Improved expansion of T cells in culture when isolated with an equipment-free,high-throughput,flow-through microfluidic module versus traditional density gradient centrifugation

Background

The isolation of lymphocytes – and removal of platelets (PLTs) and red blood cells (RBCs) – from an initial blood sample prior to culture is a key enabling step for effective manufacture of cellular therapies. Unfortunately, currently available methods suffer from various drawbacks, including low cell recovery, need for complex equipment, potential loss of sterility and/or high materials/labor cost.

Rare element concentrations indicating agglutinated character of Lower Cambrian Platysolenites tubes

Felitsyn, S. B. 1992 04 15: Rare element concentrations indicating agglutinated character of Lower Cambrian Platysolenites tubes. Lethaia , Vol. 25, pp. 131–133. Oslo. ISSN 9924–1164.
Data on rare element contents in siliceous tubes of Platysolenites antiquissimus from Lontova Beds were obtained. Low metal contents and REE patterns serve as indications of the presence of quartz in the tube substance. X-ray analysis detected the quartz and K-feldspars. Information on tube composition suggests their agglutinated character, since siliceous minerals are not a single component of the tubes and an affinity between Platysolenites and Foraminifera is quite possible. * Plarysolenites, Lower Cambrian, rare elements .     

Elevated atmospheric CO2 increases microbial growth rates in soil: results of three CO2 enrichment experiments

Increasing the belowground translocation of assimilated carbon by plants grown under elevated CO₂ can cause a shift in the structure and activity of the microbial community responsible for the turnover of organic matter in soil. We investigated the long‐term effect of elevated CO₂ in the atmosphere on microbial biomass and specific growth rates in root‐free and rhizosphere soil. The experiments were conducted under two free air carbon dioxide enrichment (FACE) systems: in Hohenheim and Braunschweig, as well as in the intensively managed forest mesocosm of the Biosphere 2 Laboratory (B2L) in Oracle, AZ. Specific microbial growth rates (μ) were determined using the substrate‐induced respiration response after glucose and/or yeast extract addition to the soil. For B2L and both FACE systems, up to 58% higher μ were observed under elevated vs. ambient CO₂, depending on site, plant species and N fertilization. The μ‐values increased linearly with atmospheric CO₂ concentration at all three sites. The effect of elevated CO₂ on rhizosphere microorganisms was plant dependent and increased for: Brassica napus=Triticum aestivum<Beta vulgaris<Populus deltoides. N deficiency affected microbial growth rates directly (N limitation) and indirectly (changing the quantity of fine roots). So, 50% decrease in N fertilization caused the overall increase or decrease of microbial growth rates depending on plant species. The μ‐value increase was lower for microorganisms growing on yeast extract then for those growing on glucose, i.e. the effect of elevated CO₂ was smoothed on rich vs. simple substrate. So, the r/K strategies ratio can be better revealed by studying growth on simple (glucose) than on rich substrate mixtures (yeast extract). Our results clearly showed that the functional characteristics of the soil microbial community (i.e. specific growth rates) rather than total microbial biomass amount are sensitive to increased atmospheric CO₂. We conclude that the more abundant available organics released by roots at elevated CO₂ altered the ecological strategy of the soil microbial community specifically a shift to a higher contribution of fast‐growing r‐selected species was observed. These changes in functional structure of the soil microbial community may counterbalance higher C input into the soil under elevated atmospheric CO₂ concentration.     

The Zooflagellates Stephanopogon and Percolomonas are a Clade (Class Percolatea: Phylum Percolozoa)

