Elongasome core proteins and class A PBP1a display zonal, processive movement at the midcell of Streptococcus pneumoniae.

Ovoid-shaped bacteria, such as Streptococcus pneumoniae (pneumococcus), have two spatially separated peptidoglycan (PG) synthase nanomachines that locate zonally to the midcell of dividing cells. The septal PG synthase bPBP2x:FtsW closes the septum of dividing pneumococcal cells, whereas the elongasome located on the outer edge of the septal annulus synthesizes peripheral PG outward. We showed previously by sm-TIRFm that the septal PG synthase moves circumferentially at midcell, driven by PG synthesis and not by FtsZ treadmilling. The pneumococcal elongasome consists of the PG synthase bPBP2b:RodA, regulators MreC, MreD, and RodZ, but not MreB, and genetically associated proteins Class A aPBP1a and muramidase MpgA. Given its zonal location separate from FtsZ, it was of considerable interest to determine the dynamics of proteins in the pneumococcal elongasome. We found that bPBP2b, RodA, and MreC move circumferentially with the same velocities and durations at midcell, driven by PG synthesis. However, outside of the midcell zone, the majority of these elongasome proteins move diffusively over the entire surface of cells. Depletion of MreC resulted in loss of circumferential movement of bPBP2b, and bPBP2b and RodA require each other for localization and circumferential movement. Notably, a fraction of aPBP1a molecules also moved circumferentially at midcell with velocities similar to those of components of the core elongasome, but for shorter durations. Other aPBP1a molecules were static at midcell or diffusing over cell bodies. Last, MpgA displayed nonprocessive, subdiffusive motion that was largely confined to the midcell region and less frequently detected over the cell body.

Stay on track - revelations of bacterial cell wall synthesis enzymes and things that go by single-molecule imaging.

In this review, we explore the regulation of septal peptidoglycan (sPG) synthesis in bacterial cell division, a critical process for cell viability and proper morphology. Recent single-molecule imaging studies have revealed the processive movement of the FtsW:bPBP synthase complex along the septum, shedding light on the spatiotemporal dynamics of sPG synthases and their regulators. In diderm bacteria (E. coli and C. crescentus), the movement occurs at two distinct speeds, reflecting active synthesis or inactivity driven by FtsZ-treadmilling. In monoderm bacteria (B. subtilis, S. pneumoniae, and S. aureus), however, these enzymes exhibit only the active sPG-track-coupled processive movement. By comparing the dynamics of sPG synthases in these organisms and that of class-A penicillin-binding proteins in vivo and in vitro, we propose a unifying model for septal cell wall synthesis regulation across species, highlighting the roles of the sPG- and Z-tracks in orchestrating a robust bacterial cell wall constriction process.

Elongasome core proteins and class A PBP1a display zonal, processive movement at the midcell of Streptococcus pneumoniae.

Ovoid-shaped bacteria, such as Streptococcus pneumoniae (pneumococcus), have two spatially separated peptidoglycan (PG) synthase nanomachines that locate zonally to the midcell of dividing cells. The septal PG synthase bPBP2x:FtsW closes the septum of dividing pneumococcal cells, whereas the elongasome located on the outer edge of the septal annulus synthesizes peripheral PG outward. We showed previously by sm-TIRFm that the septal PG synthase moves circumferentially at midcell, driven by PG synthesis and not by FtsZ treadmilling. The pneumococcal elongasome consists of the PG synthase bPBP2b:RodA, regulators MreC, MreD, and RodZ, but not MreB, and genetically associated proteins Class A aPBP1a and muramidase MpgA. Given its zonal location separate from FtsZ, it was of considerable interest to determine the dynamics of proteins in the pneumococcal elongasome. We found that bPBP2b, RodA, and MreC move circumferentially with the same velocities and durations at midcell, driven by PG synthesis. However, outside of the midcell zone, the majority of these elongasome proteins move diffusively over the entire surface of cells. Depletion of MreC resulted in loss of circumferential movement of bPBP2b, and bPBP2b and RodA require each other for localization and circumferential movement. Notably, a fraction of aPBP1a molecules also moved circumferentially at midcell with velocities similar to those of components of the core elongasome, but for shorter durations. Other aPBP1a molecules were static at midcell or diffusing over cell bodies. Last, MpgA displayed non-processive, subdiffusive motion that was largely confined to the midcell region and less frequently detected over the cell body.

Negative regulation of MurZ and MurA underlies the essentiality of GpsB- and StkP-mediated protein phosphorylation in Streptococcus pneumoniae D39.

GpsB links peptidoglycan synthases to other proteins that determine the shape of the respiratory pathogen Streptococcus pneumoniae (pneumococcus; Spn) and other low-GC Gram-positive bacteria. GpsB is also required for phosphorylation of proteins by the essential StkP(Spn) Ser/Thr protein kinase. Here we report three classes of frequently arising chromosomal duplications (≈21-176 genes) containing murZ (MurZ-family homolog of MurA) or murA that suppress ΔgpsB or ΔstkP. These duplications arose from three different repeated sequences and demonstrate the facility of pneumococcus to modulate gene dosage of numerous genes. Overproduction of MurZ or MurA alone or overproduction of MurZ caused by ΔkhpAB mutations suppressed ΔgpsB or ΔstkP phenotypes to varying extents. ΔgpsB and ΔstkP were also suppressed by MurZ amino-acid changes distant from the active site, including one in commonly studied laboratory strains, and by truncation or deletion of the homolog of IreB(ReoM). Unlike in other Gram-positive bacteria, MurZ is predominant to MurA in pneumococcal cells. However, ΔgpsB and ΔstkP were not suppressed by ΔclpCP, which did not alter MurZ or MurA amounts. These results support a model in which regulation of MurZ and MurA activity, likely by IreB(Spn), is the only essential requirement for StkP-mediated protein phosphorylation in exponentially growing D39 pneumococcal cells.

