•Flow activation enthalpy for surfactant-chitosan solutions varies from 3 to 40kJmol−1.•C12E8 addition of 5wt% induced the occurrence of a second enthalpy of activation.•DLS indicated that addition ...of C12E8 induced a second mode of relaxation at 10−3μs−1.•Relaxation rate activation-enthalpies were in the same range of flow activation ones.•Interactions between CS and wormlike C12E8 structures seemed to cause observed changes.
In this work we used rheometry and DLS to probe relaxation phenomena in solutions of chitosan and octa-ethyleneglycol-monododecylether. The dispersions had a marked pseudoplastic behavior, which became less evident, as surfactant concentration was increased. Arrhenius plots showed that systems with surfactant presented a characteristic temperature at which apparent enthalpy of activation (varying from 3 to 40kJmol−1) changed: this change was correlated to a possible transition of colloidal aggregates to a wormlike configuration. DLS intensity correlation functions were described by KWW equation: pure chitosan solutions had relaxation rate distributions centered at a characteristic relaxation rate around 4.6×10−6μS−1; as surfactant was added, a new component, with a faster characteristic relaxation rate with a magnitude order of 10−3μs−1, appeared. It was shown that the dependence between these relaxation rates and surfactant concentration could be used to describe DLS-related relaxation phenomena as an Arrhenius-activated process, agreeing with results obtained using rheometry.
The study aimed to evaluate the effects of two different sheep milk-based food matrices – fermented sheep milk and ice cream – with added probiotic bacteria (Lactobacillus casei 431) on dental enamel ...subjected to an in vitro highly cariogenic challenge. Sixty enamel blocks were selected and randomly allocated into five treatment groups (n=12): conventional fermented sheep milk (CFSM), probiotic fermented sheep milk (PFSM), conventional sheep milk ice cream (CSMIC), probiotic sheep milk ice cream (PSMIC) and control using deionized water. The blocks were subjected to highly cariogenic pH cycling and the products were applied (5min), in a blinded way, once a day to simulate a daily use for 8 consecutive days. A microhardness test was performed before and after the treatment to estimate the percentage of microhardness surface loss (% SML). Scanning electronic microscopy (SEM) was performed to confirm the mineral loss. All groups had lost microhardness after the experiment. However, CFSM and PFSM exhibited the most positive findings when compared to the control in both ice creams. Scanning electron microscopy showed less mineral loss in CFSM and PFSM compared with CSMIC, PSMIC and control after the cariogenic challenge. Overall, fermented milk decreased mineral loss from enamel subjected to a highly cariogenic challenge, regardless of the presence of probiotics in their composition, which had a higher efficacy compared to ice cream.
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•Performance of probiotic sheep milk fermented milk and ice cream through cariogenic challenge•Adequate probiotic counts in both dairy matrices•Probiotic sheep milk ice cream did not prevent the enamel hardness, regardless of probiotic presence.•Probiotic and conventional fermented milk decreased mineral loss and topographical changes.
Varroa destructor is an ectoparasite mite that attacks bees leading to colony disorders worldwide. microRNAs (miRNAs) are key molecules used by eukaryotes to post-transcriptional control of gene ...expression. Nevertheless, still lack information aboutV. destructor miRNAs and its regulatory networks. Here, we used an integrative strategy to characterize the miRNAs in the V. destructor mite. We identified 310 precursors that give rise to 500 mature miRNAs, which 257 are likely mite-specific elements. miRNAs showed canonical length ranging between 18 and 25 nucleotides and 5′ uracil preference. Top 10 elements concentrated over 80% of total miRNA expression, with bantam alone representing ~50%. We also detected non-templated bases in precursor-derived small RNAs, indicative of miRNA post-transcriptional regulatory mechanisms. Finally, we note that conserved miRNAs control similar processes in different organisms, suggesting a conservative role. Altogether, our findings contribute to the better understanding of the mite biology that can assist future studies on varroosis control.
•Characterization of Varroa destructor miRNAs•Identification of 310 precursors that give rise to 500 mature miRNAs•miRNA can be found in cluster co-regulating many targets.•Existence of miRNA post-transcriptional regulatory mechanisms•Identification of conserved elements that play similar role in different organisms.
Terpenoids, also named terpenes or isoprenoids, are a family of natural products found in all living organisms. Many plants produce terpenoids as secondary metabolites, and these make up a large part ...of essential oils. One of most important characteristic is that the compounds are volatile, have odor and can be used in a variety of applications in different industrial segments and traditional medicine. Brazil has a rich and diverse flora that can be used as a source of research for obtaining new molecules. Within the Brazilian flora, it is worth mentioning the Caatinga as an exclusively Brazilian biome where plants adapt to a specific series of weather conditions and therefore become a great storehouse of the terpenoid compounds to be described herein. Fungal infections have become increasingly common, and a great demand for new agents with low toxicity and side effects has thus emerged. Scientists must search for new molecules exhibiting antifungal activity to develop new drugs. This review aims to analyze scientific data from the principal published studies describing the use of terpenes and their biological applications as antifungals.
