60 research outputs found

    Size of anal papillae in chironomids: Does it indicate their salinity stress?

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    AbstractSalinity of inland waters is affected by a range of human activities and is regarded as a major environmental contaminant in many parts of the world. Changes in salinity are well known to be associated with changes in macroinvertebrate communities of flowing waters. However, as many environmental factors co-vary with salinity, it is not known whether, and if so how, salinity causes communities to change. Being able to measure the osmoregulatory stress that individual stream macroinvertebrates are experiencing would be useful to understand if and how salinity affects their populations and thus communities. Additionally, inferring salinity stress in individual invertebrates could provide a valuable biomonitoring tool to detect the initial effects of salinity before major ecological changes have occurred. Osmoregulation in larval Chironomidae (Diptera) takes place in the anal papillae and their size is believed to be associated with osmoregulatory stress. In two laboratory experiments and a field survey in southern Victoria, Australia, we determine if the size of the anal papillae of larva chironomids is a useful biomarker of salinity stress. Experiments with Chironomus oppositus showed that the surface area of the anal papillae was similar in larva hatched across 5 egg masses collected from 3 sites but were affected by salinity treatments. Furthermore, the (transformed) ratio of this surface area to the body length of the larva was independent of the size of C. oppositus. However, for Chironomus cloacalis, this surface area differed between larva hatched from egg masses collected from the same site. The expected trend in surface area of the anal papillae relative to the size of larva (Chironomu alternans, C. cloacalis, Dicrotendipes sp., Criptochironomus sp. and Tanypodinae) was not duplicated in the field survey. It would appear that unknown factors, other than salinity, are affecting the size of the anal papillae of chironomids in southern Victoria

    Transition metal complexes with thiosemicarbazide-based ligands. part 37. Synthesis and study of the first thiosemi-carbazide-derived copper(I) complexes: Crystal structure of [2-(diphenylphosphino)benzaldehyde thiosemicarbazonato(-l)] copper(I)nitrate-me

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    The preparation and physical characterization of two copper(I) complexes Cu(HL)NO3 and [Cu(HL)(2)]NO3 . MeOH formed with a newly synthesized tridentate [S,N,P] HL = 2-(diphenylphosphino)benzaldehyde thiosemicarbazone ligand and the crystal structure analysis of the latter have been carried out. An X-ray study of [Cu(HL)(2)]NO3 . MeOH revealed a copper(I) ion coordinated tetrahedrally to S,N,P,P atoms donated by two HL ligands. One is tridentate [S,N,P], whereas the second HL ligand is monodentate, ligating only its phosphorus atom to the copper. The geometry around the four-coordinate Cu(I) is comparable with Cu{N,S,P,X} tetrahedra (X = N, P, or S) retrieved from the Cambridge Structural Database. In addition, with a restriction to Cu{N,P,X,X} (X = C, N, P) tetrahedra - S is excluded - ca. 60 structures against three or four cases were found to be maintained by Cu(I) ions substantiating the principal role of the phosphorus ligands in the reduction of Cu(II) to Cu(I)

    Transition metal complexes with thiosemicarbazide-based ligands. part 37. Synthesis and study of the first thiosemi-carbazide-derived copper(I) complexes: Crystal structure of [2-(diphenylphosphino)benzaldehyde thiosemicarbazonato(-l)] copper(I)nitrate-me

    No full text
    The preparation and physical characterization of two copper(I) complexes Cu(HL)NO3 and [Cu(HL)(2)]NO3 . MeOH formed with a newly synthesized tridentate [S,N,P] HL = 2-(diphenylphosphino)benzaldehyde thiosemicarbazone ligand and the crystal structure analysis of the latter have been carried out. An X-ray study of [Cu(HL)(2)]NO3 . MeOH revealed a copper(I) ion coordinated tetrahedrally to S,N,P,P atoms donated by two HL ligands. One is tridentate [S,N,P], whereas the second HL ligand is monodentate, ligating only its phosphorus atom to the copper. The geometry around the four-coordinate Cu(I) is comparable with Cu{N,S,P,X} tetrahedra (X = N, P, or S) retrieved from the Cambridge Structural Database. In addition, with a restriction to Cu{N,P,X,X} (X = C, N, P) tetrahedra - S is excluded - ca. 60 structures against three or four cases were found to be maintained by Cu(I) ions substantiating the principal role of the phosphorus ligands in the reduction of Cu(II) to Cu(I)

    Dietary Supplementation with Natural Extracts Mixture : Effects on Reproductive Performances, Blood Biochemical and Antioxidant Parameters in Rabbit Does

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    The present study evaluates the effects of natural extracts on reproductive performance, haematochemical parameters, and antioxidant status of rabbit does. A total of sixty New Zealand White second parity does were divided into three groups: The first group was fed a control diet (CON), the second (T1) and the third groups (T2) were fed the same diet supplemented with prebiotic polysaccharides from brown seaweeds (Laminaria spp.) plus phenolic acid, hydroxycinnamic acids, tannins, and flavonoids from plant extracts (0.3% and 0.6%, respectively). The trial was conducted for two consecutive reproductive cycles (75 days). Reproductive performance was recorded. Blood samples were collected before the first insemination, 10 d after the first kindling, and 10 d after the second one. At the first reproductive cycle, productive parameters were negatively affected (P<0.05) by a high dosage of the dietary supplement (T2 group). At the second reproductive cycle, no differences (P>0.05) between dietary treatments on reproductive and productive performances were observed. Bilirubin was affected by dietary treatment (P<0.001) and decreased in relation to sampling time (P<0.001). The HDL cholesterol decreased by dietary treatment (P<0.01). All the plasma antioxidant markers were positively affected (P<0.001) by dietary supplementation and sampling time. No previous study has reported the effects of brown seaweeds and polyphenols on rabbit does and the present data shows that this natural extract supplement improved the antioxidant status of rabbit does
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