Effect of Zinc Nutritional Status on Growth, Protein Metabolism and Levels of Indole-3-acetic Acid and other Phytohormones in Bean (Phaseolus vulgaris L.)

Bean (Phaseolus vulgaris L. var. Prelude) plants were grownfor 17 d under controlled environmental conditions with variedZn supply in the nutrient solution. The concentrations of aminoacids; indole-3-acetic acid, IAA; abscisic acid, ABA; isopentenyladenine, I-Ade; isopentenyl adenosine, I-Ado; zeatin, Z; andzeatin riboside, ZR were determined in various shoot fractions. The growth of plants, especially shoot growth, was severelydepressed under conditions of Zn deficiency. Simultaneously,concentrations of soluble protein and chlorophyll decreased,whereas amino acid concentrations increased several-fold. Inthe Zn-deficient plants, the level of IAA in the shoot tipsand young leaves decreased to about 50% of that in Zn-sufficientplants. A similar decrease occurred in the ABA levels of shoottips. In contrast, Zn deficiency was without effect on cytokininlevels in the leaves. Re-supply of Zn to the deficient plantsfor up to 96 h significantly increased shoot growth, solubleprotein, and IAA levels up to the values of Zn-sufficient plants.Simultaneously, the concentration of amino acids dropped tolow levels. The effect of Zn nutritional status on the tryptophanlevel was parallel to that of most of the other amino acids.The results confirm the role of Zn in protein synthesis anddemonstrate that the decrease in IAA level in Zn-deficient plantsis not brought about by impaired synthesis of tryptophan. Itis also unlikely that in Zn-deficient plants the conversionof tryptophan to IAA is specifically inhibited. Key words: Indole-3-acetic acid, tryptophan, zinc deficiency     

Wintering behaviour and spatial ecology of Eurasian Woodcock Scolopax rusticola in western France

The spatial ecology of wintering Eurasian Woodcocks Scolopax rusticola was investigated to determine whether hunting-free forest reserves offer adequate protection to all individuals. The analysis of movements performed by 65 radiotagged Woodcocks during three consecutive winters in Brittany revealed the existence of three types of individual strategies. During daylight hours, 34% of birds remained in a unique core area (of 1.1 ha) during January and February while 18% used several core areas successively (never came back to a previously used core) and 48% alternated between several core areas (exploratory movements around several core areas visited several times). Alternating diurnal strategies seemed to result from a lower abundance of food (earthworms), whereas this was not the case in the unique core-use strategy. The successive core-use strategy was considered as a subset of the 'unique' strategy, for which birds were forced to change sites because of a lower abundance of food after depletion. During the night, 62% of birds showed alternative core-use whereas 33% lived in a unique core and the 'successive' strategy was almost absent. As food abundance was similar in the night cores used by birds under each strategy, we discuss the reasons for the nocturnal strategies in relation to individual differences in territoriality or the ability to detect predators. Both diurnal and nocturnal strategies led most of the birds to leave the reserve, and the important use of bocage and hedges by day (by 39% of birds) and meadows at night (83% of birds used meadows on more than 70% of nights), around the protected forest, call for their inclusion in management plans around reserves.     

Cavity selection for roosting,and roosting ecology of forest-dwelling Australian Owlet-nightjars (Aegotheles cristatus)

Abstract We compared a variety of attributes of tree cavities used for roosting by radio-tagged Australian Owlet-nightjars Aegotheles cristatus with randomly chosen prospective cavities to test which features are important for the species. Owlet-nightjars preferentially roosted in tree cavities closer to the ground, in trees with a significantly greater number of cavities and significantly closer to another tree with a cavity than expected by chance. There was also a significant interaction between cavity height and number of cavities in the tree. Tree size, decay stage and tree species were not statistically important cues used for making site choices. The requirements for Owlet-nightjars differ from those of most other Australian birds that use tree holes and also from most insectivorous bats. Telemetry data indicate that Owlet-nightjars move ～300 m between roost sites every 9 days on average. Individual birds used 2-6 different cavities during the 1–4-month period over which they were followed. The reasons for the relatively low levels of site fidelity are unknown.     

Historical DNA from museum type specimens clarifies diversity of Asian leaf turtles (Cyclemys)

Species boundaries in Asian leaf turtles of the genus Cyclemys are difficult to define on the basis of morphology, primarily because many populations exhibit considerable ontogenetic variation in shell and head coloration. Two recent molecular phylogenetic hypotheses of Cyclemys species relationships, based largely on market and pet-trade samples of uncertain provenance, were highly incongruent. We used historical DNA methods to sequence fragments of the mitochondrial cytochrome  b gene from eight type specimens of Cyclemys (including one collected by Alfred Russel Wallace), and phylogenetically placed these type sequences into the context of published cytochrome  b variation. Our phylogenetic hypothesis supports the recognition of four named species ( Cyclemys atripons , Cyclemys dentata , Cyclemys oldhamii , and C. pulchristriata ), as well as a fifth species of unknown geographical provenance obtained from the Hong Kong pet trade. The type sequences show that previous molecular phylogenetic studies were hampered by misidentifications, supporting the notion that Cyclemys of unknown provenance are not reliably identified to species solely on the basis of morphology.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 131–141.     

