Quantitative Physiology and Proteome Adaptations of Bifidobacterium breve NRBB57 at Near-Zero Growth Rates.

In natural environments, nutrients are usually scarce, causing microorganisms to grow slowly while staying metabolically active. These natural conditions can be simulated using retentostat cultivations. The present study describes the physiological and proteome adaptations of the probiotic Bifidobacterium breve NRBB57 from high (0.4 h-1) to near-zero growth rates. Lactose-limited retentostat cultivations were carried out for 21 days in which the bacterial growth rate progressively reduced to 0.00092 h-1, leading to a 3.4-fold reduction of the maintenance energy requirement. Lactose was mainly converted into acetate, formate, and ethanol at high growth rates, while in the retentostat, lactate production increased. Interestingly, the consumption of several amino acids (serine, aspartic acid, and glutamine/arginine) and glycerol increased over time in the retentostat. Morphological changes and viable but nonculturable cells were also observed in the retentostat. Proteomes were compared for all growth rates, revealing a downregulation of ribosomal proteins at near-zero growth rates and an upregulation of proteins involved in the catabolism of alternative energy sources. Finally, we observed induction of the stringent response and stress defense systems. Retentostat cultivations were proven useful to study the physiology of B. breve, mimicking the nutrient scarcity of its complex habitat, the human gut. IMPORTANCE In natural environments, nutrients are usually scarce, causing microorganisms to grow slowly while staying metabolically active. In this study we used retentostat cultivation to investigate how the probiotic Bifidobacterium breve adapts its physiology and proteome under severe nutrient limitation resulting in near-zero growth rates (<0.001 h-1). We showed that the nutrient limitation induced a multifaceted response including stress defense and stringent response, metabolic shifts, and the activation of novel alternative energy-producing pathways.

Habitat Disturbances Modulate the Barrier Effect of Resident Soil Microbiota on Listeria monocytogenes Invasion Success.

Microbial communities are continuously exposed to the arrival of alien species. In complex environments such as soil, the success of invasion depends on the characteristics of the habitat, especially the diversity and structure of the residing bacterial communities. While most data available on microbial invasion relies on experiments run under constant conditions, the fate of invading species when the habitat faces disturbances has not yet been addressed. Here, we designed experiments to assess the consequences of habitat disturbance on the success of ongoing microbial invasion. We investigated (i) if disturbance-induced alterations in resident microbial communities could mitigate or facilitate invasion of Listeria monocytogenes, (ii) if disturbance itself could either improve or reduce the invader's fitness and (iii) if the invading species alters the structure of indigenous microbial communities. Our data show that environmental disturbances affect invasion patterns of L. monocytogenes in soils. Intriguingly, successful invasion was recorded in a regimen of disturbances that triggered small changes in microbial community structure while maintaining high bacterial diversity. On the opposite, dramatic decline of the invader was recorded when disturbance resulted in emergence of specific communities albeit concomitant with a diversity loss. This suggests that community composition is more important than its diversity when it comes to prevent the establishment of an invading species. Finally, shifts in bacterial communities during the disturbance event were strengthened by the presence of the invader indicating a major impact of invasion on microbial diversity when the habitat faces disturbance.

Diagnostic performance of fractal dimension and radiomorphometric indices from digital panoramic radiographs for screening low bone mineral density

