Antibiotics and Bacterial Resistance-A Short Story of an Endless Arms Race

Despite the undisputed development of medicine, antibiotics still serve as first-choice drugs for patients with infectious disorders. The widespread use of antibiotics results from a wide spectrum of their actions encompassing mechanisms responsible for: the inhibition of bacterial cell wall biosynthesis, the disruption of cell membrane integrity, the suppression of nucleic acids and/or proteins synthesis, as well as disturbances of metabolic processes. However, the widespread availability of antibiotics, accompanied by their overprescription, acts as a double-edged sword, since the overuse and/or misuse of antibiotics leads to a growing number of multidrug-resistant microbes. This, in turn, has recently emerged as a global public health challenge facing both clinicians and their patients. In addition to intrinsic resistance, bacteria can acquire resistance to particular antimicrobial agents through the transfer of genetic material conferring resistance. Amongst the most common bacterial resistance strategies are: drug target site changes, increased cell wall permeability to antibiotics, antibiotic inactivation, and efflux pumps. A better understanding of the interplay between the mechanisms of antibiotic actions and bacterial defense strategies against particular antimicrobial agents is crucial for developing new drugs or drug combinations. Herein, we provide a brief overview of the current nanomedicine-based strategies that aim to improve the efficacy of antibiotics.

Focus group interview as a research method in the development of the e-learning in suicide prevention for students in poland

Project ELLIPSE (E-LifeLong Learning in Prevention of Suicide in Europe) was developed in response to need for preventive suicide programs. It was noticed that it is important for academic teachers and students, especially those who teach and study in the fields of medicine, nursing, psychology, sociology or those related to the media. The goal is creating an e-learning platform for students and teachers on suicide prevention along with a textbook and a free self-help application. For this purpose the milestone was the conducting of the focus group interviews in Poland. Participants were recruited from the above mentioned groups (students and professionals). The objectives of this part of the project were among others: raising awareness of the problem of suicide and prevention, giving good examples on suicide prevention in working life, preparation of a program proposal for e-learning content. Students interest in the problems of suicidology was high and they comes optimistic to the idea of prevention, they want to know especially about how to help somebody, how to talk and not to harm people and something more in their future profession. Only theoretical approach will be not enough for them, the rules of how to NOT react, will not be interesting because they know something about it. They showed a knowledge of basic concepts, extensive and multi-context knowledge of causes and warning signals and great understanding for suicides of all ages. However, they themselves were uncertain how to help such a person, and showed poor recognition of institutional help.

The role of fecal microbiota transplantation in the therapy of intestinal and extraintestinal diseases: The basics for health professionals

The knowledge of the role of the digestive tract in human physiology and pathology has expanded tremendously in recent years. The human intestine is a habitat for a host complex of bacteria, fungi, viruses and Acheaea, all contributing to food digestion, fermentation, metabolism of xenobiotics as well as immune and neuroendocrine functions. Moreover, evidence is mounting that many environmental factors such as diet, drugs, stress and infection may potentially disrupt intestinal microbial milieu. Therefore, methods aimed to modulate gut microbiota are eagerly investigated and applied into daily clinical practice. Fecal microbiota transplantation (FMT) is a transplant of gut bacteria from a healthy donor to a recipent. Usually, the stool bacteria are introduced by means of colonoscopy, gastroduodenoscopy, enema, orogastric tube or orally in the form of a capsule containing freeze-dried material. The effectivness of FMT in the treatment of recurrent Clostridioides difficile infection (CDI) has been confirmed in a numer of high quality studies and is currently recommended as evidence-based therapy in clinical settings. However, FMT is promising in the treatment of other diseases, as it has proven to be an effective method of treating ulcerative colitis (UC) and is of promise in treating Crohn’s disease (CD), metabolic and neuropsychiatric disorders. Many questions related to FMT remain unanswered. A better understanding of fecal and mucosal microbial composition is needed, followed by the optimisation of regulatory issues and selection of best possible donor. Novel protocols based on a new class of probiotics as emerging alternatives to FMT in CDI are also briefly disscussed.

