A new Miocene deep-sea chiton and early evidence for Teredinidae-sustained wood-fall communities

Deep-sea wood-falls are important biodiversity hot spots for insights on chemosynthesis-based communities. The study of deep-sea wood-fall-related palaeocommunities from the Neogene of north Italy shed light on interesting associations from the Miocene of Torrente Cinghio (Tortonian) and of Moncasale di Casina (Langhian). The most common components of this association are typical chemosynthetic/wood-fall molluscs, such as the gastropods Homalopoma sp. and Pseudonina bellardii, the bivalves Idas sp. and shipworms, and the chiton Leptochiton lignatilis n. sp., which belongs to a genus typical of recent sunken woods in tropical waters. The new species described is compared with other fossil and recent congeners, especially with those sharing the same kind of tegmental sculpture, fully covered with randomly or quincuncially arranged granules. An overview of the sunken wood-related chitons is provided. Surprisingly no taxa of the boring bivalves of the family Xylophagidae, whose species have been known to be fundamental for sustaining this kind of deep sea chemosynthetic ecosystem, were found in the studied site; however, other boring Teredinidae bivalves have been abundantly recovered. This suggests that, conversely to what has previously been observed on sunken wood communities, Teredinidae may be viewed as a counterpart for the maintenance of deep-sea wood-fall ecosystems

Inner ear embryogenesis and regeneration

Sensory hair cells (HC) of the inner ear are susceptible to damage from a variety of sources including ageing, genetic defects, noise or chemotherapeutic drugs. As the adult mammalian cochlea lacks regenerative capacity, the consequence of this damage in humans is permanent and results in hearing loss. Since the discovery that hair cells can regenerate in birds, a wide range of studies have been designed in order to understand this process. At the same time efforts have been made to identify the steps in mammalian hair cell development. The aim of this paper is to re-examine recent research on mammalian HC development and avian HC regeneration, as this process could help in understanding possible future directions and targets of mammalian inner ear regeneratio

Inner ear embryogenesis and regeneration

Sensory hair cells (HC) of the inner ear are susceptible to damage from a variety of sources including ageing, genetic defects, noise or chemotherapeutic drugs. As the adult mammalian cochlea lacks regenerative capacity, the consequence of this damage in humans is permanent and results in hearing loss. Since the discovery that hair cells can regenerate in birds, a wide range of studies have been designed in order to understand this process. At the same time efforts have been made to identify the steps in mammalian hair cell development. The aim of this paper is to re-examine recent research on mammalian HC development and avian HC regeneration, as this process could help in understanding possible future directions and targets of mammalian inner ear regeneratio

Low nanogram range quantitation of diglycerides and ceramide by high-performance liquid chromatography.

A method for ceramide (CER) and diradylglycerol (DG) determination after normal-phase HPLC separation was developed. The free oxydril group of ceramide and diradylglycerol is coupled to the carboxylic group of the fluorescent label (+)-6-methoxy-alpha-methyl-2 naphthaleneacetic acid (NAP), using as catalytic agents 4-dimethylaminopyridine and N,N'-dicyclohexylcarbodiimide. The use of NAP-free acid instead of the halide-activated form ensures higher stability of the reagent, lower reaction temperatures, and improved yield and reproducibility. The yield of the reaction is greater than 90% after a period of 3 h at the temperature of -20 degrees C. Over 85% of the starting material is recovered at the end of HPLC separation. The lower detection limit is below 5 ng for CER and 150 ng for DG. Under the conditions employed in the assay, no significant hydrolysis of triglycerides, sphingolipids, or phospholipids occurs and the esterification reaction is not affected by components of crude lipid extracts. Since separation and/or purification steps are not required, cellular levels of CER and DG can be easily and rapidly measured

All-trans retinoic acid shows multiple effects on the survival, proliferation and differentiation of human fetal CD34+ haemopoietic progenitor cells

