Presence of <Emphasis Type="Italic">C. albidus</Emphasis>, <Emphasis Type="Italic">C. laurentii</Emphasis> and <Emphasis Type="Italic">C. uniguttulatus</Emphasis> in Crop and Droppings of Pigeon Lofts (<Emphasis Type="Italic">Columba livia</Emphasis>)

Columba livia is an important reservoir and carrier of Cryptococcus neoformans, Cryptococcus uniguttulatus, Cryptococcus laurentii and Cryptococcus albidus. Upper digestive tract of this species is also known as a habitat for Cryptococcus neoformans. Given the increasing clinical interest of this microorganism, 331 swabs from crop and 174 dropping samples from pigeon lofts in Grand Canary Island have been studied. The obtained results show an extensive presence samples 81 positive (24.47%) of Cryptococcus spp. in analysed crops: 32 (9.66%) for C. neoformans, 24 (7.2%) for C. uniguttulatus, 23 (6.9%) for C. albidus and 2 (0.6%) for C. laurentii. In the same way, Cryptococcus spp was also isolated in 82 (47.13%), dropping samples: C. neoformans in 59 (33.9%), C. uniguttulatus, in 9 (5.17%), C. laurentii in 8 (4.59%) and C. albidus in 6 (3.44%) of the investigated samples, respectively. The cryptococcosis produced by species of cryptococci other than C. neoformans has become more important during the last decade, supporting the study on the role of pigeon in the epidemiology of this disease.     

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.     

Fickean and Non-Fickean Water Desorption During Vacuum Drying of <Emphasis Type="Italic">L. bulgaricus</Emphasis>

The recovery of Lactobacillus bulgaricus was studied in correlation to the kinetics of cell drying. When bacteria were dehydrated at 30 °C, either in the presence or the absence of sucrose, the drying kinetics corresponds to a Fickean diffusion in correspondence with a short lag time. In contrast, when the bacteria were dehydrated at 70 °C in the absence of sugar, the kinetics corresponds to an anomalous diffusion, and the lag time is four to five times higher than that at 30 °C. However, when drying at 70 °C was carried out in the presence of sucrose, drying kinetics turned into a Fickean process parallel to a substantial decrease in the lag time. The pattern of water desorption was correlated with the critical water activity. When the drying kinetics corresponds to a Fickean diffusion, the lag time started to increase at 0.7 water activity, but when the cells were dried at 70 °C, the damage started at 0.5 water activity. This observation indicates that the drying rate affects the pattern of water desorption, and it can change the value of critical water activity. These results put into relevance that the cell recovery is due to the drying history and that the recovery increase produced by sucrose can be related to the maintenance of kinetic barriers for water desorption.     

Experimental infections of simians with human malaria: attempts to infect Callithrix penicillata with Plasmodium falciparum

After reviewing the use of non-human primates of the Old and New Worlds for human malaria research, we concluded that another experimental animal which is easily available to use and possible to rear indoors is needed. Thus, we studied the susceptibility of the marmoset Callithrix penicillata to Plasmodium falciparum erythrocytic infections. The marmosets received various P. falciparum human isolates, directly from a patient and from continuous cultures. The Palo Alto strain, which has been adapted to the night monkey Aotus trivirgatus and further maintained in the squirrel monkey Saimiri sciureus was also used. In a total of 20 marmosets we performed 31 inoculations, with 10(5) to 10(9) parasites, intraperitoneally, intracardiacly or intravenously. Blood samples from each animal were examined daily up to day 90 post-inoculation. None of the intact marmosets developed patent infections. Four out of 19 C. penicillata, previously splenectomized, showed circulating parasites for up to five days after intravenous inoculation with the Palo Alto strain, becoming negative thereafter. Neither the addition to the simian diet of p-aminobenzoic acid, essential for the parasite metabolism, nor drug-immunosuppression, improved the marmoset susceptibility to P. falciparum.     

Binding of flunitrazepam to differentiating neurons cultured in a chemically defined,hormone-supplemented medium

[³H]Flunitrazepam (FNZ) binding to cortical neurons from fetal rat brain was investigated in vitro. The use of a synthetic medium specific for neurons made it possible to plot a developmental curve of³H-FNZ binding in an almost pure neuronal culture. Detectable specific binding was present in vitro at time 0 (that is, the 16th gestational day). A progressive increase of binding, due to an increment in the number of recognition sites, was observed on the subsequent days. The affinity of the specific binding sites to³H-FNZ was enhanced by the addition of exogenous GABA, whereas the density was not affected.     