Direct and indirect effects of plant genetic variation on enemy impact

Abstract.

• 1 The Tritrophic and Enemy Impact concepts predict that natural enemy impact varies: (a) among plant genotypes and (b) may depend on the abundance of heterospecific herbivores, respectively. I tested these predictions using three herbivore species on potted, cloned genotypes of Salik sericea Marshall in a common garden experiment.
• 2 Densities of the leaf miner (Phyllonorycter salicifoliella (Chambers)) and two leaf galling sawflies (Phyllocolpa nigrita (Marlatt) and Phyllocolpa eleanorae Smith and Fritz) varied significantly among willow clones, indicating genetic variation in resistance.
• 3 Survival and natural enemy impact caused by egg and larval parasitoids and/or unknown predators differed significantly among willow clones for each of the three herbivore species, indicating genetic variation in survival and enemy impact.
• 4 Survival of Phyllonorycter was negatively density-dependent among clones.
• 5 Survival of Phyllonorycter and Phyllocolpa eleanorae were positively correlated with densities of heterospecific herbivores among clones and parasitism of these species were negatively correlated with densities of the same heterospecific herbivores among clones.
• 6 At least for Phyllonorycter this positive correlation may suggest either facilitation of survival between herbivore species, which do not share natural enemies, or an apparent interaction caused by host plant genetic variation.
• 7 Among clones, egg parasitism of Phyllocolpa eleanorae was weakly positively correlated with density of Phyllocolpa nigrita. Since these species share the same Trichogramma egg parasitoid, this interaction could support the hypothesis of apparent competition.

     

Application of a reverse dot blot DNA–DNA hydridization method to quantify host‐feeding tendencies of two sibling species in the Anopheles gambiae complex

A DNA–DNA hybridization method, reverse dot blot analysis (RDBA), was used to identify Anopheles gambiae s.s. and Anopheles arabiensis (Diptera: Culicidae) hosts. Of 299 blood‐fed and semi‐gravid An. gambiae s.l. collected from Kisian, Kenya, 244 individuals were identifiable to species; of these, 69.5% were An. arabiensis and 29.5% were An. gambiae s.s. Host identifications with RDBA were comparable with those of conventional polymerase chain reaction (PCR) followed by direct sequencing of amplicons of the vertebrate mitochondrial cytochrome b gene. Of the 174 amplicon‐producing samples used to compare these two methods, 147 were identifiable by direct sequencing and 139 of these were identifiable by RDBA. Anopheles arabiensis bloodmeals were mostly (94.6%) bovine in origin, whereas An. gambiae s.s. fed upon humans more than 91.8% of the time. Tests by RDBA detected that two of 112 An. arabiensis contained blood from more than one host species, whereas PCR and direct sequencing did not. Recent use of insecticide‐treated bednets in Kisian is likely to have caused the shift in the dominant vector species from An. gambiae s.s. to An. arabiensis. Reverse dot blot analysis provides an opportunity to study changes in host‐feeding by members of the An. gambiae complex in response to the broadening distribution of vector control measures targeting host‐selection behaviours.     

The Contribution of TRPV4-Mediated Calcium Signaling to Calcium Homeostasis in Endothelial Cells

A large variety of cation transport systems are involved in the regulation of calcium homeostasis in endothelial cells. The focus of the present study is to determine the contribution of nonselective cation channels from the TRP (transient receptor potential) family to cellular calcium homeostasis of porcine aortic endothelial cells (PAEC). One member of the TRPV (vanniloid) subfamily, TRPV4, has previously been shown to be involved in cation transport induced by a large variety of stimulations including osmolarity, temperature, mechanical stress, and phosphorylation. Here, we demonstrate the existence of several TRP proteins, including TRPV4, in PAEC using RT-PCR. To test whether this channel is functional, we performed FURA-2 calcium measurements and whole-cell patch-clamp experiments. We observed the induction of large calcium signals following mechanical stress, altered extracellular temperature, and the selective TRPV4 activator 4-α -PDD. These effects were diminished in the presence of the TRPV4 inhibitor miconazole, suggesting the involvement of this channel in mediating endothelial calcium signals. The large amounts of transported calcium and the short signaling ways suggest a potentially important role of this channel in many physiological processes.