Polyelectrolyte membrane scaffold sustains growth of neuronal cells

Cell immobilization within nano‐thin polymeric shells can provide an optimal concentration of biological material in a defined space and facilitate its directional growth. Herein, polyelectrolyte membrane scaffolds were constructed using a layer‐by‐layer approach to determine the possibility of promoting improved growth of rat cortical neuronal cells. Membrane presence was confirmed by Fourier transform infrared spectroscopy, Zeta potential, and atomic force and scanning electron microscopy. Scaffold performance toward neuronal cell growth was assessed in vitro during a 14‐day culture. Cell conditions were analyzed immunocytochemically. Furthermore, western blot and real‐time PCR analyses were used to validate the presence of neuronal and glial cells on the scaffolds. We observed that alginate/chitosan, alginate/polylysine, and polyethyleneimine/chitosan scaffolds promote neuronal growth similarly to the control, poly‐d‐lysine/laminin. We conclude that membranes maintaining cell viability, integrity and immobilization in systems supporting neuronal regeneration can be applied in neurological disease or wound healing treatment. © 2018 The Authors. Journal of Biomedical Materials Research Part A published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 839–850, 2019.

Adaptive response to chronic mild ethanol stress involves ROS, sirtuins and changes in chromosome dosage in wine yeasts

Industrial yeast strains of economic importance used in winemaking and beer production are genomically diverse and subjected to harsh environmental conditions during fermentation. In the present study, we investigated wine yeast adaptation to chronic mild alcohol stress when cells were cultured for 100 generations in the presence of non-cytotoxic ethanol concentration. Ethanol-induced reactive oxygen species (ROS) and superoxide signals promoted growth rate during passages that was accompanied by increased expression of sirtuin proteins, Sir1, Sir2 and Sir3, and DNA-binding transcription regulator Rap1. Genome-wide array-CGH analysis revealed that yeast genome was shaped during passages. The gains of chromosomes I, III and VI and significant changes in the gene copy number in nine functional gene categories involved in metabolic processes and stress responses were observed. Ethanol-mediated gains of YRF1 and CUP1 genes were the most accented. Ethanol also induced nucleolus fragmentation that confirms that nucleolus is a stress sensor in yeasts. Taken together, we postulate that wine yeasts of different origin may adapt to mild alcohol stress by shifts in intracellular redox state promoting growth capacity, upregulation of key regulators of longevity, namely sirtuins and changes in the dosage of genes involved in the telomere maintenance and ion detoxification.

Tumor-derived fibulin-3 activates pro-invasive NF-κB signaling in glioblastoma cells and their microenvironment

Molecular profiling of glioblastomas has revealed the presence of key signaling hubs that contribute to tumor progression and acquisition of resistance. One of these main signaling mechanisms is the NF-κB pathway, which integrates multiple extracellular signals into transcriptional programs for tumor growth, invasion, and maintenance of the tumor-initiating population. We show here that an extracellular protein released by glioblastoma cells, fibulin-3, drives oncogenic NF-κB in the tumor and increases NF-κB activation in peritumoral astrocytes. Fibulin-3 expression correlates with a NF-κB-regulated “invasive signature” linked to poorer survival, being a possible tissue marker for regions of active tumor progression. Accordingly, fibulin-3 promotes glioblastoma invasion in a manner that requires NF-κB activation both in the tumor cells and their microenvironment. Mechanistically, we found that fibulin-3 activates the metalloprotease ADAM17 by competing with its endogenous inhibitor, TIMP3. This results in sustained release of soluble TNFα by ADAM17, which in turn activates TNF receptors and canonical NF-κB signaling. Taken together, our results underscore fibulin-3 as a novel extracellular signal with strong activating effect on NF-κB in malignant gliomas. Because fibulin-3 is produced de novo in these tumors and is absent from normal brain we propose that targeting the fibulin-3/NF-κB axis may provide a novel avenue to disrupt oncogenic NF-κB signaling in combination therapies for malignant brain tumors.

