipitation. The years with the highest precipitation were 2014 and 2018. The year 2018 was also the second year with the highest GPP value. The Pettit test showed a trend for 2008 and 2011 as the points of change in the CO2 flux and GPP variables. Principal component analysis clustered fire foci and precipitation on opposite sides, as well as GPP and CO2 flux, while ΔNBR clustered HS, MHS and MLS classes with the years 2020, 2019, 2002 and 2021. There was a high negative correlation between fire foci × rainfall and GPP × CO2 flux. The years with the largest areas of High severity (HS), Moderate-high severity (MHS) and Moderate-low severity (MLS) classes were 2020 and 2019, respectively. The most vulnerable areas for severe fires were the municipalities of Cáceres, Poconé, and Corumbá. The major fire catastrophe in 2020 is correlated with the low precipitation in 2019, the high precipitation in 2018, and the increased GPP, as well government policies unfavorable to the environment.

Implications of CO2 emissions on the main land and forest uses in the Brazilian Amazon.

The emission of soil carbon dioxide (CO2) in agricultural areas is a process that results from the interaction of several factors such as climate, soil, and land management practices. Agricultural practices directly affect the carbon dynamics between the soil and atmosphere. Herein, we evaluated the temporal variability (2020/2021 crop season) of soil CO2 emissions and its relationship with related variables, such as the CO2 flux model, enhanced vegetation index (EVI), gross primary productivity (GPP), and leaf area index (LAI) from orbital data and soil temperature, soil moisture, and soil CO2 emissions from in situ collections from native forests, productive pastures, degraded pastures, and areas of high-yield potential soybean and low-yield potential soybean production. A significant influence (p < 0.01) was observed for all variables and between the different land uses and occupation types. September and October had lower emissions of soil CO2 and low means of soil moisture and soil temperature, and no differences were observed among the treatments. On the other hand, there was a significant effect of the CO2 flux model in productive pastures, high-yield potential soybean areas, and low-yield potential soybean areas. The months with the highest CO2 flux values in the model, regardless of land use and land cover, were October and November, which is the beginning of the rainy season. There were positive correlations between soil CO2 emissions and GPP (0.208), LAI (0.354), EVI (0.363), and soil moisture (0.280) and negative correlations between soil CO2 emissions and soil temperature (-0.240) and CO2 flux model (-0.314) values. Land use and land cover showed negative correlations with these variables, except for the CO2 flux model variable. Soil CO2 emission values were lower for high-yield potential soybean areas (averages from 0.834 to 6.835 µmol m-2 s-1) and low-yield potential soybean areas (from 0.943 to 5.686 µmol m-2 s-1) and higher for native forests (from 2.279 to 8.131 µmol m-2 s-1), whereas the opposite was true for the CO2 flux model.

Effect of land uses and land cover on soil attributes in the southern Brazilian Amazon.

The growth of the world population has led to the expansion of agricultural areas to produce food that meets world demand, making it necessary to increase productivity and maintain environmental sustainability in these areas. Seeking sustainable food production, the agricultural use of soil must be assessed in view of optimal use or land as natural resource, as well as minimize the effects of global warming related to land use and land cover (LULC). We hypothesize that different LULC affects Amazonian soil attributes. In this study, the effect of different LULC in the southern Brazilian Amazon, namely, native forest, pasture, and rice and soybean crops, on the spatial variability of soil fertility and texture was assessed, seeking to obtain information that will guide farmers in the near future to better exploit their areas and contribute to a more sustainable agriculture. Descriptive statistical analysis was performed for the pH, H + Al, Al, Ca, Mg, P, K, Cu, Fe, Mn, Zn, V, m, organic matter, clay, silt, and sand values from soil samples under different LULC. To verify the data normality, the Shapiro-Wilk test at 5% significance was performed. Outlier analysis using boxplot graphics, principal component analysis (PCA), and cluster analysis was performed. Data were submitted to geostatistical analysis to verify the spatial dependence degree of the variables through semivariograms for interpolated kriging maps. Except for silt, all variables were well represented in the factor map. PCA revealed that the data variability can be explained mainly by pH, V, Ca, K, and Zn values, which are inversely proportional to m, P, and sand. Through geostatistical analysis, spatial dependence ranging from moderate to strong was observed, generating reliability in the prediction of most attributes in pasture, rice, and soybean areas. Yet, a spatial dependence ranging from moderate to strong was found, generating reliability in the prediction of most attributes in pasture, rice, and soybean areas. Our findings reveal a lower fertility and higher acidity in forest areas, whereas crop areas presented the opposite result.

