Temperature can play an important role in determining the feeding preferences of ectotherms. In light of the warmer temperatures arising with the current climatic changes, omnivorous ectotherms may ...perform diet shifts toward higher herbivory to optimize energetic intake. Such diet shifts may also occur during heat waves, which are projected to become more frequent, intense, and longer lasting in the future. Here, we investigated how heat waves of different duration affect feeding preferences in omnivorous anuran tadpoles and how these choices affect larval life history. In laboratory experiments, we fed tadpoles of three species on animal, plant, or mixed diet and exposed them to short heat waves (similar to the heat waves these species experience currently) or long heat waves (predicted to increase under climate change). We estimated the dietary choices of tadpoles fed on the mixed diet using stable isotopes and recorded tadpole survival and growth, larval period, and mass at metamorphosis. Tadpole feeding preferences were associated with their thermal background, with herbivory increasing with breeding temperature in nature. Patterns in survival, growth, and development generally support decreased efficiency of carnivorous diets and increased efficiency or higher relative quality of herbivorous diets at higher temperatures. All three species increased herbivory in at least one of the heat wave treatments, but the responses varied among species. Diet shifts toward higher herbivory were maladaptive in one species, but beneficial in the other two. Higher herbivory in omnivorous ectotherms under warmer temperatures may impact species differently and further contribute to changes in the structure and function of freshwater environments.
Background
Depigmentation of the substantia nigra (SN) and locus coeruleus (LC) is a conspicuous pathological feature of Parkinson's disease (PD) and is related to the loss of neuromelanin, whose ...paramagnetic properties result in high signal on specific T1‐weighted magnetic resonance imaging (MRI). Recent studies have suggested that neuromelanin decrease in the SN and LC of PD patients may emerge as a possible diagnostic biomarker. The SN neuromelanin signal in de novo and early stage PD patients was studied to assess its diagnostic accuracy. This is the first study based on a semi‐automated MRI analysis of the neuromelanin signal in de novo PD patients.
Methods
The inclusion criteria were untreated de novo PD and a 2–5 year disease duration; in addition, age matched healthy controls were enrolled. These were studied with a high‐resolution T1‐weighted MRI sequence at 3 T to visualize neuromelanin. The primary outcome was SN high signal area, length and neuromelanin/midbrain ratio obtained with semi‐automated methods.
Results
A total of 12 de novo PD patients and 10 PD patients with a 2–5 year disease duration were evaluated. The area, length of the SN T1 high signal and the SN neuromelanin/midbrain ratio were markedly decreased in the PD groups compared with age‐matched controls, with a substantial overlap between the two PD groups.
Conclusions
Neuromelanin‐sensitive MRI techniques can discriminate PD patients from healthy individuals with high sensitivity and specificity. Our findings are consistent with recent findings showing that PD neuromelanin changes remain stable during the course of the disease.
Abstract
This study assessed the diversity and distribution of filamentous fungi obtained from water sampled from six lakes in the Antarctic Peninsula. One hundred and twenty-eight fungal isolates ...were purified and identified by analysis of nuclear rDNA ITS region sequences as belonging to 31 fungal different operational taxonomic units (OTUs). The most frequently isolated fungi were Geomyces pannorum and Mortierella sp.; these species occurred in six and three of the lakes sampled, respectively, and displayed the highest total colony-forming unit per L. Different species that have not been found to these lakes and/or had adapted to cold conditions were found. In general, the fungal community displayed low richness and high dominance indices. The species Cadophora cf. luteo-olivacea, Cadophora malorum, Davidiella tassiana, G. pannorum, Mortierella cf. alpina and Thelebolus cf. microsporus that were found in the lakes in question were also previously found in other cold ecosystems, such as Arctic, temperate and Alpine regions. The results of this study suggest the presence of an interesting aquatic fungal web, including symbionts, weak and strong saprophytes and parasite/pathogen fungal species. This aquatic web fungal may be a useful community model for further ecological and evolutionary studies of extreme habitats.
Background and purpose
Magnetic resonance (MR) studies have demonstrated a significant reduction of neuromelanin in the substantia nigra (SN) of Parkinson's disease (PD) patients with high accuracy ...for differential diagnosis compared to non‐PD controls and essential tremor. However, studies state that not knowing how paramagnetic effects of iron influence neuromelanin signal is a limitation. In this study a neuromelanin‐sensitive MR sequence was combined with T2* relaxometry iron quantification analysis to study the SN of early‐stage PD patients to investigate the correlation between these parameters.
Methods
The inclusion criteria were untreated de novo PD patients and a 2–5 year disease duration (early PD); in addition, age‐matched controls were enrolled. These were studied at 3.0 T with a high‐resolution T1‐weighted MR sequence to visualize neuromelanin and a relaxometry sequence for iron quantification. The primary outcome was the correlation of the width of the neuromelanin high signal region and the T2* values in the lateral, central and medial segments of the SN.
Results
Very weak correlations of T2* values with neuromelanin width, positive for global and negative for the medial and lateral SN segments, were found in both PD groups and control subjects. The SN neuromelanin width was markedly reduced in the de novo and early PD groups compared with controls in all SN segments, but no significant difference in T2* values was found between the groups.
Conclusions
The SN neuromelanin signal does not have a significant correlation with iron content in PD patients or controls. The neuromelanin MR signal reduction in PD does not seem to be significantly influenced by paramagnetic iron effects.
