Molecular and serological prevalence of Coxiella burnetii in bovine dairy herds in southern Chile: A PCR and ELISA-based assessment of bulk tank milk samples.

Coxiella burnetii (C. burnetii) is a highly resilient zoonotic bacterium responsible for Q fever, a disease which occurs worldwide, with the exception of New Zealand. However, in Chile, the prevalence and impact of C. burnetii in cattle herds remain poorly understood due to limited research. This study aimed to assess the presence of C. burnetii in dairy cattle herds in southern Chile, using two diagnostic methods on bulk tank milk samples. The results of the study revealed a high prevalence of C. burnetii infection in the analyzed herds. Of the 271 milk tank samples tested, 76% (208/271, CI: 71.1-81.5) tested positive using ELISA, while 73% (200/271, CI: 68.0-78.8) tested positive using qPCR. These findings indicate a significant presence of C. burnetii in the cattle herds studied. Despite the high prevalence observed, no new Q fever outbreaks have been reported in the study area. This discrepancy highlights the need for further research to better understand the transmission dynamics, environmental factors, and livestock management practices associated with C. burnetii infection. These studies will contribute to the development of effective prevention and control strategies and promote public health regarding Q fever.

Extracciones e indicaciones de extracciones dentales en población rural chilena de 11 a 30 años

Introducción: A pesar de la creciente tecnología odontológica y el progresivo aumento de la cantidad de odontólogos, el precario estándar de salud oral de la población rural se ha mantenido a lo largo del tiempo. El objetivo de esta investigación es describir y cuantificar las exodoncias de piezas dentarias permanentes en población rural. Metodología: Se realizó un estudio de tipo descriptivo seleccionando el 100% de los sujetos atendidos en el Consultorio Chol-Chol, (IX Región) de 11 a 30 años de edad que obtuvieron su alta integral durante los años2001 y 2003. Los diagnósticos fueron realizados por dos odontólogos experimentados en ausencia de apoyo radiográfico (procedimiento realizado de acuerdo al instrumental y equipos disponibles). Se evaluó el estado de cada una de las piezas dentarias exceptuando los terceros molares. Resultados: Fueron analizadas 181 fichas clínicas de los cuales el 36,42% fueron del sexo masculino, siendo la edad media de la muestra 18,27 años. 143 sujetos presentaron piezas perdidas en el momento del examen, a 117 sujetos se les indico extracción de piezas dentales permanentes. Al finalizar el tratamiento 167 (92,2%) sujetos presentaron ausencia de piezas dentarias permanentes, con un promedio de 5,6 piezas al finalizar el alta integral.Conclusión: Los pacientes adolescentes y adultos jóvenes en condiciones de ruralidad presentan alta frecuencia de patologías orales que determinan la exodoncia de las piezas dentales. Estos pacientes necesitaran a corto plazo extensas rehabilitaciones para recuperar su sistema estomatognático.(AU)

Identification and localization of the Tgl protein, which is required for Myxococcus xanthus social motility.

Tgl protein is required for the production of the type IV pili found at a pole of the Myxococcus xanthus cell. These pili are essential for social motility. Evidence is presented that Tgl is a membrane protein, based on experiments with polyclonal antibody specific for Tgl that was raised against the fusion proteins beta-galactosidase-Tgl and TrpE-Tgl. Immunoaffiity-purified antibody reacted with a protein in M. xanthus having an apparent molecular mass of 27.5 kDa as measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, while the sequence of the tgl gene translates into a polypeptide of 27 kDa. Although these numbers are close, it is likely that the primary tgl translation product is processed and modified in M. xanthus. The N terminus has a signal peptidase II recognition sequence, cleavage of which is expected to remove 19 amino acid residues. When the tgl gene is expressed in Escherichia coli, the protein product consistently migrates faster in the gel than mature Tgl expressed in M. xanthus, suggesting a second modification by addition which slows migration of the protein from M. xanthus. Tgl, as detected by its specific antibody, sediments with the membrane fraction of cells. It can be extracted with detergents but not with salt or by the addition of chelators for divalent cations. In an equilibrium gradient, Tgl bands at the buoyant density of membranes and with the NADH-oxidase activity. Intact cells failed to bind anti-Tgl antibody, and less than 2% of the total Tgl is released in soluble form from the periplasm. Yet, cells that had been osmotically shocked and treated with paraformaldehyde were able to react with the specific antibody--a reaction absent from cells with a deletion of the tgl transcription unit. Assuming that osmotic shock disrupts the outer membrane, the fractionation and localization data imply that Tgl is attached to the inner or outer membranes, from which it is exposed to the intermembranous space. Tgl is necessary for synthesis of pili in M. xanthus and is the only pilus protein that can be donated by other cells (stimulation). Tgl contains six tandem copies of the tetratrico peptide repeat structural motif. Its membrane localization, capacity for stimulation, and content of tetratrico structural repeats together suggest that Tgl may be necessary for the assembly of pilin subunits into filaments.

The tgl gene: social motility and stimulation in Myxococcus xanthus.

Mutations in the tgl locus inactivate social gliding motility in Myxococcus xanthus and block production of pili. The tgl locus is distinctive among the genes for social motility because social gliding and pili can be restored transiently to tgl mutant cells by mixing them with tgl+ cells, a process known as stimulation. The tgl locus was cloned with a linked insertion of transposon Tn5 by using the kanamycin resistance encoded by that transposon. A 16-kb segment of chromosomal DNA complemented the social motility defect when introduced into tgl mutant cells to form a tandem duplication tgl+/tgl heterozygote. To delimit the autonomous tgl transcription unit, subfragments of this 16-kb piece were integrated at the ectopic Mx8 prophage attachment site. A 1.7-kb DNA fragment was identified which, when integrated at the Mx8 site, simultaneously rescued social motility and pilus production. The ability to stimulate tgl mutants was also rescued by the 1.7-kb fragment. Because rescue of stimulation from an mgl-deficient donor strain which cannot swarm was observed, this demonstrates that a stimulation donor requires a tgl+ allele but does not require the capacity to swarm actively. The nucleotide sequence of the 1.7-kb fragment revealed two protein coding regions, open reading frame A and open reading frame B (ORFB). ORFB is the tgl gene, because a 613-bp DNA fragment which includes 75% of ORFB rescues tgl-1, -2, and -3 mutants and because disruption of ORFB by deletion or insertion of transposon Tn5lac constitutes a tgl mutation.