Isolation and Molecular Characterization of a Novel Lytic Bacteriophage That Inactivates MDR Klebsiella pneumoniae Strains.

The worldwide increase in serious infections caused by multidrug-resistant (MDR) K. pneumoniae emphasizes the urgent need of new therapeutic strategies for the control of this pathogen. There is growing interest in the use of bacteriophages (or phages) to treat K. pneumoniae infections, and newly isolated phages are needed. Here, we report the isolation and physical/biological/molecular characterization of a novel lytic phage and its efficacy in the control of MDR K. pneumoniae. The phage vB_KpnS_Uniso31, referred to hereafter as phage Kpn31, was isolated from hospital wastewater using K. pneumoniae CCCD-K001 as the host. Phage Kpn31 presents a siphovirus-like morphotype and was classified as Demerecviridae; Sugarlandvirus based on its complete genome sequence. The 113,444 bp Kpn31 genome does not encode known toxins or antimicrobial resistance genes, nor does it encode depolymerases related sequences. Phage Kpn31 showed an eclipse time of 15 min and a burst size of 9.12 PFU/host cell, allowing us to conclude it replicates well in K. pneumoniae CCCD-K001 with a latency period of 30 min. Phage Kpn31 was shown to be effective against at least six MDR K. pneumoniae clinical isolates in in vitro antibacterial activity assays. Based on its features, phage Kpn31 has potential for controlling infections caused by MDR K. pneumoniae.

Pseudomonas-tailed lytic phages: genome mechanical analysis and putative correlation with virion morphogenesis yield.

Aim: To unveil a putative correlation between phage genome flexibility and virion morphogenesis yield. Materials & methods: A deeper analysis of the mechanical properties of three Pseudomonas aeruginosa lytic phage genomes was undertaken, together with full genome cyclizability calculations. Results & conclusion: A putative correlation was established among phage genome flexibility, eclipse timeframe and virion particle morphogenesis yield, with a more flexible phage genome leading to a higher burst size and a more rigid phage genome leading to lower burst sizes. The results obtained are highly relevant to understand the influence of the phage genome plasticity on the virion morphogenesis yield inside the infected bacterial host cells and assumes particular relevance in the actual context of bacterial resistance to antibiotics.

Isolation and characterization of vB_XciM_LucasX, a new jumbo phage that infects Xanthomonas citri and Xanthomonas fuscans.