Chromosomal Duplications of MurZ (MurA2) or MurA (MurA1), Amino Acid Substitutions in MurZ (MurA2), and Absence of KhpAB Obviate the Requirement for Protein Phosphorylation in Streptococcus pneumoniae D39.

GpsB links peptidoglycan synthases to other proteins that determine the shape of the respiratory pathogen Streptococcus pneumoniae (pneumococcus; Spn ) and other low-GC Gram-positive bacteria. GpsB is also required for phosphorylation of proteins by the essential StkP( Spn ) Ser/Thr protein kinase. Here we report three classes of frequently arising chromosomal duplications (≈21-176 genes) containing murZ (MurZ-family homolog of MurA) or murA that suppress Δ gpsB or Δ stkP . These duplications arose from three different repeated sequences and demonstrate the facility of pneumococcus to modulate gene dosage of numerous genes. Overproduction of MurZ or MurA alone or overexpression of MurZ caused by Δ khpAB mutations suppressed Δ gpsB or Δ stkP phenotypes to varying extents. Δ gpsB and Δ stkP were also suppressed by MurZ amino-acid changes distant from the active site, including one in commonly studied laboratory strains, and by truncation or deletion of the homolog of IreB(ReoM). Unlike in other Gram-positive bacteria, MurZ is predominant to MurA in pneumococcal cells. However, Δ gpsB and Δ stkP were not suppressed by Δ clpCP , which did not alter MurZ or MurA amounts. These results support a model in which regulation of MurZ and MurA activity, likely by IreB( Spn ), is the only essential requirement for protein phosphorylation in exponentially growing D39 pneumococcal cells.

FtsZ-Ring Regulation and Cell Division Are Mediated by Essential EzrA and Accessory Proteins ZapA and ZapJ in Streptococcus pneumoniae.

The bacterial FtsZ-ring initiates division by recruiting a large repertoire of proteins (the divisome; Z-ring) needed for septation and separation of cells. Although FtsZ is essential and its role as the main orchestrator of cell division is conserved in most eubacteria, the regulators of Z-ring presence and positioning are not universal. This study characterizes factors that regulate divisome presence and placement in the ovoid-shaped pathogen, Streptococcus pneumoniae (Spn), focusing on FtsZ, EzrA, SepF, ZapA, and ZapJ, which is reported here as a partner of ZapA. Epi-fluorescence microscopy (EFm) and high-resolution microscopy experiments showed that FtsZ and EzrA co-localize during the entire Spn cell cycle, whereas ZapA and ZapJ are late-arriving divisome proteins. Depletion and conditional mutants demonstrate that EzrA is essential in Spn and required for normal cell growth, size, shape homeostasis, and chromosome segregation. Moreover, EzrA(Spn) is required for midcell placement of FtsZ-rings and PG synthesis. Notably, overexpression of EzrA leads to the appearance of extra Z-rings in Spn. Together, these observations support a role for EzrA as a positive regulator of FtsZ-ring formation in Spn. Conversely, FtsZ is required for EzrA recruitment to equatorial rings and for the organization of PG synthesis. In contrast to EzrA depletion, which causes a bacteriostatic phenotype in Spn, depletion of FtsZ results in enlarged spherical cells that are subject to LytA-dependent autolysis. Co-immunoprecipitation and bacterial two-hybrid assays show that EzrA(Spn) is in complexes with FtsZ, Z-ring regulators (FtsA, SepF, ZapA, MapZ), division proteins (FtsK, StkP), and proteins that mediate peptidoglycan synthesis (GpsB, aPBP1a), consistent with a role for EzrA at the interface of cell division and PG synthesis. In contrast to the essentiality of FtsZ and EzrA, ZapA and SepF have accessory roles in regulating pneumococcal physiology. We further show that ZapA interacts with a non-ZapB homolog, named here as ZapJ, which is conserved in Streptococcus species. The absence of the accessory proteins, ZapA, ZapJ, and SepF, exacerbates growth defects when EzrA is depleted or MapZ is deleted. Taken together, these results provide new information about the spatially and temporally distinct proteins that regulate FtsZ-ring organization and cell division in Spn.

Organization of peptidoglycan synthesis in nodes and separate rings at different stages of cell division of Streptococcus pneumoniae.

Bacterial peptidoglycan (PG) synthesis requires strict spatiotemporal organization to reproduce specific cell shapes. In ovoid-shaped Streptococcus pneumoniae (Spn), septal and peripheral (elongation) PG synthesis occur simultaneously at midcell. To uncover the organization of proteins and activities that carry out these two modes of PG synthesis, we examined Spn cells vertically oriented onto their poles to image the division plane at the high lateral resolution of 3D-SIM (structured-illumination microscopy). Labeling with fluorescent D-amino acids (FDAA) showed that areas of new transpeptidase (TP) activity catalyzed by penicillin-binding proteins (PBPs) separate into a pair of concentric rings early in division, representing peripheral PG (pPG) synthesis (outer ring) and the leading-edge (inner ring) of septal PG (sPG) synthesis. Fluorescently tagged PBP2x or FtsZ locate primarily to the inner FDAA-marked ring, whereas PBP2b and FtsX remain in the outer ring, suggesting roles in sPG or pPG synthesis, respectively. Pulses of FDAA labeling revealed an arrangement of separate regularly spaced "nodes" of TP activity around the division site of predivisional cells. Tagged PBP2x, PBP2b, and FtsX proteins also exhibited nodal patterns with spacing comparable to that of FDAA labeling. Together, these results reveal new aspects of spatially ordered PG synthesis in ovococcal bacteria during cell division.

