The araC regulatory gene mRNA contains a leader sequence

Summary An estimation of the size of the araC gene in Escherichia coli B/r was made by sub-cloning restriction fragments of the araC-containing hybrid plasmid pTB1 into the plasmid pBR322. Plasmids which contained a functional araC gene were identified by genetic complementation tests. DNA sequence analysis of the promoter-proximal region of the araC gene revealed that araC mRNA contains a 150 nucleotide leader.     

Cheap and Nasty? The Potential Perils of Using Management Costs to Identify Global Conservation Priorities

The financial cost of biodiversity conservation varies widely around the world and such costs should be considered when identifying countries to best focus conservation investments. Previous global prioritizations have been based on global models for protected area management costs, but this metric may be related to other factors that negatively influence the effectiveness and social impacts of conservation. Here we investigate such relationships and first show that countries with low predicted costs are less politically stable. Local support and capacity can mitigate the impacts of such instability, but we also found that these countries have less civil society involvement in conservation. Therefore, externally funded projects in these countries must rely on government agencies for implementation. This can be problematic, as our analyses show that governments in countries with low predicted costs score poorly on indices of corruption, bureaucratic quality and human rights. Taken together, our results demonstrate that using national-level estimates for protected area management costs to set global conservation priorities is simplistic, as projects in apparently low-cost countries are less likely to succeed and more likely to have negative impacts on people. We identify the need for an improved approach to develop global conservation cost metrics that better capture the true costs of avoiding or overcoming such problems. Critically, conservation scientists must engage with practitioners to better understand and implement context-specific solutions. This approach assumes that measures of conservation costs, like measures of conservation value, are organization specific, and would bring a much-needed focus on reducing the negative impacts of conservation to develop projects that benefit people and biodiversity.     

Predicted warming and browning affect timing and magnitude of plankton phenological events in lakes: a mesocosm study

1. Aquatic ecosystems in Northern Europe are expected to face increases in temperature and water colour (TB) in future. While effects of these factors have been studied separately, it is unknown whether and how a combination of them might affect phenological events and trophic interactions. 2. In a mesocosm study, we combined both factors to create conditions expected to arise during the coming century. We focused on quantifying effects on timing and magnitude of plankton spring phenological events and identifying possible mismatches between resources (phytoplankton) and consumers (zooplankton). 3. We found that the increases in TB had important effects on timing and abundance of different plankton groups. While increased temperature led to an earlier peak in phytoplankton and zooplankton and a change in the relative timing of different zooplankton groups, increased water colour reduced chlorophyll‐a concentrations. 4. Increased TB together benefitted cladocerans and calanoid copepods and led to stronger top‐down control of algae by zooplankton. There was no sign of a mismatch between primary producers and grazers as reported from other studies. 5. Our results point towards an earlier onset of plankton spring growth in shallow lakes in future with a stronger top‐down control of phytoplankton by zooplankton grazers.     

Synthesis and activity of novel bile-acid conjugated glucocorticoid receptor antagonists

A series of potent steroidal glucocorticoid receptor antagonists has been discovered. After conjugation to cholic acid, the compounds retained an affinity for GR in vitro and had modest in vivo efficacy.     

Lower extremity control and dynamics during backward angular impulse generation in forward translating tasks

Observation of complex whole body movements suggests that the nervous system coordinates multiple operational subsystems using some type of hierarchical control. When comparing two forward translating tasks performed with and without backward angular impulse, we have learned that both trunk-leg coordination and reaction force-time characteristics are significantly different between tasks. This led us to hypothesize that differences in trunk-leg coordination and reaction force generation would induce between-task differences in the control of the lower extremity joints during impulse generation phase of the tasks. Eight highly skilled performers executed a series of forward jumps with and without backward rotation (reverse somersault and reverse timer, respectively). Sagittal plane kinematics, reaction forces, and electromyograms of lower extremity muscles were acquired during the take-off phase of both tasks. Lower extremity joint kinetics were calculated using inverse dynamics. The results demonstrated between-task differences in the relative angles between the lower extremity segments and the net joint forces/reaction force and the joint angular velocity profiles. Significantly less knee extensor net joint moments and net joint moment work and greater hip extensor net joint moments and net joint moment work were observed during the push interval of the reverse somersault as compared to the reverse timer. Between-task differences in lower extremity joint kinetics were regulated by selectively activating the bi-articular muscles crossing the knee and hip. These results indicate that between-task differences in the control of the center of mass relative to the reaction force alters control and dynamics of the multijoint lower extremity subsystem.     

Head impact exposure in male and female collegiate ice hockey players

The purpose of this study was to quantify head impact exposure (frequency, location and magnitude of head impacts) for individual male and female collegiate ice hockey players and to investigate differences in exposure by sex, player position, session type, and team. Ninety-nine (41 male, 58 female) players were enrolled and 37,411 impacts were recorded over three seasons. Frequency of impacts varied significantly by sex (males: 287 per season, females: 170, p<0.001) and helmet impact location (p<0.001), but not by player position (p=0.088). Head impact frequency also varied by session type; both male and female players sustained more impacts in games than in practices (p<0.001), however the magnitude of impacts did not differ between session types. There was no difference in 95th percentile peak linear acceleration between sexes (males: 41.6 g, females: 40.8 g), but 95th percentile peak rotational acceleration and HITsp (a composite severity measure) were greater for males than females (4424, 3409 rad/s², and 25.6, 22.3, respectively). Impacts to the back of the helmet resulted in the greatest 95th percentile peak linear accelerations for males (45.2 g) and females (50.4 g), while impacts to the side and back of the head were associated with the greatest 95th percentile peak rotational accelerations (males: 4719, 4256 rad/sec², females: 3567, 3784 rad/sec² respectively). It has been proposed that reducing an individual's head impact exposure is a practical approach for reducing the risk of brain injuries. Strategies to decrease an individual athlete's exposure need to be sport and gender specific, with considerations for team and session type.     

THE ROLE OF CARBONIC ANHYDRASE IN THE FORMATION OF MOUGEOTIA (CHAROPHYCEAE) BLOOMS IN ACIDIC ENVIRONMENTS

Diatoms and related algae have plastids that are surrounded by four membranes. The outer two membranes are continuous with the endoplasmic reticulum and the inner two membranes are analogous to the plastid envelope membranes of higher plants and green algae. Thus the plastids are completely compartmentalized within the ER membranes. The targeting presequences for nuclear-encoded plastid proteins have two recognizable domains. The first domain is a classic signal sequence, which presumably targets the proteins to the endoplasmic reticulum. The second domain has characteristics of a transit peptide, which targets proteins to the plastids of higher plants. To characterize these targeting domains, the presequence from the nuclear-encoded plastid protein AtpC was utilized. A series of deletions of this presequence were fused to Green Fluorescent Protein (GFP) and transformed into cells of the diatom, Phaeodactylum tricornutum. The intracelluar localization of GFP was visualized by fluorescence microscopy. This work demonstrates that the first domain of the presequence is responsible for targeting proteins to the ER lumen and is the essential first step in the plastid protein import process. The second domain is responsible to directing proteins from the ER and through the plastid envelope and only a short portion of the transit peptide-like domain is necessary to complete this second processing step. In vivo data generated from this study in a fully homologous transformation system has confirmed Gibbs' hypothesis regarding a multistep import process for plastid proteins in chromophytic algae.