Citrus canker is one of the main bacterial diseases that affect citrus crops and is caused by Xanthomonas citri which affects all citrus species worldwide. New strategies to control citrus canker are necessary and the use of bacteriophages as biocontrol agent could be an alternative. Phages that infect Xanthomonas species have been studied, such as XacN1, a myovirus that infects X. citri. Here we report the isolation and characterization of a new jumbo phage, vb_XciM_LucasX, which infects X. citri and X. fuscans. Transmission electron microscopy allowed classification of LucasX in the Myoviridae family, which was corroborated by its genomic sequencing, annotation, and proteome clustering. LucasX has a 305,651 bp-long dsDNA genome. ORF prediction and annotation revealed 157 genes encoding putative structural proteins such as capsid and tail related proteins and phage assembly associated proteins, however, for most of the structural proteins it was not possible assign specific functions. Its genome encodes several proteins related to DNA replication and nucleotide metabolism, five putative RNA polymerases, at least one homing endonuclease mobile element, a terminase large subunit (TerL), an endolysin and many proteins classified as beneficial to the host. Proteome clustering and phylogeny analyses showed that LucasX is a new jumbo phage having as its closest neighbor the Xanthomonas jumbo phage Xoo-sp14. LucasX presented a burst size of 40 PFU/infected cell of X. citri 306, was completely inactivated at temperatures above 50°C, presented survival lower than 25% after 80 s of exposition to artificial UV light and had practically no tolerance to concentrations above 2.5 g/L NaCl or 40% ethanol. LucasX presented optimum pH at 7 and a broad range of Xanthomonas hosts, infecting twenty-one of the twenty-three strains tested. Finally, the LucasX yield was dependent on the host strain utilized, resulting one order of magnitude higher in X. fuscans C 752 than in X. citri 306, which points out to the possibility of phage yield improvement, an usual challenge for biocontrol purposes.

Characterization and in vitro testing of newly isolated lytic bacteriophages for the biocontrol of Pseudomonas aeruginosa.

Aim: Two lytic phages were isolated using P. aeruginosa DSM19880 as host and fully characterized. Materials & methods: Phages were characterized physicochemically, biologically and genomically. Results & conclusion: Host range analysis revealed that the phages also infect some multidrug-resistant (MDR) P. aeruginosa clinical isolates. Increasing MOI from 1 to 1000 significantly increased phage efficiency and retarded bacteria regrowth, but phage ph0034 (reduction of 7.5 log CFU/ml) was more effective than phage ph0031 (reduction of 5.1 log CFU/ml) after 24 h. Both phages belong to Myoviridae family. Genome sequencing of phages ph0031 and ph0034 showed that they do not carry toxin, virulence, antibiotic resistance and integrase genes. The results obtained are highly relevant in the actual context of bacterial resistance to antibiotics.

Transanal minimally-invasive surgery (TAMIS): experience with no closure of the rectal defect

Background: In transanalminimally-invasive surgery (TAMIS), the closure of the rectal defect is controversial, and endoluminal suture is one of the most challenging aspects. The goal of the present study is to evaluate the short- andmedium-term complications of a consecutive series of patients with extraperitoneal rectal injuries who underwent TAMIS without closure of the rectal defect. Materials and Methods: A prospective, longitudinal, descriptive study conducted between August 2013 and July 2019 in which all patients with extraperitoneal rectal lesions, who were operated on using the TAMIS technique, were consecutively included. The lesions were: benign lesions ≥ 3 cm; neuroendocrine tumors ≤ 2 cm; adenocarcinomas in stage T1N0; and adenocarcinomas in stage T2N0, with high surgical risk, or with the patients reluctant to undergo radical surgery, and others with doubts about complete remission after the neoadjuvant therapy. Bleeding, infectious complications, rectal stenosis, perforations, and death were evaluated. Results: A total of 35 patients were treated using TAMIS without closure of the defect. The average size of the lesionswas of 3.68±2.1 cm(95% confidence interval [95%CI]: 0.7cmto 9 cm), their average distance from the anal margin was of 5.7±1.48cm, and the average operative time was of 39.2±20.5 minutes, with a minimum postoperative follow-up of 1 year. As for the pathologies, they were: 15 adenomas; 3 carcinoid tumors; and 17 adenocarcinomas. In all cases, the rectal defect was left open. The overall morbidity was of 14.2%. Two patients (grade II in the Clavien-Dindo classification) were readmitted for pain treatment, and three patients (grade III in the Clavien-Dindo classification) were assisted due to postoperative bleeding, one of whom required reoperation. Conclusion: The TAMIS technique without closure of the rectal defect yields good results, and present a high feasibility and low complication rate. (AU)

Advance of soy commodity in the southern Amazonia with deforestation via PRODES and ImazonGeo: a moratorium-based approach.