Eficiencia de solubilización de fósforo de aislados nativos guatemaltecos de Pseudomonas fluorescens / Phosphorus solubilization efficiency of native Guatemalan isolates of Pseudomonas fluorescens

El fósforo (P) es un elemento esencial en la producción agrícola, pero debido a su compleja dinámica en el suelo, solo una pequeña cantidad es aprovechable para las plantas, ya que la mayoría del P se encuentra en formas insolubles, especialmente, en suelos Andisoles de origen volcánico. Los microorganismos con capacidad solubilizadora de fósforo (MSF) son una alternativa para transformar el P a formas solubles y aprovechables por las plantas; además de brindar múltiples beneficios ambientales. Este trabajo identificó y evaluó in vitro, aislados nativos de Pseudomonas fluorescens Mingula, obtenidos de regiones guatemaltecas con suelos Andisoles que limitan la producción agrícola por la alta fijación de P. Se realizaron cultivos in vitro de la bacteria en medio National Botanical Research Instituteís phosphate growth (NBRIP), con fosfato tricálcico Ca3(PO4)2 como fuente de P insoluble y se midió el índice de solubilización de fósforo (ISF). Un total de 35 aislados de P. fluorescensfueron identificados y confirmados por PCR específico. El análisis de relaciones genéticas con el marcador AFLP, mostró dos grupos: el grupo A incluyó a los aislados con ISF mayores a 1.75, mientras el grupo B incluyó a aquellos con ISF menor a 1.75. La comparación de ISF entre los aislados y departamentos, demostró diferencia estadísticamente significativa (p < .001), con el aislado Pf_33 como más eficiente. Debido al potencial de solubilización de los aislados nativos del grupo genético A (ISF > 1.75), estos se recomiendan para futuras investigaciones que determinen su respuesta a condiciones de campo y estrategias para el desarrollo de biofertilizantes.

Phosphorus (P) is an essential element in agricultural production, but due to its complex dynamics in the soil, only a tiny amount is usable by plants. This is because most P is in insoluble forms, especially in volcanic Andisol soils. Microorganisms with phosphorus solubilizing capacity (MSF) are an alternative for transforming P into soluble forms usable by plants and providing multiple environmental benefits. This research identified and evaluated in vitro native isolates of Pseudomonas fluorescens Mingula, obtained from Guatemalan regions with Andisol soils that limit agricultural production due to high P fixation. In vitro cultures of the bacteria were grown on the National Botanical Research Instituteís phosphate medium (NBRIP), with tricalcium phosphate Ca3(PO4)2 as a source of insoluble P, and We measured the phosphorus solubilization index (PSI). We identified and confirmed a total of 35 isolates of P. fluorescens by specific PCR. Using the AFLP marker, genetic relationship analysis showed two groups: group A included isolates with PSI greater than 1.75, while group B included those with FSI less than 1.75. Comparing of PSI between isolates and departments showed statistically significant dif-ferences (p < 0.001), respectively, with the Pf_33 isolate as the most efficient. Because of the high solubilization potential of the native isolates of genetic group A (FSI > 1.75), We recommend future research to determine their response to field conditions and strategies for biofertilizer development.

Diversidad genética de materiales nativos de aguacate guatemalteco a través del marcador molecular AFLP / Genetic diversity of native Guatemalan avocado through AFLP molecular marker

El aguacate es un cultivo de consumo a nivel mundial, y según teorías recientes, se sugiere a la región de la Sierra Nevada, en California, como centro de origen y, a Guatemala, como uno de los principales centros de domesticación. Mediante caracterizaciones morfológicas se ha reportado una alta diversidad genética en el país, pero debido al comportamiento de polinización cruzada e hibridaciones interraciales, no se ha podido detallar el estado genético actual de la especie. Sin embargo, los marcadores moleculares son útiles para este tipo de estudios al enfocarse en las diferencias a nivel del ADN. Este estudio analizó la diversidad genética del aguacate nativo guatemalteco de siete poblaciones geográficas con el marcador molecular AFLP. Los datos de estructura poblacional mostraron un alto grado de diversidad a nivel de individuos (Ht = 0.1933, Hw = 0.1872) y baja diferenciación entre poblaciones (Hb = 0.0061). Los resultados sugieren una alta tasa de migración que influye directamente en el grado de mezcla genética de los materiales analizados. El bajo índice de estructura poblacional apunta a un alto flujo genético entre las poblaciones, por lo que la especie no presenta mayor riesgo ante la deriva genética, minimizándose el riesgo de pérdida de alelos por fijación. Se sugiere el resguardado del recurso fitogénetico total y no únicamente de materiales promisorios, evitando así el riesgo de erosión genética de la especie y garantizando la permanencia de la diversidad genética, la cual será la base de futuros programas de mejoramiento.