Monitoring cell viability is critical in cell biology, pathology, and drug discovery. Most cell viability assays are cell-destructive, time-consuming, expensive, and/or hazardous. Herein, we present ...a series of newly synthesized 2,4,5-triaminopyrimidine derivatives able to discriminate between live and dead cells. To our knowledge, these compounds are the first fluorescent nucleobase analogues (FNAs) with cell viability monitoring potential. These new fluorescent molecules are synthesized using highly efficient and cost-effective methods and feature unprecedented photophysical properties (longer absorption and emission wavelengths, environment-sensitive emission, and unprecedented brightness within FNAs). Using a live-dead
Saccharomyces cerevisiae
cell and theoretical assays, the fluorescent 2,4,5-triaminopyrimidine derivatives were found to specifically accumulate inside dead cells by interacting with dsDNA grooves, thus paving the way for the emergence of novel and safe fluorescent cell viability markers emitting in the blue region. As the majority of commercially available viability dyes emit in the green to red region of the visible spectrum, these novel markers might be useful to meet the needs of blue markers for co-staining combinations.
Novel and efficient synthesis of 2,4,5-triaminopyrimidines featuring blue-cyan emission whose biological and computational evaluation highlights cell viability monitoring potential.
The extension of the Hager–Zhang (HZ) nonlinear conjugate gradient method for vector optimization is discussed in the present research. In the scalar minimization case, this method generates descent ...directions whenever, for example, the line search satisfies the standard Wolfe conditions. We first show that, in general, the direct extension of the HZ method for vector optimization does not yield descent (in the vector sense) even when an exact line search is employed. By using a sufficiently accurate line search, we then propose a self-adjusting HZ method which possesses the descent property. The proposed HZ method with suitable parameters reduces to the classical one in the scalar minimization case. Global convergence of the new scheme is proved without regular restarts and any convex assumption. Finally, numerical experiments illustrating the practical behavior of the approach are presented, and comparisons with the Hestenes–Stiefel conjugate gradient and the steepest descent methods are discussed.
Abstract
Sphenoid wing meningiomas are benign tumors that can result in proptosis, visual impairment, and pain. Traditional open surgical approaches are associated with significant morbidity. ...Transorbital endoscopic surgery has been developed as a minimally invasive approach to gain access to these tumors and address the main presenting symptoms. Case series reporting transorbital endoscopic resection of sphenoid wing meningiomas using combined endonasal, pre-caruncular, and extended superior eyelid approaches have demonstrated stable and/or improved short- and medium-term visual outcomes. Earlier medial optic nerve decompression appears to result in more favorable long-term visual outcomes. Transorbital endoscopic surgery therefore represents an emerging minimally invasive alternative to deal with these challenging lesions.
We provide a global overview of the intestinal bacteriome of
in two rearing systems and after an oral challenge by the White spot syndrome virus (WSSV). By using a high-throughput 16S rRNA gene ...sequencing technology, we identified and compared the composition and abundance of bacterial communities from the midgut of shrimp reared in the super-intensive biofloc technology (BFT) and clear seawater system (CWS). The predominant bacterial group belonged to the phylum Proteobacteria, followed by the phyla Bacteroidetes, Actinobacteria, and Firmicutes. Within Proteobacteria, the family Vibrionaceae, which includes opportunistic shrimp pathogens, was more abundant in CWS than in BFT-reared shrimp. Whereas the families Rhodobacteraceae and Enterobacteriaceae accounted for almost 20% of the bacterial communities of shrimp cultured in BFT, they corresponded to less than 3% in CWS-reared animals. Interestingly, the WSSV challenge dramatically changed the bacterial communities in terms of composition and abundance in comparison to its related unchallenged group. Proteobacteria remained the dominant phylum. Vibrionaceae was the most affected in BFT-reared shrimp (from 11.35 to 20.80%). By contrast, in CWS-reared animals the abundance of this family decreased from 68.23 to 23.38%. Our results provide new evidence on the influence of both abiotic and biotic factors on the gut bacteriome of aquatic species of commercial interest.
We show that the nanoparticle sizes calculated from the X-ray powder diffraction need to be analyzed more carefully when calculated by the Scherrer equation. When nanoparticles are not perfect ...crystals, microstrain contributes to the line broadening of diffraction peaks. This additional width of the diffraction peak can introduce a wrong estimate to the nanoparticle size. In this work, we show how to calculate directly the size and the microstrain for NiO nanoparticles using the Williamson–Hall plotting and compare with results obtained from the Scherrer equation. In additional to these results is that the straight line obtained in the Williamson–Hall plotting shows the homogeneity of the nanoparticles.
► NiO nanoparticles synthesized and characterized by X-ray powder diffraction. ► Particle size calculated by Scherrer and Williamson–Hall. ► Williamson–Hall plotting provides a more completely analysis of XRPD.
Machado-Joseph disease is the most frequently found dominantly-inherited cerebellar ataxia. Over-repetition of a CAG trinucleotide in the MJD1 gene translates into a polyglutamine tract within the ...ataxin 3 protein, which upon proteolysis may trigger Machado-Joseph disease. We investigated the role of calpains in the generation of toxic ataxin 3 fragments and pathogenesis of Machado-Joseph disease. For this purpose, we inhibited calpain activity in mouse models of Machado-Joseph disease by overexpressing the endogenous calpain-inhibitor calpastatin. Calpain blockage reduced the size and number of mutant ataxin 3 inclusions, neuronal dysfunction and neurodegeneration. By reducing fragmentation of ataxin 3, calpastatin overexpression modified the subcellular localization of mutant ataxin 3 restraining the protein in the cytoplasm, reducing aggregation and nuclear toxicity and overcoming calpastatin depletion observed upon mutant ataxin 3 expression. Our findings are the first in vivo proof that mutant ataxin 3 proteolysis by calpains mediates its translocation to the nucleus, aggregation and toxicity and that inhibition of calpains may provide an effective therapy for Machado-Joseph disease.
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