ABSTRACT. The enigmatic marine protozoan Stephanopogon was first classified with ciliate protozoa because its pellicle also has rows of cilia. As ciliates have nuclear dimorphism with separate germline and somatic nuclei, Stephanopogon with several identical nuclei was regarded as a model for a hypothetical homokaryotic ancestor of ciliates. When electron microscopy revealed radical differences from ciliates this idea was abandoned, but its evolutionary position remains controversial, affinities with three other phyla being suggested. We sequenced 18S rDNA from Stephanopogon aff. minuta and actin genes from it and Stephanopogon apogon to clarify their evolutionary position. Phylogenetic analyses of 18S rRNA nest S. aff. minuta and Stephanopogon minuta securely within the protozoan phylum Percolozoa with zooflagellates of the genus Percolomonas, their closest relatives, comprising the clade Percolatea. This supports a previous grouping of Stephanopogon (order Pseudociliatida) with Percolomonas (order Percolomonadida) as a purely zooflagellate class Percolatea within Percolozoa, in contrast to the fundamentally amoeboid Heterolobosea, which are probably ancestral to Percolatea. Stephanopogon actins evolve exceptionally fast: actin trees place them as a long branch within bikont eukaryotes without revealing their sisters. We establish Percolomonadidae fam. n. for Percolomonas, excluding Pharyngomonas kirbyi g., sp. n. and Pharyngomonas (=Tetramastix=Percolomonas) salina comb. n., which unlike Percolomonas have two anterior and two posterior cilia and a pocket‐like pharynx, like “Macropharyngomonas”, now grouped with Pharyngomonas as a new purely zooflagellate class Pharyngomonadea, within a new subphylum Pharyngomonada; this contrasts them with the revised ancestrally amoeboflagellate subphylum Tetramitia. We discuss evolution of the percolozoan cytoskeleton and different body forms.     

Phylogeny of the genera of the parasitic wasps subfamily Doryctinae (Hymenoptera: Braconidae) based on morphological evidence

The evolutionary relationships among most (143 genera) of the currently recognized genera of the braconid wasp subfamily Doryctinae were investigated using maximum parsimony analysis, employing 100 characters from external morphology and four additional, less well‐studied character systems (male genitalia, ovipositor structure, venom apparatus and larval cephalic structure). We investigated the ‘performance’ of characters from external morphology and the other character systems and the effects of abundant missing entries by comparing the data decisiveness, retention and consistency indices of four different character partitions. The results indicate that the performances of the different partitions are not related to the proportions of missing entries, but instead are negatively correlated to their proportion of informative characters, suggesting that the morphological information in this group is subject to high levels of homoplasy. The external morphological partition is significantly incongruent with respect to a data set comprising the other character systems based on the ILD test. Analyses supported neither the monophyly of the large tribes Doryctini and Hecabolini, nor the monophyly of the Spathiini and Heterospilini. Relationships obtained from successive approximation weighting analysis for the complete data differ considerably from the currently accepted tribal and subtribal classifications. The only exceptions were the Ypsistocerini and the Ecphylini, whose recognized members were recovered in single clades. A close relationship between the Binaerini and Holcobraconini, and also Monarea, is consistently supported by venom apparatus and ovipositor structure characters but is not indicated by external morphological data. Low bootstrap values obtained for most of the recovered clades in all analyses do not allow us to propose a meaningful reclassification for the group at this time. A complete list of the recognized genera and their synonymies is given. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 142 , 369–404.     

Microbial characteristics of soils on a latitudinal transect in Siberia

Soil microbial properties were studied from localities on a transect along the Yenisei River, Central Siberia. The 1000 km‐long transect, from 56°N to 68°N, passed through tundra, taiga and pine forest characteristic of Northern Russia. Soil microbial properties were characterized by dehydrogenase activity, microbial biomass, composition of microbial community (PLFAs), respiration rates, denitrification and N mineralization rates. Relationships between vegetation, latitude, soil quality (pH, texture), soil organic carbon (SOC) and the microbial properties were examined using multivariate analysis. In addition, the temperature responses of microbial growth (net growth rate) and activity (soil respiration rate) were tested by laboratory experiments. The major conclusions of the study are as follows: 1. Multivariate analysis of the data revealed significant differences in microbial activity. SOC clay content was positively related to clay content. Soil texture and SOC exhibited the dominant effect on soil microbial parameters, while the vegetation and climatic effects (expressed as a function of latitude) were weaker but still significant. The effect of vegetation cover is linked to SOC quality, which can control soil microbial activity. 2. When compared to fine‐textured soils, coarse‐textured soils have (i) proportionally more SOC bound in microbial biomass, which might result in higher susceptibility of SOC transformation to fluctuation of environmental factors, and (ii) low mineralization potential, but with a substantial part of the consumed C being transformed to microbial products. 3. The soil microbial community from the northernmost study region located within the permafrost zone appears to be adapted to cold conditions. As a result, microbial net growth rate became negative when temperature rose above 5 °C and C mineralization then exceeded C accumulation.     

