Ultimate Use of Two-Photon Fluorescence Microscopy to Map Orientational Behavior of Fluorophores

The orientational distribution of fluorophores is an important reporter of the structure and function of their molecular environment. Although this distribution affects the fluorescence signal under polarized-light excitation, its retrieval is limited to a small number of parameters. Because of this limitation, the need for a geometrical model (cone, Gaussian, etc.) to effect such retrieval is often invoked. In this work, using a symmetry decomposition of the distribution function of the fluorescent molecules, we show that polarized two-photon fluorescence based on tunable linear dichroism allows for the retrieval of this distribution with reasonable fidelity and without invoking either an a priori knowledge of the system to be investigated or a geometrical model. We establish the optimal level of detail to which any distribution can be retrieved using this technique. As applied to artificial lipid vesicles and cell membranes, the ability of this method to identify and quantify specific structural properties that complement the more traditional molecular-order information is demonstrated. In particular, we analyze situations that give access to the sharpness of the angular constraint, and to the evidence of an isotropic population of fluorophores within the focal volume encompassing the membrane. Moreover, this technique has the potential to address complex situations such as the distribution of a tethered membrane protein label in an ordered environment.     

Extinction of herbivorous dinosaurs linked to Early Jurassic global warming event

Sauropods, the giant long-necked dinosaurs, became the dominant group of large herbivores in terrestrial ecosystems after multiple related lineages became extinct towards the end of the Early Jurassic (190–174 Ma). The causes and precise timing of this key faunal change, as well as the origin of eusauropods (true sauropods), have remained ambiguous mainly due to the scarce dinosaurian fossil record of this time. The terrestrial sedimentary successions of the Cañadón Asfalto Basin in central Patagonia (Argentina) document this critical interval of dinosaur evolution. Here, we report a new dinosaur with a nearly complete skull that is the oldest eusauropod known to date and provide high-precision U–Pb geochronology that constrains in time the rise of eusauropods in Patagonia. We show that eusauropod dominance was established after a massive magmatic event impacting southern Gondwana (180–184 Ma) and coincided with severe perturbations to the climate and a drastic decrease in the floral diversity characterized by the rise of conifers with small scaly leaves. Floral and faunal records from other regions suggest these were global changes that impacted the terrestrial ecosystems during the Toarcian warming event and formed part of a second-order mass extinction event.     

Independent effects of jasmonates and ethylene on inhibition of <Emphasis Type="Italic">Pharbitis nil</Emphasis> flowering

Interactions between methyl jasmonate (JA-Me) and ethylene in the photoperiodic flower induction of short-day plant Pharbitis nil were investigated. Both JA-Me and gaseous ethylene applied during the inductive long night caused a decrease in the number of flower buds generated by P. nil. Application of ethylene did not affected niether the level of endogenous jasmonates in the cotyledons during the 16 h long inductive night, nor the inhibitory effect of JA-Me on the flowering of P. nil accompanied by variations in ethylene production. The application of acetylsalicylic acid (aspirin)—a jasmonate biosynthesis inhibitor—slightly stimulated flowering. Our results have shown that the mechanisms of P. nil flower inhibition by jasmonates and ethylene are independent.     

Glioma 2021 WHO Classification: The Superiority of NGS Over IHC in Routine Diagnostics

Molecular Diagnosis & Therapy - The accurate detection of genetic variants such as single substitutions (IDH1/2, TERT), chromosomal abnormalities (CDKN2A, 1p/19q deletions, and EGFR...     