Photocatalyzed Anaerobic Oxidation of Nicotinamide Coenzyme Dimers to NAD+ by Adriamycin

The nicotinamide adenine dinucleotide dimers (NAD)₂ obtained by electrochemical reduction of NAD⁺ are oxidized by adriamycin in anaerobic photocatalyzed reaction yielding NAD⁺ and 7-deoxyadriamyci-none. Under the same conditions NADH is not oxidized.     

Phorbol 12-myristate 13-acetate induces resistance of human melanoma cells to natural-killer-and lymphokine-activated-killer-mediated cytotoxicity

Summary Human melanoma cells are sensitive to the lytic activity of natural killer (NK) and lymphokine-activated killer (LAK) cells in vitro. The events resulting in tumour cell killing by lymphocytic effectors have not been completely clarified, and the same target cell determinants regulating responsiveness to immune cytolysis have not yet been identified. Indeed, changes in the differentiative status of leukemia cells as well as in the expression of major histocompatibility complex (MHC) antigens have been described to modulate sensitivity to cytotoxic effectors; moreover surface expression of adhesion factors or extracellular matrix proteins by the cancer cells can promote the activation of the cytolytic effectors and has been described to correlate with tumour cell sensitivity to cytolytic cells. We reasoned that treatment with differentiation inducers could modulate melanoma cell sensitivity to NK and LAK cells. The present study demonstrates that human melanoma GLL-19 cells, when treated with the phorbol diester phorbol 12-myristate 13-acetate (PMA) in vitro, undergo growth inhibition and neuron-like differentiation. Moreover PMA treatment induces an evident inhibition of GLL-19 cell sensitivity to NK- and LAK-mediated cytotoxicity. GLL-19 cells express constitutively MHC class I antigens. PMA treatment, however, does not modify the expression of MHC class I and class II DR antigens in human melanoma GLL-19 cells. We have finally evaluated the effects of PMA on the expression at the cell surface of adhesion factors such as ICAM-1, and extracellular matrix proteins such as collagen IV, laminin and fibronectin; we have also studied the expression of the integrin vitronectin receptor, a membrane receptor for adhesive proteins. While adhesion factors and extracellular matrix proteins appear to play an important role in the interaction between immune effector and tumour target, it can be supposed that the modulation of such membrane-associated proteins or glycoproteins induces NK and LAK resistance in cancer cells. We indeed found that PMA treatment induced in GLL-19 a marked reduction of membrane expression of collagen IV and ICAM-1; moreover PMA reduced the cell membrane expression of the integrin vitronectin receptor. On the other hand, membrane expression of fibronectin and laminin was not affected by PMA. These data indicate that the acquisition of a NK- and LAK-resistant phenotype by GLL-19 cells occurs together with cell differentiation, down-regulation of membrane expression of collagen IV, ICAM-1 and vitronectin receptor, but in the absence of changes in MHC antigens.This work has been supported by the Italian Association for Cancer Research (A. I. R. C.) and by Istituto Superiore di Sanità, Italy-USA joint program on New Therapies on Neoplasia.     

Isolation and genetic structure of IS112, an insertion sequence responsible for the inactivation of the SalI restriction-modification system of Streptomyces albus G.

Summary IS112 is a transposable element identified in Streptomyces albus G by its frequent mutagenic insertion into the genes for the SalI restriction-modification system. IS112 is present in several copies in the genome of S. albus G. Homologous sequences were detected in other Streptomyces strains. Sequence analysis revealed that IS112 has a length of 883 by with a GC content of 67.4%. The copy that was isolated contained imperfect inverted repeats (16/20 match) at its ends and was flanked by a 2 by duplication at the target site, which was located within the gene (salIR) for the Sall endonuclease. A long open reading frame (ORF) encoding a putative polypeptide of 256-253 amino acids spans almost the entire sequence. Significant homology was detected between this polypeptide and that corresponding to ORFB of IS493, an insertion sequence recently isolated from Streptomyces lividans 66.

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