A number of panoramic radiographic measurements have been associated with osteoporotic alterations. However, little is known about the differences in sensitivity and specificity among these measurements for screening low bone mineral density (BMD). Aim: To correlate and compare precision, sensitivity and specificity of panoramic radiomorphometric indices and fractal dimension (FD) for screening low BMD (i.e. osteopenia and osteoporosis). Methods: Sixty-eight female patients (42.78±15.59 years) were included in this study. Body mass index (BMI), mandibular cortical index (MCI), mandibular cortical width (MCW), FD and connectivity (C) were assessed. Low BMD was diagnosed by peripheral dual-energy X-ray absorptiometry (p-DXA). Non-parametric correlations were assessed among all variables. In addition, sensitivity and specificity of MCI, MCW and FD were estimated for screening low BMD. Results: Significant correlation was found between FD and BMI (p=0.013; r=0.269). In addition, FD was the most sensitive method for screening low BMD (70.8%, p=0.001). FD and MCI presented a significant and relatively high sensitivity, whereas MCW presented a high specificity for screening low systemic BMD Conclusions: Among the analyzed methods, FD and MCI offer a significant and relatively high sensitivity, whereas MCW offers a high specificity for screening low BMD (Au)

Fusion or gemination? An unusual mandibular second molar.

Fusion and gemination is not an uncommon finding and affected most primary dentition and the permanent maxillary incisors. These changes can develop a series of complication. A 11-year-old male presented radiography finding: an unusual mandibular second molar. A well-documented case brings a challenge for radiologists classify between fusion and gemination. In conclusion, this alteration although common in other regions, there are no case in the literature involving "second and third" molar.

¿Dónde Ocurre el Aprendizaje? / Where Learning Happens?

Sobre la base de los planteamientos básicos del aprendizaje situado, este artículo presenta los resultados de un estudio que explora los escenarios donde los escolares de secundaria buscan información o adquieren ciertos conocimientos específicos. Metodológicamente, el estudio aplicó el enfoque de Teoría de Facetas para identificar las variables involucradas en las conexiones posibles entre escenarios y contenidos de aprendizaje. 298 estudiantes de secundaria (135 hombres y 163 mujeres) respondieron un cuestionario sobre la frecuencia de búsqueda de cierto tipo de contenidos en ciertos escenarios. Los resultados confirmaron la faceta construida para los escenarios y reconfiguraron la faceta de contenidos en una polaridad. A partir de estos resultados, se elaboraron conclusiones respecto al alcance de los planteamientos del aprendizaje situado y se formularon interrogantes para futuros estudios que exploren el papel que juegan los nuevos escenarios de aprendizaje en la formación de los estudiantes.

Under the basic principles of situated learning, this paper presents the results of a study that explores about the scenarios where information is looked up or certain specific knowledge is acquired by high school students. Methodologically, the study applied Facet Theory to identify the variables involved in the possible connections between scenarios and learning contents. A total of 298 high school students (135 males and 163 females) answered a questionnaire about the frequency with which certain contents are looked up in certain scenarios, such as: the school, the city, home and the web. The results confirm the scenarios' facet and restructure the contents' facet in terms of a polarity. Some conclusions about the extension of situated learning principles were made and questions for future studies that explore the role of new learning scenarios in students' education were asked.

Comparación de dos métodos radiológicos para evaluación de densidad ósea en mujeres posmenopáusica / Comparison of two radiological methods for evaluation of bone density in postmenopausal women

Debido a la importancia del diagnóstico precoz de osteoporosis, fue objeto de este estudio realizar la comparación de dos métodos radiológicos convencionales para la evaluación de la densidad ósea en mujeres posmenopáusicas. Fueron seleccionadas imágenes de radiografía panorámica y de radiografía carpal, correspondiente a 68 pacientes de sexo femenino, con edades comprendidas entre los 49 y 80 años de edad, realizadas en la Clínica de Radiología Odontológica, para evaluación previa a la colocación de implantes. Para la interpretación de la densidad ósea en la mandíbula a través de las radiografías panorámicas fue utilizado el método del espesor cortical mandibular (PMI). Para la evaluación de las imágenes radiológicas obtenidas por la radiografía carpal, fue aplicado el método de la radiogrametría. Se concluye que existe correlación entre la presencia de una baja densidad ósea a nivel mandibular observada en la radiografía panorámica en las pacientes de la muestra, con la baja densidad ósea presentada en la radiografía carpal.