Relationships between rDNA, Nop1 and Sir complex in biotechnologically relevant distillery yeasts

Distillery yeasts are poorly characterized physiological group among the Saccharomyces sensu stricto complex. As industrial yeasts are under constant environmental stress during fermentation processes and the nucleolus is a stress sensor, in the present study, nucleolus-related parameters were evaluated in 22 commercially available distillery yeast strains. Distillery yeasts were found to be a heterogeneous group with a variable content and length of rDNA and degree of nucleolus fragmentation. The levels of rDNA were negatively correlated with Nop1 (r = -0.59, p = 0.0038). Moreover, the protein levels of Sir transcriptional silencing complex and longevity regulators, namely Sir1, Sir2, Sir3 and Fob1, were studied and negative correlations between Sir2 and Nop1 (r = -0.45, p = 0.0332), and between Sir2 and Fob1 (r = -0.49, p = 0.0211) were revealed. In general, S. paradoxus group of distillery yeasts with higher rDNA pools and Sir2 level than S. bayanus group was found to be more tolerant to fermentation-associated stress stimuli, namely mild cold/heat stresses and KCl treatment. We postulate that rDNA state may be considered as a novel factor that may modulate a biotechnological process.

Copy number variations of genes involved in stress responses reflect the redox state and DNA damage in brewing yeasts

The yeast strains of the Saccharomyces sensu stricto complex involved in beer production are a heterogeneous group whose genetic and genomic features are not adequately determined. Thus, the aim of the present study was to provide a genetic characterization of selected group of commercially available brewing yeasts both ale top-fermenting and lager bottom-fermenting strains. Molecular karyotyping revealed that the diversity of chromosome patterns and four strains with the most accented genetic variabilities were selected and subjected to genome-wide array-based comparative genomic hybridization (array-CGH) analysis. The differences in the gene copy number were found in five functional gene categories: (1) maltose metabolism and transport, (2) response to toxin, (3) siderophore transport, (4) cellular aldehyde metabolic process, and (5) L-iditol 2-dehydrogenase activity (p < 0.05). In the Saflager W-34/70 strain (Fermentis) with the most affected array-CGH profile, loss of aryl-alcohol dehydrogenase (AAD) gene dosage correlated with an imbalanced redox state, oxidative DNA damage and breaks, lower levels of nucleolar proteins Nop1 and Fob1, and diminished tolerance to fermentation-associated stress stimuli compared to other strains. We suggest that compromised stress response may not only promote oxidant-based changes in the nucleolus state that may affect fermentation performance but also provide novel directions for future strain improvement.

Shifts in rDNA levels act as a genome buffer promoting chromosome homeostasis

The nucleolus is considered to be a stress sensor and rDNA-based regulation of cellular senescence and longevity has been proposed. However, the role of rDNA in the maintenance of genome integrity has not been investigated in detail. Using genomically diverse industrial yeasts as a model and array-based comparative genomic hybridization (aCGH), we show that chromosome level may be balanced during passages and as a response to alcohol stress that may be associated with changes in rDNA pools. Generation- and ethanol-mediated changes in genes responsible for protein and DNA/RNA metabolism were revealed using next-generation sequencing. Links between redox homeostasis, DNA stability, and telomere and nucleolus states were also established. These results suggest that yeast genome is dynamic and chromosome homeostasis may be controlled by rDNA.

Genome-wide array-CGH analysis reveals YRF1 gene copy number variation that modulates genetic stability in distillery yeasts

