Characterization of oxylipins and dioxygenase genes in the asexual fungus Aspergillus niger

Background  

Aspergillus niger is an ascomycetous fungus that is known to reproduce through asexual spores, only. Interestingly, recent genome analysis of A. niger has revealed the presence of a full complement of functional genes related to sexual reproduction [1]. An example of such genes are the dioxygenase genes which in Aspergillus nidulans, have been shown to be connected to oxylipin production and regulation of both sexual and asexual sporulation [2–4]. Nevertheless, the presence of sex related genes alone does not confirm sexual sporulation in A. niger.     

The prognostic value of baseline erosions in undifferentiated arthritis

Introduction  

Undifferentiated arthritis (UA) has a variable disease course; 40 to 50% of UA patients remit spontaneously, while 30% develop rheumatoid arthritis (RA). Identifying the UA patients who will develop RA is essential to initiate early disease-modifying anti-rheumatic drug (DMARD) therapy. Although the presence of bone erosions at baseline is predictive for a severe destructive disease course in RA, the prognostic importance of erosive joints for disease outcome in UA is unknown. This study evaluates the predictive value of erosive joints for the disease outcome in UA as measured by RA development and disease persistency.     

Adjuvant immunotherapy in acute nonlymphocytic leukemia

Summary Of 112 patients (maximum age 70 years) with acute nonlymphocytic leukemia, 62 (55%) went into remission on an induction therapy of cytosine arabinoside and daunorubicin. 20 patients were randomized for maintenance treatment consisting of chemotherapy only and 22 patients for combined chemo-immunotherapy. The chemotherapy consisted in 5-day courses of daunorubicin and cytosine arabinoside and of thioguanine and cytosine arabinoside, alternating every month. The chemo-immunotherapy group also received weekly intracutaneous injections of 10⁹ allogeneic nonirradiated leukemic myeloblasts and 10⁶ BCG organisms (Glaxo) by Heaf gun.The median duration of the first remission was 164 days for the chemotherapy group and 464 days for the chemo-immunotherapy group. The corresponding median times of survival were 344 days for the first group and 734 days for the second group. The difference concerning median duration of survival is statistically significant. Thus immunotherapy seems to prolong survival.     

Effects of cycloheximide on a cytoplasmic factor initiating meiotic maturation in Xenopus oocytes

Oocytes induced to undergo meiotic maturation by progesterone possess a cytoplasmic activity that causes germinal vesicle breakdown (GVBD). The cytoplasmic factor postulated to be responsible for this activity is designated as the maturation promoting factor (MPF). The activity of MPF was assayed by injecting cytoplasm into fully-grown oocytes to induce GVBD. It was found that maturing oocyte cytoplasm possesses MPF activity before GVBD begins. Treatment of progesterone stimulated oocytes with cycloheximide, either applied externally or injected, inhibited the appearance of MPF in the cytoplasm as well as GVBD when the inhibitor treatment was initiated before the cytoplasm exhibited MPF activity. In contrast, the same treatment did not inhibit GVBD when it was applied to oocytes after the cytoplasm possessed MPF activity. Furthermore, cycloheximide treatment of recipient oocytes did not inhibit the induction of GVBD by injected cytoplasm containing MPF. Cytoplasm of oocytes injected with MPF subsequently possessed MPF activity as high as that of the original donor cytoplasm in spite of its extensive dilution. This suggests that amplification of MPF took place in the recipient. Cycloheximide treatment did not inhibit the amplification of MPF. It was concluded that cycloheximide inhibits only the initial phase of induction of MPF activity, but neither its amplification nor its action on the nucleus that causes GVBD. From these results, a hypothesis concerning the cytoplasmic mechanism for the induction of GVBD has been proposed.     

Phylogenetic relationships within the aplocheiloid fish genus Rivulus (Cyprinodontiformes, Rivulidae): implications for Caribbean and Central American biogeography

We examined the phylogenetic relationships of 16 northern species of the aplocheiloid genus Rivulus inhabiting the Caribbean, Central America, and South America. A total of 714 base pairs per taxon were sequenced from two segments of the mitochondrial genome, 12S rRNA and cytochrome b. Both parsimony and neighbor-joining analyses suggest an ancient vicariant origin of the Greater Antillean taxa, in addition to a quite recent dispersal of species into the Lesser Antilles from the South American mainland. Combined analyses support the monophyly of the northern South American assemblage as the sister group of a Central American/Columbian biota. However, the monophyly of the Central American biota remains uncertain. Divergence estimates for the Central American taxa are calibrated from the Last Cretaceous separation of the proto-Antilles from the Americas. These data suggest that the extant Central American taxa represent the descendants of at least two separate invasions during the Cenozoic, prior to the closing of the Panamanian isthmus. Times are consistent with the extensive evidence for reptilian and mammalian exchange throughout the Cenozoic.      

Modeling residue usage in aligned protein sequences via maximum likelihood

A computational method is presented for characterizing residue usage, i.e., site-specific residue frequencies, in aligned protein sequences. The method obtains frequency estimates that maximize the likelihood of the sequences in a simple model for sequence evolution, given a tree or a set of candidate trees computed by other methods. These maximum- likelihood frequencies constitute a profile of the sequences, and thus the method offers a rigorous alternative to sequence weighting for constructing such a profile. The ability of this method to discard misleading phylogenetic effects allows the biochemical propensities of different positions in a sequence to be more clearly observed and interpreted.      

Late thrombotic occlusion of a malapposed stent 10 months after intracoronary brachytherapy

We report a patient who received a stent following intracoronary 3-irradiation. Despite a good initial angiographic result, the stent appeared to be not fully expanded on intravascular ultrasound imaging at 6-month follow-up. Four months later, sudden thrombotic occlusion occurred shortly after aspirin cessation.     

Species-specific sperm adhesion in sea urchins. A quantitative investigation of bindin- mediated egg agglutination

Bindin, a protein component of the acrosomal vesicle of sea urchin sperm, has been isolated from Arbacia punctulata and strongylocentrous purpuratus. Using this isolated bindin, we have devised a quantitative assay for bindin-mediated egg agglutination and compared the agglutination of bindin eggs from A. puntulata and S. purpuratus. Bindin- mediated agglutination is species –specific in both species, although a measurable degree of heterotypic interaction is observed. Homotypic bindin-egg interactions differ significantly from heterotypic interactions both in the extent of agglutination and the size of the resulting aggregates. We also provide direct evidence that bindin particles agglutinate eggs by adhering to the surfaces of adjacent eggs. Although the A. punctulata bindin preparation displays the same functional properties and consists of one major polypeptide of the same apparent molecular weight as S. purpuratus bindin, its morphology is very different. Unlike the spherical aggregates observed with S. purpuratus bindin, A punctulata bindin exists as lamellar vesicles and binds significant amounts of phospholipids and Triton X-100, suggesting that it may be tightly associated with the acrosomal membrane. Having defined a number of the basic parameters of bindin-mediated agglutination, we examined the effect of a number of saccharides and glycopeptides on bindin-mediated egg agglutination. Carbohydrate-containing components derived from the egg cell surface by proteolysis were found to inhibit bindin-mediated egg agglutination at low concentrations, but this inhibition is not species specific.