Biological variability dominates and influences analytical variance in HPLC-ECD studies of the human plasma metabolome

<p>Abstract</p> <p>Background</p> <p>Biomarker-based assessments of biological samples are widespread in clinical, pre-clinical, and epidemiological investigations. We previously developed serum metabolomic profiles assessed by HPLC-separations coupled with coulometric array detection that can accurately identify <it>ad libitum </it>fed and caloric-restricted rats. These profiles are being adapted for human epidemiology studies, given the importance of energy balance in human disease.</p> <p>Methods</p> <p>Human plasma samples were biochemically analyzed using HPLC separations coupled with coulometric electrode array detection.</p> <p>Results</p> <p>We identified these markers/metabolites in human plasma, and then used them to determine which human samples represent blinded duplicates with 100% accuracy (N = 30 of 30). At least 47 of 61 metabolites tested were sufficiently stable for use even after 48 hours of exposure to shipping conditions. Stability of some metabolites differed between individuals (N = 10 at 0, 24, and 48 hours), suggesting the influence of some biological factors on parameters normally considered as analytical.</p> <p>Conclusion</p> <p>Overall analytical precision (mean median CV, ~9%) and total between-person variation (median CV, ~50–70%) appear well suited to enable use of metabolomics markers in human clinical trials and epidemiological studies, including studies of the effect of caloric intake and balance on long-term cancer risk.</p

Effects of probiotic bacteria on Candida presence and IgA anti-Candida in the oral cavity of elderly

Imbalance in the resident microbiota may promote the growth of opportunistic microorganisms, such as yeasts of Candida genus and the development of diseases, especially in aged people. This study evaluated whether the consumption of the probiotic Yakult LB® (Lactobacillus casei and Bifidobacterium breve) was able to influence on the specific immunological response against Candida and on the presence of these yeasts in the oral cavity of 42 healthy aged individuals. Saliva samples were collected before and after the probiotic use for 30 days, 3 times a week. The samples were plated in Dextrose Saboraud Agar with chloramphenicol, the colony-forming units (CFU/mL) were counted and the Candida species were identified. Anti-Candida IgA analysis was conducted using the ELISA technique. ANOVA and Student's t-test were used for normally distributed data and the Wilcoxon test was used for data with non-normal distribution (α=0.05). The results showed a statistically significant reduction (p<0.05) in Candida prevalence (from 92.9% to 85.7%), in CFU/mL counts of Candida and in the number of non-albicans species after consumption of the probiotic. Immunological analysis demonstrated a significant increase (p<0.05) in anti-Candida IgA levels. In conclusion, probiotic bacteria reduced Candida numbers in the oral cavity of the elderly and increased specific secretory immune response against these yeasts, suggesting its possible use in controlling oral candidosis.Basic Institute of Biosciences UNITAU - University of Taubaté, Taubaté, SPSão José dos Campos Dental School Universidade Estadual Paulista (UNESP), São José dos Campos, SPSão José dos Campos Dental School Universidade Estadual Paulista (UNESP), São José dos Campos, S

Unravelling salt stress in plants through proteomics

Plants like other organisms are mostly under the threat of various stresses (both biotic as well as abiotic). Being sessile, plants lack the mechanisms to flee from these unfavourable situations. The development of exclusive and complicated responses to these environmental stresses in plants has fostered through evolution. Such alterations can influence plant growth, production and productivity in agriculture, plant nutritional potential and metabolic profile. Hence, plant abiotic stress has always been a matter of concern for the world economy and maintenance of human life on earth. Salinity stress, being one of the main abiotic stresses, may bring the morphological, anatomical, and physiological changes in plants. Distributed in both irrigated and non-irrigated areas of the world, around 6% of the world’s total land area is affected by salt stress. So, it is a major concern to adopt the strategies against this great challenge by unravelling the mechanisms to overcome salt stress. In order to meet the challenges for biotechnological improvement of crop productivity; various steps involving genes, transcripts, proteins and metabolites, controlling the stress resistance and/or architecture of crop plants in a wide array of environments needed to be recognized. Proteomics, the protein complement of genome, these days is one of the leading branches of research which enables the large-scale ­scanning of various substances, and offers great potential for post-genomics to elucidate the genotype-phenotype connections. The present chapter is an account of current knowledge in this regard. It focuses on effects of salt stress unrevealed by proteomics tools. It comprises information on recent advances in proteomics, which could be a new opportunity to comprehend abiotic responses and categorize genes responsible for significant crop traits

