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141.
A new cystidicolid nematode, Moravecnema segonzaci gen. et sp. n. is described from the intestine of the teleost fish Pachycara thermophilum Geistdoerfer (Zoarcidae) from the hydrothermal sites Logatchev and Snake Pit-Moose of the Mid-Atlantic Ridge, at depths of 3,008; 3,492, and 3,510 m. The new genus Moravecnema is characterised by a dorsoventrally elongated oral opening, rudimentary pseudolabia, and four pairs of precloacal and six pairs of postcloacal caudal papillae in the male. The species has two spicules of unequal length, about 330 and 80 microm long. Males are about 5 mm and females about 5-10 mm long. Eggs have long thin polar filaments. This is the first species of parasitic nematode described from a fish endemic to hydrothermal deep-sea vents. 相似文献
142.
Lieutier F Brignolas F Sauvard D Yart A Galet C Brunet M van de Sype H 《Tree physiology》2003,23(4):247-256
One hundred Norway spruce (Picea abies (L.) Karst.) clones (three ramets per clone) were analyzed for phloem phenol composition and concentration before and 10 days after wound inoculation with sterile malt agar. Fifty clones (Experiment 1) belonged to the same provenance, whereas the remaining clones (Experiment 2) belonged to five provenances from three geographic areas. In Experiment 2, two additional ramets from the same clones were mass inoculated with Ceratocystis polonica (Siem.) C. Moreau to quantify the resistance of each clone. Tree response to wound inoculations was characterized by increased catechin concentration in both experiments, accompanied by increases in astringin and decreases in piceid in Experiment 1. In both experiments, we observed a diverse group of phenolic compounds whose concentrations increased (catechin, astringin) or did not vary (taxifolin glucoside) in response to wound inoculations, whereas concentrations of a homogeneous group of stilbene compounds decreased (piceid) or did not vary (isorhapontin, unidentified stilbene). In Experiment 2, provenances from the alpine and Hercynian-Carpatic areas differed from provenances from the Baltic area with respect to the relative importance of these two groups of compounds, further indicating that the two groupings of phenolic compounds structure the Norway spruce populations. Eighty days after mass inoculation, the percentage of healthy sapwood, which was taken as a measure of tree resistance, indicated that clones from the Baltic area were less resistant to mass inoculations than clones from the alpine and Hercynian-Carpatic areas. We conclude that the degree of resistance of Norway spruce trees to mass inoculations with a bark beetle-associated fungus can be predicted based on the diversity of constitutive phloem phenols and the ability to induce phenol synthesis in response to wounding. 相似文献
143.
Laurence Mercier Ilie S Racotta Gloria Yepiz-Plascencia Adriana Muhlia-Almazán Roberto Civera Marcos F Quiñones-Arreola Mathieu Wille Patrick Sorgeloos & Elena Palacios 《Aquaculture Research》2009,40(16):1849-1863
Juveniles fed a diet containing a low or a high level of highly unsaturated fatty acids (HUFA) for 38 days were exposed to handling stress. In a first experiment, stress was applied daily for 30 days, after which the physiological and immunological variables were measured, whereas in a second experiment, stress was applied once and samples were obtained 1 and 24 h after the stressor event. Shrimp that were stressed for 30 days showed significantly lower survival, final weight and feed consumption compared with unstressed shrimp. The concentration of the high-density lipoprotein β-glucan-binding protein was significantly higher in shrimp fed the high-HUFA diet. The glucose concentration in the haemolymph was significantly higher in long-term stressed shrimp compared to controls. The lactate level in the haemolymph was significantly lower in shrimp fed the high-HUFA diet. Lactate and glucose in the haemolymph increased in the 1-h stressed shrimp, but returned to normal levels in 24-h stressed shrimp. A negative effect of repeated-handling stress applied for 30 days was mainly observed on biological performance, whereas the single-stressor event had a more pronounced effect on shrimp physiological and immune responses measured 1 and 24 h after the stressor. A beneficial role of enrichment with HUFA on tolerance to handling stress was observed on immune response capacity. 相似文献
144.
Fariborz Ehteshami Annie Christianus Hossein Rameshi Sharr Azni Harmin Che Roos Saad 《Aquaculture Research》2011,42(4):613-622
Black‐lip pearl oyster, Pinctada margaritifera broodstock was collected from the wild. Egg production, hatching rate and larval development were compared between oysters induced to spawn within 2 days after collection in the wild (T1), oysters fed a pure microalgae diet during 24 days before spawning (T2) and oysters fed the same microalgal diet in which 10% of the algae were replaced with 2 μm polyunsaturated fatty acid (PUFA)‐rich microspheres (T3). Administration of lipid microspheres resulted in larger sized eggs, a higher percentage of D‐larvae and larger sized 48‐h‐old larvae (P<0.05). The total and neutral lipid contents of the gonad increased after oysters were fed with microalgae only or with supplementary diet. The major neutral and polar fractions of saturated fatty acid (SFA) were 16C and 18C fatty acids, and not influenced by the diet (P>0.05). The gonads of oysters fed supplementary PUFA contained more docosahexaenoic acid (DHA) and less monounsaturated fatty acids. Higher level of DHA in gonads of T3 was associated with oogenesis and embryogenesis success. The n‐3/n‐6 ratio in the neutral lipid fraction provides a good indication of the spawning condition and predicting egg size and hatching rate. 相似文献
145.