Due the importance of diagnosis precocious of osteoporosis, this study carried out the comparison of two conventional radiological methods for the evaluation of bone density in postmenopausal women. X-ray images of panoramic and carpal were selected, corresponding to 68 women between 49 and 80 years old, obtained at the Clinic of Dental Radiology, for holding dental implant. The interpretation of bone density in jaw on panoramic radiography was the method to determine mandibular cortical thickness. The carpal radiography was evaluated for the radiogrammetry method. It was concluded that there was a correlation between low bone density observed in the mandibular panoramic radiography with low bone density on carpal radiography.

Performance of stress resistant variants of Listeria monocytogenes in mixed species biofilms with Lactobacillus plantarum.

Population diversity and the ability to adapt to changing environments allow Listeria monocytogenes to grow and survive under a wide range of environmental conditions. In this study, we aimed to evaluate the performance of a set of acid resistant L. monocytogenes variants in mixed-species biofilms with Lactobacillus plantarum as well as their benzalkonium chloride (BAC) resistance in these biofilms. L. monocytogenes LO28 wild type and acid resistant variants were capable of forming mixed biofilms with L. plantarum at 20°C and 30°C in BHI supplemented with manganese and glucose. Homolactic fermentation of glucose by L. plantarum created an acidic environment with pH values below the growth boundary of L. monocytogenes. Some of the variants were able to withstand the low pH in the mixed biofilms for a longer time than the WT and there were clear differences in survival between the variants which could not be correlated to (lactic) acid resistance alone. Adaptation to mild pH of liquid cultures during growth to stationary phase increased the acid resistance of some variants to a greater extent than of others, indicating differences in adaptive behaviour between the variants. Two variants that showed a high level of acid adaptation when grown in liquid cultures, showed also better performance in mixed species biofilms. There were no clear differences in BAC resistance between the wild type and variants in mixed biofilms. It can be concluded that acid resistant variants of L. monocytogenes show diversity in their adaptation to acidic conditions and their capacity to survive in mixed cultures and biofilms with L. plantarum.

Undifferentiated osteosarcoma of the mandible oblique line: a case report / Osteossarcoma indiferenciado da mandíbula: relato de caso clínico na região do trígono retromolar

O osteossarcoma (OS) é o tumor maligno primário mais comum. Entretanto, o osteossarcoma localizado na mandíbula (JOS) é raro, agressivo e maligno, constituindo de 5-13% dos casos de OS do corpo todo. O JOS tem predileção pelo sexo masculino com idade de 34-36 anos. O prognóstico da doença está associado com diversas variáveis tais como a localização do tumor, fase de desenvolvimento, existência ou não de metástases, sexo, idade, e resposta do organismo ao tratamento. Este artigo relata um caso incomum de osteossarcoma localizado na região do trígono retromolar mandibular, composto por osso mesenquimal primitivo, que comumente ocorre nas regiões de extremidades e ossos longos...

This article reports a case of 82 years old woman, who consulted in a private radiology dental clinic for implants planning. In a panoramic radiography, a radiopaque area with sun-ray appearance located above the external oblique line on the right side was observed. The incisional biopsy showed presence of sarcomatous stroma presenting osteoid tissue with irregularly shaped and large amount of osteoblasts, varied sizes and shapes, with prominent nuclei, intensely colored, arranged in a disorderly way around trabecular bone. Histopathological diagnosis was obtained for undifferentiated osteosarcoma. Osteosarcoma located in the jaw (JOS) is rare and aggressive, constituting 5% to 13% of all cases of skeletal osteosarcoma. JOS has a male predilection in third decade of life...

