Unlocking the genome of the non-sourdough Kazachstania humilis MAW1: insights into inhibitory factors and phenotypic properties.

BACKGROUND: Ascomycetous budding yeasts are ubiquitous environmental microorganisms important in food production and medicine. Due to recent intensive genomic research, the taxonomy of yeast is becoming more organized based on the identification of monophyletic taxa. This includes genera important to humans, such as Kazachstania. Until now, Kazachstania humilis (previously Candida humilis) was regarded as a sourdough-specific yeast. In addition, any antibacterial activity has not been associated with this species. RESULTS: Previously, we isolated a yeast strain that impaired bio-hydrogen production in a dark fermentation bioreactor and inhibited the growth of Gram-positive and Gram-negative bacteria. Here, using next generation sequencing technologies, we sequenced the genome of this strain named K. humilis MAW1. This is the first genome of a K. humilis isolate not originating from a fermented food. We used novel phylogenetic approach employing the 18 S-ITS-D1-D2 region to show the placement of the K. humilis MAW1 among other members of the Kazachstania genus. This strain was examined by global phenotypic profiling, including carbon sources utilized and the influence of stress conditions on growth. Using the well-recognized bacterial model Escherichia coli AB1157, we show that K. humilis MAW1 cultivated in an acidic medium inhibits bacterial growth by the disturbance of cell division, manifested by filament formation. To gain a greater understanding of the inhibitory effect of K. humilis MAW1, we selected 23 yeast proteins with recognized toxic activity against bacteria and used them for Blast searches of the K. humilis MAW1 genome assembly. The resulting panel of genes present in the K. humilis MAW1 genome included those encoding the 1,3-ß-glucan glycosidase and the 1,3-ß-glucan synthesis inhibitor that might disturb the bacterial cell envelope structures. CONCLUSIONS: We characterized a non-sourdough-derived strain of K. humilis, including its genome sequence and physiological aspects. The MAW1, together with other K. humilis strains, shows the new organization of the mating-type locus. The revealed here pH-dependent ability to inhibit bacterial growth has not been previously recognized in this species. Our study contributes to the building of genome sequence-based classification systems; better understanding of K.humilis as a cell factory in fermentation processes and exploring bacteria-yeast interactions in microbial communities.

The first homemade colonoscopy trainer.

Introduction Colonoscopy trainers have gained recognition for improving endoscopy skills and preparing for real procedures on humans. Unfortunately, due to their high price, commercial simulators are hard to obtain, especially for small medical centers. However, a solution might be to construct a device for themselves. Aim Our goal was to build a relatively cheap and easy-to-construct simulator for residents who want to start learning colonoscopy. Materials and methods The box model colonoscopy trainer was designed and constructed. The artificial colon was made from 2 layers of fabric and rubber rings between them. Velcro attached to the artificial colon and to the box, and the tarp straps that simulate peritoneal adhesions allow the bowel to be arranged in many different configurations. Moreover, some aspects of polypectomy training have been incorporated in the colonoscopy simulator. Results The self-constructed simulator was found to be an effective training device, with the total cost of parts not exceeding $30. Conclusions In this paper, we present the first homemade simulator for colonoscopy training. It offers the opportunity for skills acquisition in a preclinical setting.

[Influence of electrochemical ageing on properties of chosen medical receptacles].

BACKGROUND: Presently, most of receptacles used in medicine are made of polymeric materials. This is due to, e.g., low price, low weight, and aesthetic values of these materials. The important issue is to ensure long life of polymer in order to protect the medicines closed in the boxes. However, all materials during exploitation are exposed to many factors, which can cause degradation of polymer materials. Degradation processes lead to deterioration of thermomechanical properties of polymers. OBJECTIVES: The aim of this syudy was to examine the influence of electrochemical ageing on properties of polymeric materials used in production of receptacles for drugs and boxes for medical use. MATERIAL AND METHODS: We conducted comparative analysis of samples before and after electrochemical ageing, cut out of receptacles for drugs made from polyethylene, as well as from boxes for medical use and Eppendorf tube made from polypropylene. Investigating methods included differential scanning calorimetry (DSC) and imaging of microstructure ×400 magnification. RESULTS: We noticed different value of the degree of crystallinity for the aged samples in comparison to not aged samples. The change in value of temperature of physical transformation was also detected. In the aged samples defragmentation of crystal structure was observed. CONCLUSIONS: Electrochemical ageing results in changes of properties of polymeric materials used in production of medical receptacles.

Synthesis and fungistatic activity of bicyclic lactones and lactams against Botrytis cinerea, Penicillium citrinum, and Aspergillus glaucus.

Six analogues of natural trans-4-butyl-cis-3-oxabicyclo[4.3.0]nonan-2-one (3) and three derivatives, 11, 12, and 13, of Vince lactam (10) were synthesized and tested as fungistatic agents against Botrytis cinerea AM235, Penicillium citrinum AM354, and six strains of Aspergillus. Moreover, bioresolution carried out by means of whole cell microorganisms and commercially available enzymes afforded opposite enantiomerically enriched (-) and (+) isomers of Vince lactam (10), respectively. The effect of compound structures and stereogenic centers on biological activity has been discussed. The highest fungistatic activity was observed for four lactones: 3, 4, 7, and 8 (IC50 = 104.6-115.2 µg/mL) toward B. cinerea AM235. cis-5,6-Epoxy-2-aza[2.2.1]heptan-3-one (13) indicated significant fungistatic activity (IC50 = 107.1 µg/mL) against Aspergillus glaucus AM211. trans-4-Butyl-cis-3-oxabicyclo[4.3.0]nonan-2-one (3) and trans-4-butyl-cis-3-oxabicyclo[4.3.0]non-7-en-2-one (7) exhibited high fungistatic activity (IC50 = 143.2 and 110.2 µg/mL, respectively) against P. citrinum AM354 as well.