Avocado is one of the most widely consumed crops worldwide and according to new theories, the Sierra Nevada region in California is suggested as the center of origin and Guatemala as one of the main domestication cen-ters. Through morphological characterizations, a high genetic diversity has been reported in the country, but due to the behavior of cross pollination and interracial hybridizations, it has not been possible to detail the current genetic status of the species. Molecular markers are useful for this type of study by focusing on differences at DNA level. This study analyzed the genetic diversity of the native Guatemalan avocado from seven geographic populations with AFLP molecular marker. Population structure data showed a high degree of diversity at the individual level (Ht = 0.1933, Hw = 0.1872) and low differentiation between populations (Hb = 0.0061). The results suggest a high rate of migration that directly influences the degree of genetic mixing of the analyzed materials. The low index of population structure points to a high genetic flow between populations, so that the species does not present a greater risk due to genetic drift, minimizing the risk of loss of alleles due to fixation. The protection of the total genetic resource is suggested, and not only of promising materials, thus avoiding the risk of genetic erosion of the species and guaranteeing the permanence of genetic diversity, which will be the basis of future breeding programs.

Detección de patógenos asociados a la enfermedad punta morada en los cultivos de papa y tomate en Guatemala / Detection of pathogens associated to potato purple top disease in potato and tomato crops in Guatemala

La punta morada es una enfermedad que afecta la producción de algunas especies de solanáceas como la papa y el tomate, causando enrollamiento en las puntas de las hojas con una marcada coloración morada, decaimiento temprano de la planta y en la papa se observa tuberización aérea. Como patógenos asociados a la enfermedad se consideran al fitoplasma BLTVA y la bacteria Candidatus Liberibacter solanacearum. Dada la similitud en la sin-tomatología foliar que generan ambos patógenos, es difícil precisar cuál de ellos está implicado en la enfermedad. En Guatemala, existen reportes de la sintomatología típica de punta morada en las principales zonas productoras de papa y tomate, desconociéndose el agente asociado. La investigación determinó cuál de los dos patógenos reportados está asociados a la enfermedad en 12 municipios productores de papa y/o tomate en el país. Se realizaron ampli-ficaciones de ADN con cebadores específicos para cada patógeno asociado a la enfermedad. Por la alta incidencia del fitoplasma BLTVA en las muestras de papa (73.9%), en comparación a C. Liberibacter solanacearum (26%), este es considerado como el patógeno asociado más importante en papa. En las muestras de tomate, la incidencia del fitoplasma BLTVA (29.8%) y C. Liberibacter solanacearum del (27.6%) fue similar. Además, sobresale el primer reporte de la detección del fitoplasma BLTVA afectando el cultivo de tomate en Guatemala. Se sugiere un monitoreo constante, mediante métodos moleculares, para un diagnóstico certero y establecer medidas de manejo de la enfermedad para evitar su diseminación hacia zonas aún no afectadas.

The potato purple top is a disease that affects the production of some solanaceous species such as potatoes and tomatoes, causing curl at the tips of the leaves with a marked purple coloration, early decay of the plant, and aerial tuberization is observed in the potato. BLTVA phytoplasma and Candidatus Liberibacter solanacearum are considered as pathogens associated with the disease. Given the similarity in foliar symptoms generated by both pathogens, it is difficult to determine which one is involved in the disease. There are reports of the typical potato purple top symptoms in the main potato and tomato producing areas in Guatemala, being unknown the associated agent. The research determined which of the two reported pathogens is associated with the disease in 12 potatoes and/or tomato producing areas in the country. We performed DNA amplification with specific primers for each disease-associated pathogen. Due to the high incidence of BLTVA phytoplasma in potato samples (73.9%), com-pared to C. liberibacter solanacearum (26%), this is considered the most important associated pathogen in potatoes. In tomato samples, the incidence of BLTVA phytoplasma (29.8%) and C. liberibacter solanacearum (27.6%) was similar. Besides, the first report of the detection of the BLTVA phytoplasma affecting tomato cultivation in Gua-temala stands out. Using molecular methods, constant monitoring is suggested for an accurate diagnosis and to establish management measures for the disease to prevent its spread to areas not yet affected.

Movement dynamics of divisome proteins and PBP2x:FtsW in cells of Streptococcus pneumoniae.

Bacterial cell division and peptidoglycan (PG) synthesis are orchestrated by the coordinated dynamic movement of essential protein complexes. Recent studies show that bidirectional treadmilling of FtsZ filaments/bundles is tightly coupled to and limiting for both septal PG synthesis and septum closure in some bacteria, but not in others. Here we report the dynamics of FtsZ movement leading to septal and equatorial ring formation in the ovoid-shaped pathogen, Streptococcus pneumoniae Conventional and single-molecule total internal reflection fluorescence microscopy (TIRFm) showed that nascent rings of FtsZ and its anchoring and stabilizing proteins FtsA and EzrA move out from mature septal rings coincident with MapZ rings early in cell division. This mode of continuous nascent ring movement contrasts with a failsafe streaming mechanism of FtsZ/FtsA/EzrA observed in a ΔmapZ mutant and another Streptococcus species. This analysis also provides several parameters of FtsZ treadmilling in nascent and mature rings, including treadmilling velocity in wild-type cells and ftsZ(GTPase) mutants, lifetimes of FtsZ subunits in filaments and of entire FtsZ filaments/bundles, and the processivity length of treadmilling of FtsZ filament/bundles. In addition, we delineated the motion of the septal PBP2x transpeptidase and its FtsW glycosyl transferase-binding partner relative to FtsZ treadmilling in S. pneumoniae cells. Five lines of evidence support the conclusion that movement of the bPBP2x:FtsW complex in septa depends on PG synthesis and not on FtsZ treadmilling. Together, these results support a model in which FtsZ dynamics and associations organize and distribute septal PG synthesis, but do not control its rate in S. pneumoniae.

