237 research outputs found

    Infusion of Essentail Oils in Agarose Gels to Create Antimicrobial Surfaces

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    The current use of antibiotics is very excessive in multiple settings, from treating patients to being present in cleaning products. This overuse of antibiotics is resulting in multiple consequences, ranging from having a negative impact on human health to breeding antibiotic-resistant strains of microorganisms. Antimicrobial surfaces are useful today to aid in sterilization, especially in the medical setting. This would help prevent the spread of infection of microorganisms in these settings. In our research, agarose acts as the antimicrobial surface and essential oils would act as the solution incorporated into the surface that has the antimicrobial properties. Agarose is a polysaccharide that derives from red algae. It forms long chains and has charged groups linked to it, like sulfate. These residues are responsible for many of agarose’s properties, such as electroendosmosis, which allows it to undergo gel electrophoresis. Thirty-three essential oils tested against bacteria to see if they had any antimicrobial properties. Many of them have historical uses that include as a medicine to treat infections. To create the agarose plates, agarose powder and the solvent heat up to dissolve. The solution went into the plates and multiple essential oils underwent testing for antimicrobial properties by the dispersion of the oils in the plates. Bacteria inoculated the plates and they grew. The results show that of the thirty-three oils tested, oregano, clove, ginger, lemongrass, and frankincense have antimicrobial properties. Of these oils, oregano, clove, and lemongrass have similar results to others in the same field. Ginger and frankincense oils did not have as much research conducted on their antimicrobial properties to determine, so these experiments helped bring new information about these oils to light. Essential oils can help bring natural products to medicine where natural products are rarely used. Future research on this topic can help us determine more essential oils that can be used and more ways these oils can work in a medical setting

    Consumption of a high-salt diet by ewes during pregnancy alters nephrogenesis in 5-month-old offspring

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    Maternal nutrition during pregnancy can affect kidney development in the foetus, which may lead to adverse consequences in the mature kidney. It was expected that high-salt intake by pregnant ewes would lead to a reduction in foetal glomerular number but that the ovine kidney would adapt to maintain homoeostasis, in part by increasing the size of each glomerulus. Merino ewes that were fed either a control (1.5% NaCl) or high-salt (10.5% NaCl) diet during pregnancy, as well as their 5-month-old offspring, were subjected to a dietary salt challenge, and glomerular number and size and sodium excretion were measured. The high-salt offspring had 20% fewer glomeruli compared with the control offspring ( P,0.001), but they also had larger glomerular radii compared with the control offspring ( P,0.001). Consequently, the cross-sectional area of glomeruli was 18% larger in the high-salt offspring than in the control offspring ( P,0.05). There was no difference in the daily urinary sodium excretion between the two offspring groups ( P.0.05), although the high-salt offspring produced urine with a higher concentration of sodium. Our results demonstrated that maternal high-salt intake during pregnancy affected foetal nephrogenesis, altering glomerular number at birth. However, the ability to concentrate and excrete salt was not compromised, which indicates that the kidney was able to adapt to the reduction in the number of glomeruli

    Large-Scale Purification, Characterization, and Spore Outgrowth Inhibitory Effect of Thurincin H, a Bacteriocin Produced by Bacillus thuringiensis SF361

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    Large-scale purification of the highly hydrophobic bacteriocin thurincin H was accomplished via a novel and simple two-step method: ammonia sulfate precipitation and C18 solid-phase extraction. The inhibition spectrum and stability of thurincin H as well as its antagonistic activity against Bacillus cereus F4552 spores were further characterized. In the purification method, secreted proteins contained in the supernatant of a 40h incubated culture of B. thuringiensis SF361 were precipitated by 68% ammonia sulfate and purified by reverse-phase chromatography, with a yield of 18.53mg/l of pure thurincin H. Silver-stained SDS-PAGE, high-performance liquid chromatography, and liquid chromatography-mass spectrometry confirmed the high purity of the prepared sample. Thurincin H exhibited a broad antimicrobial activity against 22 tested bacterial strains among six different genera including Bacillus, Carnobacterium, Geobacillus, Enterococcus, Listeria, and Staphylococcus. There was no detectable activity against any of the selected yeast or fungi. The bacteriocin activity was stable for 30min at 50°C and decreased to undetectable levels within 10min at temperatures above 80°C. Thurincin H is also stable from pH 2-7 for at least 24hat room temperature. Thurincin H is germicidal against B. cereus spores in brain heart infusion broth, but not in Tris-NaCl buffer. The efficient purification method enables the large-scale production of pure thurincin H. The broad inhibitory spectrum of this bacteriocin may be of interest as a potential natural biopreservative in the food industry, particularly in post-processed and ready-to-eat food

