Chemistry of the Nudibranch Aldisa andersoni: Structure and Biological Activity of Phorbazole Metabolites

The first chemical study of the Indo-Pacific dorid nudibranch Aldisa andersoni resulted in the isolation of five chlorinated phenyl-pyrrolyloxazoles belonging to the phorbazole series. Two new molecules, 9-chloro-phorbazole D and N1-methyl-phorbazole A, co-occurring with known phorbazoles A, B and D, have been characterized. Phorbazoles were found to be present mainly in the external part of the mollusc. The structures of the new compounds were determined by interpretation of spectroscopic data, mainly NMR and mass spectrometry and by comparison with the literature data. Evaluation of feeding-deterrence activity as well as in vitro growth inhibitory properties in human cancer cells was also carried out.     

Anti-melanogenic property of geoditin A in murine B16 melanoma cells

Geoditin A, an isomalabaricane triterpene isolated from marine sponge Geodia japonica, has been demonstrated to induce apoptosis in leukemia HL60 cells and human colon HT29 cancer cells through an oxidative stress, a process also interfering with normal melanogenesis in pigment cells. Treatment of murine melanoma B16 cells with geoditin A decreased expression of melanogenic proteins and cell melanogenesis which was aggravated with adenylate cyclase inhibitor SQ22536, indicating melanogenic inhibition was mediated through a cAMP-dependent signaling pathway. Immunofluorescence microscopy and glycosylation studies revealed abnormal glycosylation patterns of melanogenic proteins (tyrosinase and tyrosinase-related protein 1), and a co-localization of tyrosinase with calnexin (CNX) and lysosome-associated membrane protein 1 (LAMP-1), implicating a post-translational modification in the ER and a degradation of tyrosinase in the lysosome. Taken together, potent anti-melanogenic property and the relatively low cytotoxicity of geoditin A have demonstrated its therapeutic potential as a skin lightening agent.     

Estimating direct genetic and maternal effects affecting rabbit growth and feed efficiency with a factorial design

The aim of this experiment was to evaluate the significance of neonatal environment on feed efficiency. For that purpose, rabbits from a line selected for residual feed intake (RFI) during 10 generations (G10 kits) were cross‐fostered with non‐selected control does (i.e., G0 line), and reciprocally. In parallel, sibs were fostered by mothers from their original line. Nine hundred animals were raised in individual (N = 456) or collective (N = 320) cages. Traits analysed in this study were body weight at 32 days and at 63 days, average daily gain (ADG), feed intake between weaning and 63 days (FI), feed conversion ratio (FCR) and RFI. The maternal environment offered by does from the line selected for RFI deteriorated the FCR of the kits, independently of their line of origin, during fattening (+0.08 ± 0.02) compared to FCR of kits nursed by G0 does. The line, the type of housing and the batch were significant effects for all the measured traits: G10 kits were lighter than their G0 counterparts at 32 days (?82.9 ± 9 g, p < 0.0001) and at 63 days (?161 ± 16 g, p < 0.0001). They also had a lower ADG (?2.36 ± 0.36 g/day, p < 0.0001), RFI (?521 ± 24 g/day, p < 0.0001) and a lower FI (?855 ± 31 g, p < 0.0001), resulting in a more desirable feed efficiency (FCR: ?0.35 ± 0.02). There was no significant difference in the contrast of G10 and G0 performances between collective and individual/digestive cages (p > 0.22): ?2.35 g/day versus 2.94 g/day for ADG, ?0.39 versus ?0.40 for FCR, ?577 g versus ?565 g for RFI and ?879 g versus ?859 g for FI, respectively). Thus, no genotype‐by‐environment (housing) interaction is expected at the commercial level, that is, no re‐ranking of the animals due to collective housing.     

Photosynthesis limitations of grapevine after treatment with the fungicide fludioxonil

The aim of this work was to determine the major limitations to photosynthesis induced by the fungicide fludioxonil (fdx) on nontarget grapevines using cutting as a model. The fdx treatments (1.2, 6, and 30 mM) induced a net photosynthetic rate ( P n) decrease without changes in stomatal conductance, suggesting a nonstomatal limitation. Fdx effects on P n were related neither to photosynthetic capacity alteration in leaves nor to loss in PSII activity. The mechanism underlying photosynthesis reduction differed according to the concentration. Fdx at 6 mM led to an increase of light requirement for photosynthesis while 30 mM fdx induced an increase in the respiration rate in the light. P n decrease after 1.2 mM fdx could rather be related to wetness caused by the spraying than to fungicide toxicity. P n recovered 10 days after treatment, meaning that fdx had little deleterious effect on plant physiology or that grapevine has a great capacity to overcome this temporary stress.     

Transmission and storage properties of a tropical loamy sand soil as influenced by organic-based and inorganic fertilizers