Floral resources and hummingbirds on an island of flooded forest in Central Brazil

Nectar availability for hummingbirds was studied for two and a half years in an island of flooded forest in Uberlândia, MG, in the Cerrado region, the Neotropical savanna areas in Central Brazil. Flowering individuals of ten plant species from eight families that offered resources potentially used by hummingbirds were recorded along transects crisscrossing the area, which were surveyed every other week. The number of flowers was estimated for each plant. The volume and concentration of nectar were measured for a sample of flowers of each species, and the data were used to estimate the caloric content available per flower and the general resource availability in the area throughout the study period. Focal observations of hummingbird visits were carried out on blooming individuals of all plant species. Hummingbird flowers occurred throughout the study period between January 2001 and June 2003. Only three of the studied plants did not present clear ornithophilous features. Six hummingbird species were recorded in the area, but total nectar availability in the area was seldom sufficient for the daily energy requirements of a single bird. Therefore, it can be inferred from the study that these hummingbirds need to move among the mosaic of different plant physiognomies in the region in order to obtain enough energy for their survival. These movements may also contribute to increasing gene flow and regeneration of plant populations isolated in forest patches as the one studied here.     

Using RAD seq for reconstructing phylogenies of highly diverged taxa: A test using the tribe Scandiceae (Apiaceae)

The angiosperm Apiaceae tribe Scandiceae includes four major clades—subtribes Daucinae, Ferulinae, Torilidinae, and Scandicinae—that originated ca. 20 Mya. Although all four subtribes are highly supported in molecular analyses, and morphological data indicate a sister relationship between Daucinae and Torilidinae, their branching order has not been resolved using standard Sanger multilocus data. Therefore, in this study, we test the utility of genomic RAD seq data in resolving deep phylogenetic relationships (up to 20 Mya) in Apiaceae subfamily Apioideae, with special emphasis on tribe Scandiceae using 12 representative species. We used two bioinformatic pipelines, pyRAD and RADIS (based on STACKS), to assemble RAD seq data and we tested the influence of various combinations of parameters on the robustness of the inferred tree topologies. Although different data processing approaches produced alignments with various amounts of missing data, they converged to two well‐supported topologies, irrespective of the phylogenetic method applied. Highly supported trees showed Scandicinae as sister to all other clades and indicated that Daucinae and Torilidinae are sister groups, thus confirming the relationship inferred from morphology. We conclude that the RAD seq method can be successfully used to resolve deep relationships formed 20 Mya within Apiaceae. We provide recommendations for parameter settings in RADIS and pyRAD for the analysis of taxa that have accumulated considerable genomic divergence.     

Correlation between the concentrations of lactoferrin and neutrophil gelatinase-associated lipocalin in meconium

Neutrophil gelatinase-associated lipocalin (NGAL) and lactoferrin (Lf) are among the key components of the innate immune system due to their ability to bind iron with high affinity and thus control inflammation. The aim of this study was to test the use of NGAL and LF measurements in meconium for the assessment of the intrauterine homeostasis. NGAL and Lf concentrations were measured using ELISA kits in all serial meconium portions (n = 81) collected from 20 healthy neonates. Mean ± SD meconium concentration of Lf was 45.07 ± 78.53 µg/g and more than 1000-fold higher compared with that of NGAL at 1.93 ± 2.46 ng/g. The correlation between the two proteins (r = 0.83, p < 0.0001) was found only for portions with Lf concentrations > 25 μg/g. High variability of NGAL and Lf concentrations in meconium and their correlations prove their key role as biomarkers of the fetal condition in utero. NGAL and Lf measured in meconium are candidate biomarkers for fetal iron status.     

Translation of an esophagus histopathological FT‐IR imaging model to a fast quantum cascade laser modality

The technical progress in fast quantum cascade laser (QCL) microscopy offers a platform where chemical imaging becomes feasible for clinical diagnostics. QCL systems allow the integration of previously developed FT‐IR‐based pathology recognition models in a faster workflow. The translation of such models requires a systematic approach, focusing only on the spectral frequencies that carry crucial information for discrimination of pathologic features. In this study, we optimize an FT‐IR‐based histopathological method for esophageal cancer detection to work with a QCL system. We explore whether the classifier's performance is affected by paraffin presence from tissue blocks compared to removing it chemically. Working with paraffin‐embedded samples reduces preprocessing time in the lab and allows samples to be archived after analysis. Moreover, we test, whether the creation of a QCL model requires a preestablished FTIR model or can be optimized using solely QCL measurements.