    Exploring the longitudinal relationships between the use of grammar in text messaging and performance on grammatical tasks

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    Research has demonstrated that use of texting slang (textisms) when text messaging does not appear to impact negatively on children's literacy outcomes and may even benefit children's spelling attainment. However, less attention has been paid to the impact of text messaging on the development of children's and young people's understanding of grammar. This study therefore examined the interrelationships between children's and young adults' tendency to make grammatical violations when texting and their performance on formal assessments of spoken and written grammatical understanding, orthographic processing and spelling ability over the course of 1 year. Zero-order correlations showed patterns consistent with previous research on textism use and spelling, and there was no evidence of any negative associations between the development of the children's performance on the grammar tasks and their use of grammatical violations when texting. Adults' tendency to use ungrammatical word forms ('does you') was positively related to performance on the test of written grammar. Grammatical violations were found to be positively associated with growth in spelling for secondary school children. However, not all forms of violation were observed to be consistently used in samples of text messages taken 12 months apart or were characteristic of typical text messages. The need to differentiate between genuine errors and deliberate violation of rules is discussed, as are the educational implications of these findings

    Adolescent weak decoders writing in a shallow orthography: process and product

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    It has been hypothesised that students with dyslexia struggle with writing because of a word level focus that reduces attention to higher level textual features (structure, theme development). This may result from difficulties with spelling and/or from difficulties with reading. 26 Norwegian upper secondary students (M = 16.9 years) with weak decoding skills and 26 age-matched controls composed expository texts by keyboard under two conditions: normally and with letters masked to prevent them reading what they were writing. Weak decoders made more spelling errors and produced poorer quality text. Their inter key-press latencies were substantially longer pre-word, at word-end, and within-word. These findings provide some support for the word-level focus hypothesis, although we found that weak decoders were slightly less likely to engage in word-level editing. Masking did not affect differences between weak decoders and controls indicating that reduced fluency was associated with production rather than monitoring what they had produced

    Gamma Irradiation Influences the Survival and Regrowth of Antibiotic-Resistant Bacteria and Antibiotic-Resistance Genes on Romaine Lettuce

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    Contamination of romaine lettuce with human pathogens, antibiotic-resistant bacteria (ARB), and antibiotic resistance genes (ARGs) occurs during production. Post-harvest interventions are emplaced to mitigate pathogens, but could also mitigate ARB and ARGs on vegetables. The objective of this research was to determine changes to lettuce phyllosphere microbiota, inoculated ARB, and the resistome (profile of ARGs) following washing with a sanitizer, gamma irradiation, and cold storage. To simulate potential sources of pre-harvest contamination, romaine lettuce leaves were inoculated with compost slurry containing antibiotic-resistant strains of pathogenic (Escherichia coli O157:H7) and representative of spoilage bacteria (Pseudomonas aeruginosa). Various combinations of washing with sodium hypochlorite (50 ppm free chlorine), packaging under modified atmosphere (98% nitrogen), irradiating (1.0 kGy) and storing at 4°C for 1 day versus 14 days were compared. Effects of post-harvest treatments on the resistome were profiled by shotgun metagenomic sequencing. Bacterial 16S rRNA gene amplicon sequencing was performed to determine changes to the phyllosphere microbiota. Survival and regrowth of inoculated ARB were evaluated by enumeration on selective media. Washing lettuce in water containing sanitizer was associated with reduced abundance of ARG classes that confer resistance to glycopeptides, β-lactams, phenicols, and sulfonamides (Wilcoxon, p < 0.05). Washing followed by irradiation resulted in a different resistome chiefly due to reductions in multidrug, triclosan, polymyxin, β-lactam, and quinolone ARG classes (Wilcoxon, p < 0.05). Irradiation followed by storage at 4°C for 14 days led to distinct changes to the β-diversity of the host bacteria of ARGs compared to 1 day after treatment (ANOSIM, R = 0.331; p = 0.003). Storage of washed and irradiated lettuce at 4°C for 14 days increased the relative abundance of Pseudomonadaceae and Carnobacteriaceae (Wilcoxon, p < 0.05), two groups whose presence correlated with detection of 10 ARG classes on the lettuce phyllosphere (p < 0.05). Irradiation resulted in a significant reduction (∼3.5 log CFU/g) of inoculated strains of E. coli O157:H7 and P. aeruginosa (ANOVA, p < 0.05). Results indicate that washing, irradiation and storage of modified atmosphere packaged lettuce at 4°C are effective strategies to reduce antibiotic-resistant E. coli O157:H7 and P. aeruginosa and relative abundance of various ARG classes

