Assessing sub-Saharan Erythrina for efficacy: traditional uses, biological activities and phytochemistry

The genus Erythrina comprises more than 100 species, widely distributed in tropical and subtropical areas. In Africa, 31 wild species and 14 cultivated species have been described. In sub-Saharan Africa, Erythrina species are used to treat frequent parasitic and microbial diseases, inflammation, cancer, wounds. The rationale of these traditional uses in African traditional medicine was established by screening several species for biological activities. Promising activities were found against bacteria, parasites (Plasmodium), human and phytopathogenic fungi, some of which were multidrug resistant (MDR) micro organisms. Some species also exhibited antioxidant, anti-inflammatory activities and enzymes inhibitory properties. Most of the species chemically investigated were reported to contain flavanones, prenylated isoflavones, isoflavanones and pterocarpans. Some phytochemicals (vogelin B, vogelin C, isowightcone, abyssinin II, derrone) were the active principles as antibacterials, antifungals, antiplasmodials and inhibitors of enzyme borne diseases (PTP1B, HIV protease, DGAT). This review highlights the important role of Erythrina species as sources of lead compounds or new class of phytotherapeutic agents for fighting against major public health (MDR infections, cancer, diabetes, obesity) in sub-Saharan Africa.     

Olfactometric determination of the most potent odor-active compounds in salmon muscle (Salmo salar) smoked by using four smoke generation techniques

The volatile compounds of salmon fillets smoked according to four smoked generation techniques (smoldering, thermostated plates, friction, and liquid smoke) were investigated. The main odor-active compounds were identified by gas chromatography coupled with olfactometry and mass spectrometry. Only the odorant volatile compounds detected by at least six judges (out of eight) were identified as potent odorants. Phenolic compounds and guaiacol derivatives were the most detected compounds in the olfactometric profile whatever the smoking process and could constitute the smoky odorant skeleton of these products. They were recovered in the aromatic extracts of salmon smoked by smoldering and by friction, which were characterized by 18 and 25 odor-active compounds, respectively. Furannic compounds were more detected in products smoked with thermostated plates characterized by 26 odorants compounds. Finally, the 27 odorants of products treated with liquid smoke were significantly different from the three others techniques applying wood pyrolysis because pyridine derivatives and lipid oxidation products were perceived in the aroma profile.     

Immune responses after local administration of IgY loaded-PLGA microspheres in gut-associated lymphoid tissue in pigs

Oral vaccination of large animals using PLGA MS (poly(D,L-lactide-co-glycolide)microspheres) appeared to be more challenging than immunization of mice. The purpose of this study was to deliver to GALT an immunogenic model protein (IgY), free or encapsulated by spray-drying in PLGA MS, and to evaluate systemic immune response in SPF Large White pigs. Pigs were surgically processed for local administration of IgY in three sets of experiments. In two sets of experiments, administration was locally performed in temporary ligatured intestinal segments, in jejunal Peyer's patches and in mesenteric lymph nodes. In the third experiment, pigs received IgY via an intestinal cannula. Total IgY-specific antibodies were detected in the sera of pigs after a single local immunization, but not in the sera of cannulated pigs. The study of IgG1 and IgG2 isotypes indicated that PLGA MS are able to elicit a combined serum IgG2/G1 response with a predominance of IgG1 response when locally administered. PLGA MS can be a potential oral delivery system for antigen but our results underlined the difficulty to immunize large animals like pigs. Transposition of data between small and large animals appears to be complex and suggests that physiological features need to be considered to increase intestinal availability of oral encapsulated vaccines.     

Use of a trap garden to find additional genetically distinct isolates of the rust fungus <Emphasis Type="Italic">Phragmidium violaceum</Emphasis> to enhance biological control of European blackberry in Australia

