Bioremediation potential of Cd by transgenic yeast expressing a metallothionein gene from Populus trichocarpa.

Cadmium (Cd) is an extremely toxic environmental pollutant with high mobility in soils, which can contaminate groundwater, increasing its risk of entering the food chain. Yeast biosorption can be a low-cost and effective method for removing Cd from contaminated aqueous solutions. We transformed wild-type Saccharomyces cerevisiae (WT) with two versions of a Populus trichocarpa gene (PtMT2b) coding for a metallothionein: one with the original sequence (PtMT2b 'C') and the other with a mutated sequence, with an amino acid substitution (C3Y, named here: PtMT2b 'Y'). WT and both transformed yeasts were grown under Cd stress, in agar (0; 10; 20; 50 µM Cd) and liquid medium (0; 10; 20 µM Cd). Yeast growth was assessed visually and by spectrometry OD600. Cd removal from contaminated media and intracellular accumulation were also quantified. PtMT2b 'Y' was also inserted into mutant strains: fet3fet4, zrt1zrt2 and smf1, and grown under Fe-, Zn- and Mn-deficient media, respectively. Yeast strains had similar growth under 0 µM, but differed under 20 µM Cd, the order of tolerance was: WT < PtMT2b 'C' < PtMT2b 'Y', the latter presenting 37% higher growth than the strain with PtMT2b 'C'. It also extracted ~80% of the Cd in solution, and had higher intracellular Cd than WT. Mutant yeasts carrying PtMT2b 'Y' had slightly higher growth in Mn- and Fe-deficient media than their non-transgenic counterparts, suggesting the transgenic protein may chelate these metals. S. cerevisiae carrying the altered poplar gene offers potential for bioremediation of Cd from wastewaters or other contaminated liquids.

Cadmium background concentrations to establish reference quality values for soils of São Paulo State, Brazil.

Proper assessment of soil cadmium (Cd) concentrations is essential to establish legislative limits. The present study aimed to assess background Cd concentrations in soils from the state of São Paulo, Brazil, and to correlate such concentrations with several soil attributes. The topsoil samples (n = 191) were assessed for total Cd contents and for other metals using the USEPA 3051A method. The background concentration was determined according to the third quartile (75th). Principal component analysis, Spearman correlation, and multiple regressions between Cd contents and other soil attributes (pH, cation exchange capacity (CEC), clay content, sum of bases, organic matter, and total Fe, Al, Zn, and Pb levels) were performed. The mean Cd concentration of all 191 samples was 0.4 mg kg(-1), and the background concentration was 0.5 mg kg(-1). After the samples were grouped by parent material (rock origin) and soil type, the background Cd content varied, i.e., soils from igneous, metamorphic, and sedimentary rocks harbored 1.5, 0.4, and 0.2 mg kg(-1) of Cd, respectively. The background Cd content in Oxisols (0.8 mg kg(-1)) was higher than in Ultisols (0.3 mg kg(-1)). Multiple regression demonstrated that Fe was primarily attributed to the natural Cd contents in the soils (R (2) = 0.79). Instead of a single Cd background concentration value representing all São Paulo soils, we propose that the concentrations should be specific for at least Oxisols and Ultisols, which are the primary soil types.

Case-specific characteristics of pink teeth in dental autopsies - A systematic review.

