Growth and temperature‐related phenotypic plasticity in the cyanobacterium Cylindrospermopsis raciborskii

Cylindrospermopsis raciborskii is an invasive and potentially toxic cyanobacterium, which has recently spread worldwide, mainly because of its tolerance to a wide range of climatic conditions. C. raciborskii is able to change several traits in response to environmental changes and its morphology is also affected by these changes (especially in nutrients). We also expected temperature to affect the morphology of this cyanobacterium. We examined the growth and morphology of C. raciborskii at different temperatures and compared laboratory results to the morphology of this cyanobacterium in situ. As expected, growth rates increased with temperature. In addition, a high carrying capacity at 32°C suggests that this cyanobacterium is able to form more dense blooms at high temperatures. Fragile trichomes and low growth rates were observed at 12°C. An increase in the growth rate related to temperature resulted in a decrease in trichome length, with shorter trichomes at 32°C. The same pattern was observed in wild populations of C. raciborskii in a tropical reservoir, where shorter trichomes were observed in warmer months, when biomass was highest. This species' high ability to adapt to different environmental conditions throughout the year (i.e., nutrients, temperature) may have provided it with an additional advantage to increase its perennial blooms, mainly in tropical regions.     

Effect of long-term water immersion on the fracture toughness of denture base and reline resins

doi: 10.1111/j.1741‐2358.2011.00573.x
Effect of long‐term water immersion on the fracture toughness of denture base and reline resins purpose: This study evaluated the fracture toughness (FT) of one denture base (Lucitone 550 – L) and four hard reline resins [Ufi Gel Hard (UH), Tokuyama Rebase II (TR), New Truliner (NT) and Kooliner (K)], and the effect of long‐term water storage on this property. Materials and methods: Forty specimens (40 × 8 × 4 mm) of each material were made, and FT was assessed after polymerisation (control of reliners), after 48 ± 2 h in water at 37°C (control of denture base resin) and after storage in water at 37°C for 7, 90 or 180 days (all materials). Data (MPa.m^1/2) were analysed by two‐way anova and Games–Howell test (p = 0.05). Results: Resin L exhibited the highest FT mean values. After 180 days of storage, FT mean values of L (3.37), UH (1.53) and K (1.20) were higher than those of the other periods. FT mean values of NT decreased from control (1.63) to 7 days (1.30) and then remained constant. FT mean values of TR (1.13) were similar in all periods of analysis. Conclusion: The denture base resin L showed higher FT mean values than the reline resins. Long‐term water storage increased the FT of L, UH and K, reduced the FT of NT and did not influence the FT of TR.     

Molecular confinement of human amylin in lipidic nanoparticles

Amylin is a pancreatic hormone involved in the regulation of glucose metabolism and homeostasis. Restoration of the post-prandial and basal levels of human amylin in diabetic individuals is a key in controlling glycemia, controlling glucagon, reducing the insulin dose and increasing satiety, among other physiologic functions. Human amylin has a high propensity to aggregate. We have addressed this issue by designing a liposomal human amylin formulation. Nanoparticles of multilamellar liposomes comprising human amylin were obtained with 53% encapsulation efficiency. The in vitro kinetic release assay shows a biphasic profile. The stabilization of the lipidic nanoparticle against freeze-drying was achieved by using mannitol as a cryoprotectant, as evidenced by morphological characterization. The effectiveness of the human amylin entrapped in lipidic nanoparticles was tested by the measurement of its pharmacological effect in vivo after subcutaneous administration in mice. Collectively these results demonstrate the compatibility of human amylin with the lipidic interface as an effective pharmaceutical delivery system.     

Glutamate Uptake Is Stimulated by Extracellular S100B in Hippocampal Astrocytes

Summary  

Central Coherence in Eating Disorders: A Synthesis of Studies Using the Rey Osterrieth Complex Figure Test

BackgroundLarge variability in tests and differences in scoring systems used to study central coherence in eating disorders may lead to different interpretations, inconsistent findings and between study discrepancies. This study aimed to address inconsistencies by collating data from several studies from the same research group that used the Rey Osterrieth Complex Figure Test (Rey Figure) in order to produce norms to provide benchmark data for future studies.MethodData was collated from 984 participants in total. Anorexia Nervosa, Bulimia Nervosa, recovered Anorexia Nervosa, unaffected family members and healthy controls were compared using the Rey Figure.ResultsPoor global processing was observed across all current eating disorder sub-groups and in unaffected relatives. There was no difference in performance between recovered AN and HC groups.ConclusionsThis is the largest dataset reported in the literature and supports previous studies implicating poor global processing across eating disorders using the Rey Figure. It provides robust normative data useful for future studies.     

