Alteration of Soil Rhizosphere Communities following Genetic Transformation of White Spruce

The application of plant genetic manipulations to agriculture and forestry with the aim of alleviating insect damage through Bacillus thuringiensis transformation could lead to a significant reduction in the release of pesticides into the environment. However, many groups have come forward with very valid and important questions related to potentially adverse effects, and it is crucial to assess and better understand the impact that this technology might have on ecosystems. In this study, we analyzed rhizosphere soil samples collected from the first B. thuringiensis-transformed trees [with insertion of the CryIA(b) toxin-encoding gene] grown in Canada (Val-Cartier, QC, Canada) as part of an ecological impact assessment project. Using a robust amplified rRNA gene restriction analysis approach coupled with 16S rRNA gene sequencing, the rhizosphere-inhabiting microbial communities of white spruce (Picea glauca) genetically modified by biolistic insertion of the cryIA(b), uidA (beta-glucuronidase), and nptII genes were compared with the microbial communities associated with non-genetically modified counterparts and with trees in which only the genetic marker genes uidA and nptII have been inserted. Analysis of 1,728 rhizosphere bacterial clones (576 clones per treatment) using a Cramér-von Mises statistic analysis combined with a Monte Carlo comparison clearly indicated that there was a statistically significant difference (P < 0.05) between the microbial communities inhabiting the rhizospheres of trees carrying the cryIA(b), uidA, and nptII transgenes, trees carrying only the uidA and nptII transgenes, and control trees. Clear rhizosphere microbial community alterations due to B. thuringiensis tree genetic modification have to our knowledge never been described previously and open the door to interesting questions related to B. thuringiensis genetic transformation and also to the impact of commonly used uidA and nptII genetic marker genes.     

Neuroprotective Effect of Riboflavin Producing Lactic Acid Bacteria in Parkinsonian Models

Neurochemical Research - Oxidative stress and inflammatory processes might contribute to the cascade of events leading Parkinson disease (PD); and vitamins such as riboflavin can exert protection...     

Neural adaptation facilitates oscillatory responses to static inputs in a recurrent network of ON and OFF cells

We investigate the role of adaptation in a neural field model, composed of ON and OFF cells, with delayed all-to-all recurrent connections. As external spatially profiled inputs drive the network, ON cells receive inputs directly, while OFF cells receive an inverted image of the original signals. Via global and delayed inhibitory connections, these signals can cause the system to enter states of sustained oscillatory activity. We perform a bifurcation analysis of our model to elucidate how neural adaptation influences the ability of the network to exhibit oscillatory activity. We show that slow adaptation encourages input-induced rhythmic states by decreasing the Andronov–Hopf bifurcation threshold. We further determine how the feedback and adaptation together shape the resonant properties of the ON and OFF cell network and how this affects the response to time-periodic input. By introducing an additional frequency in the system, adaptation alters the resonance frequency by shifting the peaks where the response is maximal. We support these results with numerical experiments of the neural field model. Although developed in the context of the circuitry of the electric sense, these results are applicable to any network of spontaneously firing cells with global inhibitory feedback to themselves, in which a fraction of these cells receive external input directly, while the remaining ones receive an inverted version of this input via feedforward di-synaptic inhibition. Thus the results are relevant beyond the many sensory systems where ON and OFF cells are usually identified, and provide the backbone for understanding dynamical network effects of lateral connections and various forms of ON/OFF responses.     

B-group vitamin production by lactic acid bacteria--current knowledge and potential applications

Although most vitamins are present in a variety of foods, human vitamin deficiencies still occur in many countries, mainly because of malnutrition not only as a result of insufficient food intake but also because of unbalanced diets. Even though most lactic acid bacteria (LAB) are auxotrophic for several vitamins, it is now known that certain strains have the capability to synthesize water-soluble vitamins such as those included in the B-group (folates, riboflavin and vitamin B(12) amongst others). This review article will show the current knowledge of vitamin biosynthesis by LAB and show how the proper selection of starter cultures and probiotic strains could be useful in preventing clinical and subclinical vitamin deficiencies. Here, several examples will be presented where vitamin-producing LAB led to the elaboration of novel fermented foods with increased and bioavailable vitamins. In addition, the use of genetic engineering strategies to increase vitamin production or to create novel vitamin-producing strains will also be discussed. This review will show that the use of vitamin-producing LAB could be a cost-effective alternative to current vitamin fortification programmes and be useful in the elaboration of novel vitamin-enriched products.     