Industrial yeasts, economically important microorganisms, are widely used in diverse biotechnological processes including brewing, winemaking and distilling. In contrast to a well-established genome of brewer's and wine yeast strains, the comprehensive evaluation of genomic features of distillery strains is lacking. In the present study, twenty two distillery yeast strains were subjected to electrophoretic karyotyping and array-based comparative genomic hybridization (array-CGH). The strains analyzed were assigned to the Saccharomyces sensu stricto complex and grouped into four species categories: S. bayanus, S. paradoxus, S. cerevisiae and S. kudriavzevii. The genomic diversity was mainly revealed within subtelomeric regions and the losses and/or gains of fragments of chromosomes I, III, VI and IX were the most frequently observed. Statistically significant differences in the gene copy number were documented in six functional gene categories: 1) telomere maintenance via recombination, DNA helicase activity or DNA binding, 2) maltose metabolism process, glucose transmembrane transporter activity; 3) asparagine catabolism, cellular response to nitrogen starvation, localized in cell wall-bounded periplasmic space, 4) siderophore transport, 5) response to copper ion, cadmium ion binding and 6) L-iditol 2- dehydrogenase activity. The losses of YRF1 genes (Y' element ATP-dependent helicase) were accompanied by decreased level of Y' sequences and an increase in DNA double and single strand breaks, and oxidative DNA damage in the S. paradoxus group compared to the S. bayanus group. We postulate that naturally occurring diversity in the YRF1 gene copy number may promote genetic stability in the S. bayanus group of distillery yeast strains.

The age-dependent epigenetic and physiological changes in an Arabidopsis T87 cell suspension culture during long-term cultivation

Plant cell suspension cultures represent good model systems applicable for both basic research and biotechnological purposes. Nevertheless, it is widely known that a prolonged in vitro cultivation of plant cells is associated with genetic and epigenetic instabilities, which may limit the usefulness of plant lines. In this study, the age-dependent epigenetic and physiological changes in an asynchronous Arabidopsis T87 cell culture were examined. A prolonged cultivation period was found to be correlated with a decrease in the proliferation rate and a simultaneous increase in the expression of senescence-associated genes, indicating that the aging process started at the late growth phase of the culture. In addition, increases in the heterochromatin-specific epigenetic markers, i.e., global DNA methylation, H3K9 dimethylation, and H3K27 trimethylation, were observed, suggesting the onset of chromatin condensation, a hallmark of the early stages of plant senescence. Although the number of live cells decreased with an increase in the age of the culture, the remaining viable cells retained a high potential to efficiently perform photosynthesis and did not exhibit any symptoms of photosystem II damage.

Up-regulation of stress-inducible genes in tobacco and Arabidopsis cells in response to abiotic stresses and ABA treatment correlates with dynamic changes in histone H3 and H4 modifications

Animal cells react to mitogenic or stress stimuli by rapid up-regulation of immediate-early (IE) genes and a parallel increase in characteristic modifications of core histones: chromatin changes, collectively termed the nucleosomal response. With regard to plants little is known about the accompanying changes at the chromatin level. We have used tobacco BY-2 and Arabidopsis T87 cell lines to study the nucleosomal response of plant cells to high salinity, cold and exogenous abscisic acid (ABA). When in quiescent stage, both tobacco and Arabidopsis cells show the typical nucleosomal response to high salinity and cold stress, manifested by rapid transient up-regulation of histone H3 Ser-10 phosphorylation, immediately followed by transient up-regulation of H3 phosphoacetylation and histone H4 acetylation. For each of the studied stresses the observed nucleosomal response was strictly correlated with the induction of stress-type specific genes. The dynamics of histone modifications in BY-2 cells in response to exogenous ABA exhibited a more complex pattern than that evoked by the two abiotic stresses, probably due to superposition of the primary and secondary effects of ABA. A rapid increase in H3 Ser-10 phosphorylation was also observed in whole leaves subjected to high salinity; however, the rate of change in this modification was much slower than in cultured cells. Together, these results indicate that the quiescent BY-2 and T87 cell lines show a typical nucleosomal response to abiotic stresses and ABA treatment and may represent suitable models for the study of chromatin-mediated mechanisms of stress tolerance in plants.