Propriedades tensiométricas do peritônio da paca (Cuniculus paca) a fresco e conservado em glicerina 98 por cento / Tensiometer peritoneum properties of the paca (Cuniculus paca) fresh and preserved in glycerin 98 por cento

In constant searching for alternative biological material to perform implants and new options of experimental animal models, the objective of this investigation was to describe the mechanical properties of the peritoneum paca (Cuniculus paca Linnaeus, 1766) fresh and preserved in 98% glycerin. Samples of fresh and preserved in glycerin for periods of 30, 60 and 90 days were subjected to mechanical tests. Four adult animals, male or female, with mean body weight of eight kilograms, were used for collecting samples of the peritoneum. All tissues preserved in glycerin 98% showed a decrease in stiffness and increase in ductility and toughness. Considering the maximum force applied to the peritoneum, significant increase was observed in values (p<0.01) of samples stored for 60 and 90 days when compared to fresh material. In relation to the stretch variable, an increase was observed in all storage time of glycerin samples, verifying significant difference (p<0,01) when compared with the fresh samples. The variable area also showed significance (p <0.01) between the values of the fresh samples (5.40 mm²) and preserved in the glycerin by periods of 30 days (4.50 mm²), 60 days (9.00 mm²) and 90 days (7.20 mm²), thus indicating that the area of this membrane increased by 0.033 mm² per day. Generally, it was concluded that the 98% glycerin is a substance effective for the preservation of the peritoneum of the agouti paca, therefore improves its mechanical properties allowing the support membranes greater deformation forces. Thus, the results obtained in mechanical tests of the peritoneum of paca suggest its use as an alternative biological material.

Na busca constante, tanto de material biológico alternativo para a realização de implantes, quanto de novas opções de modelos de experimentação animal, o objetivo desta investigação foi descrever o comportamento mecânico do peritônio da paca (Cuniculus paca Linnaeus, 1766) a fresco e conservado em glicerina a 98%. Amostras frescas e conservadas em glicerina por períodos de 30, 60 e 90 dias foram submetidas a testes mecânicos de tração. Quatro animais adultos, três machos e uma fêmeas, com peso corporal médio de oito quilogramas, foram utilizados para colheita das amostras de peritônio. Todos os tecidos conservados em glicerina a 98% apresentaram diminuição na rigidez e aumento na ductibilidade e tenacidade. Considerando-se a força máxima aplicada ao peritônio, evidenciou-se aumento significativo nos valores (p<0,01) das amostras conservadas por 60 e 90 dias, quando comparado ao material a fresco. Com relação a variável alongamento, notou-se aumento nos valores relativos aos materiais em glicerina em todos os tempos de conservação, verificando-se diferença significativa (p<0,01) entre os valores das amostras a fresco. A variável área também se apresentou significativa (p<0,01) entre os valores das amostras a fresco (5,40 mm²) e os preservados em glicerina pelos períodos de 30 dias (4,50 mm²), 60 dias (9,00 mm²) e 90 dias (7,20 mm²), indicando assim, que a área desta membrana aumentou em 0,033 mm² por dia. Mediante os resultados observados, concluiu-se que a glicerina 98% é uma substância eficiente para a conservação do peritônio da paca, pois melhorou suas propriedades mecânicas permitindo que as membranas suportem maiores forças de deformação. Assim, os resultados obtidos nos ensaios mecânicos do peritônio da paca sugerem sua utilização como mais uma opção de material biológico.

Caracterização das paredes corticais do canal da mandíbula para avaliação de alterações causadas pela osteopenia/osteoporose / Characterization the mandibular canal walls to evaluate changes caused by osteopenia / osteoporosis