Biological control agents can be more effective if their populations are genetically diverse, particularly when the target invasive plant comprises a range of genotypes with different susceptibilities and occurs across various microclimates. We report on the use of an efficient approach to find, in the native range, diverse isolates of a rust fungus for biological control. An outdoor trap garden containing various clones of invasive European blackberry (Rubus fruticosus agg.) collected in Australia, each with a different DNA phenotype, was established in France. Within 4 weeks of establishment, the leaf-rust fungus Phragmidium violaceum was recovered from all clones in the garden. Molecular analyses of eight recovered and purified isolates of the fungus from the garden revealed that they were genetically distinct from each other and from isolates already present in Australia. These garden isolates also represented a subset of the population existing in Europe, when compared to isolates collected about 30 years ago. Two pathogenicity phenotypes were observed among the garden isolates in bioassays consisting of representative blackberry clones from Australia, and together the isolates were capable of infecting all clones. Results from host-specificity tests on key non-target plant species closely related to European blackberry concurred with previous findings that the leaf-rust fungus does not pose a threat to commercial blackberry cultivars and Rubus species native to Australia. The release and establishment of the garden isolates in Australia has potential to increase the genetic diversity and evolutionary potential of the leaf-rust fungus for more effective biological control.     

Anatomical and biochemical trait network underlying genetic variations in tomato fruit texture

Firmness is an indicator of fruit freshness and a main component of tomato (Solanum lycopersicum) fruit texture. In this work, the genetic variability in fruit firmness and stiffness was analyzed in pre- and postharvest periods and underlying anatomical and biochemical traits were identified. Three tomato contrasted parental lines and six derived quantitative trait loci (QTL)-NILs harboring texture QTL on chromosome 4 (QTL4) and 9 (QTL9) were analyzed; the seasonal variability was assessed on two distant trusses. Firmness and stiffness were measured by compression and puncture tests at harvest and after 7-day storage at 20 °C. QTL4 poorly influenced the textural variables, on the contrary to QTL9 which increased firmness measured by puncture test and had similar effects in the two genetic backgrounds. According to this test, firmness increased along the season, but ranks among genotypes and QTL effects were hardly affected. Only some of the QTL effects were still significant after storage and firmness losses were not predicted by firmness at harvest. Fruit firmness and stiffness measured by puncture tests correlated with both morphological (locular number, R = −0.89), histological (cell size, R < −0.80) and biochemical (dry matter (R > 0.82) and soluble sugar content (R < −0.74)) fruit traits. In contrast, compression test values hardly correlated with any of the measured traits. This work provided an original comprehensive approach to analyse fleshy fruit firmness and paves the way for a future predictive model.     

Diversity and genetic structure of teak (<Emphasis Type="Italic">Tectona grandis</Emphasis> L.f) in its natural range using DNA microsatellite markers

Teak (Tectona grandis L.f.) is considered to be an extraordinarily durable building timber with a worldwide reputation. Its widespread use has entailed the over-exploitation of natural forests and a large reduction in natural diversity. Fifteen microsatellite markers were used to study the genetic variability and structure of 166 teak trees distributed over the whole natural area of teak. Analysis showed that in the teak natural area there were four main centers of genetic variability. Two clusters were in India and could be considered as main centers of genetic diversity in teak. The third cluster mainly consisting of populations in Thailand and Laos was genetically very distinct from the Indian populations but presented only half as much allelic variability. A fourth cluster from Central Laos showed even less genetic variability. The use of SSR markers for conservation of teak forest diversity is discussed.     

Geomorphological evidence for fluvial change during the Roman period in the lower Rhone valley (southern France)

The hydrological and geomorphological dynamics of the lower Rhone river (southern France) are studied during the Roman period (2nd–1st centuries BC, 2nd–3rd centuries AD). The crossing of archaeological and radiocarbon dating methods allow to study events at a pluridecadal to centennial scale. From the Avignon town to the delta, the 15 sites where Roman fluvial dynamics were recorded show higher flooding frequencies, higher energy levels during floods, rises in the marshes or groundwater levels, and/or active morphological dynamics such as channel migrations from 1st century BC to 1st–2nd centuries AD, with respect to the encircling periods. Although this fluvial change does not reach the amplitude of great climatic events such as the Little Ice Age in the Rhone valley, we show that it is also perceived in other parts of the catchment and could have a climatic origin. However, this event is not recorded in the immediate Mediterranean environment of the lower Rhone, so that the Rhone appears to efficiently transmit a foreign climatic change.     

