Cloning of a cytosolic ascorbate peroxidase gene from Lycium chinense Mill. and enhanced salt tolerance by overexpressing in tobacco

To evaluate the physiological importance of cytosolic ascorbate peroxidase (APX) in the reactive oxygen species (ROS)-scavenging system, a full-length cDNA clone, named LmAPX, encoding a cytosolic ascorbate peroxidase was isolated from Lycium chinense Mill. using homologous cloning, then the expression of LmAPX under salt stress was investigated. After sequencing and related analysis, the LmAPX cDNA sequence was 965 bp in length and had an open reading frame (ORF) of 750 bp coding for 250 amino acids. Furthermore, the LmAPX sequence was sub-cloned into prokaryotic expression vector pET28a and the recombinant proteins had a high expression level in Escherichia coli. Results from a southern blot analysis indicated that three inserts of this gene existed in the tobacco genome encoding LmAPX. Compared with the control plants (wild-type and empty vector control), the transgenic plants expressing the LmAPX gene exhibited lower amount of hydrogen peroxide (H₂O₂) and relatively higher values of ascorbate peroxidase activity, proline content, and net photosynthetic rate (P_n) under the same salt stress. These results suggested that overexpression of the LmAPX gene could decrease ROS production caused by salt stress and protect plants from oxidative stress.     

Allometric relationship between body mass and aerobic metabolism in zebrafish Danio rerio

The relationship between body mass (M) and metabolic rate was investigated through the assessment of active (R_A) and standard (R_S) metabolic rate at different life stages in zebrafish Danio rerio (5 day‐old larvae, 2 month‐old juveniles and 6 month‐old adults). Scaling exponents and constants were assessed for standard (R_S = 0·273M^0·965 in mgO₂ g^?1 h^?1) and active metabolic rate (R_A = 0·799M^0·926 in mgO₂ g^?1 h^?1). These data provide the basis for further experiments regarding the effects of environmental factors on aerobic metabolism throughout the life cycle of this species.     

Habitat‐driven population structure of bottlenose dolphins,Tursiops truncatus,in the North‐East Atlantic

Despite no obvious barrier to gene flow, historical environmental processes and ecological specializations can lead to genetic differentiation in highly mobile animals. Ecotypes emerged in several large mammal species as a result of niche specializations and/or social organization. In the North‐West Atlantic, two distinct bottlenose dolphin (Tursiops truncatus) ecotypes (i.e. ‘coastal’ and ‘pelagic’) have been identified. Here, we investigated the genetic population structure of North‐East Atlantic (NEA) bottlenose dolphins on a large scale through the analysis of 381 biopsy‐sampled or stranded animals using 25 microsatellites and a 682‐bp portion of the mitochondrial control region. We shed light on the likely origin of stranded animals using a carcass drift prediction model. We showed, for the first time, that coastal and pelagic bottlenose dolphins were highly differentiated in the NEA. Finer‐scale population structure was found within the two groups. We suggest that distinct founding events followed by parallel adaptation may have occurred independently from a large Atlantic pelagic population in the two sides of the basin. Divergence could be maintained by philopatry possibly as a result of foraging specializations and social organization. As coastal environments are under increasing anthropogenic pressures, small and isolated populations might be at risk and require appropriate conservation policies to preserve their habitats. While genetics can be a powerful first step to delineate ecotypes in protected and difficult to access taxa, ecotype distinction should be further documented through diet studies and the examination of cranial skull features associated with feeding.     