A osteoporose é uma epidemia mundial, exprime altas taxas de morbidade e mortalidade, resultando também em altos custos sociais. O exame de densitometria óssea por emissão dupla de raios-X (DXA) é o exame padrão ouro para o diagnóstico da doença. Porém, o alto custo e a disponibilidade de equipamentos, dificultam o acesso ao exame, principalmente nos países pobres e nos emergentes. Triar melhor, e mais precocemente os pacientes para realizar o DXA, é uma estratégia fundamental no combate a essa enfermidade. A radiografia panorâmica vem sendo utilizada na rotina do atendimento odontológico no mundo todo, e tem sido empregada como um método de triagem eficiente de pacientes com baixa densidade mineral óssea. O objetivo deste estudo foi analisar as paredes corticais do canal da mandíbula para a avaliação de possíveis alterações causadas pela osteopenia /osteoporose, na expectativa de indicar ou não a correlação entre a qualidade óssea mandibular e a qualidade óssea sistêmica. A amostra constituiu-se por 52 mulheres, com idade superior a 45 anos (56.4 ± 8.4 anos) divididas em três grupos de acordo com o exame de DXA: Grupo N (n= 26) normal nos três sítios (antebraço, quadril e coluna); Grupo E (n= 18) com osteopenia nos três sítios e Grupo O (n= 8) com osteoporose nos três sítios.

Os resultados demonstraram que houve diferenças significativas na quantidade relativa de pixels pretos na região de ramo (R) do canal da mandíbula (p < 0.05) entre as médias verdadeiras quando comparada entre os grupos da amostra. Nas regiões do canal da mandíbula próximo ao forame mentual (FM) e no ângulo (A) e na análise da quantidade de fragmentos os testes estatísticos não evidenciaram a existência de diferenças significativas, apesar dos valores relativos apontarem uma tendência à maior reabsorção das paredes no grupo O e E em relação ao Grupo N. Concluiu-se que a análise das corticais do canal da mandíbula por meio da quantidade de pixels pretos pode ser um instrumento útil ao cirurgião-dentista na avaliação de baixa densidade mineral óssea.

Osteoporosis is a worldwide epidemic, expresses high morbidity and mortality, resulting also in high social costs. The bone densitometry by dual-energy X-ray absorptiometry (DXA) is the gold standard test for diagnosing the disease. However, its high cost and viability are restricted, especially in poor countries and emerging. Screening better and earlier patients to perform DXA, is a key strategy in combating this disease. Panoramic radiography has been used in routine dental care around the world, and has been employed as an efficient method of screening patients with low bone mineral density. The aim of this study was to analyze the cortical walls of the mandibular canal to evaluate possible changes caused by osteopenia / osteoporosis, hoping to indicate or not the correlation between mandibular bone quality and systemic. 52 women were included aged over 45 years (56.4 ± 8.4 years) were divided into three groups according to the DXA exam: Group N (n = 26) normal in three sites (forearm, hip and spine), Group E (n = 18) with osteopenia at the three sites and Group O (n = 8) with osteoporosis in the three sites. Significant differences were found between relative amount of black pixels in the region of the branch (R) of the mandibular canal (p <0.05) and the mean true when compared among groups of samples. In regions of the mandibular canal near the mental foramen (MF), angle (A) and analysis of the amount of fragments statistical tests did not show the significant differences, despite the figures suggest a trend to higher absorption in the walls the E group and to the detriment of group N. It was concluded that the analysis of the cortical the mandibular canal by the number of black pixels may be a useful to the dentist in the evaluation of low bone mineral density.

Langerhans cell histiocytosis (Histiocytosis X) – in the mandible / Histiocitose das células de Langerhans (Histiocitose X): na mandíbula

This article reports a case of 65 year-old man consulted in a private radiology dental clinic for a panoramic radiography, where was indicated a radiolucent area, extending into the periapical region of the teeth 35 to 43 to the base of the mandible. Radiography diagnosis was difficult. The immunohistochemical examination showed immunoreactivity for the proteins CD 68, S-100 and CD 1a. Histopathological diagnosis was obtained for Langerhans cell granuloma (histiocytosis X). Langerhans cell histiocytosis is caused by the abnormal proliferation of histiocytes, previously called Histiocytosis X. It is a rare disease that preferentially affects children and young adults with a predilection for males and can affect different parts of the body.