Evaluación de la resistencia de genotipos de tomate frente a aislados de Phytophthora infestans provenientes de Guatemala / Evaluation of the resistance of tomato genotypes against isolates of Phytophthora infestans from Guatemala

El oomicete Phytophthora infestans (Mont) DeBary es el patógeno responsable de causar la enfermedad denominada comúnmente como tizón tardío. Dicho patógeno afecta cultivos de importancia económica para el país, entre ellos el tomate, cultivo en el cual puede generar pérdidas totales en la producción. Dada la agresividad del patógeno, los programas de mejoramiento desarrollan nuevos genotipos de tomate resistentes a esta enfermedad mediante la incorporación de genes de resistencia, como los genes Ph. Sin embargo, las nuevas cepas de P. infestans, producto de la recombinación genética, pueden sobrepasar la resistencia de los genotipos mejorados. En este estudio se evaluó la resistencia genética de 13 genotipos de tomate mejorados, ante cinco aislados de P. infestans obtenidos de un estudio previo. Mediante inoculaciones in vitro y con la variable de respuesta de área bajo la curva del progreso de la enfermedad (AUDPC), se determinó que existió diferencia estadísticamente significativa (p < 0.05) entre el comportamiento de la resistencia, la agresividad de los aislados del patógeno y la interacción entre ambos factores. Además, se sugiere el uso de algunas líneas para ser incorporadas en programas de mejoramiento genético y así desarrollar nuevos genotipos aptos para el país y, por último, la profundización para establecer las bases genéticas de la resistencia de los dos cultivares evaluados en este estudio.

The oomycete Phytophthora infestans (Mont) DeBary causes late blight disease. This pathogen affects economically important crops for the country, including tomato, a crop in which it can causes total losses in production. Given the aggressiveness of the pathogen, tomato breeding programs develop new genotypes with resistance to P. infestans, being a source of resistance Ph genes. However, the new strains of P. infestans, product of the genetic variability of their populations, can overcome the resistance of the genotypes. In this study, the genetic resistance of 13 tomato materials was evaluated against 5 isolates of P. infestans obtained from a previous study. Through in vitro inoculations and with the area under the disease progress curve (AUDPC), it was determined that there was a statistically significant difference (p < 0.05) between the behavior of the genetic resistance, the aggressiveness of the isolates of the pathogen and the interaction between both factors. It is also suggested the use of some lines to be incorporated into tomato breeding programs and develop new genotypes suitable for the country and, finally, to establish the genetic basis of the resistance of the two cultivars evaluated in this study.

Disfunción tiroidea inducida por amiodarona en pacientes portadores de arritmias / Thyroid dysfunction induced by Amiodarone in patient with arrhythmias

Evaluar la presencia de disfunción tiroidea en pacientes con arritmias cardíacas tratados con Amiodarona (AMD) Métodos: se realizó el estudio en 24 pacientes que presentaron arritmias supraventriculares o ventriculares tratados con AMD, atendidos en el Servicio de Medicina Interna de la Ciudad Hospitalaria "Dr. Enrique Tejera" durante el período julio 2015 ­ abril 2016. Se les determinaron T3L, T4L y TSH a manera de tamizaje previo a la administración de AMD y fueron citados y divididos en 3 grupos de 3, 6 y 12 meses de tratmiento de AMD con determinación del perfil tiroideo en la consulta. Resultados: El hipotiroidismo inducido por AMD (HIA) se presentó en 20,83% (n=5), siendo más frecuente en aquellos pacientes asculinos que tenían 3 meses de tratamiento y que recibían una dosis de 1400 mg/semanal. La tirotoxicosis inducida por AMD (TIA) se presentó en 8,33% (n=2) ambos masculinos con dosis de 1400 mg/semanal. No se encontró asociación entre HIA y TIA con el tiempo, dosis, grupo etario ni género (P>0,05). T3L, T4L y TSH registraron el mayor y menor promedio a los 12 y 3 meses (P < 0,05); 12 y 6 meses; 3 y 12 meses respectivamente. Conclusión: La frecuencia de HIA fue de 20,83 % y TIA de 8,33 %. No hubo asociación estadísticamente significativa entre la HIA o TIA con la duración de consumo, dosis, grupo etario ni género. La TSH presentó el mayor promedio a los 3 meses, la T3L y T4L a los 12 meses (AU)

to evaluate the presence of thyroid dysfunction in patients with cardiac arrhythmia who were treated with Amiodarone (AMD). Methods: the study was done in 24 patients who were treated for supraventricular or ventricular arrhythmia at the Department of Internal Medicine of Hospital "Dr. Enrique Tejera" in Valencia, Venezuela from July 2015 to April 2016. FT3, FT4 and TSH were measured to the administration of AMD. The patients were divided in 3 groups according to time of use of the drug as follows: 3, 6 and 12 months, and their thyroid function was measured at each of these periods. Results: 20.83 % (n=5) presented Amiodarone induced hypothyroidism (AIH), which was more frequent in males at 3 months of treatment and who received 1400 mg weekly. Amiodarone induced thyrotoxicosis (AIT) was found in 8.33% (n=2) also in male patients using 1400mg weekly. There was no association between AIH or AIT and duration, dose of AMD, age or gender. (p>0.05) FT3, FT4 and TSH registered their higher and lower averages on 12 and 3 months (P < 0,05); 12 and 6 months; 3 and 12 months respectively. Conclusion: AIH's frequency was 20.83 % and 8.33% for AIT. There was no statistically significant association between AIH or AIT and duration, dose of AMD, age or gender TSH average measure was higher at 3 months and the FT3 and FT4 at 12 months(AU)