Short-term effect of organic and inorganic amendments on soil physical quality (SPQ) is marked when dealing with tropical soils which are naturally exposed to a high risk of water erosion. This study assessed the suitability of Tithonia diversifolia (Mexican Sunflower) when incorporated as green manure (GM) and also composted with poultry manure (PM) and other organic-based and inorganic fertilizers to improve some hydraulic properties of an Alfisol subject to excessive drainage. Treatments applied include fresh T. diversifolia (GM), PM, T. diversifolia composted with PM, organo-mineral fertilizers (OMF), neem fertilizer (NF), inorganic fertilizer (20-10-10 NPK), and control in a randomized complete block design and replicated four times. Soil samples were collected at 0–20 cm depth to determine near steady-state infiltration rates (I_s), sorptivity, transmissivity, saturated hydraulic conductivity (K_s), macroporosity (MacP), microporosity (MicP), air capacity (AC), and relative water capacity (RWC). The I_s rates were significantly (P ≤ 0.05) reduced to optimum range with the addition of the organic fertilizers over very high value (128.7 cm hr^?1) observed for control. Whereas, K_s was enhanced in the order: GM > compost (CP) > NF > inorganic fertilizer > control > organo-mineral fertilizer > PM. Sorptivity and transmissivity were highest in control and inorganic fertilizer plots, indicating that the addition of organic fertilizers lowered these parameters while MacP, MicP, AC, and RWC were generally increased with the addition of organic-based and inorganic fertilizers. Specifically, NF increased MicP by 34% over control. Values for RWC which were within the optimum range (0.60–0.70) were only obtained with NF (0.74), OMF (0.72), NPK (0.70), and GM (0.60). The SPQ parameters assessed in this study were enhanced by the addition of fresh T. diversifolia applied as GM and CP compared to other treatments. Therefore, T. diversifolia usually burned by farmers should instead be incorporated into the soil as manure.     

Effect of habitat spatiotemporal structure on collembolan diversity

Landscape fragmentation is a major threat to biodiversity. It results in the transformation of continuous (hence large) habitat patches into isolated (hence smaller) patches, embedded in a matrix of another habitat type. Many populations are harmed by fragmentation because remnant patches do not fulfil their ecological and demographic requirements. In turn, this leads to a loss of biodiversity, especially if species have poor dispersal abilities. Moreover, landscape fragmentation is a dynamic process in which patches can be converted from one type of habitat to another. A recently created habitat might suffer from a reduced biodiversity because of the absence of adapted species that need a certain amount of time to colonize the new patch (e.g. direct meta-population effect). Thus landscape dynamics lead to complex habitat spatiotemporal structured, in which each patch is more or less continuous in space and time. In this study, we define habitat spatial structure as the degree to which a habitat is isolated from another habitat of the same kind and temporal structure as the time since the habitat is in place. Patches can also display reduced biodiversity because their spatial or temporal structures are correlated with habitat quality (e.g. indirect effects). We discriminated direct meta-community effects from indirect (habitat quality) effects of the spatiotemporal structure of habitats on biodiversity using Collembola as a model. We tested the relative importance of spatial and temporal structure of habitats for collembolan diversity, taking soil properties into account. In an agroforested landscape, we set up a sampling design comprised of two types of habitats (agriculture versus forest), a gradient of habitat isolation (three isolation classes) and two contrasting ages of habitats. Our results showed that habitat temporal structure is a key factor shaping collembolan diversity. A reduced diversity was detected in recent habitats, especially in forests. Interactions between temporal continuity and habitat quality were also detected by taking into account soil properties: diversity increased with soil carbon content, especially in old forests. Negative effects of habitat age on diversity were stronger in isolated patches. We conclude that habitat temporal structure is a key factor shaping collembolan diversity, while direction and amplitude of its effect depend on land use type and spatial isolation.     

Synthesis and regulation of 17α-hydroxy-20β-dihydroprogesterone in immature males of Oncorhynchus mykiss

Three experimental approaches were chosen to study the question if the progestin 17-hydroxy-20-dihydroprogesterone (1720OHP) is synthesised in testes of young Oncorhynchus mykiss, in which the absence of spermatozoa was verified histologically: first, in order to detect 20-hydroxysteroid dehydrogenase activity (20HSD), testes homogenates were incubated with ³H-labeled 17OHP.Metabolites were analysed by TLC, HPLC, and repeated crystallization to constant isotope ratios. One of the metabolites was identified as 1720OHP-³H, indicating that already immature testes contain 20HSD activity and are able to produce 20-reduced steroids. Second, 1720OHP was quantified by radioimmunoassay in incubates of testes fragments. The sensitivity of the gonads to gonadotropin II (GtH II) became evident when comparing incubations in the absence and presence of GtH II. Third, plasma levels of 1720OHP were significantly higher in animals injected with partially purified salmon gonadotropin, compared to controls. Thus, for the first time, it could be shown that 20HSD is present in testicular cells other than spermatozoa. Furthermore, 1720OHP is indeed secreted at a very early stage of testicular development; 1720OHP secretion is also responsive to GtH II. Future studies will have to show if the functions of this progestin include the stimulation of spermatogenesis.     

High resolution protein electrophoresis of 100 paired canine cerebrospinal fluid and serum

This study was performed to investigate the diagnostic relevance of cerebrospinal fluid (CSF) high resolution electrophoresis. The laboratory technique was applied to 100 paired samples of canine CSF and serum, with paired samples tested during the same analytical run, as recommended in human medicine. Ninety four of the dogs had a neurological disease and 6 healthy dogs served as a control group. A strong linear correlation between CSF total protein concentration and the albumin quota (AQ) was found in the control group and in the inflammatory (infectious or noninfectious), neoplastic, and miscellaneous groups: AQ = 0.015 CSF total protein--0.102, r = 0.990. This correlation suggests that an increased CSF total protein concentration can be an indicator of blood brain barrier dysfunction. The highest median AQ value was found in the aseptic suppurative meningitis group, but no statistical differences were found between this and the other groups. The AQ, calculated with this technique, did not provide any additional information. Moreover, although unexpected, the electrophoretic profiles were not characteristic of any particular disease. In conclusion, this study did not confirm high resolution electrophoresis of paired CSF and serum samples to be a valuable ancillary diagnostic tool for canine neurological diseases.