The guidance on decision-making regarding deforestation in Amazonia has been efficient as a result of monitoring programs using remote sensing techniques. Thus, the objective of this study was to identify the expansion of soybean farming in disagreement with the Soy Moratorium (SoyM) in the Amazonia biome of Mato Grosso from 2008 to 2019. Deforestation data provided by two Amazonia monitoring programs were used: PRODES (Program for Calculating Deforestation in Amazonia) and ImazonGeo (Geoinformation Program on Amazonia). For the identification of soybean areas, the Perpendicular Crop Enhancement Index (PCEI) spectral model was calculated using a cloud platform. To verify areas (polygons) of largest converted forest-soybean occurrences, the Kernel Density (KD) estimator was applied. Mann-Kendall and Pettitt tests were used to identify trends over the time series. Our findings reveal that 1,387,288 ha were deforested from August 2008 to October 2019 according to PRODES data, of which 108,411 ha (7.81%) were converted into soybean. The ImazonGeo data showed 729,204 hectares deforested and 46,182 hectares (6.33%) converted into soybean areas. Based on the deforestation polygons of the two databases, the KD estimator indicated that the municipalities of Feliz Natal, Tabaporã, Nova Ubiratã, and União do Sul presented higher occurrences of soybean fields in disagreement with the SoyM. The results indicate that the PRODES system presents higher data variability and means statistically superior to ImazonGeo.

Evaluation of pulping therapy in deciduous teeth using chlorhephenicol tetracycline and Zinc oxide / Avaliação da terapia pulpar em dentes decíduos com uso da pasta cloranfenicol tetraciclina e óxido de Zinco

ABSTRACT The technique using CTZ paste (chloramphenicol, tetracycline, and zinc oxide-eugenol) in the endodontic treatment of deciduous teeth is easy to perform and requires a single session, which is an advantage with child patients. The inexistence of clinical protocols with the use of CTZ and the multifactorial endodontic repair process in deciduous teeth evidence the need for research on the subject. This study aimed to suggest a clinical protocol model for the systematization and standardization of the endodontic treatment of deciduous teeth using CTZ paste. In the case report presented, after pulp therapy, clinical-radiographical follow-up was conducted after 30, 60, 90 and 180 days. It was concluded that using CTZ paste is a simple, viable, and satisfactory alternative. Future clinical studies are needed regarding CTZ use in child clinic with strong scientific evidence.

RESUMO A técnica com pasta CTZ (cloranfenicol, tetraciclina e óxido de zinco-eugenol) no tratamento endodôntico de dentes decíduos é de fácil execução e requer sessão única, o que é uma vantagem em pacientes infantis. A inexistência de protocolos clínicos com o uso do CTZ e do processo de reparo endodôntico em dentes decíduos evidencia a necessidade de pesquisas sobre o assunto. Este estudo teve como objetivo sugerir um modelo de protocolo clínico para a sistematização e padronização do tratamento endodôntico de dentes decíduos com a pasta CTZ. No relato de caso apresentado, após a terapia pulpar, o acompanhamento clínico-radiográfico foi realizado após 30, 60, 90 e 180 dias. Concluiu-se que o uso da pasta CTZ é uma alternativa simples, viável e satisfatória. Futuros estudos clínicos são necessários a respeito do uso de CTZ em clínica infantil com fortes evidências científicas.

