Transport of acyclic polyols inSaccharomyces cerevisiae

Acyclic polyols (erythritol, xylitol, ribitol, D-arabinitol, mannitol, sorbitol and galactitol) are not metabolized by Saccharomyces cerevisiae. They are taken up by a fast non-active process, reaching 40-70% distribution referred to total cell water. The uptake is insensitive to temperature, pH (between 4 and 8), 2,4-dinitrophenol and uranyl ions. Its initial rate rises linearly with concentration from 10(-5)M to 1M. The process resembles simple diffusion through large pores or the trapping of the whole solution on the surface. Protoplasts behave like whole cells in this respect. Only erythritol shows a second type of uptake which is inhibitor-insensitive but temperature-dependent.     

The dynamics of a non-forested stand in the Krušné Mts.: the effect of a short-lived medieval village on the local environment

Vegetation History and Archaeobotany - Medieval vegetation–human–climate interactions were studied from a sediment profile situated in the centre of a short-lived medieval village...     

The inhibitory effect of neonatal rat smooth muscle cells and elastic extracellular matrix on development of the newly seeded cell population in culture

Neonatal smooth muscle cells were seeded in standard plastic Falcon flasks, on top of another 2-month-old culture of the same cell population or on top of an acellular matrix prepared by removal of these cells. The effect of both complete and acellular layers on the production of elastin, collagen and total extracellular matrix (EM) proteins as well as on cell division was measured. Compared with the standard population grown on plastic, the complete cell layer almost completely prevented the newly seeded cells from dividing. The acellular matrix did not affect cell doubling but caused a distinct decrease in the production of EM components.     

The Egyptian fruit bat Rousettus aegyptiacus (Chiroptera: Pteropodidae) in the Palaearctic: Geographical variation and taxonomic status

Two metrically defined subspecies have traditionally been recognised within the Palaearctic distribution range of the Egyptian fruit bat Rousettus aegyptiacus; the larger R. a. aegyptiacus in Egypt and the northern part of the Middle East and the smaller R. a. arabicus in the southern Middle East. An extensive material of R. aegyptiacus from all parts of this area, i.e. the Levant (incl. Turkey and Cyprus), Egypt (incl. Sinai), northern Sudan, Yemen, Oman, Iran, and Pakistan, as well as comparative samples from its sub-Saharan range, were tested using both morphological and genetic approaches in order to revise the species’ taxonomic status. The results indicated two possible processes, depending on the method used. Genetic analysis of the mitochondrial genome (nd1 and cytb) indicated low variation (< 2.0% of genetic distance) and lack of geographical structure while morphometric analysis indicated significant metric differences. Two basic size morphotypes were found within the Palaearctic range, with a rather mosaic-like geographical distribution and a lack of clear size distinction between the two categories, though intermediate types were detected. Thus, we suggest that all Palaearctic populations of R. aegyptiacus represent one form, the nominotypical subspecies, which is uniform in genetic traits but plastic in metric traits.     

Hereditary melanoblastoma in miniature pigs and its successful therapy by devitalization technique.

Applying selective breeding for 10 years we established the MeLiM (Melanoblastoma-bearing Libechov Minipigs) strain. Melanoblastoma (MB) in this strain shows a hereditary occurrence. Cutaneous tumours are usually nodular, multiple and distributed on various parts of body. They appear in darkly pigmented animals already at the birth or during two months thereafter (57% of all animals). Numerous organ metastases mainly into the spleen, lymph nodes and lungs are regularly ascertained in animals with cutaneous MB. Tumour cells were surprisingly found also in the inner organs of phenotypically healthy minipigs in which no cutaneous MBs were observed visually (27% of all animals). About 34% of all affected piglets die during the first 2 months of age. These features document a malignancy of this tumour in the MeLiM strain. Original surgical technique was applied in more than 40 affected minipigs at 1-2 months of age. It consists in a devitalization (ischemization) of one of cutaneous tumours by the mattress sutures conducted around the tumour base without any excision of tumour tissue. This simple procedure causes a total destruction of MB cells in all cutaneous tumours as well as in all organ metastases during 4-6 months. Animals treated by this technique were fully healed of tumour cells and no relapses were observed. This technique could bring similar positive results also in therapy of human MB.     

Cytoplasmic HDPR1 Is Involved in Regional Lymph Node Metastasis and Tumor Development via Beta-Catenin Accumulation in Esophageal Squamous Cell Carcinoma

The aim of this study was to evaluate HDPR1 expression in esophageal squamous cell carcinoma (ESCC) and the relationship between HDPR1 and beta-catenin by immunohistochemical analysis. The clinical relevance of these proteins was also analyzed. Immunohistochemistry was performed on paraffin-embedded tissue specimens from 184 ESCC patients to detect the expression of HDPR1 and beta-catenin. The correlation between the results of immunoexpression and the clinicopathologic features was processed statistically. Increased cytoplasmic and nuclear HDPR1 expression was noted in 100 (54.3%) and 131 (71.2%) of 184 specimens, respectively. Statistical analysis showed significant associations of cytoplasmic HDPR1 with regional lymph node metastasis (p = 0.021) and P-stage (p = 0.004). The increased nuclear staining was only correlated with P-stage (p = 0.047). Significant associations of coexpression of cytoplasmic and nuclear HDPR1 with regional lymph node metastasis (p = 0.015) or P-stage (p = 0.002) were observed. Enhanced cytoplasmic expression of HDPR1 was positively correlated with increased cytoplasmic but not reduced membranous beta-catenin expression (r = 0.239, p = 0.027 and r = 0.126, p = 0.089, respectively). These finding suggested that cytoplasmic HDPR1 protein expression was associated with tumor malignant progression via beta-catenin accumulation. It implicated that cytoplasmic HDPR1 expression may serve as a potential predictive factor for lymph node metastasis and tumor development in ESCC.     

Specificity of trans-inhibition of amino acid transport in Baker’s yeast

The trans-inhibition potency of intracellular amino acids on the transport of various amino acids follows the same sequence,viz. Pro(Lys), Phe, Glu, Ala, Gly, Leu, and α-aminoisobutyric acid. The same sequence was found for the reciprocal of trans-inhibition constants. It appears that the intracellular amino acid itself or a derivative thereof acts on a component that is common to all amino acid transport systems of baker’s yeast.