Agnieszka K. Olejnik-Schmidt

Conversion of glycerol to 1,3-propanediol by Citrobacter freundii and Hafnia alvei - newly isolated strains from the Enterobacteriaceae.

In this study, nearly 4000 bacterial strains from the family of Enterobacteriaceae isolated from different environments were screened for ability to convert glycerol to 1,3-propanediol (1,3-PD). The aim of the research was to isolate 1,3-PD producers from the natural environment, identify and characterize the best isolates. Three selective media were tested to usefulness in the isolation of bacteria from the family Enterobacteriaceae. Only, 28% of examined isolates could synthesize 1,3-PD from glycerol. 1,3-PD producing bacteria were identified by API 20E tests and 16S rRNA sequences to be Klebsiella pneumoniae, Klebsiella oxytoca, Citrobacter freundii and Hafnia alvei. It is the first time, when the fermentation glycerol to 1,3-PD by H. alvei was investigated. The selected strains (C. freundii AD119 and H. alvei AD27) were analyzed on a bioreactor scale under constant pH value 7.0 at temperature of 30°C and 37°C. After 40h in batch fermentation, H. alvei AD27 produced 11.3g/L of 1,3-PD at 37°C. For C. freundii AD119, the best results were obtained at temperature of 30°C. After 24h of fermentation, the 1,3-PD concentration reached above 23 g/L of 1,3-PD.

Isolation process of industrially useful Clostridium bifermentans from natural samples

A selective isolation procedure of clostridial strains from natural samples able to convert glycerol to 1,3-propanediol (1,3-PD) and organic acids was investigated. The modified PY medium of high concentration of NaHCO(3) was shown to be highly selective for Clostridium bifermentans. Obtained isolates produced mainly 1,3-PD, lactic, acetic, and formic acids from glycerol.

Search for cellular partners of human papillomavirus type 16 E2 protein

Human papillomaviruses (HPVs) are small, double-stranded DNA viruses that infect cutaneous and mucosal epithelia. Type 16 (HPV16) displays tropism to genital epithelia, giving rise to genital warts and cervical intraepithelial neoplasia (CIN), which is a precursor lesion to invasive carcinoma of the cervix. The great majority of human cervical cancers contain integrated HPV DNA where the E2 gene is usually disrupted, suggesting that the loss of the E2 protein is an important step in HPV-induced carcinogenesis. The HPV16 E2 protein is a regulatory protein that seems to be essential for creating favourable conditions for establishment of infection and proper completion of the viral life cycle. Recently, diverse activities of the E2 proteins have been described, but the molecular basis of these processes has not beenfully elucidated. Using a yeast two-hybrid system, we have identified epithelial cellular proteins that bind to the E2 protein of HPV16.

Influence of phenolic acids on indole acetic acid production and on the type III secretion system gene transcription in food-associated Pseudomonas fluorescens KM05

The purpose of these investigations was to evaluate the reduction capability of phenolic acids (ferulic, chlorogenic, gallic, and p-coumaric acids) on indole acetic acid synthesis by food-associated Pseudomonas fluorescens KM05. Specific genetic primer for the type III secretion system (TTSS) in P. fluorescens KM05 was designed and the influence of phenolic acids on its expression was investigated. In the work the ferulic and chlorogenic acids at the concentration of 0.02 and 0.04 μg/ml affected on bacterial growth pattern and the signal molecules production. The phenolic acids, that were appreciable effective against P. fluorescens KM05 indole acetic acid production, significantly suppressed TTSS gene.

Orphan nuclear hormone receptor NR4A1 interacts with HPV16 E2 regulatory protein

The human NR4A1 orphan receptor is a member of the TR3 steroid receptor superfamily, which binds DNA at the NBRE and NurRE responsive elements. The TR3 receptors are involved in the regulation of differentiation, proliferation and apoptosis. We report that NR4A1 interacts with human papillomavirus type 16 (HPV16) E2 protein — a key papillomavirus regulatory factor. This interaction might be involved in the transcription regulation of the HPV16 genes and the regulation of infected cell homeostasis.

Induction of Loci Mutation during Lactococcus lactis Spontaneous Conversion to Bacteriophage-Insensitive Phenotype

The dairy industry utilizes Lactococcus lactis strains as starter cultures to manufacture fermented products. Bacteriophages specific for the cultures are an important and persistent problem for the industry. The development of phage-insensitive strains is one approach to handle the problem. We have identified loci that were spontaneously mutated in Lactococcus lactis ssp. cremoris MG1363 during its natural conversion to the phage-resistant phenotype as a challenge to sk1 phage. Whole genome analysis by PCR fingerprinting technique pinpointed genes encoding proteins involved in cell wall metabolism, transmembrane and membrane associated proteins, transcriptional regulators, prophage components, and enzymes of basal metabolism.