What patients consider to be a good doctor, and what doctors consider to be a good patient / Cómo definen los pacientes a un buen médico, y cómo definen los médicos a un buen paciente

ABSTRACT Background: From a patient's point of view, an 'ideal' doctor could be defined as one having personal qualities for interpersonal relationships, technical skills and good intentions. However, doctors' opinions about what it means to be a 'good' patient have not been systematically investigated. Aim: To explore how patients define the characteristics of a 'good' and a 'bad' doctor, and how doctors define a 'good' and a 'bad' patient. Material and Methods: We surveyed a cohort of 107 consecutive patients attending a community teaching hospital in February 2019, who were asked to define the desirable characteristics of a good/bad doctor. Additionally, a cohort of 115 physicians working at the same hospital was asked to define the desirable characteristics of a good/bad patient. Responses were subjected to content analysis. Simultaneously, an algorithm in Python was used to automatically categorize responses throughout text-mining. Results: The predominant patients' perspective alluded to desirable personal qualities more importantly than proficiency in knowledge and technical skills. Doctors would be satisfied if patients manifested positive personality characteristics, were prone to avoid decisional and personal conflicts, had a high adherence to treatment, and trusted the doctor. The text-mining algorithm was accurate to classify individuals' opinions. Conclusions: Ideally, fusing the skills of the scientist to the reflective capabilities of the medical humanist will fulfill the archetype of what patients consider to be a 'good' doctor. Doctors' preferences reveal a "paternalistic" style, and his/her opinions should be managed carefully to avoid stigmatizing certain patients' behaviors.

Antecedentes: Desde la perspectiva del paciente, un médico "ideal" podría definirse como aquel que tiene cualidades para las relaciones interpersonales, habilidades técnicas y buenas intenciones. Sin embargo, las opiniones de los médicos sobre lo que significa ser un "buen" paciente no se han investigado sistemáticamente. Objetivo: Explorar cómo los pacientes definen las características de un "buen" y "mal" médico, y cómo los médicos definen un "buen" y "mal" paciente. Material y Métodos: Encuestamos a una cohorte de 107 pacientes consecutivos que asistieron a un hospital comunitario en febrero de 2019, a quienes se les pidió que definieran las características deseables de un médico bueno/malo. Además, se pidió a una cohorte de 115 médicos que trabajaban en el mismo hospital que definieran las características deseables de un paciente bueno/malo. Las respuestas se sometieron a un análisis de contenido. Simultáneamente, se utilizó un algoritmo en Python para clasificar automáticamente las respuestas mediante minería de texto. Resultados: Los pacientes aludieron que las cualidades personales del médico eran más importantes que la competencia en conocimiento y las habilidades técnicas. Los médicos estarían satisfechos si los pacientes mostraran características positivas de personalidad, fueran propensos a evitar conflictos, tuvieran una alta adherencia al tratamiento y confiaran en el médico. El algoritmo de minería de texto clasificó las opiniones de los encuestados en forma precisa. Conclusiones: Idealmente, fusionar las habilidades del científico con las capacidades reflexivas del médico humanista cumplirá con el arquetipo de lo que los pacientes consideran un "buen" médico. Las preferencias de los médicos revelan un estilo "paternalista", y sus opiniones deben manejarse con cuidado para evitar estigmatizar los comportamientos de ciertos pacientes.

What patients consider to be a 'good' doctor, and what doctors consider to be a 'good' patient.

BACKGROUND: From a patient's point of view, an 'ideal' doctor could be defined as one having personal qualities for interpersonal relationships, technical skills and good intentions. However, doctors' opinions about what it means to be a 'good' patient have not been systematically investigated. AIM: To explore how patients define the characteristics of a 'good' and a 'bad' doctor, and how doctors define a 'good' and a 'bad' patient. MATERIAL AND METHODS: We surveyed a cohort of 107 consecutive patients attending a community teaching hospital in February 2019, who were asked to define the desirable characteristics of a good/bad doctor. Additionally, a cohort of 115 physicians working at the same hospital was asked to define the desirable characteristics of a good/bad patient. Responses were subjected to content analysis. Simultaneously, an algorithm in Python was used to automatically categorize responses throughout text-mining. RESULTS: The predominant patients' perspective alluded to desirable personal qualities more importantly than proficiency in knowledge and technical skills. Doctors would be satisfied if patients manifested positive personality characteristics, were prone to avoid decisional and personal conflicts, had a high adherence to treatment, and trusted the doctor. The text-mining algorithm was accurate to classify individuals' opinions. CONCLUSIONS: Ideally, fusing the skills of the scientist to the reflective capabilities of the medical humanist will fulfill the archetype of what patients consider to be a 'good' doctor. Doctors' preferences reveal a "paternalistic" style, and his/her opinions should be managed carefully to avoid stigmatizing certain patients' behaviors.

