The Diplommatinidae of Fiji – a hotspot of Pacific land snail biodiversity (Caenogastropoda,Cyclophoroidea)

The minute (adult size 1.3–4.8 mm) land snail species of the family Diplommatinidae in the Fiji archipelago are revised based on historical material and modern (1998–99) collections targeting limestone outcrops on the largest island, Viti Levu, and several smaller islands in the Lau group. The forty-two species (including 30 new species) belong to the genera Moussonia Semper, 1865, Palaina Semper, 1865 and Diancta Martens, 1867, which are briefly characterized and keyed. The diagnostic structure of the inner lamellar system of each species is illustrated. All species except one are endemic to Fiji. In Viti Levu, the 12 localities surveyed each had 1–13 (average 5) species of Diplommatinidae; ten species were each found at a single site only. In the Lau islands, five islands were visited, with 1–4 species per island; four species are known from single islands. The number of historically known species not recollected in 1998–99 (7 species), the number of single-site occurrences (14 species), and the numerous islands — including limestone islands — that have not been surveyed at all, indicate that the 42 species of Diplommatinidae currently known from Fiji represent perhaps only half of the Fiji diplommatinid fauna. Such numbers approach the diplommatinid diversity of Palau (39 described and more than 60 undescribed species), and surpasses by far the diversity of other South Pacific archipelagos of comparable land area (New Caledonia, Vanuatu, Samoa).Nomenclatural acts: Lectotypes designated: Diplommatina fuscula, Diplommatina fuscula var. vitiana, Diplommatina godeffroyana, Diplommatina godeffroyana var. latecostata, Diplommatina tuberosa, Diplommatina martensi var. macrostoma, all Mousson, 1870. Neotypes designated: Diplommatina subregularis, Diplommatina ascendens, Diplommatina quadrata, all Mousson, 1870. New species: Diancta aurea sp. n., Diancta aurita sp. n., Diancta basiplana sp. n., Diancta controversa sp. n., Diancta densecostulata sp. n., Diancta dextra sp. n., Diancta dilatata sp. n., Diancta distorta sp. n., Diancta pulchella sp. n., Diancta rotunda sp. n., Diancta subquadrata sp. n., Diancta trilamellata sp. n., Moussonia acuta sp. n., Moussonia barkeri sp. n., Moussonia brodieae sp. n., Moussonia longipalatalis sp. n., Moussonia minutissima sp. n., Moussonia obesa sp. n., Moussonia polita sp. n., Moussonia uncinata sp. n., Moussonia vitianoides sp. n., Palaina alberti sp. n., Palaina flammulata sp. n., Palaina glabella sp. n., Palaina kitteli sp. n., Palaina labeosa sp. n., Palaina parietalis sp. n., Palaina sulcata sp. n., Palaina truncata sp. n., Palaina tuberosissima sp. n.     

Immunolabelling of intervessel pits for polysaccharides and lignin helps in understanding their hydraulic properties in Populus tremula?×?alba

Background and Aims The efficiency and safety functions of xylem hydraulics are strongly dependent on the pits that connect the xylem vessels. However, little is known about their biochemical composition and thus about their hydraulic properties. In this study, the distribution of the epitopes of different wall components (cellulose, hemicelluloses, pectins and lignins) was analysed in intervessel pits of hybrid poplar (Populus tremula × alba).Methods Immunogold labelling with transmission electron microscopy was carried out with a set of antibodies raised against different epitopes for each wall polysaccharide type and for lignins. Analyses were performed on both immature and mature vessels. The effect of sap ionic strength on xylem conductance was also tested.Key Results In mature vessels, the pit membrane (PM) was composed of crystalline cellulose and lignins. None of the hemicellulose epitopes were found in the PM. Pectin epitopes in mature vessels were highly concentrated in the annulus, a restricted area of the PM, whereas they were initially found in the whole PM in immature vessels. The pit border also showed a specific labelling pattern, with higher cellulose labelling compared with the secondary wall of the vessel. Ion-mediated variation of 24 % was found for hydraulic conductance.Conclusions Cellulose microfibrils, lignins and annulus-restricted pectins have different physicochemical properties (rigidity, hydrophobicity, porosity) that have different effects on the hydraulic functions of the PM, and these influence both the hydraulic efficiency and vulnerability to cavitation of the pits, including ion-mediated control of hydraulic conductance. Impregnation of the cellulose microfibrils of the PM with lignins, which have low wettability, may result in lower cavitation pressure for a given pore size and thus help to explain the vulnerability of this species to cavitation.     

