Chemotactic activity of pertussis toxin on murine lymphocytes. Its potential role on lymphocyte accumulation in the lung

Abstract The effects of pertussis toxin on lymphocyte migration were studied in vitro. In this study pertussis toxin significantly stimulated lymphocyte migration at concentrations of 0.1 and 1 μg ml⁻¹ using a microchamber and the leading-front method. Checkerboard analysis demonstrated that pertussis toxin causes directed migration of lymphocytes (chemotaxis). Heat-treatment of pertussis toxin abolished its capacity to cause this migration. When murine lymphocytes were preincubated with different concentrations of pertussis toxin, an inhibition of chemotaxis at the dosages of 0.1 and 1 μg ml⁻¹ was observed. On the other hand, lymphocytes derived from mice treated with pertussis toxin were not inhibited after subsequent exposure to pertussis toxin in vitro. Since lymphocyte accumulation in the lungs of mice treated with pertussis toxin has been well domenstrated, the results of our study could suggest a chemotactic activity of pertussis toxin in determining accumulation of lymphocytes in this organ.     

Ovarian structure and oogenesis of the oviparous goodeids Crenichthys baileyi (Gilbert, 1893) and Empetrichthys latos Miller, 1948 (teleostei,Cyprinodontiformes)

The cyprinodontiform family Goodeidae comprises two biogeographically disjunct subfamilies: the viviparous Goodeinae endemic to the Mexican Plateau, and the oviparous Empetrichthyinae, known only from relict taxa in Nevada and California. Ovarian characteristics of two oviparous species of goodeid, Crenichthys baileyi and Empetrichthys latos, studied using museum collections, are compared with those of viviparous species of goodeids. Both subfamilies have a single, cystovarian ovary. The ovary in the viviparous Goodeinae has an internal septum that divides the ovarian lumen into two compartments, and it may possess oogonia. There is no ovarian septum in the oviparous C. baileyi and E. latos. Oogenesis is similar in both subfamilies with regard to the proliferation of oogonia, initiation of meiosis, primary growth and development of an oocyte during secondary growth in which fluid yolk progressively fuses into a single globule. Notably, eggs of C. baileyi and E. latos are approximately double the size of those of the viviparous Goodeinae in which embryos develop inside the ovarian lumen and are nourished, in part, by nutrients transferred from the maternal tissues, a mode of embryo development called matrotrophy. Egg envelopes of the two subfamilies differ in that those of C. baileyi and E. latos have a relatively thick zona pellucida, attachment fibrils or filaments that develop between the follicle cells during oogenesis, and a micropyle observed only in E. latos. In contrast, viviparous goodeid eggs have a relatively thin zona pellucida, but lack adhesive fibrils, and a micropyle was not observed. These reproductive characters are compared with those of species of the eastern North American Fundulus, a representative oviparous cyprinodontiform. One newlyrecognized shared, derived character, a single, median ovoid ovary with no obvious external evidence of fusion, supports monophyly of the Goodeidae. Differences among the goodeid subfamilies and Fundulus are interpreted relative to the oviparous versus viviparous modes of reproduction. J. Morphol., 2012. © 2011 Wiley Periodicals, Inc.     

Isolation of an Aspergillus terreus mutant impaired in arginine biosynthesis and its complementation with the argB gene from Aspergillus nidulans

Using filtration enrichment techniques, an Aspergillus terreus arginine auxotrophic strain which contains a mutation that abolishes ornithine transcarbamylase (OTCase) activity has been isolated. This mutant has been genetically transformed with the cloned Aspergillus nidulans OTCase gene. Prototrophic transformants arose at a frequency of about 50 transformants per microgram of plasmid DNA. Southern blot analysis of DNA from the transformants showed that the transforming DNA was ectopically integrated at different locations in the A. terreus genome, often in multiple tandem copies. The transformants were phenotypically stable for several mitotic divisions and retained their capacity to produce extracellular enzymes.     

Deconstructing the long-standing a priori assumption that serial homology generally involves ancestral similarity followed by anatomical divergence

It has long been assumed that serial homologues are ancestrally similar—polysomerism resulting from a “duplication” or “repetition” of forms—and then often diverge—anisomerism, for example, as they become adapted to perform different tasks as is the case with the forelimb and hind limbs of humans. However, such an assumption, with crucial implications for comparative, evolutionary, and developmental biology, and for evolutionary developmental biology, has in general not really been tested by a broad analysis of the available empirical data. Perhaps not surprisingly, more recent anatomical comparisons, as well as molecular knowledge of how, for example, serial appendicular structures are patterned along with different anteroposterior regions of the body axis of bilateral animals, and how “homologous” patterning domains do not necessarily mark “homologous” morphological domains, are putting in question this paradigm. In fact, apart from showing that many so-called “serial homologues” might not be similar at all, recent works have shown that in at least some cases some “serial” structures are indeed more similar to each other in derived taxa than in phylogenetically more ancestral ones, as pointed out by authors such as Owen. In this article, we are taking a step back to question whether such assumptions are actually correct at all, in the first place. In particular, we review other cases of so-called “serial homologues” such as insect wings, arthropod walking appendages, Dipteran thoracic bristles, and the vertebrae, ribs, teeth, myomeres, feathers, and hairs of chordate animals. We show that: (a) there are almost never cases of true ancestral similarity; (b) in evolution, such structures—for example, vertebra—and/or their subparts—for example, “transverse processes”—many times display trends toward less similarity while in many others display trends toward more similarity, that is, one cannot say that there is a clear, overall trend to anisomerism.     

Increased incidence of disomic sperm nuclei in a 47,XYY male assessed by fluorescent in situ hybridization (FISH)

Using triple-colour fluorescent in situ hybridization in decondensed sperm heads, we assessed the sex-chromosome distribution in spermatozoa from a 47,XYY male compared with controls. The incidence of spermatozoa with 24,XY (0.30%) and 24,YY (1.01%) disomy was significantly higher than in our control series. Diploid meiocytes present in the ejaculate were mainly 47,XYY (60.6–86.7%), and haploid meiocytes were mainly 24,XY (78.1%).These results suggest that, although the extra Y chromosome is thought to be eliminated during spermatogenesis, XYY germ cells can complete meiosis and produce disomic spermatozoa. Received: 5 August 1996 / Revised: 2 October 1996     

A Combined Approach for the Assessment of Cell Viability and Cell Functionality of Human Fibrochondrocytes for Use in Tissue Engineering

Temporo-mandibular joint disc disorders are highly prevalent in adult populations. Autologous chondrocyte implantation is a well-established method for the treatment of several chondral defects. However, very few studies have been carried out using human fibrous chondrocytes from the temporo-mandibular joint (TMJ). One of the main drawbacks associated to chondrocyte cell culture is the possibility that chondrocyte cells kept in culture tend to de-differentiate and to lose cell viability under in in-vitro conditions. In this work, we have isolated human temporo-mandibular joint fibrochondrocytes (TMJF) from human disc and we have used a highly-sensitive technique to determine cell viability, cell proliferation and gene expression of nine consecutive cell passages to determine the most appropriate cell passage for use in tissue engineering and future clinical use. Our results revealed that the most potentially viable and functional cell passages were P5–P6, in which an adequate equilibrium between cell viability and the capability to synthesize all major extracellular matrix components exists. The combined action of pro-apoptotic (TRAF5, PHLDA1) and anti-apoptotic genes (SON, HTT, FAIM2) may explain the differential cell viability levels that we found in this study. These results suggest that TMJF should be used at P5–P6 for cell therapy protocols.     

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.