Diversidad genética de aislados de Phytophthora infestans colectados en zonas productoras de papa y tomate de Guatemala / Genetic diversity of Phytophthora infestans isolates collected from tomato and potato producing areas in Guatemala

Phytophthora infestans (Mont) DeBary es el agente causal de la enfermedad conocida como tizón tardío, la cual ha sido catalogada como la enfermedad de plantas más devastadora reportada en la historia de la humanidad. Este patógeno afecta plantas de importancia económica de la familia solanaceae, como el tomate y la papa. P. infestans es un oomicete heterotálico y necesita de dos tipos de apareamiento, A1 y A2, para presentar reproducción sexual, la cual es la vía por la que este patógeno incrementa su grado de diversidad, a través de una recombinación de su material genético, que representa el mayor desafío para el manejo de la enfermedad. Este estudio determinó el nivel de variabilidad genética, a través del marcador molecular amplified fragment length polymorphism (AFLP), de 22 aislados de P. infestans colectados en diferentes zonas productoras de papa y tomate. Con el perfil de bandas generado por el marcador molecular, se realizó un análisis cluster y se elaboró un dendograma de tipo unweighted pair group method with arithmetic mean (UPGMA), con el índice de Dice, mediante una matriz de distancias genéticas. Los aislados fueron situados en tres grupos principales, los cuales responden al lugar de procedencia y al tipo de planta hospedera. Se encontró un valor de similitud de 0.49 entre los aislados analizados, por lo que se concluyó que la variabilidad genética de P. infestans en Guatemala es alta.

Phytophthora infestans (Mont) DeBary is the causal agent of late blight disease, which has been cataloged as the most devasting plant disease in the history of humankind. This pathogen is capable of affecting economically important plants of the solanaceae family, such as tomato and potato. P. infestans is a heterothallic oomycete for which it needs two types of mating known as A1 and A2 to present a sexual reproduction, which is the main way by this pathogen increases its degree of genetic diversity through a recombination of its genetic material; this condition represents the major defiance to control this disease. This study determined the level of genetic variability, through the molecular marker amplified fragment length polymorphism (AFLP), of 22 P. infestans isolates collected in different potato and tomato producing areas in Guatemala. With the band profile generated by the molecular marker AFLP, a cluster analysis was performed creating a UPGMA dendrogram with Dice´s index through a genetic distances matrix. The isolates were located in three main groups, which respond to the place of origin and the type of host plant. A similarity value of 0.49 was found among the analyzed isolates. It is concluded that genetic variability of the isolates analyzed is high.

Absence of the KhpA and KhpB (JAG/EloR) RNA-binding proteins suppresses the requirement for PBP2b by overproduction of FtsA in Streptococcus pneumoniae D39.

Suppressor mutations were isolated that obviate the requirement for essential PBP2b in peripheral elongation of peptidoglycan from the midcells of dividing Streptococcus pneumoniae D39 background cells. One suppressor was in a gene encoding a single KH-domain protein (KhpA). ΔkhpA suppresses deletions in most, but not all (mltG), genes involved in peripheral PG synthesis and in the gpsB regulatory gene. ΔkhpA mutations reduce growth rate, decrease cell size, minimally affect shape and induce expression of the WalRK cell-wall stress regulon. Reciprocal co-immunoprecipitations show that KhpA forms a complex in cells with another KH-domain protein (KhpB/JAG/EloR). ΔkhpA and ΔkhpB mutants phenocopy each other exactly, consistent with a direct interaction. RNA-immunoprecipitation showed that KhpA/KhpB bind an overlapping set of RNAs in cells. Phosphorylation of KhpB reported previously does not affect KhpB function in the D39 progenitor background. A chromosome duplication implicated FtsA overproduction in Δpbp2b suppression. We show that cellular FtsA concentration is negatively regulated by KhpA/B at the post-transcriptional level and that FtsA overproduction is necessary and sufficient for suppression of Δpbp2b. However, increased FtsA only partially accounts for the phenotypes of ΔkhpA mutants. Together, these results suggest that multimeric KhpA/B may function as a pleiotropic RNA chaperone controlling pneumococcal cell division.

Suppression and synthetic-lethal genetic relationships of ΔgpsB mutations indicate that GpsB mediates protein phosphorylation and penicillin-binding protein interactions in Streptococcus pneumoniae D39.