Microglia-derived TGF-β as an important regulator of glioblastoma invasion—an inhibition of TGF-β-dependent effects by shRNA against human TGF-β type II receptor

The invasion of tumor cells into brain tissue is a pathologic hallmark of malignant gliomas and contributes to treatment failures. Diffuse glioblastomas contain numerous microglial cells, which enhance the progression of gliomas; however, factors responsible for invasion-promoting role of microglia are unknown. Transforming growth factor-beta (TGF-beta) can enhance tumor growth, invasion, angiogenesis and immunosuppression. Antagonizing TGF-beta activity has been shown to inhibit tumor invasion in vitro and tumorigenicity, but a systemic inhibition or lack of TGF-beta signaling results in acute inflammation and disruption of immune system homeostasis. We developed plasmid-transcribed small hairpin RNAs (shRNAs) to downregulate the TGF-beta type II receptor (TbetaIIR) expression, which effectively inhibited cytokine-induced signaling pathways and transcriptional responses in transiently transfected human glioblastoma cells. Silencing of TbetaIIR abolished TGF-beta-induced glioblastoma invasiveness and migratory responses in vitro. Moreover, tumorigenicity of glioblastoma cells stably expressing TbetaIIR shRNAs in nude mice was reduced by 50%. Microglia strongly enhanced glioma invasiveness in the co-culture system, but this invasion-promoting activity was lost in glioma cells stably expressing shTbetaRII, indicating a crucial role of microglia-derived TGF-beta in tumor-host interactions. Our results demonstrate a successful targeting of TGF-beta-dependent invasiveness and tumorigenicity of glioblastoma cells by RNAi-mediated gene silencing.

SWI3 subunits of putative SWI/SNF chromatin-remodeling complexes play distinct roles during Arabidopsis development

SWITCH/SUCROSE NONFERMENTING (SWI/SNF) chromatin-remodeling complexes mediate ATP-dependent alterations of DNA-histone contacts. The minimal functional core of conserved SWI/SNF complexes consists of a SWI2/SNF2 ATPase, SNF5, SWP73, and a pair of SWI3 subunits. Because of early duplication of the SWI3 gene family in plants, Arabidopsis thaliana encodes four SWI3-like proteins that show remarkable functional diversification. Whereas ATSWI3A and ATSWI3B form homodimers and heterodimers and interact with BSH/SNF5, ATSWI3C, and the flowering regulator FCA, ATSWI3D can only bind ATSWI3B in yeast two-hybrid assays. Mutations of ATSWI3A and ATSWI3B arrest embryo development at the globular stage. By a possible imprinting effect, the atswi3b mutations result in death for approximately half of both macrospores and microspores. Mutations in ATSWI3C cause semidwarf stature, inhibition of root elongation, leaf curling, aberrant stamen development, and reduced fertility. Plants carrying atswi3d mutations display severe dwarfism, alterations in the number and development of flower organs, and complete male and female sterility. These data indicate that, by possible contribution to the combinatorial assembly of different SWI/SNF complexes, the ATSWI3 proteins perform nonredundant regulatory functions that affect embryogenesis and both the vegetative and reproductive phases of plant development.

[Occurrence of defects of connective tissue attachment in adults with periodontal diseases]

The position of the connective tissue attachment was determined by Ramfjord's method in subjects aged 20-29 and 40-49 years. In the determination four surfaces of all remaining incisors, canines, and premolars were considered. A defect of the connective tissue attachment was found in about 95% of the analysed dental surfaces in subjects aged 40-49 years. The frequency of occurrence of these defects varied depending on the type dental surface.

[Position of the connective tissue attachment and the image of alveolar process bone in pantomograms in a selected group of adults]

In 20 subjects aged 20-29 years the position of the connective tissue attachment was determined and the atrophy of the alveolar process bone was assessed by means of an analysis of pantomograms. The radiological image of the paradontium was compared with the result of clinical examination. It was found that radiological diagnosis by means of pantomography may be a valuable supplementation of clinical examination in case of advanced parodontitis with loss of connective tissue attachment by at least 6 mm.

The effect of freezing on the sensory properties of Xerocomus badius (Fr, Kühn) and Tricholoma equestre (L ex Fr, Quel)

As the result of sensory and gas chromatographic investigation of the edible mushrooms Xerocomus badius and Tricholoma equestre aroma properties it was stated that freezing preserves the general character of typical aroma. The observed changes were mostly favourable for sensory value intensifying the characteristic for investigated species small and, in the case of T. equestre, lowering the threshold concentration.