26 research outputs found
The Effects of Larval Nutrition on Reproductive Performance in a Food-Limited Adult Environment
It is often assumed that larval food stress reduces lifetime fitness regardless
of the conditions subsequently faced by adults. However, according to the
environment-matching hypothesis, a plastic developmental response to poor
nutrition results in an adult phenotype that is better adapted to restricted
food conditions than one having developed in high food conditions. Such a
strategy might evolve when current conditions are a reliable predictor of future
conditions. To test this hypothesis, we assessed the effects of larval food
conditions (low, improving and high food) on reproductive fitness in both low
and high food adults environments. Contrary to this hypothesis, we found no
evidence that food restriction in larval ladybird beetles produced adults that
were better suited to continuing food stress. In fact, reproductive rate was
invariably lower in females that were reared at low food, regardless of whether
adults were well fed or food stressed. Juveniles that encountered improving
conditions during the larval stage compensated for delayed growth by
accelerating subsequent growth, and thus showed no evidence of a reduced
reproductive rate. However, these same individuals lost more mass during the
period of starvation in adults, which indicates that accelerated growth results
in an increased risk of starvation during subsequent periods of food stress
BioSimulators: a central registry of simulation engines and services for recommending specific tools
Computational models have great potential to accelerate bioscience, bioengineering, and medicine. However, it remains challenging to reproduce and reuse simulations, in part, because the numerous formats and methods for simulating various subsystems and scales remain siloed by different software tools. For example, each tool must be executed through a distinct interface. To help investigators find and use simulation tools, we developed BioSimulators (https://biosimulators.org), a central registry of the capabilities of simulation tools and consistent Python, command-line and containerized interfaces to each version of each tool. The foundation of BioSimulators is standards, such as CellML, SBML, SED-ML and the COMBINE archive format, and validation tools for simulation projects and simulation tools that ensure these standards are used consistently. To help modelers find tools for particular projects, we have also used the registry to develop recommendation services. We anticipate that BioSimulators will help modelers exchange, reproduce, and combine simulations
Highly Efficient Computation of the Basal <i>k</i><sub><i>on</i></sub> using Direct Simulation of Protein–Protein Association with Flexible Molecular Models
An essential baseline for determining
the extent to which electrostatic
interactions enhance the kinetics of protein–protein association
is the “basal” <i>k</i><sub><i>on</i></sub>, which is the rate constant for association in the absence
of electrostatic interactions. However, since such association events
are beyond the milliseconds time scale, it has not been practical
to compute the basal <i>k</i><sub><i>on</i></sub> by directly simulating the association with flexible models. Here,
we computed the basal <i>k</i><sub><i>on</i></sub> for barnase and barstar, two of the most rapidly associating proteins,
using highly efficient, flexible molecular simulations. These simulations
involved (a) pseudoatomic protein models that reproduce the molecular
shapes, electrostatic, and diffusion properties of all-atom models,
and (b) application of the weighted ensemble path sampling strategy,
which enhanced the efficiency of generating association events by
>130-fold. We also examined the extent to which the computed basal <i>k</i><sub><i>on</i></sub> is affected by inclusion
of intermolecular hydrodynamic interactions in the simulations
Is low level laser therapy or ozone therapy more effective for bone healing? Understanding the mechanisms of HIF-1 alpha, RANKL and OPG
Periodontitis is a common chronic infection of dental tissues. Ozone therapy (OT) and low level laser therapy (LLLT) are useful treatments for periodontitis. We investigated the effects of OT and LLLT on periodontal disease-induced bone destruction in rats with experimentally induced periodontitis (EP). We used 30 male Wistar rats divided into three groups: control, OT and LLLT. EP was induced by placing a 3.0 silk suture around the cervix of the left mandibular first molar tooth. OT was performed using an ozone generator at 80% concentration. LLLT was applied using a diode laser. Both OT and LLLT were performed for two weeks at two day intervals. Histomorphometric and immunohistochemical analyses also were performed. Alveolar bone loss was significantly less in the LLLT group compared to the control group. The number of HIF-1 alpha positive cells was significantly less in the LLLT group compared to the control group. We found significantly fewer RANKL-positive cells in the OT group compared to the control group. The number of osteoprotegerin (OPG) positive cells was significantly greater for the LLLT group than for the control group. Although both treatments produced positive effects, LLLT appears to be more effective for increasing alveolar bone formation
Art. 110
The
first synthesis of all five possible monomethylated [4]Âdendralenes
has been achieved via two distinct synthetic strategies. The Diels–Alder
chemistry of these new dendralenes (as multidienes) with an electron
poor dienophile, <i>N</i>-methylmaleimide (NMM), has been
studied. Thus, simply upon mixing the dendralene and an excess of
dienophile at ambient temperature in a common solvent, sequences of
cycloadditions result in the rapid generation of complex multicyclic
products. Distinct product distributions are obtained with differently
substituted dendralenes, demonstrating that dendralene substitution
influences the pathway followed, when a matrix of mechanistic possibilities
exists. Dendralene site selectivities are traced to electronic, steric
and conformational effects, thereby allowing predictive tools for
applications of substituted dendralenes in future synthetic endeavors
The Evolutionary Basis of Premature Migration in Pacific Salmon Highlights the Utility of Genomics for Informing Conservation
Accounting for specific alleles can be necessary to prevent the loss of significant biodiversity and ecosystem services., The delineation of conservation units (CUs) is a challenging issue that has profound implications for minimizing the loss of biodiversity and ecosystem services. CU delineation typically seeks to prioritize evolutionary significance, and genetic methods play a pivotal role in the delineation process by quantifying overall differentiation between populations. Although CUs that primarily reflect overall genetic differentiation do protect adaptive differences between distant populations, they do not necessarily protect adaptive variation within highly connected populations. Advances in genomic methodology facilitate the characterization of adaptive genetic variation, but the potential utility of this information for CU delineation is unclear. We use genomic methods to investigate the evolutionary basis of premature migration in Pacific salmon, a complex behavioral and physiological phenotype that exists within highly connected populations and has experienced severe declines. Strikingly, we find that premature migration is associated with the same single locus across multiple populations in each of two different species. Patterns of variation at this locus suggest that the premature migration alleles arose from a single evolutionary event within each species and were subsequently spread to distant populations through straying and positive selection. Our results reveal that complex adaptive variation can depend on rare mutational events at a single locus, demonstrate that CUs reflecting overall genetic differentiation can fail to protect evolutionarily significant variation that has substantial ecological and societal benefits, and suggest that a supplemental framework for protecting specific adaptive variation will sometimes be necessary to prevent the loss of significant biodiversity and ecosystem services.PubMedWoSScopu