Electrophysiological localization of blue light sensory sites in etiolated dicotyledon seedlings

Changes induced by blue light (BL) in ion fluxes and pH in etiolated seedlings of dicotyledons (Cucumis sativus L., Phaseolus lunatus L., Pisum sativum L.) were studied using a non‐invasive ion‐selective microelectrode technique (MIFE). BL induced significant Ca²⁺ uptake within the first 5 min after onset in upper parts of the whole cucumber seedling. To locate the sites of the BL perception, studies on excised segments were performed. The data obtained demonstrated that the observed Ca²⁺ uptake is associated with the very top of the hypocotyl hook of cucumber and butter bean, and with the whole epicotyl of pea, although the response was stronger for the upper parts of the epicotyl. Addition of Gd³⁺ and La³⁺ into the bathing solution completely prevented Ca²⁺ influx, implicating the involvement of Ca²⁺ channels in the regulation of Ca²⁺ transport during BL exposure. BL‐induced changes in H+ and Ca²⁺ fluxes were not likely to be linked to the one mechanism, as they were separated spatially and pharmacologically.     

H+ flux kinetics around plant roots after short-term exposure to low temperature: identifying critical temperatures for plant chilling tolerance

H⁺ flux kinetics were measured in solution around the roots of chilling-tolerant pea (Pisum sativum) and bean (Vicia faba), chilling-sensitive cucumber (Cucumis sativus) and pumpkin (Cucurbita pepo), and intermediate corn (Zea mays) species using a microelectrode technique to measure net flux. As a root warmed to room temperature alter 90 min at 4°C, at which temperature the H⁺ flux was near zero, the flux rose (influx) and then fell. These changes occurred at two apparent critical temperatures, which were higher for the more chilling-sensitive species. The First, lower, apparent critical temperature may represent the start of passive inward H⁺ transport. The higher critical temperature may represent the start of active H⁺ extrusion. From these apparent critical temperatures we have calculated the real critical temperature and the time delay of the chilling signal transduction process. Passive and active H⁺ transporters appear to have the same real critical temperature of chilling sensitivity, about 9°C, but have, respectively, 4 min and 11 min time delays. Measurement of these apparent critical temperatures may provide quick and reliable screening for chilling sensitivity in plant breeding programmes. Future ion flux studies may show the cellular location of chilling stress perception and the signal transduction pathways.     

Kinetics of xylem loading,membrane potential maintenance,and sensitivity of K+‐permeable channels to reactive oxygen species: physiological traits that differentiate salinity tolerance between pea and barley

Salt sensitive (pea) and salt tolerant (barley) species were used to understand the physiological basis of differential salinity tolerance in crops. Pea plants were much more efficient in restoring otherwise depolarized membrane potential thereby effectively decreasing K⁺ efflux through depolarization‐activated outward rectifying potassium channels. At the same time, pea root apex was 10‐fold more sensitive to physiologically relevant H₂O₂ concentration and accumulated larger amounts of H₂O₂ under saline conditions. This resulted in a rapid loss of cell viability in the pea root apex. Barley plants rapidly loaded Na⁺ into the xylem; this increase was only transient, and xylem and leaf Na⁺ concentration remained at a steady level for weeks. On the contrary, pea plants restricted xylem Na⁺ loading during the first few days of treatment but failed to prevent shoot Na⁺ elevation in the long term. It is concluded that superior salinity tolerance of barley plants compared with pea is conferred by at least three different mechanisms: (1) efficient control of xylem Na⁺ loading; (2) efficient control of H₂O₂ accumulation and reduced sensitivity of non‐selective cation channels to H₂O₂ in the root apex; and (3) higher energy saving efficiency, with less ATP spent to maintain membrane potential under saline conditions.