Probing the Gelation Synergies and Anti-Escherichia coli Activity of Fmoc-Phenylalanine/Graphene Oxide Hybrid Hydrogel.

The N-fluorenyl-9-methyloxycarbonyl (Fmoc)-protected amino acids have shown high antimicrobial application potential, among which the phenylalanine derivative (Fmoc-F) is the most well-known representative. However, the activity spectrum of Fmoc-F is restricted to Gram-positive bacteria only. The demand for efficient antimicrobial materials expanded research into graphene and its derivatives, although the reported results are somewhat controversial. Herein, we combined graphene oxide (GO) flakes with Fmoc-F amino acid to form Fmoc-F/GO hybrid hydrogel for the first time. We studied the synergistic effect of each component on gelation and assessed the material's bactericidal activity on Gram-negative Escherichia coli (E. coli). GO flakes do not affect Fmoc-F self-assembly per se but modulate the elasticity of the gel and speed up its formation. The hybrid hydrogel affects E. coli survival, initially causing abrupt bacterial death followed by the recovery of the surviving ones due to the inoculum effect (IE). The combination of graphene with amino acids is a step forward in developing antimicrobial gels due to their easy preparation, chemical modification, graphene functionalization, cost-effectiveness, and physicochemical/biological synergy of each component.

Reliability and validity in Mexico of the Spanish version of the Children's Fear Survey Schedule - Dental Subsca.

AIM: Low attendance and abandonment of dental treatment caused by dental fear varies from 6% to 20%. Various specific scales have been used to evaluate and measure dental fear, like Children´s Fear Survey Schedule - Dental Subscale, which is considered the "gold standard", due to its efficacy and validity. However, not all the studies that have been conducted have performed the Exploratory Factorial and Confirmation Analysis to infer the validity of the scale's content, which is why this study has as its main objective to analyse the confidentiality and validation of this scale. MATERIALS AND METHODS: In a sample of 163 school age children, from 6 to 12 years old, of both genders, from a public school, a Children's Fear Survey Schedule - Dental Subscale was applied to measure dental fear. The internal consistency of the scale was estimated with the Cronbach's alpha, we also performed the Exploratory Factorial Analysis with the method of the main component with Varimax rotation and the Confirmatory Factorial Analysis to confirm the structure of the factors. RESULTS: The Cronbach's alpha was obtained with a .837 (p?.05). The adequate coefficients were determined with the Kaiser-Meyer-Olkin (KMO = .843) and the Bartlett's test of specificity (?2 = 565,325, p= .000), in which there was a good adequate data, expressing an appropriate and intercorrelation between items or strongly related. The factorial structure showed four factors extracted, 4 factors explain the 53.57% of the accumulated variation; 14 items were above the .40. The statistics of the second and third model obtained adequate values in the statistics of goodness of fit index. CONCLUSION: The Mexican version of the CFSS-DS in the present study gives us data about the adaptation and validation of the dental fear scale of CFSSS-DS by the Exploratory Factorial Analysis through a model of structural equations. This means that this instrument is a trusting and valid tool to measure dental fear in the children's population of Mexico.

Aflatoxin-degrading Bacillus sp. strains degrade zearalenone and produce proteases, amylases and cellulases of agro-industrial interest.

Zearalenone, an oestogenic mycotoxin produced by Fusarium sp., occurs naturally in agricultural commodities. Economic losses and health concerns associated to mycotoxins has attracted research interest towards exploring novel approaches to detoxify mycotoxin-contaminated food and feed. The aim of the present work was to study the ability of 11 aflatoxin-degrading Bacillus strains to degrade ZEA. In addition, a qualitative assessment of protease, amylase and cellulase activity of the studied Bacillus strains was made. All strains were able to degrade 58-96.9% ZEA after 72 h. Toxicity towards Artemia salina was significantly reduced (P < 0.0001). Degradation extracts fluorescence decreased 50% indicating a probable cleavage of the lactone ring. Strains RC1A, RC3A and RC6A showed a remarkable enzymatic activity, showing potential to be used as feed additives.

Ubiquitous giants: a plethora of giant viruses found in Brazil and Antarctica.

BACKGROUND: Since the discovery of giant viruses infecting amoebae in 2003, many dogmas of virology have been revised and the search for these viruses has been intensified. Over the last few years, several new groups of these viruses have been discovered in various types of samples and environments.In this work, we describe the isolation of 68 giant viruses of amoeba obtained from environmental samples from Brazil and Antarctica. METHODS: Isolated viruses were identified by hemacolor staining, PCR assays and electron microscopy (scanning and/or transmission). RESULTS: A total of 64 viruses belonging to the Mimiviridae family were isolated (26 from lineage A, 13 from lineage B, 2 from lineage C and 23 from unidentified lineages) from different types of samples, including marine water from Antarctica, thus being the first mimiviruses isolated in this extreme environment to date. Furthermore, a marseillevirus was isolated from sewage samples along with two pandoraviruses and a cedratvirus (the third to be isolated in the world so far). CONCLUSIONS: Considering the different type of samples, we found a higher number of viral groups in sewage samples. Our results reinforce the importance of prospective studies in different environmental samples, therefore improving our comprehension about the circulation anddiversity of these viruses in nature.