A 9.1-kb gap in the genome reference map is shown to be a stable deletion/insertion polymorphism of ancestral origin

We show a mute 9.1-kb gap in the human genome reference map, unraveled by RDA studies, to be a worldwide deletion/insertion polymorphism of stable type. The molecular and population data presented suggest its origin from a unique ancestral transposition event in chromosomal region 22q11.2, overlapping the IglambdaV genes at about 450 kb from the cluster of the IglambdaJ-C genes. These findings are not meant to be just another report of a polymorphic marker suitable for population studies. Rather, we wish to stress that a large number of inborn mute gaps may be spread all over the genome and that the many RDA-detected microdeletions already available are efficient tools for the discovery of this otherwise hidden category of genetic variation. Apart from their possible impact on expression of structural genes, mute gaps must be filled for the reference map of our genome to be truly completed.     

Trypanosoma cruzi: effect of parasite subpopulation on murine pregnancy outcome

C3H/HeN female mice infected with distinct Trypanosoma cruzi subpopulations (RA strain [pantropic/reticulotropic] and K98 clone of the CA-I strain [myotropic]) show differences both in inflammatory compromise of the genital tract and in the outcome of pregnancy. The group of mice infected with the K98 clone show lymphomononuclear infiltrates in pelvian fat and in uterus interstitium, coexisting with the presence of T. cruzi DNA, and show moderate oophoritis, perioophoritis, and vasculitis. However, neither parasite DNA nor inflammatory foci were detected in the uterus, and only mild oophoritis was observed among RA-infected mice at mating time. Independently from the parasite subpopulation, females developed estrous 30 days postinoculation (PI), and at the same time, parasite counts were similar for K98 and for RA-infected mice. However, fertility was significantly diminished in K98-infected females. On day 14 of gestation, fetal resorptions increased in this group and cannot be attributed to hormonal disbalance because similar serum progesterone levels were found in all groups. At this time (44 days PI), parasitemia was higher in K98- than in RA-infected mice. However, resorptions were not triggered by massive infection because polymerase chain reaction failed to prove parasite DNA in resorbing fetuses. In contrast with K98 females, RA-infected mice delivered T. cruzi-infected newborns.     

Silybin and its bioavailable phospholipid complex (IdB 1016) potentiate in vitro and in vivo the activity of cisplatin

In this study we investigated whether the flavonoid silybin and its bioavailable derivative IdB 1016 (silipide) could enhance the antitumour activity of cisplatin (CDDP), the most commonly used drug in the treatment of gynaecological malignancies. Silybin alone up to 10 (M was unable to produce a relevant in vitro growth inhibition of A2780 cells, whereas CDDP was effective, giving an IC50 value of 0.5+/-0.14 microM. When silybin was combined with CDDP, a dose-dependent and statistically significant (p<0.05) increase of the CDDP activity was noticed, yielding IC50 values of 0.35+/-0.07 and 0.263+/-0.004 microM at silybin concentrations of 1 and 10 microM, respectively. The same trend was observed for in vivo experiments. IdB 1016 alone (1350 mg/kg) did not significantly affect tumour growth, whereas CDDP at the Maximum Tolerated Dose (12 mg/kg) produced a tumour weight inhibition (TWI%) of 80% and a log10 cell kill (LCK) of 0.7. Administration of both drugs resulted in a potentiation of the antitumour activity and TWI% and LCK increased to 90% and 1, respectively. Interestingly, mice receiving the combination recovered earlier in terms of body weight loss as compared to CDDP-treated mice. CDDP at 6 mg/kg yielded TWI of 44% and LCK of 0. The concomitant administration of IdB 1016 (1800 mg/kg) enhanced CDDP anti-tumour activity, with 68% TWI and 0.6 LCK. Finally, an antiangiogenic effect of IdB 1016 in an in vivo experimental model was demonstrated. Median haemoglobin value for the Matrigel from the vehicle-treated controls was 2.43 versus a value of 0.321 for the IdB 1016-treated animals.     

Role of the Multidrug Resistance Protein 1 in protection from heavy metal oxyanions: investigations in vitro and in MRP1-deficient mice

The Multidrug Resistance Protein 1 (MRP1) is a membrane pump that mediates the efflux of a wide variety of xenobiotics, including arsenical and antimonial compounds, as demonstrated by the study of MRP1-transfected cell lines. We have previously shown that mrp1(-/-) cells are hypersensitive to sodium arsenite, sodium arsenate, and antimony potassium tartrate. We now report that the retroviral vector-mediated overexpression of MRP1 and of the two subunits of gamma-GCS (heavy and light) resulted in higher intracellular glutathione levels and in a greater level of resistance to sodium arsenite and antimony potassium tartrate, compared to the overexpression of MRP1 and gamma-GCS heavy alone. These observations further demonstrate that glutathione is an important component of MRP1-mediated cellular resistance to arsenite and antimony. However, the constitutive expression of MRP1 did not protect mice from the lethality of sodium arsenite and antimony potassium tartrate nor reduced the tissue accumulation of arsenic in mice injected i.p. with sodium arsenite. It is conceivable that, in vivo, other pump(s) effectively vicariate for MRP1-mediated transport of heavy metal oxyanions.     