GpsB regulatory protein and StkP protein kinase have been proposed as molecular switches that balance septal and peripheral (side-wall like) peptidoglycan (PG) synthesis in Streptococcus pneumoniae (pneumococcus); yet, mechanisms of this switching remain unknown. We report that ΔdivIVA mutations are not epistatic to ΔgpsB division-protein mutations in progenitor D39 and related genetic backgrounds; nor is GpsB required for StkP localization or FDAA labeling at septal division rings. However, we confirm that reduction of GpsB amount leads to decreased protein phosphorylation by StkP and report that the essentiality of ΔgpsB mutations is suppressed by inactivation of PhpP protein phosphatase, which concomitantly restores protein phosphorylation levels. ΔgpsB mutations are also suppressed by other classes of mutations, including one that eliminates protein phosphorylation and may alter division. Moreover, ΔgpsB mutations are synthetically lethal with Δpbp1a, but not Δpbp2a or Δpbp1b mutations, suggesting GpsB activation of PBP2a activity. Consistent with this result, co-IP experiments showed that GpsB complexes with EzrA, StkP, PBP2a, PBP2b and MreC in pneumococcal cells. Furthermore, depletion of GpsB prevents PBP2x migration to septal centers. These results support a model in which GpsB negatively regulates peripheral PG synthesis by PBP2b and positively regulates septal ring closure through its interactions with StkP-PBP2x.

Roles of the Essential Protein FtsA in Cell Growth and Division in Streptococcus pneumoniae.

Streptococcus pneumoniae is an ovoid-shaped Gram-positive bacterium that grows by carrying out peripheral and septal peptidoglycan (PG) synthesis, analogous to model bacilli, such as Escherichia coli and Bacillus subtilis In the model bacilli, FtsZ and FtsA proteins assemble into a ring at midcell and are dedicated to septal PG synthesis but not peripheral PG synthesis; hence, inactivation of FtsZ or FtsA results in long filamentous cells unable to divide. Here, we demonstrate that FtsA and FtsZ colocalize at midcell in S. pneumoniae and that partial depletion of FtsA perturbs septum synthesis, resulting in elongated cells with multiple FtsZ rings that fail to complete septation. Unexpectedly, complete depletion of FtsA resulted in the delocalization of FtsZ rings and ultimately cell ballooning and lysis. In contrast, depletion or deletion of gpsB and sepF, which in B. subtilis are synthetically lethal with ftsA, resulted in enlarged and elongated cells with multiple FtsZ rings, with deletion of sepF mimicking partial depletion of FtsA. Notably, cell ballooning was not observed, consistent with later recruitment of these proteins to midcell after Z-ring assembly. The overproduction of FtsA stimulates septation and suppresses the cell division defects caused by the deletion of sepF and gpsB under some conditions, supporting the notion that FtsA shares overlapping functions with GpsB and SepF at later steps in the division process. Our results indicate that, in S. pneumoniae, both GpsB and SepF are involved in septal PG synthesis, whereas FtsA and FtsZ coordinate both peripheral and septal PG synthesis and are codependent for localization at midcell.IMPORTANCEStreptococcus pneumoniae (pneumococcus) is a clinically important human pathogen for which more therapies against unexploited essential targets, like cell growth and division proteins, are needed. Pneumococcus is an ovoid-shaped Gram-positive bacterium with cell growth and division properties that have important distinctions from those of rod-shaped bacteria. Gaining insights into these processes can thus provide valuable information to develop novel antimicrobials. Whereas rods use distinctly localized protein machines at different cellular locations to synthesize peripheral and septal peptidoglycans, we present evidence that S. pneumoniae organizes these two machines at a single location in the middle of dividing cells. Here, we focus on the properties of the actin-like protein FtsA as an essential orchestrator of peripheral and septal growth in this bacterium.

Tratamiento de heridas del complejo buco-facial con Tisuacryl® / Treatment of buco-facial complex wound with Tisuacryl®

Introducción: el adhesivo hístico Tisuacryl® tiene la propiedad de adherirse al tejido vivo y sellar heridas recientes, por lo que se emplea en el tratamiento de las heridas faciales y de la mucosa oral.Objetivo: evaluar la efectividad y seguridad del Tisuacryl® en el cierre de heridas faciales y de la mucosa oral.Método: se realizó un estudio monocéntrico controlado, aleatorizado no secuencial, paralelo abierto y de extensión terapéutica en el Servicio de Cirugía Maxilofacial del Hospital Provincial General Docente Dr. Antonio Luaces Iraola de Ciego de Ávila, en el período de julio de 2002 a julio de 2014. La muestra se compuso de 340 pacientes que acudieron al Servicio en ese período, distribuidos en dos grupos: el Grupo A (de estudio), tratado con Tisuacryl®, y el B (de control) con sutura. Se realizaron evaluaciones secuenciales para determinar la efectividad de los tratamientos; los datos se recogieron en tablas y se procesaron estadísticamente.Resultados: las heridas se localizaron más frecuentemente en la mucosa bucal; de los casos tratados con Tisuacryl®, 99,4 por ciento no presentaron dehiscencias. Los pacientes del Grupo A lograron la hemostasia en un tiempo de cinco a 15 minutos, no presentaron infección ni reacciones adversas; la cicatrización a los 10 días se evaluó de satisfactoria, y a los 30 de buena en la mayoría de los casos. Las diferencias con los pacientes del Grupo B fueron estadísticamente significativas.Conclusiones: el Tisuacryl® resultó ser efectivo y seguro en el cierre de las heridas faciales y de la mucosa oral(AU)

