The SOS Response Master Regulator LexA Is Associated with Sporulation,Motility and Biofilm Formation in Clostridium difficile

The LexA regulated SOS network is a bacterial response to DNA damage of metabolic or environmental origin. In Clostridium difficile, a nosocomial pathogen causing a range of intestinal diseases, the in-silico deduced LexA network included the core SOS genes involved in the DNA repair and genes involved in various other biological functions that vary among different ribotypes. Here we describe the construction and characterization of a lexA ClosTron mutant in C. difficile {"type":"entrez-nucleotide","attrs":{"text":"R20291","term_id":"774925"}}R20291 strain. The mutation of lexA caused inhibition of cell division resulting in a filamentous phenotype. The lexA mutant also showed decreased sporulation, a reduction in swimming motility, greater sensitivity to metronidazole, and increased biofilm formation. Changes in the regulation of toxin A, but not toxin B, were observed in the lexA mutant in the presence of sub-inhibitory concentrations of levofloxacin. C. difficile LexA is, therefore, not only a regulator of DNA damage but also controls many biological functions associated with virulence.     

Two fluorogenic substrates for purine nucleoside phosphorylase,selective for mammalian and bacterial forms of the enzyme

Two nontypical nucleosides, 7-β-d-ribosyl-2,6-diamino-8-azapurine and 8-β-d-ribosyl-2,6-diamino-8-azapurine, have been found to exhibit moderately good, and selective, substrate properties toward calf and bacterial (Escherichia coli) forms of purine nucleoside phosphorylase (PNP). The former compound is effectively phosphorolysed by calf PNP and the latter by PNP from E. coli. Both compounds are fluorescent with λ_max ∼ 425 to 430 nm, but the reaction product, 2,6-diamino-8-azapurine, emits in a different spectral region (λ_max ∼ 363 nm) with nearly 40% yield, providing a strong fluorogenic effect at 350 to 360 nm.     

Leaf optical properties in amphibious plant species are affected by multiple leaf traits

The amphibious plant species Sagittaria sagittifolia and Ranunculus lingua here serve as model systems to study differences in leaf optical properties of different leaf types that develop in aquatic and terrestrial environments. We aimed to determine leaf traits that explain most of the variability in the reflectance and transmittance spectra in the range from 280 to 880 nm. Comparisons of leaves of the same form revealed marked differences in their structures and particularly in the content of total methanol-soluble UV-absorbing compounds. Submerged leaves transmit radiation over the whole range measured, but emerged leaves transmit only at wavelengths from 500 to 650 nm, and above 690 nm. Redundancy analysis shows that biochemical leaf traits, namely the UV-absorbing compounds chlorophyll a and b, together with the specific leaf area (SLA), significantly affect the reflectance spectra, explaining 60% of the spectra variability. Pigment levels negatively affect reflectance, while the effect of SLA is positive. Physical traits like thickness of the palisade mesophyll, SLA, and thickness of the lower and upper epidermis, along with anthocyanin content, explain 62% of the transmittance spectra variability. This study provides new insight into the understanding of data collected for aquatic and semi-aquatic plants based on spectral analyses.     

The activity of selected glycosidases in salivary gland tumors

The monitoring of the patients after salivary gland tumors surgery is an important clinical issue. Still imperfect diagnostic procedures also remain a challenge for searching new sensitive and specific biomarkers of neoplastic processes in salivary glands. The aim of the presented study was an the assessment of the activity of HEX, with its isoforms HEX-A and HEX-B, GLU, GAL, MAN and FUC in salivary gland tumor tissues in comparison to a healthy salivary gland tissues taken during autopsy. A group of 42 patients with benign and malignant salivary gland tumors, aged 25-65 were examined. Fragments of salivary gland tumor tissue, fragments of healthy tissue removed during autopsy, blood serum and saliva were collected from patients with salivary gland tumors and healthy volunteers. In salivary gland tumor tissue the activity of HEX, HEX-A, HEX-B, GAL, FUC was considerably higher than in comparison to healthy salivary gland tissue and ascending trend of activity of GLU, MAN was also noticed. The activity of all lysosomal exoglycosidases in blood serum in patients with salivary gland tumors was considerably higher in comparison to healthy volunteers blood serum. The considerably higher activity of HEX, HEX-A, GLU, GAL, MAN, FUC and descending trend of activity of HEX-B were noticed in saliva of patients with salivary gland tumors in comparison to healthy volunteers. The assessment of HEX in blood serum and saliva of patients with salivary gland tumor can be possibly used in diagnostics and monitoring of salivary glands tumors.     

