Legionella pneumophila in Cooling Towers: Fluctuations in Counts, Determination of Genetic Variability by Pulsed-Field Gel Electrophoresis (PFGE), and Persistence of PFGE Patterns

The concentrations of Legionella pneumophila in cooling towers may vary considerably over short periods of time, producing significant fluctuations throughout the year. Despite genetic variability, in small geographical areas the same indistinguishable pulsed-field gel electrophoresis patterns may be shared among different cooling towers and persist over time.     

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.     

Engineering crops, a deserving venture.

Plant transformation has had a deep impact on several aspects of basic and applied research. Genetic transformation has offered new opportunities compared to traditional breeding practises since it allows the integration into a host genome of specific sequences leading to a strong reduction of the casualness of gene transfer. One of the first target areas was plant protection against pests, pathogens and environmental stresses while the recent plant engineering programs are aimed at increasing food quality, in particular at increasing nutritional characteristics of food crops. Moreover, transgenic plants, tissue or cell cultures represent an attractive biological system for producing heterologous proteins since they offer economic and qualitative benefits. High yield production can be obtained and large-scale commercial production will take advantage of the existing infrastructure for crop cultivation, processing and storage. There are also qualitative benefits since protein synthesis secretion and post-translational modifications are similar in plants and animal cells. There are no human viral pathogens harboured by plants: thus, especially for pharmaceuticals, plants represent the safer production system. Plant transformation has become an essential instrument also for basic research, in particular for the functional characterisation of genes identified by sequencing of whole genomes. Large collections of insertion mutants have been obtained in the model plant Arabidopsis to provide a high level of genome saturation that means 95% chance of inactivating any gene at least once. To instil greater public confidence in modern plant biotechnology recent advances have already been made to overcome the potential risks for human health and environment.     

Outdoor mass culture of Spirulina maxima in sea-water

Summary The results of a whole year experiment on the outdoor mass culture of Spirulina maxima strain 4Mx on fertilized sea-water are reported. Carbonate and phosphate precipitation in the sea-water media was prevented by maintaining a low concentration of phosphate and by controlling the pH in the range of 8.0–8.3. The mean annual yield of biomass on sea-water plus urea as nitrogen source was 7.35 g (dry weight) m^-2· day^-1, a value slightly lower than that obtained on the standard bicarbonate medium (8.14 g · m^-2 · day^-1). On sea-water plus nitrate the yield was only 5.2 g·m^-2·day^-1. The nitrogen content of the biomass was higher in summer and lower in winter. The seasonal effect was more evident when nitrate was the nitrogen source.     

Minor pollinosis fromCryptomeria japonica in Varese,northern Italy. Aerobiological monitoring and main clinical features

In the last 2 years we have conducted an aerobiological monitoring program ofCryptomeria japonica, a plant belonging to the family of Taxodiaceae that sometimes causes pollinosis in the period from February to April. Throughout 1994, we checked the incidence of its sensitization and the clinical effects in 85 subjects with correlated seasonal symptoms, who gave a positive skin prick test (SPT) for Betulaceae and/or Corylaceae. Twenty-five patients (29.4%; 19 M; 6 F; mean age, 38.8 years) all with oculorhinitis, were SPT positive to an allergenic extract ofCryptomeria. RAST confirmed this positivity in 44% of the cases. No patients showed monosensitization forCryptomeria to either SPT or RAST. Two subjects gave a positive result on specific nasal provocation. RAST inhibition showed no cross-reaction betweenCryptomeria and birch pollen. During the pollen season each patient made a list, scoring symptoms and specifying any drugs used, so we could correlate these elements with aerobiological observations. The pollen concentration probably exceeded the allergizing threshold forCryptomeria on 8 days during 3 months of recording. The intensity and duration of symptoms seemed to be mainly influenced by sensitization to Betulaceae and Corylaceae. It is thus possible that a combination of minor pollinosis may produce seasonal symptoms in allergic patients.     

Spermatophore development and sperm ultrastructure inCraterostigmus tasmanianus (Chilopoda,Craterostigmomorpha)

 Spermatophore development and ultrastructure of the mature sperm of Craterostigmus tasmanianus were studied using light and electron microscopy. In C. tasmanianus, as in the Scolopendromorpha, the spermatophore develops within the vas deferens. The latter consists of three parts, each with a different morphology. The first may be involved in guiding the sperm to roll up into typical ring-like structures, while the other two, which show an evident secretory activity, secrete the acellular wall of the spermatophores. The ultrastructure of mature spermatozoa showed that a very close similarity exists between Craterostigmomorpha and Lithobiomorpha, especially regarding the organization of the connecting piece. Based on this similarity, we consider the Craterostigmomorpha together with the Scolopendromorpha, Geophilomorpha and Lithobiomorpha (=Pleurostigmophora) to be the sister group of the Scutigeromorpha. Accepted: 2 June 1996     

Photocontrol of somatic embryogenesis and polyamine content in Araujia sericifera petals

The effects of photoperiod and end-of-day phytochrome control on somatic embryogenesis and polyamine (PA) content in Araujia sericifera petals have been studied. Petals from immature flowers were cultured under 16- and 8-h photoperiods. Far red (FR), red (R) and FR followed by R light treatments were applied at the end of the photoperiods for three weeks. The number of somatic embryos, callus weight and the levels of free and bound PAs in the cultured petal explants were determined 40 days after the beginning of light treatments. Long day (LD) promoted somatic embryogenesis but did not have any significant effect on PA content. Short day (SD) reduced somatic embryogenesis and enhanced total PAs, mainly in the form of bound spermidine. End-of-day FR treatment increased PA content and inhibited somatic embryogensis under LD but had no significant effect under SD. This effect of FR on PA levels was cancelled by R and was independent of the presence of silver thiosulphate in the medium. End-of-day R treatment reduced the total PA content under SD. However, end-of-day R increased or reduced somatic embryogenesis under SD depending on the presence or absence of silver in the medium. The results suggest a photoperiodic control of somatic embryogenesis and PA content in A. sericifera. The effects of end-of-day R and FR treatments depend on the length of the photoperiod. This finding and the FR/R photoreversibility of end-of-day treatments indicate that phytochrome may be involved in both somatic embryogenesis and accumulation of PA.     

Modulation of drug-induced cytotoxicity by a bispecific monoclonal antibody that recognizes the epidermal growth factor receptor and doxorubicin

A hybrid hybridoma secreting a bispecific hybrid mAb (bsmAb), which recognizes both the epidermal growth factor receptor (EGF-R) and the drug doxorubicin, was produced by somatic hybridization of two hybridomas. The bsmAb obtained was able to retarget doxorubicin cytotoxicity in vitro specifically on EGF-R-positive cells exerting at the same time an antidotal effect on cells that did not overexpress the EGF-R. Distribution studies in mice indicate that the bsmAb selectively delivers the drug to tumour cells and modifies doxorubicin biodistribution with a statistically significant decrease of drug concentration in the intestine, which is the main target of early anthracycline toxicity. In keeping with this finding is the remarkable antidotal activity exerted by bsmAb in mice treated with doxorubiein, which is proved by retardation in loss of body weight and mortality. The effectiveness on tumour growth of the mAb followed by the administration of doxorubicin appears to be equal to that of the drug alone; however, the bsmAb exerts a remarkable antidotal activity.