Introduction: the tissue adhesive Tisuacryl® has the property of adhering to living tissue and seal recent injuries, so it is used in the treatment of facial and oral mucosa injuries.Objective: to evaluate the effectiveness and safety of Tisuacryl® in closing facial and oral mucosa injuries.Method: a monocentric controlled, randomized nonsequential, open parallel and therapeutic extension study was carried out in the Service of Maxillofacial Surgery at the Provincial General Teaching Hospital Dr. Antonio Luaces Iraola of Ciego de Ávila, from July 2002 to July 2014. The sample consisted of 340 patients who attended the service in that period, divided into two groups: Group A (study), treated with Tisuacryl®, and B (control) with suture. Sequential evaluations were conducted to determine the effectiveness of treatments; data was collected in tables and were statistically processed.Results: wounds were most frequently located in the oral mucosa; of cases treated with Tisuacryl®, 99,4 percent had no dehiscence. Patients in Group A achieved haemostasis in a time of five to 15 minutes, they showed no infection or adverse reactions; healing at 10 days was evaluated as satisfactory, and at 30 days was evaluated good in most cases. Differences with patients in Group B were statistically significant.Conclusions: Tisuacryl® proved to be effective and safe in closing facial and oral mucosa wounds(AU)

Injerto óseo onlay. Presentación de un caso / Onlay bone graft. One case presentation

Introducción: la cirugía implantológica se clasifica en cirugía implantológica básica y de avanzada. Las técnicas quirúrgicas de cirugía implantológica de avanzada comprenden la dilatación ósea del reborde alveolar, la distracción osteogénica, la elevación de la mucosa del seno maxilar, reposición del nervio mentoniano, regeneración ósea guiada e injerto óseo. El injerto óseo se indica cuando es necesario aumentar la cantidad de tejido óseo en zonas que van a recibir implantes dentales.Presentación del caso: se presenta un paciente al que se le realizó cirugía implantológica de avanzada mediante injerto óseo onlay; se utiliza como zona donante de hueso un torus mandibular.Conclusiones: en ocasiones la falta de hueso en sentido anteroposterior dificulta la implantología dental, por lo que se debe realizar un injerto óseo previo a la misma; en este caso se utilizó el torus mandibular como zona donante de hueso para el injerto óseo. Se ilustra el trabajo con fotografías del acto quirúrgico (AU)

Introduction: implant surgery is classified into basic and advanced implant surgery. Surgical techniques of advanced implant surgery include the alveolar bone dilation, the osteogenesis distraction, the lifting of the mucosa of the maxillary sinus, chins nerve replacement, guided bone regeneration and bone graft. The bone graft is indicated when it is necessary to increase the amount of bone tissue in areas that will receive dental implants.Case report: a patient who underwent implant surgery using advanced bone graft onlay is presented. It is used bone mandibular torus as a donor site.Conclusions: sometimes the lack of bone in anteroposterior direction difficult dental implant, so that must be done a prior bone graft to the same; in this case the torus mandibular area was used as donor bone for bone grafting. The work is illustrated with photographs of surgery (AU)

Comportamiento de la salud bucal de la población perteneciente a la Clínica Estomatológica Centro / Oral health behavior of the population belonging to the Dental Clinic of the Center Area

Introducción: las afecciones bucales constituyen un importante problema de salud por su alta prevalencia, fuerte impacto sobre el individuo y la sociedad en términos de dolor, malestar, discapacidad funcional y social, así como también por su demanda de servicios públicos.Método: se realizó un estudio observacional descriptivo en 1487 personas pertenecientes al área de atención de la Clínica Estomatológica Centro de la ciudad de Ciego de Ávila, en el período comprendido de enero a diciembre del año 2014. Los datos se obtuvieron en las viviendas de las familias objeto de estudio y se aplicó la encuesta de salud buco-dental a los mayores de 15 años.Resultados: la población, en su mayoría, es adulta. Los factores de riesgo que más incidieron fueron la deficiente higiene bucal y los antecedentes de caries. En la población menor de 19 años el índice de dientes con caries con obturación permanente fue de 4,2 en los varones de 10-19 años. Entre los adultos el 47,6 por ciento de los pacientes masculinos están afectados con alguna periodontopatía; el 36,5 por ciento, de los pacientes masculinos de la tercera edad necesitan prótesis.Conclusiones: la clasificación epidemiológica que predominó fue enfermo . Los principales problemas detectados fueron la caries dental, la enfermedad periodontal, la disfunción masticatoria y, en menor grado, las maloclusiones. El nivel de conocimientos sobre salud buco-dental de la población en estudio se evaluó de regular , según los resultados de la encuesta aplicada(AU)

Introduction: oral diseases are a major health problem because of its high prevalence, strong impact on the individual and society in terms of pain, discomfort, functional and social disabilities as well as their demand for public services. Method: a descriptive observational study was conducted on 1487 people from the Dental Clinic of Center Area of the city of Ciego de Avila, in the period from January to December 2014. Data were collected in the homes of the families studied and a health survey dentibuccal was applied to patients older than 15 years.Results: the population, mostly, is adult. The most influenced risk factors were poor oral hygiene and caries experience. In the population under 19 years the rate of decayed teeth with permanent filling was 4,2 in males 10-19 years. Among adults, 47,6 percent of male patients are affected with some periodontal disease; 36,5 percent of male patients seniors need prostheses.Conclusions: prevailed the epidemiological classification as sick. The main problems were dental caries, periodontal disease, masticatory dysfunction and, in lesser degree, malocclusions. The level of knowledge about oral health of the population under study is evaluated as regular according to the results of the survey applied(AU)