Metabolomics for crop improvement against salinity stress

In the post-genomic era, increasing efforts have been done to describe the relationship between genome and phenotype in plants. It has become clear that even a complete understanding of the state of the genes, messages, and proteins in a living system does not reveal its phenotype. Metabolites are the main readouts of gene vs environment interactions and represent the sum of all the levels of regula- tion in between gene and enzyme. Therefore, metabolome can be considered as the final recipient of biological information flow. Some metabolites have a very short lifetime and are indicators of specific metabolic reaction and of plant status. Indeed, it is well known that many of them are transformed during specific stresses and involved in plant stress response and resistance. Salinity provides an important example of the effectiveness of metabolic changes in response to stress. In fact, exposure to salinity triggers specific strategies for cell osmotic adjustment and control of ion and water homeostasis to minimize stress damage and to reestablish growth. A ubiquitous mechanism that plants have evolved to adapt to salinity involves sodium sequestration in the vacuole, as a cheap osmoticum, and synthesis and accumulation of compatible compounds, both for osmotic adjustment and oxidative stress protection in the cytosol. Metabolomics has been utilized for the study of plants in response to salinity stress in order to dissect particular patterns associated with stress tolerance. These studies have proven that certain metabolites are present in case of salt-induced met- abolic dysfunction and can act as effectors of osmotic readjustment or antioxidant response. Thus, the presence of particular metabolite patterns can be associated with stress tolerance and could serve as accurate markers for salt-tolerant crop selection in breeding programs

Antimicrobial Activity and pH of Calcium Hydroxide and Zinc Oxide Nanoparticles Intracanal Medication and Association with Chlorhexidine

AIM: To evaluate pH and antibacterial activity of pastes with calcium hydroxide [Ca(OH)2] and zinc oxide (ZnO) microparticles (micro) or nanoparticles (nano) and association with 0.4% chlorhexidine against Enterococcus faecalis. MATERIALS AND METHODS: The following pastes were analyzed: Ca(OH)2/ZnO micro, (2) Ca(OH)2/ZnO nano, (3) Ca(OH)2/ ZnO micro + 0.4% chlorhexidine, (4) Ca(OH)2/ZnO nano + 0.4% chlorhexidine. Antibacterial activity against E. faecalis was evaluated by agar diffusion test. The direct contact test on planktonic cells of E. faecalis was performed for 30 and 60 seconds. Root canals from bovine teeth were filled with the pastes and pH was evaluated after 1, 7, 14, 21, 30 and 60 days. The data obtained were submitted to the statistical tests analysis of variance (ANOVA) and Tukey or Kruskal-Wallis and Dunn test, with a 5% significance level. RESULTS: Calcium hydroxide and zinc oxide nano, and the pastes with 0.4% chlorhexidine were more effective in agar diffusion test. In the direct contact test, the pastes with chlorhexidine showed the highest effect after 30 seconds. All pastes eliminated E. faecalis after 60 seconds. All pastes promoted an increase in pH. The highest increase in pH was observed with nanoparticle medications after 1 and 7 days (p < 0.05). After this period, the pastes presented similar pH increase. CONCLUSION: It was concluded that calcium hydroxide and zinc oxide nanoparticles promoted greater initial alkalinization. The antimicrobial activity of the pastes against E. faecalis is favored by the association with chlorhexidine. CLINICAL SIGNIFICANCE: Although nanoparticles of calcium hydroxide and zinc oxide promoted antibacterial effect, the activity against E. faecalis is favored by association with chlorhexidine.Department of Restorative Dentistry Araraquara Dental Schoo