A receptor-like kinase mediates the response of Arabidopsis cells to the inhibition of cellulose synthesis

BACKGROUND: A major challenge is to understand how the walls of expanding plant cells are correctly assembled and remodeled, often in the presence of wall-degrading micro-organisms. Plant cells, like yeast, react to cell-wall perturbations as shown by changes in gene expression, accumulation of ectopic lignin, and growth arrest caused by the inhibition of cellulose synthesis. RESULTS: We have identified a plasma-membrane-bound receptor-like kinase (THESEUS1), which is present in elongating cells. Mutations in THE1 and overexpression of a functional THE1-GFP fusion protein did not affect wild-type (WT) plants but respectively attenuated and enhanced growth inhibition and ectopic lignification in seedlings mutated in cellulose synthase CESA6 without influencing the cellulose deficiency. A T-DNA insertion mutant for THE1 also attenuated the growth defect and ectopic-lignin production in other but not all cellulose-deficient mutants. The deregulation of a small number of genes in cesA6 mutants depended on the presence of THE1. Some of these genes are involved in pathogen defense, in wall crosslinking, or in protecting the cell against reactive oxygen species. CONCLUSIONS: The results show that THE1 mediates the response of growing plant cells to the perturbation of cellulose synthesis and may act as a cell-wall-integrity sensor.     

Effect of interleukin-1 receptor antagonist (IL-1RA) on histamine and serotonin release by rat basophilic leukemia cells (RBL-2H3) and peritoneal mast cells

Recently, it has been appreciated that cultured mast cells are significant sources of cytokines. However, the role of interkeukin-1 (IL-1) on mast cells and/or basophil degranulation is still unclear. In this report we provide evidence that rat basophilic leukemia cells (RBLC) cultured with a natural inhibitor of IL-1, interleukin-1 receptor antagonist (IL-1RA) (500 ng/ml) for 48 h, strongly inhibited the spontaneous release of serotonin (5HT) and histamine (from 22.50 to 43.49%), compared to untreated cells (control). When IL-1RA-treated and untreated RBLC were stimulated with a secretagogue (anti-IgE), no difference was found in the percent of 5HT and histamine release. Moreover, in another set of experiments using rat peritoneal mast cells (RPMC) treated and untreated with IL-1RA, we found that IL-1RA did not affect the release of 5HT or histamine, even when the secretagogue anti-IgE or compound 48/80 (C48/80) were used. The present studies describe an additional biological activity of IL-1RA, inhibiting histamine and 5HT release from RBLC cultures.Abbreviations IL-1 interleukin-1 - RA receptor antagonist - 5HT serotonin - RBLC rat basophilic leukemia cells - RPMC rat peritoneal mast cells - IgE immunoglobulin E - Fc immunoglobulin E receptor - CPM counts per minute - BSA bovine serum albumin - C48/80 compound 48/80 - TNF tumor necrosis factor     

New Genera and Species of Psychodoid Flies from the Lower Cretaceous Amber Lebanon

Until now, only two Psychodoidea were known from Lebanese amber. We describe two new genera and species of Phlebotomidae ( Mesophlebotomites hennigi gen. et sp. nov., Libanophlebotomus lutfallahi gen. et sp. nov.) and four new genera with six new species of Psychodidae ( Paleopsychoda solignaci gen. et sp. nov., Paleopsychoda jacquelinae sp. nov., Protopsychoda nadiae gen. et sp. nov., Protopsychoda hammanaensis sp. nov., Libanopsychoda abillamai gen. et sp. nov., Cretapsychoda inexpectata gen. et sp. nov.) from the Lower Cretaceous amber of Hammana/Mdeirij, Lebanon. These fossils are included in a phylogenetic analysis of the subfamilies of Psychodoidea. This superfamily was probably as diverse in the Early Cretaceous as now.     

