Differential expression of keratin 19 in normal human epithelial tissues revealed by monospecific monoclonal antibodies

Summary Three monospecific monoclonal antibodies (BA16, BA17 and A53—B/A2) recognizing different epitopes of the human keratin 19 were used to determine tissue distribution of this 40 kDa keratin polypeptide. Immunohistochemical methods revealed four different staining patterns among normal human epithelial tissues: firstly, complete negativity of the epidermis, sebaceous glands, hepatocytes and other tissues; secondly, homogeneous positivity as seen for example in the gall bladder and urinary bladder epithelium, endometrium and many other epithelia; thirdly, a mosaic of positive and negative cells among mammary gland luminal cells, prostate epithelia and some other epithelia and fourthly, a more complex heterogeneous pattern found in non-keratinizing squamous epithelia and hair follicles with generally the basal layer being the most strongly or sometimes exclusively stained. The pattern seen in non-keratinizing squamous epithelia varied considerably according to the fixation method and the antibody used as well as among different donors and in different areas of the same organ. The other three staining patterns were on the other hand nearly identical with all three antibodies on both frozen sections and sections of methacarn-fixed paraffinembedded tissues. Our results provide evidence for differential expression of the human keratin 19 at the single cell level, an observation which could be exploited in the study of epithelial differentiation and pathology.     

Developmentally regulated surface structures of teratocarcinoma stem cells studied by mutant cell lines

Monoclonal antibodies TEC-01, TEC-02, and TEC-03, which define three developmentally regulated antigens TEC-1 (SSEA-1-like), TEC-2, and TEC-3, have been used to isolate and characterize teratocarcinoma stem cell mutants with altered expression of surface glycoconjugates. Mutants lacking TEC-1 antigen have been isolated by exposing mutagenized P19S1801A1 cells to TEC-01 antibody, which was conjugated to the toxin from Ricinus communis. None of the mutants exhibits significant changes in the expression of TEC-3 antigen, but some are defective in the expression of TEC-2 antigen. Analysis of the expression of TEC-1,2,3 antigens in different lectin-resistant F9 and OTF9-63 cell lines has shown that all express TEC-1 antigen, but some lectin-resistant phenotypes exhibit reduction in the expression of TEC-2 and/or TEC-3 antigens. Mutational events in genes regulating the expression of specific glycosyltransferases or glycosidases appear to be the biochemical mechanism regulating the expression of TEC-1 and TEC-2 antigens.     

Enamel microarchitecture of a tribosphenic molar

The tribosphenic molar is a dental apomorphy of mammals and the molar type from which all derived types originated. Its enamel coat is expected to be ancestral: a thin, evenly distributed layer of radial prismatic enamel. In the bat Myotis myotis, we reinvestigated the 3D architecture of the dental enamel using serial sectioning combined with scanning electron microscopy analyses, biometrics of enamel prisms and crystallites, and X‐ray diffraction. We found distinct heterotopies in enamel thickness (thick enamel on the convex sides of the crests, thin on the concave ones), angularity of enamel prisms, and in distribution of particular enamel types (prismatic, interprismatic, aprismatic) and demonstrated structural relations of these heterotopies to the cusp and crest organization of the tribosphenic molar. X‐ray diffraction demonstrated that the crystallites composing the enamel are actually the aggregates of much smaller primary crystallites. The differences among particular enamel types in degree of crystallite aggregation and the variation in structural microstrain of the primary crystallites (depending upon the duration and the mechanical context of mineralization) represent factors not fully understood as yet that may contribute to the complexity of enamel microarchitecture in a significant way. J. Morphol., 2010. © 2010 Wiley‐Liss, Inc.     

How does surrounding vegetation affect the course of succession: A five‐year container experiment

Question: How does location and time of insertion affect the course of succession in experimental containers? Location: Benešov nad Lipou, Českomoravská vrchovina (Czech-Moravian uplands), Czech Republic Methods: We designed a 5-year container experiment in which plant succession started from scratch. Soil conditions were constant and all containers were filled with homogeneous substrate containing no propagules. We placed the containers in two contrasting habitats (meadow and floodplain) under identical climatic conditions but differing in surrounding vegetations and hence seed input. New containers were installed (and hence succession started) in two subsequent years, twice in each year (spring and autumn). We assume that the individual dates would lead to differences in propagule input and weather conditions. Results: Although both year and season of succession initiation considerably affected the initial species composition, we observed a pronounced convergence within the set of containers located in each habitat. However, the similarity of containers initiated at the same time but located in different habitats decreased over the course of succession. Final composition of the meadow and floodplain containers was therefore mostly determined by permanent seed input from their nearby neighborhood. Conclusions: This study demonstrated that propagule availability is an important determinant of the course of succession, and that differential seed input leads to different pathways of succession, even when all other environmental conditions are equal.     

Glucose isomerase production byStreptomyces sp. CCM 4102

The newly isolatedStreptomyces sp. CCM 4102 strain produced a high level of intracellular glucose isomerase in the media containingd-xylose as inducer of the enzyme, corn-steep liquor, yeast extract and magnesium sulfate. The enzyme synthesis was repressed byd-glucose andd-fructose. The strain did not require cobalt ions for enzyme production.     

Effect of pyruvate decarboxylaxe activity and of pyruvate concentration on the production of 1-hydroxy-1-phenylpropanone inSaccharomyces carlsbergensis

The assumption that the pyruvate decarboxylase activity ofSaccharomyces carlsbergensis is the main limiting factor determining the formation rate and the total amount ofD(—)-l-hydroxy-l-phenylpropanone (phenylacetylcarbinol, PAC) produced was not confirmed. An increase of about 30 % of the total amount of the PAC produced was obtained when 8.5 % sodium pyruvate was gradually added. The total PAC production is probably influenced both by the pyruvate decarboxylase activity and the pyruvate concentration in the cells, the later being actually the determining rate-limiting factor.     

Detection of ultrasonic cavitation based on low-frequency analysis of acoustic signal

The acoustic cavitation phenomenon constitutes a potential hazard in ultrasound diagnostics and therapy so that early and effective detection of cavitation is of great interest. However, cavitation might even bring a higher risk especially when an echocontrast agent based on microbubbles is used. The major goal of the present work was to develop a cavitation detection method based on increased level of cavitation noise in the range of low frequencies (about 1 Hz). This method was applied in vitro using a model of body fluid containing a model echocontrast agent, such as 5% solution of lyophilized egg albumin, which was sonicated by ultrasound disintegrator. Ultrasound signal evokes cavitation in microbubble suspension accompanied by a certain level of cavitation acoustic noise. The level of noise voltage increased in the frequency range of 0.1 to 2 Hz in the presence of cavitation. Hence, this method makes it possible to determine the value of cavitation threshold. In addition, we examined how the cavitation threshold is affected by temperature and viscosity. It was found that the cavitation threshold decreased with growing temperature while it increased with growing viscosity.     

Hay-bait traps are a useful tool for sampling of soil dwelling millipedes and centipedes

Some species of centipedes and millipedes inhabit upper soil layers exclusively and are not recorded by pitfall trapping. Because of their sensitivity to soil conditions, they can be sampled quantitatively for evaluation of soil conditions. Soil samples are heavy to transport and their processing is time consuming, and such sampling leads to disturbance of the soil surface which land-owners do not like. We evaluated the use of hay-bait traps to sample soil dwelling millipedes and centipedes. The effectiveness of this method was found to be similar to the effectiveness of soil sampling. Hay-bait traps installed for 8–10 weeks can substitute for direct soil sampling in ecological and inventory studies.