Este artigo relata o caso de um homem de 65 anos que procurou uma clínica de radiologia dental particular para a realização de uma radiografia panorâmica. Foi detectada uma área radiolúcida na região apical dos dentes 35 a 43 que se estendia até a base da mandíbula. O exame imunoistoquimico da lesão mostrou proteínas reativas como a CD 68, S-100 e CD 1a. O diagnóstico do histopatológico foi de Granuloma de Células de Langerhans (Histiocitose X). A Histiocitose das células de Langerhans é causada pela proliferação anormal de histiócitos. É uma doença rara que preferencialmente acomete crianças e adultos jovens e tem predileção pelo sexo masculino, podendo afetar diferentes partes do corpo.

Assessment of panoramic radiomorphometric indices of the mandible in a brazilian population.

The aim of this study was to evaluate radiomorphometric indices in dental panoramic radiographs in order to identify possible interrelationships between these indices and the sex and age of the patients analyzed. The study included 1287 digital panoramic radiographic images of patients that were grouped into five age groups (1 = age 17-20; 2 = age 21-35; 3 = age 36-55; 4 = age 56-69; 5 = over age 70). Two indices-cortical width at the gonion (GI) and below the mental foramen (MI)-were measured bilaterally in all panoramic radiographs. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney tests (alpha = 0.05). Results for the indices measurements showed significant differences among patient age groups of both sexes, considering that groups 4 and 5 presented lower values for the cortical width of both indices. The present paper supports the role of sex- and age-related changes in mandibular radiomorphometric indices in identifying skeletal osteopenia.

Evaluación de la capacidad probiótica in vitro de una cepa nativa de Saccharomyces cerevisiae / In vitro evaluation of the probiotic capacity of a native strain of saccharomyces cerevisiae

En el presente estudio se evaluó la capacidad probiótica in vitro de una cepa nativa de Saccharomyces cerevisiae (A) y se comparó con una cepa comercial (B) utilizada como probiótico. Para esto se determinó la concentración de melaza de caña (10, 20 y 30 por ciento (p/v)) que permitiera obtener la mayor cantidad de biomasa de las cepas, así mismo se determinaron parámetros cinéticos. La concentración de melaza que arrojó mejores resultados fue 20por ciento (p/v) y se encontró diferencia en la producción de biomasa para la cepa en estudio A (28g/L) y la cepa control B (3g/L) en medio melaza. Se realizaron pruebas in vitro como resistencia a sales biliares, tolerancia a rangos de pH y jugos gástricos, donde no se observaron diferencias entre la cepa A y B al medir el crecimiento. La reducción del colesterol en presencia de sales biliares después de 12 horas de incubación fue de 54 por ciento para la cepa A y 58 por ciento para la B. Por último se realizó una prueba de adherencia en células Caco-2, encontrando adherencia a estas por parte de ambas cepas. De acuerdo con los resultados anteriores se demostró que la cepa A tiene propiedades probióticas in vitro que pueden ser corroboradas con posteriores estudios in vivo que confirmen su utilización como probiótico en nutrición animal.

The in vitro probiotic capacity of a native strain of Saccharomyces cerevisiae (A) was evaluated and compared with a commercial strain (B) used as a probiotic. The effect of the concentration of sugarcane molasses (10, 20 and 30% (w/v)) on the biomass production was investigated and kinetic parameters were determined. The best molasses concentration was 20% (w/v) and differences in biomass production on molasses medium between strain A (28 g/L) and control strain B (3 g/L) were observed. In vitro tests such as tolerance to bile salts, pH and gastric juices were carried out, and no differences in growth between strain A and B were found. Cholesterolreduction on presence of bile salts after 12 hours of incubation was of 54% for strain A and 58% for strain B. Both strains showed adherence to Caco-2 cells. Results reveal that strain A possesses in vitro probiotic propertiesthat can be verified with further in vivo studies to confirm its suitability as probiotic in animal nutrition.