Heterogeneous phenotype of human glioblastoma: In vitro study

Glioblastomas (GBMs) are the most lethal primary brain tumours. Increasing evidence shows that brain tumours contain the population of stem cells, so‐called cancer stem cells (CSCs). Stem cell marker CD133 was reported to identify CSC population in GBM. Further studies have indicated that CD133 negative cells exhibiting similar properties and are able to initiate the tumour, self‐renew and undergo multilineage differentiation. GBM is a highly heterogeneous tumour and may contain different stem cell populations with different functional properties. We characterized five GBM cell lines, established from surgical samples, according to the marker expression, proliferation and differentiation potential. CD133 positive cell lines showed increased proliferation rate in neurosphere condition and marked differentiation potential towards neuronal lineages. Whereas two cell lines low‐expressing CD133 marker showed mesenchymal properties in vitro, that is high proliferation rate in serum condition and differentiation in mesenchymal cell types. Further, we compared therapy resistance capacity of GBM cell lines treated with hydroxyurea. Our results suggest that CSC concept is more complex than it was believed before, and CD133 could not define entire stem cell population within GBM. At least two different subtypes of GBM CSCs exist, which may have different biological characteristics and imply different therapeutic strategies. Copyright © 2013 John Wiley & Sons, Ltd.     

Suppression of growth defects of α-amylase secreting Escherichia coli by signal sequence fusion

Abstract In a previous study, we have described unusual cross-reactions among monoclonal antibodies (Mabs) to bacteria and in particular to the Inaba and Ogawa serotypes of Vibrio cholerae . In this study, the extent to which the binding sites of both antibodies and antigens overlap has been investigated by competitive binding and idiotypic analysis. The competitive binding data indicate that the cross-reactive binding of the Inaba Mabs to the Ogawa vibrios can be abolished by incubation with higher affinity Ogawa Mabs. However, rabbit antiserum raised against the Inaba series does not react with the Ogawa series, indicating that anti-Inaba Mabs do not share idiotypic determinants with anti-Ogawa Mabs. The results therefore suggest that the two sets of antibodies recognise different determinants which are closely related in spatial terms, and which consequently do not permit simultaneous binding of the two types of monoclonal antibody.     

Statistic evaluation of the influence of species variation,culture conditions,surface wettability and fluid shear on attachment and biofilm development of marine bacteria

A budding coccoid bacterium, (CH1), a Vibrio sp. and a Pseudomonas sp. were investigated for factors governing their attachment to glass surfaces in static batch culture and laminar flow continuous culture systems. An analysis of variance showed that the three species exhibited very different responses. For CH1 attachment was dependent on cell density, incubation time and nutrient concentration. The Vibrio sp. was affected by nutrient concentration while the attachment of the Pseudomonas sp. was independent of cell density, incubation time and nutrient concentration. A comparison of attachment to hydrophilic and hydrophobic surfaces showed that attachment of the Vibrio sp. and CH1 to hydrophilic surfaces was 3 and 10 times greater respectively than to hydrophobic surfaces while Pseudomonas attached in equal numbers to both surfaces. The continuous culture system with defined flow hydrodynamics and growth conditions at steady state revealed a random sampling effect 3 times smaller than the batch culture system did. When the biofilm development of Pseudomonas sp. was followed during 46 h at different fluid shear under laminar and turbulent flow conditions, the former biofilm reached 3.3·10⁸ cells·cm^-2 and the latter 8.2·10⁷ cells·cm^-2.Non-common abbreviation NSS Nine salt solution     

Molecular weights of Cucurbita sieve tube proteins

Summary By means of SDS-polyacrylamide-gel electrophoresis, molecular weights of 15000, 28000, 59000, 116000 and 220000 were determined for the main sieve tube proteins from Cucurbita maxima.     

Ultrastructure of the Genital Organs in the Interstitial Syllid Petitia amphophthalma (Annelida,Polychaeta)

Abstract The gonochoristic syllid Petitia amphophthalma is one of the truly interstitial polychaetes. P. amphophthalma does not show any epitokous modifications at maturity such as those that usually occur in syllids. The reproductive structures are unique: the male genital organs consist of a seminal vesicle in chaetigers 6–10, subdivided into a dorsal part tightly filled with spermatozoa and a ventral part with contents in different stages of spermatogenesis, one pair of sperm ducts and conspicuous gland cells situated in chaetigers 10 and 11. Their glandular secretions are discharged into the sperm duct together with those of other types of gland cells that form the duct. The oocytes develop freely within the body cavity of the females. Each of the fertile segments possesses a paired oviduct ending in a large ciliated funnel. Sperm ducts and oviducts are probably modifications of excretory organs; nephridia are absent in segments where gonoducts occur. A direct sperm transfer by lytic opening of the integument of the female and internal fertilization are inferred. Copyright © 1996 Published by Elsevier Science Ltd on behalf of the Royal Swedish Academy of Sciences