The cadaveric alterations that derive from the decomposition of the human body are often investigated and examined in medical autopsies together with any other evidence of thanatological interest. This study aimed to systematically review case-specific characteristics of dental autopsies that reported the pink tooth phenomenon (PTP). The review was performed in October/2018 and followed PRISMA and Cochrane guidelines. Seven databases were searched as primary study sources (PubMed, Scopus, LILACS, SciELO, Web of Science, Science Direct and Embase) and three (OATD, Open Grey and Open Thesis) were searched for "grey literature". Only descriptive studies were collected, namely case reports and case series. The risk of bias among the studies was assessed with The Joanna Briggs Institute Critical Appraisal tool. From each case, the sex and age of the victims were registered, together with the place of body recovery, time of death, cadaveric status, cause of death, and number and position of pink teeth. Additionally, a supplemental quantitative analysis was conducted within a sampled subgroup. Poisson regression with robust variance was used to analyze relative risks of presenting pink teeth according to age and tooth position. Eleven studies out of 1004 were eligible. In total 71 cases of cadavers with pink teeth were reported. Two (2.81%) victims had unknown sex, while 17 (23.95%) were females and 52 (73.24%) were males. The victims were aged between 4 and 85 years (mean age 31.13 ±â€¯13.32). Dental autopsies registered 331 pink teeth (163 anterior, 87 premolars and 81 molars). The age did not influence on presenting an additional pink tooth, regardless of tooth position (p > 0.05). Forensic dentists must be aware of pink teeth in dental autopsies. This is an unspecific phenomenon and must not be misinterpreted in medico-legal investigations.

Influence of Maternal Satisfaction with the Dentist in Children's Oral Care: Cross-Sectional Study / Influencia de la Satisfacción Materna con el Dentista en la Salud Oral del Niño: Estudio Transversal

ABSTRACT: Childhood is a period of life when the human being is constantly going through progressive steps of psychosocial, physical, and mental development. The quality of hygiene habits of family members will be reflected on the characteristics and attitudes of children, which significantly increases the responsibility of the family in oral hygiene education. The present study aimed to observe the influence of maternal satisfaction with the dentist in children's oral care. This is a cross-sectional design, which sample included 100 mothers from a city in Southern Brazil. From a questionnaire prepared for this purpose and adapted from previous research, the mothers were interviewed from January to July 2015. The results presented showed that most mothers work outside the home (46.4 %) but monitor their children during toothbrushing (50.7 %). For most mothers, the dentist represents satisfaction (37.1 %) and the main reason for seeking the dentist is oral health (44.3 %). It was found that mothers who encourage their children to use dental floss and monitor them during toothbrushing are the mothers who feel satisfied with the dentist (P < 0.05). In addition, mothers know that caries is a disease and its occurrence is related to diet habits, however, they add chocolate milk and sugar to their children's bottle. Thus, it was concluded that satisfaction with the dentist influences mothers on oral hygiene habits adopted by their children regarding the use of dental floss and toothbrushing monitoring.

RESUMEN: La infancia es un período de la vida en que el ser humano está en constante y progresivo desarrollo psicológico, físico y mental. La calidad de la higiene oral de otros miembros de la familia se va a reflejar directamente en las características y actitudes de los niños, aumentando significativamente la responsabilidad de la familia en la educación sobre higiene oral. El presente trabajo tuvo como objetivo observar la influencia que tiene la satisfacción de la madre con el cirujano dentista respecto a las acciones de la salud oral de los niños. Se trató de un estudio de tipo transversal, cuya muestra no probabilística contó con 100 madres de una ciudad del Sur de Brasil. A partir de un cuestionario elaborado para este fin y adaptado de investigaciones anteriores, las madres fueron entrevistadas en el período de enero a julio de 2015. Los resultados mostraron que la mayoría de las madres trabajaban fuera de la casa (46,4 %), pero acompañaban a su hijo durante el cepillado (50,7 %). La mayoría de ellas estaba conforme con la atención del cirujano dentista (37,1 %) y el mayor motivo de su búsqueda fue la salud oral (44,3 %). Se verificó que las madres que incentivaban el uso del hilo dental por parte de los hijos y que realizaban el acompañamiento durante el cepillado eran las madres que se sentían conformes con la atención del cirujano dentista (p<0,05). Además de esto, las madres saben que la caries es una enfermedad y que su surgimiento tiene relación con la alimentación, pero igualmente le incorporaban cacao en polvo y azúcar a la mamadera de sus hijos. De esta manera, fue posible concluir que, la satisfacción con la atención del cirujano dentista influye a las madres en los hábitos de higiene oral adoptados por sus hijos, en lo relativo al uso del hilo dental y el cepillado dental.