Actin remodeling driven by circLIMA1: sperm cell as an intriguing cellular model

CircRNA cargo in spermatozoa (SPZ) participates in setting cell quality, in terms of morphology and motility. Cannabinoid receptor CB1 activity is correlated with a proper spermatogenesis and epididymal sperm maturation. Despite CB1 promotes endogenous skill to circularize mRNAs in SPZ, few notions are reported regarding the functional link between endocannabinoids and spermatic circRNA cargo. In CB1 knock-out male mice, we performed a complete dataset of spermatic circRNA content by microarray strategy.Differentially expressed (DE)-circRNAs, as a function of genotype, were identified. Within DE-circRNAs, we focused the attention on circLIMA1, as putative actin-cytoskeleton architecture regulator. The validation of circLIMA1 dependent-competitive endogenous RNA (ceRNA) network (ceRNET) in in vitro cell line confirmed its activity in the regulation of the cytoskeletal actin. Interestingly, a dynamic actin regulation in SPZ nuclei was found during their epididymal maturation.In this scenario, we showed for the first time an intriguing sperm nuclear actin remodeling, regulated via a ceRNET-independent pathway, consisting in the nuclear shuttling of circLIMA1-QKI interactome and downstream in Gelsolin regulation. In particular, the increased levels of circLIMA1 in CB1 knock-out SPZ, associated with an inefficient depolymerization of nuclear actin, specifically illustrate how endocannabinoids, by regulating circRNA cargo, may contribute to sperm morpho-cellular maturation.     

Delayed larval development in <Emphasis Type="Italic">Anopheles</Emphasis> mosquitoes deprived of <Emphasis Type="Italic">Asaia</Emphasis>bacterial symbionts

BACKGROUND: In recent years, acetic acid bacteria have been shown to be frequently associated with insects, but knowledge on their biological role in the arthropod host is limited. The discovery that acetic acid bacteria of the genus Asaia are a main component of the microbiota of Anopheles stephensi makes this mosquito a useful model for studies on this novel group of symbionts. Here we present experimental results that provide a first evidence for a beneficial role of Asaia in An. stephensi. RESULTS: Larvae of An. stephensi at different stages were treated with rifampicin, an antibiotic effective on wild-type Asaia spp., and the effects on the larval development were evaluated. Larvae treated with the antibiotic showed a delay in the development and an asynchrony in the appearance of later instars. In larvae treated with rifampicin, but supplemented with a rifampicin-resistant mutant strain of Asaia, larval development was comparable to that of control larvae not exposed to the antibiotic. Analysis of the bacterial diversity of the three mosquito populations confirmed that the level of Asaia was strongly decreased in the antibiotic-treated larvae, since the symbiont was not detectable by PCR-DGGE (denaturing gradient gel electrophoresis), while Asaia was consistently found in insects supplemented with rifampicin plus the antibiotic-resistant mutant in the diet, and in those not exposed to the antibiotic. CONCLUSIONS: The results here reported indicate that Asaia symbionts play a beneficial role in the normal development of An. stephensi larvae.     

Chemical modification of human placental glutathione transferase by pyridoxal 5'-phosphate.

Incubation of GST pi from human placenta with 8 mM PLP resulted in a rapid loss of activity during the first 10 min, concomitant with a Schiff base formation. This inactivation was probably due to the formation of a reversible adduct between PLP and the enzyme. After sodium borohydride treatment this adduct was reduced and stabilized. Stoichiometry and peptide isolation studies showed that three lysine residues were modified during reaction of GST and PLP. Protection of the enzyme against inactivation was achieved in the presence of 4 mM GSH suggesting that at least one lysyl residue is associated with the substrate binding site. Peptide mapping by digesting the enzyme with trypsin revealed that lysine shielded by GSH is Lys-127. Our results suggest that this residue may play an important role in enzymatic activity.     

Life histories of some species of Rotifera Bdelloidea

Nine species of Rotifera Bdelloidea have been cultured under laboratory conditions. The species were collected from two different environments: one group from water courses, the other from terrestrial mosses. Life tables have been determined and population dynamics parameters have been calculated. The characteristics of the life history seem to be related to the natural environmental conditions of the species. The patterns of reproductive output may develop as adaptations to different selective pressures: species from unpredictable environments face the probability of leaving no young at all, while species from stable environments are less conservative in their energy budget. Life characteristics are discussed from the point of view of adaptive strategies.     

Aerobiological monitoring ofAlternaria fungal spores: a comparison between surveys in 1992 and 1993 and local meteorological conditions

A study of airborneAlternaria spores was carried out over the period from April 1992 to October 1993, in the Rehabilitation Medical Centre of Montescano (PV), using an automatic volumetric spore trap (VPPS 2000 Lanzoni). The evaluation of the air concentration of these spores is becoming ever more important as it is this mycophyte which is the commonest cause of a positive allergy test. In 1993 the concentration ofAlternaria spores was much higher than in the previous year and the period of highest sporulation was different, depending on the different rainfall pattern of the 2 years.     

Dwarf males in monogonont rotifers

The main characteristics of the monogonont rotifer males are haploidy, dwarfism, progenesis and gut vestigialization to varying extents. Although these traits co-occur, they are probably unlinked from the evolutionary point of view. Commonly, all of these characteristics are directly related to the small size of the male egg, equipped with a reduced amount of yolk. A more ecological approach can, however, provide additional insights. Haploidy acts as a sex determining mechanism, dwarfism and progenesis derive directly from the egg size, while gut reduction is more evident in planktonic species than in benthic ones. This discrepancy suggests that the rotifers in the two habitats are exposed to different selection pressures.