Mosquito and West Nile virus surveillance in northeast Montana,U.S.A., 2005 and 2006

Mosquito and West Nile virus (WNV) surveillance was conducted on a national wildlife refuge in northeast Montana in 2005 and 2006, during which outbreaks of WNV in a colony of American white pelicans (Pelecanus erythrorhynchos Gmelin) (Pelecaniformes: Pelecanidae) resulted in juvenile mortality rates of ～ 31%. Both years, floodwater species Ochlerotatus dorsalis (Meigen) (Diptera: Culicidae), Aedes vexans (Meigen) (Diptera: Culicidae) and Ochlerotatus flavescens (Muller) (Diptera: Culicidae) comprised 78% of the total collection and heightened host‐seeking activity was observed from mid‐June to mid‐July. Culex tarsalis Coquillett (Diptera: Culicidae) was most active from mid‐July to mid‐August and comprised 18% of the collection in 2005 and 20% in 2006. However, fewer than 10% of the Cx. tarsalis females collected in 2006 were obtained adjacent to the pelicans' nesting grounds. Minimum infection rates per 1000 Cx. tarsalis tested for WNV were 1.36 in 2005 and 1.41 in 2006. All pools in which WNV was detected in 2006 were composed of females collected 10 km from the nesting grounds. Substantial juvenile pelican mortality in 2006 despite reductions in the population of the primary vector and in mosquito infection rates near the colony suggests that the methods used to detect the introduction of WNV were too coarse and that amplification of the virus within the colony may reflect causes other than mosquito infection.     

One step forward: contrasting the effects of Toe clipping and PIT tagging on frog survival and recapture probability

Amphibians have been declining worldwide and the comprehension of the threats that they face could be improved by using mark–recapture models to estimate vital rates of natural populations. Recently, the consequences of marking amphibians have been under discussion and the effects of toe clipping on survival are debatable, although it is still the most common technique for individually identifying amphibians. The passive integrated transponder (PIT tag) is an alternative technique, but comparisons among marking techniques in free‐ranging populations are still lacking. We compared these two marking techniques using mark–recapture models to estimate apparent survival and recapture probability of a neotropical population of the blacksmith tree frog, Hypsiboas faber. We tested the effects of marking technique and number of toe pads removed while controlling for sex. Survival was similar among groups, although slightly decreased from individuals with one toe pad removed, to individuals with two and three toe pads removed, and finally to PIT‐tagged individuals. No sex differences were detected. Recapture probability slightly increased with the number of toe pads removed and was the lowest for PIT‐tagged individuals. Sex was an important predictor for recapture probability, with males being nearly five times more likely to be recaptured. Potential negative effects of both techniques may include reduced locomotion and high stress levels. We recommend the use of covariates in models to better understand the effects of marking techniques on frogs. Accounting for the effect of the technique on the results should be considered, because most techniques may reduce survival. Based on our results, but also on logistical and cost issues associated with PIT tagging, we suggest the use of toe clipping with anurans like the blacksmith tree frog.     

Under pressure: morphological and ecological correlates of bite force in the rock‐dwelling lizards Ouroborus cataphractus and Karusasaurus polyzonus (Squamata: Cordylidae)

Rock‐dwelling lizards are hypothesized to be highly constrained in the evolution of head morphology and, consequently, bite force. Because the ability to generate a high bite force might be advantageous for a species' dietary ecology, morphological changes in head configuration that allow individuals to maintain or improve their bite force under the constraint of crevice‐dwelling behaviour are to be expected. The present study addressed this issue by examining head morphology, bite force, and a number of dietary traits in the rock‐dwelling cordylid lizards Ouroborus cataphractus and Karusasaurus polyzonus. The results obtained show that O. cataphractus has a larger head and higher bite force than K. polyzonus. In K. polyzonus, head width, lower jaw length, and jaw closing‐in lever are the best predictors of bite force, whereas head height is the main determinant of bite force in O. cataphractus. Although the observed difference in bite force between the species does not appear to be related to dietary patterns or prey handling, the prey spectrum available for intake was greater in O. cataphractus compared to K. polyzonus. We discuss the influence of interspecific differences in anti‐predator morphology on head morphology and bite force in these rock‐dwelling species. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 823–833.     

Reduction of oviposition time and enhanced larval feeding: two potential benefits of aggregative oviposition for the viburnum leaf beetle

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