Secondary abiotic mice generated by broad-spectrum antibiotic treatment provide a valuable tool for association studies with microbiota derived from different vertebrate hosts. We here generated human microbiota-associated (hma) mice by human fecal microbiota transplantation of secondary abiotic mice and performed a comprehensive survey of the intestinal microbiota dynamics in offspring of hma mice over 18 weeks following weaning as compared to their mothers applying both cultural and molecular methods. Mice were maintained under standard hygienic conditions with open cages, handled under aseptic conditions, and fed autoclaved chow and water. Within 1 week post weaning, fecal loads of commensal enterobacteria and enterococci had decreased, whereas obligate anaerobic bacteria such as Bacteroides/Prevotella species and clostridia were stably colonizing the intestines of hma offspring at high loads. Lactobacilli numbers were successively increasing until 18 weeks post weaning in both hma offspring and mothers, whereas by then, bifidobacteria were virtually undetectable in the former only. Interestingly, fecal lactobacilli and bifidobacteria were higher in mothers as compared to their offspring at 5 and 18 weeks post weaning. We conclude that the intestinal microbiota composition changes in offspring of hma mice, but also their mothers over time particularly affecting aerobic and microaerobic species.

Polyphenol oxidase (PPO) was purified from Lactarius piperatus (L.) Pers. by using Sepharose 4B‐L‐tyrosine‐p‐amino benzoic acid affinity column. Optimum pH and temperature of purified PPOs of L. piperatus were found to be 7.0 and 20C, respectively, by using catechol as a substrate. The enzyme retained 100% of its original activity at 4C and its optimum pH value for 24 and 72 h. L. piperatus PPO was also quite stable at 20C after 4 h incubation. The Km and Vmax values were calculated as 1 mM and 25 U/mg protein, respectively. Ascorbic acid was found to be the most potent inhibitor for the enzyme. The mushroom PPO was an effective biocatalyst in the selected organic solvents such as dichloromethane, heptane and toluene when using catechin as a substrate. All data support that L. piperatus has a highly active PPO possessing similar biochemical and kinetic characteristics to some plant PPO enzymes. PRACTICAL APPLICATIONS Polyphenol oxidases (PPOs) are a group of copper‐containing enzymes that are widely distributed from bacteria to mammals. Some different mushroom PPOs are subjected to further characterization studies in terms of their biochemical characteristics and their potentials in biotechnological applications. So, purification and characterization studies for PPOs from new sources are very important to explain their biochemical properties and behavior. Thus, one more enzyme may also find applications in food or drug industries.

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An esterase from a thermophilic bacterium, Geobacillus sp. DF20, was partially purified. Final purification factor was found to be 64.5-fold using Q-Sepharose ion exchange column chromatography. Native polyacrylamide gel electrophoresis indicated the presence of a single active esterase. The substrate specificity of this esterase was high for p -nitrophenyl butyrate ( p NPB) substrate. The optimum pH and temperature for the enzyme activity were 7.0 and 50• C, respectively. The pH and heat stability profiles show that this enzyme is more stable under neutral conditions at 50• C. Km and Vmax values for this esterase acting on p NPB were 0.12 mM and 54.6 U/mg protein, respectively.Presence of 10% (v/v) acetonitrile in the reaction medium indicated that purified enzyme was strongly inhibited. It was also detected that some metal ions affected enzyme activity at different rates. As a result, it was observed that esterase from Geobacillus sp. DF20 has extreme temperature and pH stabilities. Therefore, the stability and Km value of the enzyme make this study interesting when compared with the literature.

Özet Küresel olarak yaşadığımız Covid-19 pandemisi sonucunda, dünyada ve ülkemizde tüm tıp fakültelerinde yüz yüze yapılan tüm teorik dersler ve uygulamalar sonlandırılmış, uzaktan eğitim, dijital eğitim olanakları ile verilmeye başlanmıştır. Fakültemizde 2019-2020 bahar döneminde derslerin büyük bir çoğunluğu asenkron olarak yapıldı. Pandemi ile üniversitelerde sınavların yüz yüze yapılmaması kararları doğrultusunda sınavlar, Trakya Üniversitesi Uzaktan Eğitim Merkezi ve Medu-Trakya üzerinden online (asenkron) olarak yapılmıştır. Ulusal çekirdek eğitim programı 2020 yayınlandıktan hemen sonra teorik derslerin ve uygulamaların düzenlenmesi, pandemi koşullarında derslerin yüz yüze, asenkron veya senkron olarak hangi oranlarda yapılacağı ilgili ders ve staj kurulları tarafından planlandı. Sonuç olarak, COVID-19 pandemisinin tıp fakülteleri mezunlarında bulunması gereken yetkinlikler ve yeterlikler üzerinde yeniden düşünme ihtiyacını ortaya çıkardığı kanısındayız. Ayrıca tıp fakültelerinde yüz yüze eğitimin önemi bir kez daha ortaya çıkarken, uzaktan eğitim olanaklarının da etkin bir şekilde kullanılabileceğinin deneyimlendiği düşüncesindeyiz. Buradan hareketle gelecekte normalleşme süreciyle birlikte tıp eğitimi programlarının gözden geçirilerek yeniden yapılandırılmak suretiyle farklı boyutlara taşınacağı öngörülebilir.