Fusidic and helvolic acid inhibition of elongation factor 2 from the archaeon Sulfolobus solfataricus

Fusidic acid (FA) and helvolic acid (HA) belong to a small family of naturally occurring steroidal antibiotics known as fusidanes. FA was studied for its ability to alter the biochemical properties supported by elongation factor 2 isolated from the archaeon Sulfolobus solfataricus (SsEF-2). Both poly(Phe) synthesis and ribosome-dependent GTPase (GTPase(r)) were progressively impaired by increasing concentrations of FA up to 1 mM, whereas no effect was measured in the intrinsic GTPase of SsEF-2 triggered by ethylene glycol in the presence of barium chloride (GTPase(g)). The highest antibiotic concentration caused inhibition of either poly(Phe) synthesis or GTPase(r) only slightly above 50%. A greater response of SsEF-2 was observed when HA was used instead of FA. HA caused even a weak impairment of GTPase(g). A mutated form of SsEF-2 carrying the L452R substitution exhibited an increased sensitivity to fusidane inhibition in either poly(Phe) synthesis or GTPase(r). Furthermore, both FA and HA were able to cause impairment of GTPase(g). The antibiotic concentrations leading to 50% inhibition (IC(50)) indicate that increased fusidane responsiveness due to the use of HA or the L452R amino acid replacement is mutually independent. However, their combined effect decreased the IC(50) up to 0.1 mM. Despite the difficulties in reaching complete inhibition of the translocation process in S. solfataricus, these findings suggest that fusidane sensibility is partially maintained in the archaeon S. solfataricus. Therefore, it is likely that SsEF-2 harbors the structural requirements for forming complexes with fusidane antibiotics. This hypothesis is further evidenced by the observed low level of impairment of GTPase(g), a finding suggesting a weak direct interaction between the archaeal factor and fusidanes even in the absence of the ribosome. However, the ribosome remains essential for the sensitivity of SsEF-2 toward fusidane antibiotics.     

Fine Structure of the Female Genital System in Phytoseiid Mites with Remarks on Egg Nutrimentary Development, Sperm-Access System, Sperm Transfer, and Capacitation (Acari, Gamasida, Phytoseiidae)

The fine structure of the female genital system is described in two phytoseiid species: Phytoseiulus persimilis Athias-Henriot (mating females) and Typhlodromus rhenanoides Athias-Henriot (overwintering females). The female genital tract is composed of an unpaired gonad, the uterus (oviduct I), and the vaginal duct (oviduct II). The latter leads to the vagina (genital atrium), into which a pair of vaginal glands opens. The gonad (ovary s.l.) has two components: the ovary (s.str.) where germ cells develop and the lyrate organ serving as a nutrimentary compartment. In the ovary (s.str.), somacells and germ cells are observed. The germ cells surround a central tissue, to which they have direct contact with a nutritive cord at least in the previtellogenic phase during oogenesis. In fertilized females, cells likely representing capacitated sperm cells are also found in the ovary. The lyrate organ has two arms that extend anteriorly but join in their posterior part in front of the ovary (s.str.). The lyrate organ is composed of a somatic (supporting) and a nutritive tissue. The nutritive tissue, which is a syncytium, is continuous with the central tissue. The uterus starts from the ventral region of the central tissue. Finally, the ultrastructure of the sperm-access system, composed of paired solenostomes, major and minor ducts, emboli, calyces, and vesicles, is reported and functional aspects are discussed. The minor ducts end in the somatic tissue of the ovary s.str. However, because of its extremely reduced lumen and the peculiar morphology of its beginning, it seems unlikely that the minor duct lumen serves as a simple route for the sperm towards the ovary.     

Copulatory Courtship in Drosophila: Behavior and Songs of D. birchii and D. serrata

D. birchii and D. serrata, two endemic Australian Drosophila species, have a copulatory courtship. The males of these species begin to court the female after mounting her and often go on with the courtship after the copulation is over. In the present paper we have described behavioral interactions between the male and the female and analyzed acoustic signals produced by the flies during courtship. Species differences were more pronounced in female than in male behavior. Variation within the species was obvious in the relative proportions of time the flies spent in different behaviors. Even though courtship took place nearly solely during copulation, some remains of precopulatory courtship were observed in both species. It is suggested that copulatory courtship exhibited by D. birchii and D. serrata flies is a derived rather than a primitive character.