Effects of microalgae‐added diets on growth performance and meat composition of tilapia (Oreochromis mossambicus)

Two floating diets and one sinking diet were prepared for tilapia with local ingredients by extrusion or steam‐pelleting methods. Indoor and outdoor feeding trials were conducted to evaluate their effects on growth performance and quality of tilapia products. Local ingredients included defatted Haematococcus and Spirulina by‐products from Hawaii. The three diets, plus a commercial feed, were each assigned to three replicate tanks, and each tank (120 L) was stocked with 12 juvenile tilapia in an 8‐week indoor trial. The results showed that (1) the floating diet had significantly (P < 0.05) higher weight growth than the sinking diet; (2) increased inclusion of local microalgae by‐product (defatted Haematococcus) in floating diet from 12% to 24% significantly (P < 0.05) decreased tilapia weight growth; and (3) the three microalgae‐added diets obtained higher (P < 0.05) weight growth than the commercial feed, although they contained lower protein (36.9% to 37.7%) and lipid (7.1% to 8.1%) than the commercial feed (42.3%; 8.6%). The floating diet (containing 12% microalgae) and the commercial feed were also tested in outdoor green water tanks, simulating the commercial production conditions of local tilapia farms. Each diet had three replicate tanks (1200 L) stocked with 100 juvenile tilapia. The 12‐week trial showed that the local diet had significantly (P < 0.05) lower growth (12.0 g week^?1) than the commercial feed (14.8 g week^?1). All tilapia meat products were measured with low n‐3 fatty acid contents. These results provide important information for feed formulation and production using local ingredients for tilapia.     

First evidence of palytoxin and 42-hydroxy-palytoxin in the marine cyanobacterium Trichodesmium

Marine pelagic diazotrophic cyanobacteria of the genus Trichodesmium (Oscillatoriales) are widespread throughout the tropics and subtropics, and are particularly common in the waters of New Caledonia. Blooms of Trichodesmium are suspected to be a potential source of toxins in the ciguatera food chain and were previously reported to contain several types of paralyzing toxins. The toxicity of water-soluble extracts of Trichodesmium spp. were analyzed by mouse bioassay and Neuroblastoma assay and their toxic compounds characterized using liquid chromatography coupled with tandem mass spectrometry techniques. Here, we report the first identification of palytoxin and one of its derivatives, 42-hydroxy-palytoxin, in field samples of Trichodesmium collected in the New Caledonian lagoon. The possible role played by Trichodesmium blooms in the development of clupeotoxism, this human intoxication following the ingestion of plankton-eating fish and classically associated with Ostreopsis blooms, is also discussed.     

Influences stationnelles sur l'alteration chimique des sols derives de till (Sherbrooke, Que., Canada)

In a small watershed of the canadian Appalachians, five trenches were studied in two catenas facing each other, one forested, the other under recent prairie vegetation (100 years of age), to investigate the character of chemical weathering in these sites. On the top of the forested catena there was a humo-ferric fragic podzol, and further down, and orthic gleysol. The other catena had a humo-ferric fragic podzol, then, downwards, a grey gleyified luvisol and a luvic fragic gleysol. Percolating waters near these trenches were sampled regularly, at various depth. The distribution of the ions on the meadow side indicated on one hand that H₄SiO₄, Na⁺ and Mg²⁺ in percolating waters are related to the total volume of soil through wich waters percolate, that the dissolution of aluminium is accelerated in acid sites (upslope) and that the solubility of iron reaches a maximum in the zone influenced by the water table. On the other hand, calcium, which is easily liberated in the high sections, is in part fixed when the solutions get concentrated, iron and aluminium are soon traped, silicium is less mobile than the basic cations. The constituants of primary minerals organize as follows: concentration of Al₂O₃ and Fe₂O₃ upslope, when the contrary is for the basic oxydes and SiO₂; this trend stands out more clearly in the top 30 cm. Thus on top of the forested catena, chemical weathering is intense, the aluminium and iron oxydes are highly evacuated in this podzol. At the same altitude, in the prairie podzol, which probaly had 100 years ago a less acidifying vegetation (hardwoods) than in the first case, feldspars and micas are degraded and we find mostly transformed minerals (montmorillonite — Al). Minerals are very much less degraded downslope because of their confined position and the high ionic content of the percolating waters.