Bacterial endophyte-mediated naphthalene phytoprotection and phytoremediation

Polyaromatic hydrocarbons (PAHs) are major and recalcitrant pollutants of the environment and their removal presents a significant problem. Phytoremediation has shown much promise in PAH removal from contaminated soil, but may be inhibited because the plant experiences phytotoxic effects from low-molecular-weight PAHs such as naphthalene. This paper describes the construction of a naphthalene-degrading endophytic strain designated Pseudomonas putida VM1441(pNAH7). This strain was found to be an efficient colonizer of plants, colonizing both the rhizosphere and interior root tissues. The inoculation of plants with P. putida VM1441(pNAH7) resulted in the protection of the host plant from the phytotoxic effects of naphthalene. When inoculated plants were exposed to naphthalene, both seed germination and plant transpiration rates were higher than those of the uninoculated controls. The inoculation of plants with this strain also facilitated higher (40%) naphthalene degradation rates compared with uninoculated plants in artificially contaminated soil.     

GRAY WHALE (ESCHRICHTIUS ROBUSTUS) HABITAT UTILIZATION AND PREY SPECIES OFF VANCOUVER ISLAND, B. C.

Habitat utilization and prey species of Vancouver Island gray whales were investigated by (1) summarizing 26 yr of distribution and feeding data and (2) conducting intensive observations in Clayoquot Sound, Vancouver Island, from 1989 to 1996. Whale distribution and movements were monitored from March to November through systematic boat surveys and whale-watch sighting programs. Prey species were collected by suction hose and plankton net or determined through analysis of fecal samples. Gray whales utilized virtually all of the southern west coast of Vancouver Island over the 26-yr observation period. Distribution, prey species, and feeding behavior showed marked variability during any one season and between years. Some feeding areas were used on an annual basis, others with >10-yr intervals between use. Feeding occurred in shallow sand or mud bays, eel grass beds, kelp beds, in the open water column, and at the surface. Young whales appeared to utilize habitat and prey species differently than adults. Main prey species included herring eggs/larvae ( Clupea harengus pallasi ), crab larvae ( Cancer magister megalops, Pachycbeles spp. zoea), mysids ( Holmesimysis sculpta, Neomysis rayii, Acanthomysis spp.), amphipods ( Ampelisca spp., Atylus borealis ), and ghost shrimp ( Callianassa californiensis ). The definition and relative importance of specific feeding grounds and the study of human impacts on this population are complicated by its broad and variable use of habitat and prey species.     

Head shape evolution in monitor lizards (Varanus): interactions between extreme size disparity,phylogeny and ecology

Characterizing patterns of observed current variation, and testing hypotheses concerning the potential drivers of this variation, is fundamental to understanding how morphology evolves. Phylogenetic history, size and ecology are all central components driving the evolution of morphological variation, but only recently have methods become available to tease these aspects apart for particular body structures. Extant monitor lizards (Varanus) have radiated into an incredible range of habitats and display the largest body size range of any terrestrial vertebrate genus. Although their body morphology remains remarkably conservative, they have obvious head shape variation. We use two‐dimensional geometric morphometric techniques to characterize the patterns of dorsal head shape variation in 36 species (375 specimens) of varanid, and test how this variation relates to size, phylogenetic history and ecology as represented by habitat. Interspecific head shape disparity is strongly allometric. Once size effects are removed, principal component analysis shows that most shape variation relates to changes in the snout and head width. Size‐corrected head shape variation has strong phylogenetic signal at a broad level, but habitat use is predictive of shape disparity within phylogenetic lineages. Size often explains shape disparity among organisms; however, the ability to separate size and shape variation using geometric morphometrics has enabled the identification of phylogenetic history and habitat as additional key factors contributing to the evolution of head shape disparity among varanid lizards.     

Molecular phylogeny and phylogeography of the Australian Diplodactylus stenodactylus (Gekkota; Reptilia) species-group based on mitochondrial and nuclear genes reveals an ancient split between Pilbara and non-Pilbara D. stenodactylus

There is a paucity of research on intra-specific morphological and genetic diversity in Australian arid-zone reptiles, and a number of Australian reptile species have for many years been regarded as "species complexes" that classical morphological analyses could not resolve. We conducted a phylogenetic and phylogeographic study of a widespread species group of Australian geckonid lizards to address two main aims. First, based on a large mitochondrial and nuclear gene data set, we have generated the first molecular phylogeny for the Diplodactylus stenodactylus species group (D. alboguttatus, D. damaeus, D. maini, and D. squarrosus, D. stenodactylus) and multiple outgroups to examine the evolutionary relationships among these arid-zone species and phylogenetic patterns within some species. The edited alignment of 41 individuals comprises 2485 characters (1163 ND2+tRNAs; 490 16s; 832 RAG-1), and of these 717 (29%) were variable and parsimony informative (568 ND2+tRNAs; 89 16s; 60 RAG-1). This broad-scale, multi-gene phylogeny has supported previous conjectures on the higher-level phylogenetic relationships among members of the D. stenodactylus species-group based on morphology, but also has uncovered hidden diversity within the group with two new species identified. Analysis at this broad level has identified patterns associated with the distribution of the D. stenodactylus species group that appear to be influenced by environmental processes operating at large geographic scales. Two major clades within the species group were associated with broad differences in habitat types, with one group largely restricted to the temperate zone of the Southwest Province and another largely restricted to central and northern Western Australia north of Kalgoorlie, in line with the Eremaean Province of the Eremaean Zone and the Northern Province of the Tropical Zone. Second, we have assembled phylogeographic data based on a mitochondrial gene (ND2+tRNAs) for five species (Rhynchoedura ornata, Diplodactylus maini, D. pulcher, D. squarrosus, D. stenodactylus) where larger sampling is available, with particular focus on D. stenodactylus, which is distributed both in the iconic but little-known Pilbara area of endemism in north-western Australia as well as in other parts of the Australian arid zone. The edited alignment of 95 individuals comprises 1142 characters and of these 601 (53%) are variable and parsimony informative. We found significant intra-specific genetic variation in all five species, highlighting the need for large-scale screening of cryptic species, with sampling specifically targeted at determining the geographic limits of such taxa. In particular, within D. stenodactylus, a deep and ancient phylogenetic split distinguishes populations in the Pilbara region from non-Pilbara populations. This split may be the result of broad differences in underlying geological substrate, with the Pilbara clade generally preferring harder soils and the non-Pilbara clade adapted to sand.     