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► Chitosan nanoparticles obtained using the coacervation method are subjected to enthalpic and entropic influences. ► Enthalpic effect relates to interactions between electrically ...charged sites and enthalpic effect to spatial arrangement of counter-ions. ► Initially chitosan macromolecular coils shrink, then they collapse, forming clusters of nanometric dimensions. ► If acid concentration is high enough, nanoparticle formation is mainly driven by entropic effects.
Chitosan nanoparticles have been used in several systems destined to controlled release of active agents. In this manuscript the process of formation of chitosan nanoparticles, obtained employing the coacervation method with sodium sulfate is analyzed using zeta potential and small angle X-ray scattering (SAXS) measurements. Dispersions were obtained at pH
=
1 and pH
=
3 and presented a behavior, in terms of surface charging, that was independent of pH. However, SAXS results indicated a dependence of size-related behavior on pH. The difference in terms of behavior was explained through the influence of enthalpic and entropically driven components.
Alevi et al cite that currently, there are 153 species of triatomines, distributed in 18 genera, being all species considered as potential vector of Chagas disease. The genus Panstrongylus Berg, 1879 ...is composed of 15 species, being 14 species alive and one fossil. Cytogenetic analyses in Panstrongylus were initiated in 1950 with the karyotype description of P megistus. Until now the number of chromosomes in seven species of Panstrongylus was described, of which with the exception of P megistus which has 21 chromosomes, all other species analyzed have 23 chromosomes. Here, they describe the number of chromosomes of P lutzi 2n = 24 (20A + X1X2X3Y), suggests that karyotype arose from one agmatoploidy event of the X sex chromosome and mainly apply these data as taxonomic tool to differentiate this vector of other species of the genus Panstrongylus, as well as subfamily Triatominae.
Since historical times, the inherent human fascination with pearls turned the freshwater pearl mussel Margaritifera margaritifera (Linnaeus, 1758) into a highly valuable cultural and economic ...resource. Although pearl harvesting in M. margaritifera is nowadays residual, other human threats have aggravated the species conservation status, especially in Europe. This mussel presents a myriad of rare biological features, e.g. high longevity coupled with low senescence and Doubly Uniparental Inheritance of mitochondrial DNA, for which the underlying molecular mechanisms are poorly known. Here, the first draft genome assembly of M. margaritifera was produced using a combination of Illumina Paired-end and Mate-pair approaches. The genome assembly was 2.4 Gb long, possessing 105,185 scaffolds and a scaffold N50 length of 288,726 bp. The ab initio gene prediction allowed the identification of 35,119 protein-coding genes. This genome represents an essential resource for studying this species' unique biological and evolutionary features and ultimately will help to develop new tools to promote its conservation.
Particulate systems composed of polyelectrolyte complexes (PEC) based on chitosan and poly(methacrylic acid) were obtained via template polymerization. The resultant particles were characterized as ...having regions with different charge densities: chitosan predominating in the core and poly(methacrylic acid) at the surface, the particles being negatively charged, as a consequence. Albumin was adsorbed on these particles (after cross-linking with glutardialdehyde), and pH was controlled to obtain two conditions: (i) adsorption of positively charged albumin and (ii) adsorption of albumin at its isoelectric point. Adsorption isotherms and ζ-potential measurements showed that albumin adsorption was controlled by hydrogen bonding/van der Waals interactions and that brush-like structures may enhance the adsorption of albumin on these particles. It was also found that shearing can induce desorption of albumin from the PEC surface, depending on the continuous phase albumin concentration.
In this work two kinds of material were studied: chitosan cross-linked with glutaraldehyde and in a blend with PEO. The resulting products as well as chitosan and PEO raw materials, were analyzed by ...TG/DTG, DSC and DMTA to determinate the in?uence of cross-linking and PEO addition on thermal properties of the resulting materials. It was observed by thermogravimetry that the water-polymer interaction will be different for the cross-linked material compared to the blend, according to the specific site availability. The in?uence of such modifications (cross-linking and PEO addition), on chitosan thermal stability was also studied. The DSC results showed a good agreement with the TG/DTG results, reinforcing the interpretation given for TG/DTG results. DMTA results indicate that glass transition temperature is around 50
°C for the polymer under study.
Inflammatory breast cancer (IBC) is a rare and aggressive type of breast cancer whose molecular basis is poorly understood. We performed a comprehensive molecular analysis of 24 IBC biopsies naïve of ...treatment, using a high-resolution microarray platform and targeted next-generation sequencing (105 cancer-related genes). The genes more frequently affected by gains were MYC (75%) and MDM4 (71%), while frequent losses encompassed TP53 (71%) and RB1 (58%). Increased MYC and MDM4 protein expression levels were detected in 18 cases. These genes have been related to IBC aggressiveness, and MDM4 is a potential therapeutic target in IBC. Functional enrichment analysis revealed genes associated with inflammatory regulation and immune response. High homologous recombination (HR) deficiency scores were detected in triple-negative and metastatic IBC cases. A high telomeric allelic imbalance score was found in patients having worse overall survival (OS). The mutational profiling was compared with non-IBC (TCGA, n = 250) and IBC (n = 118) from four datasets, validating our findings. Higher frequency of TP53 and BRCA2 variants were detected compared to non-IBC, while PIKC3A showed similar frequency. Variants in mismatch repair and HR genes were associated with worse OS. Our study provided a framework for improved diagnosis and therapeutic alternatives for this aggressive tumor type.
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