Assessment of S100 protein expression in the epididymis of juvenile and adult European bison

In our study, we decided to compare S100 protein expression in the material obtained from the epididymes of 5- and 12-month-old calves, and adult European bison, and to detect any differences in S100 expression according to the animal age and size of the organ examined. We used the epididymes obtained from 6 adult European bison aged 6-12 years, from 6 at the age of 12 months and 6 calves aged 5 months. Immunocytochemical reactions were performed using the avidin-biotinylated-peroxidase (ABC) technique according to HSU. Specific polyclonal rabbit antiserum against bovine S100 protein (Bio Genex Laboratories) at a dilution at 1:400 was applied. We found the expression of S100 protein in endothelial cells of arteries, veins and lymphatic vessels in all the study animals. At the same time, we found no differences in the expression of S100 protein in vascular endothelial cells. Our observations seem to indicate that S100 expression in endothelial cells of European bison epididymis is not correlated with age or maturity of the organ tested. We found S100 protein in smooth muscle cells of arteries and veins in all European bison specimens examined. Interestingly in the current study, in young 5-month-old sexually immature European bison specimens we observed weaker expression of S100 protein in smooth muscle cells of small vessels as compared to the same cell type both in large vessels in these animals and in small vessels in adult specimens.     

Biological and Molecular Characterization of Polish Isolates of Tomato torrado virus*

Three isolates of Tomato torrado virus (ToTV) were found in Poland. The isolates were characterized on the basis of their symptomatology on plant species, serological reactions, electron microscopy, and nucleotide and amino acid sequence analyses of coat protein subunit genes. In comparative tests, the Polish ToTV isolates were shown to be closely related to each other and also to the isolate from Spain.     

Ultrastructural studies of epidermis keratinization in grass snake embryos Natrix natrix L. (Lepidosauria, Serpentes) during late embryogenesis

The changes and biochemical features of the epidermis that accompany the differentiation and embryonic shedding complex formation in grass snake Natrix natrix L. embryos were studied ultrastructurally and immunocytochemically with two panels of antibodies (AE1, AE3, AE1/AE3; anti-cytokeratin, pan mixture, Lu-5 and PCK-26). All observed changes in the ultrastructure of the cells forming the epidermal layers were associated with the physiological changes that occurred in the embryonic epidermis, such as changing of the manner of nutrition and keratinization leading to the embryonic shedding complex formation. The layers that originated first (basal, outer and inner periderm and clear layer) differentiated very early and rapidly. Rapid differentiation was also observed in the layers that are very important for the functioning of the epidermis in Natrix embryos (oberhäutchen and beta-layers). They started to differentiate at developmental stage IX, and then fused and formed the embryonic shedding complex at developmental stage XI. During the embryonic development of the grass snake the smallest changes appeared in the ultrastructure of the cells in the mesos and alpha-layers because they perform supplementary functions in the process of embryonic molting. They were undifferentiated until the end of embryonic development and started to differentiate just before the first adult molting. AE1/AE3, anti-cytokeratin, pan mixture, Lu-5 and PCK-26 antibodies immunolabeled clear layer, oberhäutchen and beta-layers at the latest phase of developmental stage XI. It should be noted that these antibodies did not immunolabel the alpha-layer until hatching. The presence of alpha-keratin immunolabeling in layers that were keratinized, particularly in the oberhäutchen and beta-layers in embryos, indicated that they were not as hard as in fully mature individuals.     

Fight to the death: Arabidopsis thaliana defense response to fungal necrotrophic pathogens

Necrotrophic fungi, being the largest class of fungal plant pathogens, pose a serious economic problem to crop production. They are the cause of heavy losses in agriculture worldwide. Understanding the process of plant infection by necrotrophic fungi, including subtle interaction networks connecting such evolutionarily distinct organisms has recently been given high research priority. Such studies are now possible mainly because of the utility of the model plant Arabidopsis thaliana. A. thaliana has a sequenced genome and thousands of mutants available, allowing investigation of virtually all aspects of plant pathogenesis. This review focuses on morphological and molecular changes in A. thaliana, which occur during response to infection by necrotrophic fungi. These responses in relation to resistance and susceptibility of the plant will be discussed.     

Characteristics of <Emphasis Type="Italic">Phomopsis sclareae</Emphasis> obtained from sage (<Emphasis Type="Italic">Salvia officinalis</Emphasis>)

In the years 2004–2006 the species P. sclareae was isolated from sage stems showing the symptoms in the form of bark peeling off and breaking. On the basis of 5 isolates randomly chosen from the fungus population, morphology and the conditions of temperatures favourable for the most intensive growth and creation of the fungus infectious material were studied. The temperature of −6°C was viewed as unfavourable for the fungus growth, and that of 32°C was considered to prevent the formation of picnidia and conidia. The dynamic growth of the colonies and the formation of numerous picnidia and conidia were observed at the temperatures ranging from 20°C to 28°C.     

Intestinal microflora of autistic children

Autistic behavior is often accompanied by numerous disturbing symptoms on the part of gastrointestinal system, such as abdominal pain, constipation or diarrhea. These problems are often connected with deregulation of physiological microflora in intestine. The aim of this study was to determine differences in intestinal microflora of autistic and healthy children. Strains of Clostridium spp. and enterococci were isolated more frequently from stool samples of autistic children and rarely lactobacilli. Quantitative differences were observed maliny among staphylococci, Candida spp. and Clostridium perfringens. Monitoring and stabilization of intestinal microflora and knowledge about role of particular strains in etiology of autistic disorders can increase the chances for appropriate therapy.