High-Precision Radiosurgical Dose Delivery by Interlaced Microbeam Arrays of High-Flux Low-Energy Synchrotron X-Rays

Microbeam Radiation Therapy (MRT) is a preclinical form of radiosurgery dedicated to brain tumor treatment. It uses micrometer-wide synchrotron-generated X-ray beams on the basis of spatial beam fractionation. Due to the radioresistance of normal brain vasculature to MRT, a continuous blood supply can be maintained which would in part explain the surprising tolerance of normal tissues to very high radiation doses (hundreds of Gy). Based on this well described normal tissue sparing effect of microplanar beams, we developed a new irradiation geometry which allows the delivery of a high uniform dose deposition at a given brain target whereas surrounding normal tissues are irradiated by well tolerated parallel microbeams only. Normal rat brains were exposed to 4 focally interlaced arrays of 10 microplanar beams (52 µm wide, spaced 200 µm on-center, 50 to 350 keV in energy range), targeted from 4 different ports, with a peak entrance dose of 200Gy each, to deliver an homogenous dose to a target volume of 7 mm³ in the caudate nucleus. Magnetic resonance imaging follow-up of rats showed a highly localized increase in blood vessel permeability, starting 1 week after irradiation. Contrast agent diffusion was confined to the target volume and was still observed 1 month after irradiation, along with histopathological changes, including damaged blood vessels. No changes in vessel permeability were detected in the normal brain tissue surrounding the target. The interlacing radiation-induced reduction of spontaneous seizures of epileptic rats illustrated the potential pre-clinical applications of this new irradiation geometry. Finally, Monte Carlo simulations performed on a human-sized head phantom suggested that synchrotron photons can be used for human radiosurgical applications. Our data show that interlaced microbeam irradiation allows a high homogeneous dose deposition in a brain target and leads to a confined tissue necrosis while sparing surrounding tissues. The use of synchrotron-generated X-rays enables delivery of high doses for destruction of small focal regions in human brains, with sharper dose fall-offs than those described in any other conventional radiation therapy.     

Chronorhythms of the circulating erythrocytes and leukocytes--correlation with the E.S.R. cycles

2750 healthy and fasting subjects, 20-30 years old, were studied over a half-year period in 1980. Considering the mean day value as a basic piece of information for statistics, the Erythrocyte Sedimentation Rate (E.S.R.) and the blood counts (erythrocytes, leukocytes, polymorphonuclears, lymphocytes, monocytes and eosinophils) were compared. The timeless relation between E.S.R. and each cell type number or percentage is rectilinear. The stronger slope and relation apply to the polymorphonuclears (PMN) or to the overall leukocytes. The chronological normalized variations of the E.S.R. and of the PMN or leukocyte number or percentage are highly correlated. E.S.R. is less correlated with monocytes, eosinophils and Lymphocytes. Contrary to what could have been expected, the erythrocyte situation is but an intermediate one. The spectra derived from the time variations show that all the cell types, whatever they are, are to be taken into account to explain the E.S.R. value and variation with time, even if, for a given cell type, the correlation and timeless relation were but faint ones. Each cell type has a specific spectrum. Erythrocytes are subject to low frequency variations (316-158 days). PMNs oscillate with time within the medium frequency range (90 days). Lymphocytes, monocytes and eosinophils fluctuate more quickly (53 days).     

Starting to unravel the toxoglossan knot: molecular phylogeny of the "turrids" (Neogastropoda: Conoidea)

The superfamily Conoidea is one of the most speciose groups of marine mollusks, with estimates of about 340 recent valid genera and subgenera, and 4000 named living species. Previous classifications were based on shell and anatomical characters, and clades and phylogenetic relationships are far from well assessed. Based on a dataset of ca. 100 terminal taxa belonging to 57 genera, information provided by fragments of one mitochondrial (COI) and three nuclear (28S, 18S and H3) genes is used to infer the first molecular phylogeny of this group. Analyses are performed on each gene independently as well as for a data matrix where all genes are concatenated, using Maximum Likelihood, Maximum Parsimony and Bayesian approaches. Several well-supported clades are defined and are only partly identifiable to currently recognized families and subfamilies. The nested sampling used in our study allows a discussion of the classification at various taxonomical levels, and several genera, subfamilies and families are found polyphyletic.