Blood feeding patterns of mosquitoes: random or structured?

Background

During the non-breeding period, many birds migrate to milder areas, found closer to the equator than their breeding sites. Opposite movements are very rare. In the Southern Ocean, the abundance of ¹³C declines markedly with more southern latitude, providing a characteristic ¹³C isoscape. This can be used as a tracer for the movement of seabirds between breeding and inter-breeding areas, by comparing stable isotope ratios of feathers grown at different times of the year.

Results

We studied seasonal movements of Thin-billed prions (Aves, Procellariiformes), breeding at the Subantarctic Falkland/Malvinas Islands, compared with those of Wilson's storm-petrels breeding in the Antarctic South Shetland Islands. The two species showed opposite migratory movements. While Wilson's storm-petrels moved to warmer waters north of the Drake Passage in winter, Thin-billed prions showed a reversed movement towards more polar waters. Carbon stable isotope ratios in recent and historical feathers indicated that poleward winter movements of Thin-billed prions were less common historically (45% in 1913-1915), and have only recently become dominant (92% in 2003-2005), apparently in response to warming sea temperatures.

Conclusions

This study shows that pelagic seabirds can rapidly change migration strategies within populations, including migration towards more poleward waters in winter.     

A biomechanical analysis of straight and hexagonal barbell deadlifts using submaximal loads

The purpose of the investigation was to compare the kinematics and kinetics of the deadlift performed with 2 distinct barbells across a range of submaximal loads. Nineteen male powerlifters performed the deadlift with a conventional straight barbell and a hexagonal barbell that allowed the lifter to stand within its frame. Subjects performed trials at maximum speed with loads of 10, 20, 30, 40, 50, 60, 70, and 80% of their predetermined 1-repetition maximum (1RM). Inverse dynamics and spatial tracking of the external resistance were used to quantify kinematic and kinetic variables. Subjects were able to lift a heavier 1RM load in the hexagonal barbell deadlift (HBD) than the straight barbell deadlift (SBD) (265 ± 41 kg vs. 245 ± 39 kg, p < 0.05). The design of the hexagonal barbell significantly altered the resistance moment at the joints analyzed (p < 0.05), resulting in lower peak moments at the lumbar spine, hip, and ankle (p < 0.05) and an increased peak moment at the knee (p < 0.05). Maximum peak power values of 4,388 ± 713 and 4,872 ± 636 W were obtained for the SBD and HBD, respectively (p < 0.05). Across the submaximal loads, significantly greater peak force, peak velocity and peak power values were produced during the HBD compared to during the SBD (p < 0.05). The results demonstrate that the choice of barbell used to perform the deadlift has a significant effect on a range of kinematic and kinetic variables. The enhanced mechanical stimulus obtained with the hexagonal barbell suggests that in general the HBD is a more effective exercise than the SBD.     

Acute effects of verbal feedback on upper-body performance in elite athletes

Argus, CK, Gill, ND, Keogh, JWL, and Hopkins, WG. Acute effects of verbal feedback on upper-body performance in elite athletes. J Strength Cond Res 25(12): 3282-3287, 2011-Improved training quality has the potential to enhance training adaptations. Previous research suggests that receiving feedback improves single-effort maximal strength and power tasks, but whether quality of a training session with repeated efforts can be improved remains unclear. The purpose of this investigation was to determine the effects of verbal feedback on upper-body performance in a resistance training session consisting of multiple sets and repetitions in well-trained athletes. Nine elite rugby union athletes were assessed using the bench throw exercise on 4 separate occasions each separated by 7 days. Each athlete completed 2 sessions consisting of 3 sets of 4 repetitions of the bench throw with feedback provided after each repetition and 2 identical sessions where no feedback was provided after each repetition. When feedback was received, there was a small increase of 1.8% (90% confidence limits, ±2.7%) and 1.3% (±0.7%) in mean peak power and velocity when averaged over the 3 sets. When individual sets were compared, there was a tendency toward the improvements in mean peak power being greater in the second and third sets. These results indicate that providing verbal feedback produced acute improvements in upper-body power output of well-trained athletes. The benefits of feedback may be greatest in the latter sets of training and could improve training quality and result in greater long-term adaptation.