Blood Biochemistry of Sea Turtles Captured in Gillnets in the Lower Cape Fear River,North Carolina,USA

ABSTRACT Mortality due to fisheries interactions has been implicated as a contributor to population decline for several species of sea turtle. The incidental capture of sea turtles in the coastal gillnet fisheries of North Carolina, USA, has received much attention in recent years, and mitigation measures to reduce sea turtle mortality due to gillnet entanglement are a high priority for managers and conservationists. Efforts to evaluate effects of gillnet entanglement on sea turtle populations are complicated by the lack of information on health status of turtles released alive from nets and postrelease mortality. We obtained blood samples from green (Chelonia mydas) and Kemp's ridley (Lepidochelys kempii) sea turtles captured in gillnets for 20–240 minutes to assess the impacts of gillnet entanglement on blood biochemistry and physiological status. We measured concentrations of lactate, corticosterone, ions (Na⁺, K⁺, Cl^-, P, Ca²⁺), enzymes (lactate dehydrogenase [LDH], creatine phosphokinase [CPK], aspartate aminotransferase [AST]), protein, and glucose in the blood and also performed physical examinations of turtles to document external indicators of health status (injuries, lethargy, muted reflexes). We evaluated the effects of entanglement time on blood biochemistry and to look for correlations between blood biochemistry and results of the physical examinations. We observed a significant increase in blood lactate, LDH, CPK, phosphorus, and glucose with increased entanglement time. Alterations in blood biochemistry were generally associated with a decline in health status as indicated by results of the physical examination. Although entanglement time plays an important role in determining the health status of sea turtles upon release from a gillnet, our results suggest that factors such as the depth and severity of entanglement may also have an effect on health status of turtles and the probability of postrelease survival. We were unable to set a maximum unattended gillnet soak time to minimize impacts on captured sea turtles, and therefore recommend that fisheries managers continue to enforce the net attendance regulations currently in place in the lower Cape Fear River, North Carolina, during the summer months.     

The Active and the Inactive Form of the hAT1 Receptor Have an Identical Ligand-Binding Environment: An MPA Study on a Constitutively Active Angiotensin II Receptor Mutant

Several models of activation mechanisms were proposed for G protein-coupled receptors (GPCRs), yet no direct methods exist for their elucidation. The availability of constitutively active mutants has given an opportunity to study active receptor conformations within acceptable limits using models such as the angiotensin II type 1 (AT₁)¹ receptor mutant N111G-hAT₁ which displays an important constitutive activity. Recently, by using methionine proximity assay, we showed for the hAT₁ receptor that TMD III, VI, and VII form the ligand-binding pocket of the C-terminal amino acid of an antagonistic AngII analogue. In the present contribution, we investigated whether the same residues would also constitute the ligand-binding contacts in constitutively activated mutant (CAM) receptors. For this purpose, the same Met mutagenesis strategy was carried out on the N111G double mutants. Analysis of 43 receptors mutants in the N111G-hAT₁ series, photolabeled and CNBr digested, showed that there were only subtle structural changes between the wt-receptor and its constitutively active form.     

Adaptive risk group refinement

We construct interpretable prognostic rules based on a sequence of "box-shaped" regions in the predictor space indexed by the fraction of patients in the prognostic group. In addition, the method can be used as a building block to construct more general prognostic rules based on unions of boxes, or even as a tool to find multiple prognostic groups. Simulations are used to study the properties of the new method and compare it to constructing prognostic groups based on regression trees and linear proportional hazards (PH) models. We consider an example based on data from several completed clinical trials for patients with multiple myeloma.     

Synthesis and evaluation of novel dipeptidyl benzoyloxymethyl ketones as caspase inhibitors

We describe novel peptide-based caspase inhibitors. Potent and comparatively selective compounds containing a dipeptide scaffold and a substituted oxymethyl ketone as a warhead were developed. The newly synthesized compounds were tested for inhibition in in vitro enzymatic assays of caspases-1, -3, -6, -8, and -9. The benzyloxycarbonyl-phenylglycyl-aspartyl benzoyloxymethyl ketone (Z-Phg-Asp-CH2OCO-Ph, coded as HU44) was the most potent inhibitor of caspase-1 and caspase-3. Of several analogs of HU44 that were made, the beta-Asp methyl ester (2) is an effective inhibitor against caspase-3 and caspase-8, and less effective against caspase-1. These compounds did not inhibit caspase-6 and caspase-9 significantly.