Impact of long‐term chromosomal shuffling on the multispecies coalescent analysis of two anthropoid primate lineages

Multispecies coalescent (MSC) theory assumes that gene trees inferred from individual loci are independent trials of the MSC process. As genes might be physically close in syntenic associations spanning along chromosome regions, these assumptions might be flawed in evolutionary lineages with substantial karyotypic shuffling. Neotropical primates (NP) represent an ideal case for assessing the performance of MSC methods in such scenarios because chromosome diploid number varies significantly in this lineage. To this end, we investigated the effect of sequence length on the theoretical expectations of MSC model, as well as the results of coalescent‐based tree inference methods. This was carried out by comparing NP with hominids, a lineage in which chromosome macrostructure has been stable for at least 15 million years. We found that departure from the MSC model in Neotropical primates decreased with smaller sequence fragments, where sites sharing the same evolutionary history were more frequently found than in longer fragments. This scenario probably resulted from extensive karyotypic rearrangement occurring during the radiation of NP, contrary to the comparatively stable chromosome evolution in hominids.     

Cyanobacterial dominance in Brazil: distribution and environmental preferences

Based on a literature survey, we evaluated the periods of cyanobacterial dominance in Brazil. We hypothesized that variability of environmental forces along the country will promote or facilitate temporal and spatial mosaic in cyanobacterial dominance. The most striking outcomes are related to the dominance of Cylindrospermopsis, Dolichospermum, and Microcystis. Although they share important adaptive strategies (e.g., aerotopes, large size and toxins production), our findings suggest that they have different environmental preferences. Dolichospermum and Microcystis dominated mainly in warm-rainy periods whereas Cylindrospermopsis was more common during dry periods and in mixed systems, or formed perennial dominance. Maximum phosphorus concentrations were observed in reservoirs dominated by Cylindrospermopsis. Although the main genera reached high biomass levels individually, different abilities to form dominance and co-dominance were observed. The number of co-dominance of Chroococales and Nostocales was almost the same as the individual occurrence of the main genera from these groups. This dataset reveals patterns of dominance of these cyanobacteria and also indicates that physiological features will cause differences in the mechanisms of interactions between species. The understanding of these processes and their relationship to environmental conditions will promote better understanding of cyanobacterial dominance and increase our ability to predict and manage these events.     

In Silico Repositioning-Chemogenomics Strategy Identifies New Drugs with Potential Activity against Multiple Life Stages of Schistosoma mansoni

Morbidity and mortality caused by schistosomiasis are serious public health problems in developing countries. Because praziquantel is the only drug in therapeutic use, the risk of drug resistance is a concern. In the search for new schistosomicidal drugs, we performed a target-based chemogenomics screen of a dataset of 2,114 proteins to identify drugs that are approved for clinical use in humans that may be active against multiple life stages of Schistosoma mansoni. Each of these proteins was treated as a potential drug target, and its amino acid sequence was used to interrogate three databases: Therapeutic Target Database (TTD), DrugBank and STITCH. Predicted drug-target interactions were refined using a combination of approaches, including pairwise alignment, conservation state of functional regions and chemical space analysis. To validate our strategy, several drugs previously shown to be active against Schistosoma species were correctly predicted, such as clonazepam, auranofin, nifedipine, and artesunate. We were also able to identify 115 drugs that have not yet been experimentally tested against schistosomes and that require further assessment. Some examples are aprindine, gentamicin, clotrimazole, tetrabenazine, griseofulvin, and cinnarizine. In conclusion, we have developed a systematic and focused computer-aided approach to propose approved drugs that may warrant testing and/or serve as lead compounds for the design of new drugs against schistosomes.