Climate signal strength in tree-ring width of spruce growing in the Solovetsky Islands (Russia)

In this study we used 14 spruce tree-ring width local chronologies from sites that are located in different landscape conditions. The climatic response function for the entire period (116 years) shows that all local chronologies without exception have a positive relationship with June temperature (from 0.196 to 0.408) despite quite different local environmental conditions. This finding allowed us to combine all tree-ring width local chronologies into a composite spruce chronology covering the period of 1676–2016 CE with EPS exceeding the 0.85 threshold. The composite chronology was scaled against June air temperatures (CRU TS 4.01) in order to reconstruct it. Monthly air temperature records from the Arkhangelsk weather station were used as an additional source to validate tree-ring based June temperature reconstruction. It is quite remarkable that our reconstruction matches the Archangelsk records not only in the 20th-early 21st centuries but also in the 19th century, confirming the reliability of the reconstruction over more than two centuries. We also used daily records from the nearest Kem’-Port station to identify a more precise target-window. Current research shows that the spruce response to daily temperature is not limited by June, but also extends up to almost half of July. The warmest reconstructed year occurred in 1856 as confirmed by the data published in the local chronicle. The cooling recorded in the historical evidences (describing extremely severe ice conditions in the Arctic seas during the Great Northern Expedition (1733–1743)) was not corroborated by our reconstruction. In the study, we discuss the reasons of the discrepancies found between Solovki June temperature reconstructions and other data such as different seasonality of the compared records, real local climate warming in Solovki, the applied standardization technique, and low of chronologies’ replication. The most reliable part of the reconstruction part lasting from the early 19th to the early 21st centuries is also discussed in terms of its properties like wavelength analyses, and the assessment of influence of volcanic eruptions.     

Variation in mandible shape and body size of house mice Mus musculus in five separate New Zealand forest habitats

This study investigates variation in house mouse Mus musculus body size and mandible shape across New Zealand, using geometric morphometrics and biomechanical advantage analyses. The Mus phylogroups currently known in New Zealand include Mus musculus domesticus, M. m. musculus and M. m. castaneus. We examined samples of house mice inhabiting five different podocarp and beech forest environments across the North and South Islands (Pureora Forest, Zealandia Wildlife Sanctuary, Craigieburn Forest Park, Eglinton Valley and Hollyford Valley). Significant variation in mandible shape and body size was found between all five forest populations. South Island mice had larger bodies and greater mechanical advantage in the temporalis muscle compared with their North Island counterparts. Zealandia Sanctuary mouse mandibles were broader and shorter than South Island mouse mandibles, and had greater masseter muscle advantage. Centroid size and body weight, but not head-body length, varied significantly with two distinct genetic haplotypes. Finally, annual rainfall was the most significant covariate with mandible shape. Higher rainfall locations were generally associated with soft-food related mandible shapes, while lower rainfall correlated with hard-food mandible shapes. This preliminary investigation provides the framework for further research into mandible shape and body size variation in New Zealand house mice.     

Amperometric measurements of catecholamine release from single vesicles in MN9D cells

MN9D cells have been used as a successful model to investigate dopamine pharmacology and to test the specific effects of drugs for the treatment of Parkinson’s disease. However, quantitative measurements of quantal release from these cells have not been carried out. In this work, we used amperometry to investigate catecholamine release from MN9D cells. Amperometric events were observed in both undifferentiated and differentiated (butyric acid‐treated) cells. An increase in quantal size and half‐width was observed for differentiated cells versus undifferentiated cells; however, the number of events per cell and the amplitude remained constant. In transmission electron microscopy images, no obvious cluster of small synaptic vesicles was observed, and large dense‐core vesicles were present in the cell body of undifferentiated cells; however, after differentiation, vesicles were concentrated in the cell processes. In differentiated cells, l ‐DOPA caused an increase in quantal size and half‐width, which could be blocked by the vesicular monoamine transporter inhibitor, reserpine.     

Dendroclimatic signals in the pine and spruce chronologies in the Solovetsky Archipelago

Searching for a robust tree-ring parameter useful for paleoclimatic purposes is one of the most demanding topics in the modern paleoscience. Since Blue Intensity has already expressed itself in different geographical locations all over the world as a possible replacement for maximum density, close attention is paid to investigate features of the inferred signal. The Solovki Islands is a unique location in Northern Russia where two important factors that make this territory attractive for developing a long tree-ring chronology have been met: modern long-living trees and building activities using old trees that were started by monks in the middle of the 16th century. The main goal of the research is to develop pine and spruce chronologies based on tree-ring width (TRW) and delta Blue Intensity (dBI) and to assess the ability of these parameters to be used as climate predictors. As a result, 14 conifer chronologies from 7 sites (4 for pine and 3 for spruce) were developed. The composite pine and spruce chronologies span a period of 474 and 378 years each. Cross-correlation of dBI-based chronologies of both conifers is high (r = up to 0.71 while for TRW-based chronologies it is lower on average (−0.18 to 0.63). Intra-species correlation of TRW chronologies in some cases achieved even negative values (r = −0.18. Discrepancies found between TRW chronologies of pine and spruce could be explained by differences in climatic signals. Response function analysis with monthly temperatures revealed that growth of pine depends on the previous August, while spruce has a temporally stable and strong relation to June temperatures. Compared to TRW, dBI-based chronologies have a high correlation with summer temperatures (r = 0.64 and 0.66 for spruce and pine, respectively). Presented research points out the importance of the response function analysis suggesting that depending on goals of the study several tree-ring parameters could be used, e.g., tree-ring width of spruce responses to June temperatures, while dBI to the whole summer.     

Development of a flow cytometry–based pulse-width assay for detection of aggregates in cellular therapeutics to be infused by catheter

Background aimsDelivery of cell-based therapies through the carotid artery with the use of an intra-arterial catheter could introduce aggregates and cause focal ischemia in the brain. We developed a pulse-width flow cytometry method for aggregate detection and quantification. The assay was designed to be used as a cell product release assay in a clinical trial seeking to treat ischemic stroke with sorted cells brightly expressing aldehyde dehydrogenase (ALDH^br cells) delivered through intra-arterial catheters.MethodsThe forward light scatter pulse-width axis of a flow cytometer was calibrated for particle diameter measurements through the use of traceable standard microspheres and linear regression. As a positive control, Concanavalin A–aggregated cells were counted manually and sorted onto slides to compare with pulse width–determined values. Known numbers of aggregates were spiked into purified singlet cells for quantification. A clinical standard for aggregate count and diameter was determined. The assay was used to qualify catheters with the use of ALDH^br cells.ResultsThe pulse-width axis was highly linear for microsphere diameter (r² > 0.99), which allowed for size calibration. Microscopically determined counts and diameters corresponded to pulse width-determined values. Known aggregate counts were linear with pulse width–determined aggregate counts (r² = 0.98). The limit of detection was determined to be 0.004%. Flow of ALDH^br cells through catheters did not generate aggregates. The final method to be used as a release assay for the stroke clinical trial was tested successfully on samples from volunteer donors.ConclusionsThe pulse-width aggregate detection assay provides a reliable, reproducible, accurate and rapid means of detection, classification and quantification of aggregates in cell therapy products.