    Grammatical understanding, literacy and text messaging in school children and undergraduate students: a concurrent analysis

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    Recent research has demonstrated that use of texting slang when text messaging does not appear to impact negatively on children and young people's literacy and may even benefit children's spelling attainment. However, less attention has been paid to the impact of text messaging on children's and young people's understanding of grammatical forms. This study examined the interrelationships between 243 children and undergraduate students' grammatical violations made when text messaging and their performance on assessments of spoken and written grammatical understanding, orthographic processing and conventional spelling ability. The children were found to make significantly more capitalisation and punctuation errors, and to use unconventional punctuation more frequently that the adults, when the length of their messages was taken into account. For the primary and secondary school children there was no relationship between the tendency to make grammatical violations when texting and their understanding of conventional grammar or orthography. For the young adult sample, there was some evidence of an association between the tendency to make capitalisation and punctuation errors when texting, and poorer performance in selecting the grammatically correct orthographic representation of a pseudoword. This relationship remained after controlling for individual differences in undergraduates' IQ and spelling ability. Overall, there is little evidence that ungrammatical texting behaviour is linked to grammatical understanding or knowledge of orthographic representations of language in children. However, there is some evidence that young adults' violation of grammatical conventions when texting may be linked to limited understanding of grammatically-related orthographic conventions

    Detrimental effects of ocean acidification on the economically important Mediterranean red coral (Corallium rubrum)

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    The mean predicted decrease of 0.3-0.4 pH units in the global surface ocean by the end of the century has prompted urgent research to assess the potential effects of ocean acidification on the marine environment, with strong emphasis on calcifying organisms. Among them, the Mediterranean red coral (Corallium rubrum) is expected to be particularly susceptible to acidification effects, due to the elevated solubility of its Mg-calcite skeleton. This, together with the large overexploitation of this species, depicts a bleak future for this organism over the next decades. In this study, we evaluated the effects of low pH on the species from aquaria experiments. Several colonies of C. rubrum were long-term maintained for 314 days in aquaria at two different pH levels (8.10 and 7.81, pHT). Calcification rate, spicule morphology, major biochemical constituents (protein, carbohydrates and lipids) and fatty acids composition were measured periodically. Exposure to lower pH conditions caused a significant decrease in the skeletal growth rate in comparison with the control treatment. Similarly, the spicule morphology clearly differed between both treatments at the end of the experiment, with aberrant shapes being observed only under the acidified conditions. On the other hand, while total organic matter was significantly higher under low pH conditions, no significant differences were detected between treatments regarding total carbohydrate, lipid, protein and fatty acid composition. However, the lower variability found among samples maintained in acidified conditions relative to controls, suggests a possible effect of pH decrease on the metabolism of the colonies. Our results show, for the first time, evidence of detrimental ocean acidification effects on this valuable and endangered coral species
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