To evaluate the effect of all-trans retinoic acid (RA) on fetal haemopoiesis, we performed serum-free liquid and semisolid cultures using CD34+ cells purified from midtrimester human fetal blood samples. RA, at both physiological (10(-11) and 10(-12)M) and pharmacological (10(-6) and 10(-7)M) concentrations, significantly (P < 0.01) promoted the survival of fetal CD34+ cells in liquid cultures from day 3 onwards, by suppressing apoptosis induced by serum and growth factor deprivation. On the other hand, RA alone had no significant effect on the proliferation and differentiation of fetal haemopoietic progenitors. In the presence of optimal concentrations of recombinant interleukin-3 (IL-3), stem cell factor (SCF), granulocyte/macrophage-colony stimulating factor (GM-CSF), and erythropoietin (Epo), low and high doses of RA induced striking differential effects on CD34+ cell proliferation in liquid cultures and colony formation in semisolid assays. In fact, 10(-11)M and 10(-12)M RA were able to: (i) significantly (P < 0.05) increase 3H-thymidine uptake by fetal CD34+ cells in liquid cultures, and (ii) variably promote the growth of pluripotent (CFU-GEMM, P < 0.05), early (BFU-meg) and late (CFU-meg, P < 0.01) megakaryocyte, granulocyte/macrophage (CFU-GM, P < 0.01) and erythroid (BFU-E) progenitors in semisolid cultures. On the contrary, 10(-6) and 10(-7)M RA induced: (i) an overall inhibition (P < 0.01) of CD34+ cell growth in liquid cultures; (ii) a marked suppression of BFU-E colony formation (P < 0.01) at all Epo concentrations examined (0.002-4 IU/ml); and (iii) a significant (P < 0.01) stimulation of CFU-GM with a shift from mixed granulocyte/macrophage to pure granulocyte colonies, whereas it had little effect on the growth of CFU-GEMM, BFU-meg and CFU-meg. Our data, as a whole, demonstrate that RA has direct complex effects on the survival, growth and clonal expansion of fetal haemopoietic progenitor cells, mainly depending on the presence of recombinant cytokines, the type of progenitor and the concentrations of RA

Protective effects of minocycline and MDL 28170 in gentamicin ototoxicity

Gentamicin side-effects on cochlear structures and function are well known, but not the detailed intracellular molecular mechanisms which lead to aminoglycoside induced ototoxicity. Hair cell death occurs by apoptosis, by the activation of enzymatic cascades known to be involved in the programmed cell death, or by the release of cytochrome-c from the damaged mitochondria. In this paper we have investigated the active role of minocycline, a second-generation tetracycline, and of MDL 28170, a selective calpain inhibitor, in the protection of hair cells from GM damage in in vitro organospecific cultures of the organ of Corti. We used cultures from neonatal (P3) rat cochlea, treated with different dosages of GM, alone, or with the two protector drugs. We have observed a dose-dependent OHC and IHC loss. The GM damage was reduced after treatment with both drugs. These results were also supported by the Disk Diffusion Susceptibility Test (Kirby-Bauer Method), in which we used drug treated organs of Corti. The data suggest that minocycline, previously reported to inhibit the release of cytochrome-c, and MDL 28170, prevent GM induced programmed cell death pathway in cochlear HC

All-trans retinoic acid shows multiple effects on the survival, proliferation and differentiation of human fetal CD34+ haemopoietic progenitor cells.

To evaluate the effect of all-trans retinoic acid (RA) on fetal haemopoiesis, we performed serum-free liquid and semisolid cultures using CD34+ cells purified from midtrimester human fetal blood samples. RA, at both physiological (10(-11) and 10(-12)M) and pharmacological (10(-6) and 10(-7)M) concentrations, significantly (P < 0.01) promoted the survival of fetal CD34+ cells in liquid cultures from day 3 onwards, by suppressing apoptosis induced by serum and growth factor deprivation. On the other hand, RA alone had no significant effect on the proliferation and differentiation of fetal haemopoietic progenitors. In the presence of optimal concentrations of recombinant interleukin-3 (IL-3), stem cell factor (SCF), granulocyte/macrophage-colony stimulating factor (GM-CSF), and erythropoietin (Epo), low and high doses of RA induced striking differential effects on CD34+ cell proliferation in liquid cultures and colony formation in semisolid assays. In fact, 10(-11)M and 10(-12)M RA were able to: (i) significantly (P < 0.05) increase 3H-thymidine uptake by fetal CD34+ cells in liquid cultures, and (ii) variably promote the growth of pluripotent (CFU-GEMM, P < 0.05), early (BFU-meg) and late (CFU-meg, P < 0.01) megakaryocyte, granulocyte/macrophage (CFU-GM, P < 0.01) and erythroid (BFU-E) progenitors in semisolid cultures. On the contrary, 10(-6) and 10(-7)M RA induced: (i) an overall inhibition (P < 0.01) of CD34+ cell growth in liquid cultures; (ii) a marked suppression of BFU-E colony formation (P < 0.01) at all Epo concentrations examined (0.002-4 IU/ml); and (iii) a significant (P < 0.01) stimulation of CFU-GM with a shift from mixed granulocyte/macrophage to pure granulocyte colonies, whereas it had little effect on the growth of CFU-GEMM, BFU-meg and CFU-meg. Our data, as a whole, demonstrate that RA has direct complex effects on the survival, growth and clonal expansion of fetal haemopoietic progenitor cells, mainly depending on the presence of recombinant cytokines, the type of progenitor and the concentrations of RA