Structure and function of the archaeal response regulator CheY.

Motility is a central feature of many microorganisms and provides an efficient strategy to respond to environmental changes. Bacteria and archaea have developed fundamentally different rotary motors enabling their motility, termed flagellum and archaellum, respectively. Bacterial motility along chemical gradients, called chemotaxis, critically relies on the response regulator CheY, which, when phosphorylated, inverses the rotational direction of the flagellum via a switch complex at the base of the motor. The structural difference between archaellum and flagellum and the presence of functional CheY in archaea raises the question of how the CheY protein changed to allow communication with the archaeal motility machinery. Here we show that archaeal CheY shares the overall structure and mechanism of magnesium-dependent phosphorylation with its bacterial counterpart. However, bacterial and archaeal CheY differ in the electrostatic potential of the helix α4. The helix α4 is important in bacteria for interaction with the flagellar switch complex, a structure that is absent in archaea. We demonstrated that phosphorylation-dependent activation, and conserved residues in the archaeal CheY helix α4, are important for interaction with the archaeal-specific adaptor protein CheF. This forms a bridge between the chemotaxis system and the archaeal motility machinery. Conclusively, archaeal CheY proteins conserved the central mechanistic features between bacteria and archaea, but differ in the helix α4 to allow binding to an archaellum-specific interaction partner.

Resveratrol and Brain Mitochondria: a Review.

Resveratrol (3,4',5-trihydroxystilbene; C14H12O3) is a polyphenolic phytoalexin found in grapes, berries, peanuts, and wines. Resveratrol has been viewed as an antioxidant, anti-inflammatory, anti-apoptotic, and anticancer agent. Moreover, it has been reported that resveratrol modulates mitochondrial function, redox biology, and dynamics in both in vitro and in vivo experimental models. Resveratrol also attenuates mitochondrial impairment induced by certain stressors. Resveratrol upregulates, for example, mitochondria-located antioxidant enzymes, decreasing the production of reactive species by these organelles. Resveratrol also triggers mitochondrial biogenesis, ameliorating the mitochondria-related bioenergetics status in mammalian cells. In the present work, we discuss about the effects of resveratrol on brain mitochondria. Brain cells (both neuronal and glial) are susceptible to mitochondrial dysfunction due to their high demand for adenosine triphosphate (ATP). Additionally, brain cells consume oxygen (O2) at very high rates, leading to a proportionally high mitochondrial production of reactive species. Therefore, strategies focusing on the maintenance of mitochondrial function in these cell types are of pharmacological interest in the case of neurodegenerative diseases, which involve mitochondrial impairment and increased generation of reactive species, leading to neuroinflammation and cell death. The mechanism by which resveratrol protects mitochondrial function and dynamics is not completely understood, and further research would be necessary in order to investigate exactly how resveratrol affects mitochondria-related parameters. Furthermore, it is particularly important because resveratrol is able to induce cytotoxicity depending on its dosage.

In Azospirillum brasilense, mutations in flmA or flmB genes affect polar flagellum assembly, surface polysaccharides, and attachment to maize roots.