- Fungal species stimulating tree defenses are generally not those that grow the best in the sapwood.
- We argue that beetle development in the phloem, fungal invasion of the sapwood and phloem, and tree death, occur after tree defenses are exhausted, and that any fungus present in the beetle gallery could thus potentially invade the sapwood after defense exhaustion.
- any beetle species would be helped in its establishment in a given tree species by developing an association, even loosely, with a fungus species belonging to the Ophiostomatoid flora of that tree species;
- the necessity of a considerably low level of tree resistance for fungus extension into the tree is the selection pressure that has led fungi to develop their intrinsic ability to stimulate tree defenses, through their ability to grow into the phloem. This association can be completed by antagonistic fungal species controlling extension of the previous fungal species in the tree tissues;
- Beetle species using the strategy of overcoming tree resistance are associated with a fungal complex, of which species could assume three roles regarding relationships between beetles and trees: 1- to stimulate tree defenses in the phloem and superficial sapwood, 2- to grow into the sapwood after tree resistance is overcome, and 3- to control phloem extension of the first other two categories. Bringing nutrients to the beetle progeny can be a fourth role.
146.
Comparing needle and shoot phenology with xylem development on three conifer species in Italy 总被引:1,自引:0,他引:1
147.
148.
Benoît Sauphanor Veronique Brosse Jean Charles Bouvier Pierre Speich Annie Micoud Christophe Martinet 《Pest management science》2000,56(1):74-82
French populations of codling moth have developed resistance to several insecticide classes. The susceptibility of susceptible and resistant laboratory strains to diflubenzuron and deltamethrin was evaluated using different exposure methods against various life stages. The tarsal contact method for adults was found to be an appropriate method for testing neurotoxic compounds such as deltamethrin. Insect growth inhibitors, like diflubenzuron, need to be analysed on juvenile instars. Monitoring methodologies were developed and evaluated (a) on neonates obtained by crossing field‐collected males with virgin females from the susceptible laboratory strain so as to overcome the problem of reduced fertility of wild females and (b) on diapausing larvae. All 36 populations analysed exhibited significant levels of resistance to both diflubenzuron and deltamethrin. Resistance to the two compounds was linked, regardless of the cultivation methods used in the monitored area. The monitoring methodologies will be implemented to evaluate the evolution of resistance according to the resistance management strategies that have been adopted. © 2000 Society of Chemical Industry 相似文献
149.
We examined the influence of seasonal water stress on the resistance of Pinus yunnanensis (Franch.) to inoculation with Leptographium yunnanense, a pathogenic fungus associated with the aggressive bark beetle, Tomicus n. sp. Experiments took place between October 1997 and November 1999 in two plots located at the top and at the foot of a hill in Shaogiu, China, a region characterized by dry winters and wet summers. Following isolated and mass fungal inoculations, we observed the reaction zone length, fungal growth in the phloem, and the occlusion, blue-staining and specific hydraulic conductivity of the sapwood. Measurements of soil and needle water contents and predawn needle water potentials confirmed that trees were subject to mild water stress during winter, especially at the drier hilltop site. Measures of tree resistance to fungal infection of phloem and sapwood were congruent and indicated that trees were most susceptible to inoculation during the wet summer, especially at the lower-elevation plot. Specific hydraulic conductivity decreased after inoculation in summer. The results indicate that mild seasonal water stress is not likely responsible for the recent extensive damage to young P. yunnanensis stands by Tomicus n. sp. in the vicinity of our study plots. Rather, the results suggest that mild water stress enhances tree resistance to fungal pathogens associated with Tomicus n. sp. 相似文献
150.
Vialatte Aude Barnaud Cecile Blanco Julien Ouin Annie Choisis Jean-Philippe Andrieu Emilie Sheeren David Ladet Sylvie Deconchat Marc Clément Floriane Esquerré Diane Sirami Clelia 《Landscape Ecology》2019,34(7):1653-1673
Landscape Ecology - While the concept of ecosystem services (ES) is well established in the scientific and policy arenas, its operationalization faces many challenges. Indeed, ES supply, demand and... 相似文献