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.     

Temperature influences the expression of fimbriae and flagella in <Emphasis Type="Italic">Hafnia alvei</Emphasis> strains: an immunofluorescence study

Hafnia alvei, a Gram negative bacillus related to the Enterobacteriaceae family, is considered an opportunistic pathogen of several animal species and humans. In this communication, we describe fimbrial-like structures from different strains of H. alvei that cannot be easily ascribed to any of the previously reported fimbrial types in this species (type I or type III). Polymerase chain reaction (PCR) and immunofluorescence assays were carried out to study fimbriae and flagella in H. alvei strains isolated from different sources. No correlation between the results obtained by PCR and those obtained by phenotypic methods were found, and the antibodies used gave cross or different recognition patterns of the surface structures present in these strains. We report as well that strain and growth temperature influence fimbriation and expression of flagella in human and animal isolates of H. alvei. This study also indicates that the absence of fimbriae have a significant positive influence on the initial adhesion of H. alvei to human epithelial cells.     

Depicting the Spatial Distribution of Proteins in Human Tumor Tissue Combining SELDI and MALDI Imaging and Immunohistochemistry

Carcinoma tissue consists of not only tumor cells but also fibroblasts, endothelial cells or vascular structures, and inflammatory cells forming the supportive tumor stroma. Therefore, the spatial distribution of proteins that promote growth and proliferation in these complex functional units is of high interest. Matrix-assisted laser desorption/ionization imaging mass spectrometry is a newly developed technique that generates spatially resolved profiles of protein signals directly from thin tissue sections. Surface-enhanced laser desorption/ionization mass spectrometry (MS)combined with tissue microdissection allows analysis of defined parts of the tissue with a higher sensitivity and a broader mass range. Nevertheless, both MS-based techniques have a limited spatial resolution. IHC is a technique that allows a resolution down to the subcellular level. However, the detection and measurement of a specific protein expression level is possible only by semiquantitative methods. Moreover, prior knowledge about the identity of the proteins of interest is necessary. In this study, we combined all three techniques to gain highest spatial resolution, sensitivity, and quantitative information. We used frozen tissue from head and neck tumors and chose two exemplary proteins (HNP1–3 and S100A8) to highlight the advantages and disadvantages of each technique. It could be shown that the combination of these three techniques results in congruent but also synergetic data. (J Histochem Cytochem 58:929–937, 2010)     

INTERVENTION OF BRAIN CORTEX PHOSPHOLIPIDS IN PYRIDOXAL PHOSPHATE-DEPENDENT REACTIONS

We have examined the role of brain cortex phospholipids in regulating some enzymic reactions specific to the CNS. The study was carried out at the level of the reactions concerned with GABA formation, both in vivo and in vitro, and included investigation of the specificity of the effect. It was found that the brain cortex phospholipids enhance the transformation of exogenous vitamin B₆ into pyridoxal-5-phosphate by activating the pyridoxal 5-phosphate-kinase enzyme, in contrast to other phospholipids of different origins. The possible role of brain cortex phospholipids in regulating an enzyme contained in the soluble fraction is discussed. Moreover, it is suggested that the specific effect of the phospholipids from various sources is linked to their fatty acid composition and to be therefore dependent on the aliphatic chains.     

p82H identifies sequences at every human centromere

Summary A cloned alphoid sequence, p82H, hybridizes in situ to the centromere of every human chromosome. After washing under stringent conditions, no more than 8% of the grains are located on any specific chromosome. p82H thus differs from other centromeric sequences which are reported to be chromosome specific, because it detects sequences that are conserved among the chromosomes. Two experimental approaches show that the p82H sequences are closely associated with the centromere. First, p82H remains with the relocated centromeres in an inv(19) and an inv(6) chromosome. Second, p82H hybridizes at the centromere but not to the centromeric heterochromatin of chromosomes 1, 9 and 16 that have elongated 1qh, 9qh and 16qh regions produced by short growth in 5-azacytidine. The only noncentromeric site of hybridization is at the distal end of the 9qh region.     

Chromosome-specific subsets of human alphoid DNA identified by a chromosome 2-derived clone

We have cloned an alphoid DNA fragment, pBS4D, from the DNA of a human-hamster hybrid cell line containing chromosome 2 as its only cytologically detectable human component. Under high stringency conditions, pBS4D hybridized in situ mostly to chromosome 2 and to a lesser extent to chromosomes 18 and 20. Restriction analysis using the DNA from selected somatic hybrid cell lines revealed that the genomic organization of this alphoid DNA differs on each of these three chromosomes.     

Beta-adrenergic receptor characteristics of postnatal rat myocardial cell preparations

Summary Primary mycolardial cell cultures and freshly isolated cardiac cells in suspension resprensent two isolated, whole cell models for investigating cellular transsarcolemmal⁴⁵Ca⁺⁺ exchange in response to a receptor-coupled stimulus. Studies were performed to characterize beta-adrenergic receptor binding, beta-adrenergic receptor mediated cellular calcium (⁴⁵Ca⁺⁺) exchange, and viability in purified primary myocardial cell cultures and freshly isolated cardiac cells in suspension obtained from 3-to 3-d-old Sprague-Dawley rats. In addition, beta-adrenergic receptor binding was characterized in whole-heart crude membrane preparations. All three preparations had saturable beta-adrenergic binding sites with the antagonist [¹²⁵I]iodopindolol ([¹²⁵I]IPIN). The suspensions had a significantly lower B _max (42±6 fmol/mg protein) than the membranes and cultures (77±8 and 95±10 fmol/mg protein, respectively). The K _D of the cultures (218±2.0 pM) was significantly higher than that for the suspensions (107 ±1.3 pM) and membranes (93±1.3 pM). Viability was significantly lower in the suspensions (57%) when compared to 94% viability in myocardial cell cultures after 3 h of incubation in Kreb's Henseleit buffer. Incubation of the cultures with 5.0×10⁻⁷ M isoproterenol resulted in a significant increase in⁴⁵Ca⁺⁺ exchange as early as 15 s. In contrast,⁴⁵Ca⁺⁺ exchange into the suspensions was not increased. Although both primary cell cultures and cardiac cells in suspension possess saturable beta-adrenergic receptors, only the monolayer cultures exhibited functional beta-adrenergic receptor-mediated⁴⁵Ca⁺⁺ exchange. Of the two intact cell models investigated, these data suggest that primary myocardial cell cultures are more suitable than cell suspensions for investigating beta-adrenergic receptor binding and functions in the postnatal rat heart. This research was supported by The University of Texas Research Institute, a grant from the Texas Advanced Research Technology Program awarded to S. W. Leslie and R. E. Wilcox, and contract 223-86-2109 from the Food and Drug Administration.     

The problem of the acts duration measurement in relation to the “focal-animal” technique of behavioral recording

The focal-animal technique assumes the continuous recording of the behavior of an individual during a certain time interval. The length of this interval (sampling unit) can be problematic when estimating the duration of behavioral acts. Two acts from the behavioral repertoire of the ant Leptothorax fuenteiwere focused on in this work at different ranges of temporal scales. Analyzing these acts we show the possibility of existence of a sampling artifact, in such a way that the estimates of the durations of the acts would be forced to depend upon the length of the sampling unit that is being used.