Azospirillum brasilense is a soil bacterium capable of promoting plant growth. Several surface components were previously reported to be involved in the attachment of A. brasilense to root plants. Among these components are the exopolysaccharide (EPS), lipopolysaccharide (LPS) and the polar flagellum. Flagellin from polar flagellum is glycosylated and it was suggested that genes involved in such a posttranslational modification are the same ones involved in the biosynthesis of sugars present in the O-antigen of the LPS. In this work, we report on the characterization of two homologs present in A. brasilense Cd, to the well characterized flagellin modification genes, flmA and flmB, from Aeromonas caviae. We show that mutations in either flmA or flmB genes of A. brasilense resulted in non-motile cells due to alterations in the polar flagellum assembly. Moreover, these mutations also affected the capability of A. brasilense cells to adsorb to maize roots and to produce LPS and EPS. By generating a mutant containing the polar flagellum affected in their rotation, we show the importance of the bacterial motility for the early colonization of maize roots.

Sinorhizobium meliloti low molecular mass phosphotyrosine phosphatase SMc02309 modifies activity of the UDP-glucose pyrophosphorylase ExoN involved in succinoglycan biosynthesis.

In Gram-negative bacteria, tyrosine phosphorylation has been shown to play a role in the control of exopolysaccharide (EPS) production. This study demonstrated that the chromosomal ORF SMc02309 from Sinorhizobium meliloti 2011 encodes a protein with significant sequence similarity to low molecular mass protein-tyrosine phosphatases (LMW-PTPs), such as the Escherichia coli Wzb. Unlike other well-characterized EPS biosynthesis gene clusters, which contain neighbouring LMW-PTPs and kinase, the S. meliloti succinoglycan (EPS I) gene cluster located on megaplasmid pSymB does not encode a phosphatase. Biochemical assays revealed that the SMc02309 protein hydrolyses p-nitrophenyl phosphate (p-NPP) with kinetic parameters similar to other bacterial LMW-PTPs. Furthermore, we show evidence that SMc02309 is not the LMW-PTP of the bacterial tyrosine-kinase (BY-kinase) ExoP. Nevertheless, ExoN, a UDP-glucose pyrophosphorylase involved in the first stages of EPS I biosynthesis, is phosphorylated at tyrosine residues and constitutes an endogenous substrate of the SMc02309 protein. Additionally, we show that the UDP-glucose pyrophosphorylase activity is modulated by SMc02309-mediated tyrosine dephosphorylation. Moreover, a mutation in the SMc02309 gene decreases EPS I production and delays nodulation on Medicago sativa roots.

Tuberculosis oral asociada al HIV: presentación de un caso clínico / HIV-related oral tuberculosis: report of a clinical case

La tuberculosis (TBC) es una enfermedad infecciosa causada principalmente por una bacteria, el Micobacterium tuberculosis. La estrecha vinculación entre TBC y VIH oermite hablar de una coepidemia dual. La localización oral de la TBC extrapulmon es rara, tanto en pacientes inmunocompetentes como VIH+. Las manifestaciones clínicas son inespecíficas, pudiendo presentarse como úlceras, fisuras, nódulos, granulomas o tumores. La falta de especificidad de las lesiones dificulta el diagnóstico. En este artículo se presenta un caso clínico de un paciente con TBC extrapulomonar en la cavidad oral asociado a HIV, atendido en el Servicio de Odontología del H.I.G.A. Gral. San Martín de la ciudad de La Plata.(AU)

Tuberculosis oral asociada al HIV: presentación de un caso clínico / HIV-related oral tuberculosis: report of a clinical case

La tuberculosis (TBC) es una enfermedad infecciosa causada principalmente por una bacteria, el Micobacterium tuberculosis. La estrecha vinculación entre TBC y VIH oermite hablar de una coepidemia dual. La localización oral de la TBC extrapulmon es rara, tanto en pacientes inmunocompetentes como VIH+. Las manifestaciones clínicas son inespecíficas, pudiendo presentarse como úlceras, fisuras, nódulos, granulomas o tumores. La falta de especificidad de las lesiones dificulta el diagnóstico. En este artículo se presenta un caso clínico de un paciente con TBC extrapulomonar en la cavidad oral asociado a HIV, atendido en el Servicio de Odontología del H.I.G.A. Gral. San Martín de la ciudad de La Plata.