The abundance of alpha-tubulin mRNA increases during ciliary regeneration in Tetrahymena, and this occurs independently of the soluble tubulin content

Control mechanisms of tubulin synthesis are analyzed during ciliary regeneration of the ciliate Tetrahymena. Titration of the alpha-tubulin mRNA concentrations during the regeneration period reveal that enhancement of tubulin synthesis is preceded and accompanied by increased concentrations of tubulin mRNA molecules. Stimulation of tubulin synthesis is independent of the pool size of soluble tubulin molecules, as suggested by at least two independent lines of evidence: First, like cells of normal phenotype a temperature sensitive size mutant enhances tubulin synthesis as well as tubulin mRNA concentration during ciliary regeneration, although these large mutant cells have a much higher concentration and amount of soluble tubulin molecules in the cytoplasm. Second, slowly regenerating cells of normal phenotype shift-up their concentration of tubulin mRNA molecules already before a time, when ciliary outgrowth might cause a significant depletion of the pool of soluble tubulin molecules. Thus, neither an induction of tubulin synthesis nor an increase in tubulin mRNA molecules is mediated via changes in the pool size of soluble tubulin molecules.     

Haemocompatibility of coronary catheters.

BACKGROUND: Unwanted side-effects like thrombotic-thromboembolic processes accompany the intravascular use of catheters. The influence of the physico-chemical properties of the catheter materials on these processes is not completely understood. METHODS: The haemocompatibility of angiography-catheters (n = 10) (Super Torque Plus, CORDIS, Johnson & Johnson company) was examined in a perfusion-model filled with platelet-rich plasma and either compared to a non-thrombogenic (silicon-tube) or to a thrombogenic surface (glass). As test-parameters the number of single circulating thrombocytes, of circulating platelet-aggregates, of circulating activated thrombocytes (CD62) and the thrombin generation (thrombin antithrombin III-complexes) were evaluated. RESULTS: None of the test-parameters showed differences between the non-thrombogenic control-system and the angiography-catheters. Both systems, however, differed significantly and relevantly from the system filled with the glass-beads (the thrombogenic control-systems). CONCLUSION: With respect to the platelet reactivity angiography-catheters of the examined type can therefore be regarded as non-thrombogenic or haemocompatible.     

All three promoters of the acetyl-coenzyme A-carboxylase alpha-encoding gene are expressed in mammary epithelial cells of ruminants.

The activity of the enzyme acetyl-CoA-carboxylase alpha (ACC-alpha) is rate limiting for the de novo synthesis of fatty acids. The encoding gene is expressed from three promoters in ruminants (PI-PIII). Their individual contribution to the formation of milk fat is unknown. Promoter-specific molecular probes were hybridized in situ to serial sections of mammary glands from cows and sheep to determine their developmental and spatial expression profile in the udder. We show that all three promoters are active in mammary epithelial cells (MECs) of udders from both species. This implies that, in principle, none of these promoters can be singled out as the key element controlling the ACC-alpha-related contribution to establishment of milk fat content, although the activity of PIII only is known to be disproportionally stimulated by lactation in MECs. We propose that all three promoters may be relevant for milk fat synthesis in cattle, whereas PII and PIII are crucial for milk fat formation in sheep. We show also that ACC-alpha synthesis is not strictly coupled to casein synthesis, particularly during pregnancy and involution.     

Localization of the genetic determinants of meiosis suppression in Daphnia pulex

Although approximately 1 in 10,000 animal species is capable of parthenogenetic reproduction, the evolutionary causes and consequences of such transitions remain uncertain. The microcrustacean Daphnia pulex provides a potentially powerful tool for investigating these issues because lineages that are obligately asexual in terms of female function can nevertheless transmit meiosis-suppressing genes to sexual populations via haploid sperm produced by environmentally induced males. The application of association mapping to a wide geographic collection of D. pulex clones suggests that sex-limited meiosis suppression in D. pulex has spread westward from a northeastern glacial refugium, conveyed by a dominant epistatic interaction among the products of at least four unlinked loci, with one entire chromosome being inherited through males in a nearly nonrecombining fashion. With the enormous set of genomic tools now available for D. pulex, these results set the stage for the determination of the functional underpinnings of the conversion of meiosis to a mitotic-like mode of inheritance.     

Porcine spermatozoa inhibit post-breeding cytokine induction in uterine epithelial cells in vivo

Early endometrial cytokine responses after exposure to various inseminate components were investigated for a better understanding of the immunological reactions occurring in the porcine uterus after insemination. Baseline values were established for the mRNA concentrations of GM-CSF, IL-6, IL-10, CXCL8 (interleukin-8), Tumour Necrosis Factor α (TNF-α), TGF-β, cyclooxygenase-2 (COX-2) and arachidonate 5-lipooxygenase (ALOX-5) in periovulatory uterine endometrial tissue using quantitative RT-PCR. Synchronized gilts were inseminated with spermatozoa diluted either in the semen extender Androhep™ or seminal plasma. Uterine infusions of media without spermatozoa were used as controls. Three hours after insemination sows were slaughtered and the expression of the above mentioned cytokines was measured in uterine epithelial cells. Simultaneously, the influx of polymorphonuclear neutrophilic (PMN) granulocytes into the uterus was quantified. Compared to baseline values seminal plasma (SP) and Androhep™ (AH) respectively, if used alone, caused a significant increase in mRNA concentrations of IL-10 (SP: 1.5-fold), TGF-β (AH: 1.5-fold), CXCL8 (AH: 7.1-fold), TNF-α (AH: 1.9-fold) and COX-2 (AH: 7-fold). Surprisingly, in the presence of spermatozoa, none of the tested cytokines revealed mRNA concentrations higher than baseline values. The number of immigrated, intra-luminal PMN correlated only with mRNA concentrations of CXCL8 in presence of Androhep™ (r = 0.51). None of the other cytokines tested seemed to be involved in the regulation of neutrophil recruitment. However, the most interesting result was the sperm-induced down-regulation in the expression of TNF-α, TGF-β, IL-10, CXCL8 and COX-2 to mRNA concentration levels similar to or even below baseline values. In conclusion the results show that CXCL8 contributes significantly to uterine PMN recruitment and indicate a so far underestimated role of porcine spermatozoa in the general regulation of the uterine post-mating inflammatory response.     

Post-meiotic DNA synthesis in nocodazole-blocked nuclei during conjugation of Tetrahymena thermophila : Induction of polyploidy in the micronucleus

The formation of single, polyploid micronuclei was induced during conjugation of Tetrahymena thermophila with Nocodazole (ND) according to Kaczanowski et al. The increase in DNA content in these nuclei was measured cytophotometrically in conjugating pairs continuously exposed to the drug. ND-treated micronuclei ('restitution nuclei') undergo two complete rounds of DNA replication and enter the third at the time of pair separation. The DNA content of these micronuclei in late pairs was in the range 16-30C (mean 20C). This amount was similar to the sum of the DNA content of all post-meiotic products during normal conjugation at about the same stage. Thus the increase in DNA content in 'restitution' nuclei reflects some intrinsic ability of nuclei in pairing cells to replicate DNA independently of nuclear division.     

Cerebrospinal fluid cell preparation methods. An evaluation.

Although the cells from cerebrospinal fluid are widely used for diagnostic purposes, the cell yield on the microscopic slide is only rarely considered and mostly unsatisfactory. A reevaluation of several preparatory methods showed a very low yield with the Sayk-type chamber, a modest yield with the cytocentrifuge and the best yield with a simple, self-adhering chamber on slides coated with a polycation.