Influence of nitrogen and sulphur form on manganese acquisition by barley (<Emphasis Type="Italic">shape Hordeum vulgare</Emphasis>)

The influence of various nitrogen (N) and sulphur (S) forms on the uptake of manganese (Mn) in young spring barley (Hordeum vulgare L cv Golf) plants was examined in both a hydroponic system and in a soil-based system. The soil was a typical Danish Mn-deficient soil viz. a sandy loam soil developed on old marine sediments. Plants growing in solution culture with NO₃^– as the only N source had a higher Mn uptake than plants receiving mixtures of NO₃^– and NH₄⁺. These findings were opposite to the results obtained in the soil-based experiments, where plants fertilized with NO₃^– as the only N source accumulated much less Mn than plants fertilized with NH₄⁺. Combining the results of these experiments confirmed that NH₄⁺ acted as a powerful antagonist to Mn²⁺ during uptake but that this antagonistic effect was more than compensated for by the influence of NH₄⁺ in reducing plant-unavailable Mn(IV) to plant-available Mn(II) in the soil. Furthermore the soil experiments showed that fertilizers containing sulphur in the form of reduced S (thiosulphate) had a strong mobilizing effect on Mn, and enabled the plants to accumulate large amounts of Mn in the biomass compared with oxidized S (sulphate). Thus, fertilization with thiosulphate may be very effective in alleviating Mn-deficiency in soils developed on old marine sediments where Mn availability is limiting plant growth.     

Media evaluation for production and expansion of anti-CD19 chimeric antigen receptor T cells

Background

The use of CD19 chimeric antigen receptor (CAR) T cells to treat B-cell malignancies has proven beneficial. Several groups use serum to produce CD19 CAR T cells. Today, ready-to-use serum-free media that require no addition of serum are commercially available. Therefore, it becomes important to evaluate the production of CD19 CAR T cells with and without the addition of serum.

Leaf-Atmosphere NH3 Exchange in Barley Mutants with Reduced Activities of Glutamine Synthetase

Mutants of barley (Hordeum vulgare L. cv Maris Mink) with 47 or 66% of the glutamine synthetase (GS) activity of the wild type were used for studies of NH3 exchange with the atmosphere. Under normal light and temperature conditions, tissue NH4+ concentrations were higher in the two mutants compared with wild-type plants, and this was accompanied by higher NH3 emission from the leaves. The emission of NH3 increased with increasing leaf temperatures in both wild-type and mutant plants, but the increase was much more pronounced in the mutants. Similar results were found when the light intensity (photosynthetic photon flux density) was increased. Compensation points for NH3 were estimated by exposing intact shoots to 10 nmol NH3 mol-1 air under conditions with increasing temperatures until the plants started to emit NH3. Referenced to 25[deg]C, the compensation points were 5.0 nmol mol-1 for wild-type plants, 8.3 nmol mol-1 for 47% GS mutants, and 11.8 nmol mol-1 for 66% GS mutants. Compensation points for NH3 in single, nonsenescent leaves were estimated on the basis of apoplastic pH and NH4+ concentrations. These values were 0.75, 3.46, and 7.72 nmol mol-1 for wild type, 47% GS mutants, and 66% GS mutants, respectively. The 66% GS mutant always showed higher tissue NH4+ concentrations, NH3 emission rates, and NH3 compensation points compared with the 47% GS mutant, indicating that NH4+ release was curtailed by some kind of compensatory mechanism in plants with only 47% GS activity.     

Differences in the release ofl-glutamate andd-aspartate from primary neuronal chick cultures

Primary neuronal cultures were made from eight-day-old embryonic chick telencephalon. Ten-day-old cultures were used to study the release ofd-[³H]aspartate andl-[³H]glutamate. Thed-[³H]aspartate release was stimulated by increasing potassium concentrations, but it was not calcium dependent. In contrast, the potassium dependentl-[³H]glutamate release was calcium dependent, and furthermorel-[³H]glutamate release was optimal at potassium concentrations<30 mM. The inhibitors of glutamate uptake, dihydrokainate and 1-aminocyclobutane-trans-1,3-dicarboxylic acid (CACB), also referred to as cis-1-aminocyclobutane-1,3-dicarboxylate, were used in the release experiments. Dihydrokainate had no effect on aspartate release, whereas CACB increased both the basal efflux ofd-[³H]aspartate and the potassium evoked release. CACB had no effect on the potassium stimulatedl-glutamate release. We believe thatl-glutamate is released mainly by a vesicular mechanism from the presumably glutamatergic neurons present in our culture.d-aspartate release observed by us, could be mediated by a transporter protein. The cellular origin of this release remains to be assessed.     

Division frequency of pea protoplasts in relation to starch accumulation

Division frequency of alginate-embedded pea (Pisum sativum var. Belman) protoplasts derived from embryonic shoot tips was studied quantitatively by image analysis in relation to starch accumulation and protoplast size. Protoplast divisions were observed from day 4 on and the number of protoplasts undergoing division increased in a stepwise manner to 70% the following days. The starch content increased rapidly during the first 3 days of culture prior to the onset of division and resulted a 4.2-fold increase in the intracellular starch area and a 3.0-fold increase (from 27% to 80%) in the number of protoplasts containing starch. Subsequent periods with rapid increases the number of dividing protoplasts were preceded by further starch accumulation. Dividing protoplasts were 33–60% smaller and contained 8–42% less starch than non-dividing protoplasts. However, calculations showed that, in the dividing protoplasts, the relative area covered by starch was 6–12% higher than in non-dividing protoplasts. These data suggest that starch accumulation precedes division of pea protoplasts.     

Physiological significance of ECL-cell histamine.

In the oxyntic mucosa of the mammalian stomach, histamine is stored in ECL cells and in mucosal mast cells. In the rat, at least 80 percent of oxyntic mucosal histamine resides in the ECL cells. Histamine is a key factor in the regulation of gastric acid secretion. Following depletion of ECL-cell histamine by treatment with alpha-fluoromethylhistidine (alpha-FMH), basal acid secretion was reduced, and gastrin-stimulated acid secretion was abolished. Vagally-induced acid secretion (by insulin injection or pylorus ligation) was unaffected by alpha-FMH treatment but inhibited by an H2 antagonist. These results suggest that gastrin stimulates acid secretion via release of ECL-cell histamine, whereas vagally-induced acid secretion--although histamine-dependent--does not rely on ECL-cell histamine. Gastrin is known to have a trophic effect on the oxyntic mucosa. By combining long-term hypergastrinemia with continuous infusion of alpha-FMH, we were able to show that gastrin-evoked trophic effects in the stomach do not depend on ECL-cell histamine.     

Estimating the per‐capita contribution of habitats and pathways in a migratory network: a modelling approach

Every year, migratory species undertake seasonal movements along different pathways between discrete regions and habitats. The ability to assess the relative demographic contributions of these different habitats and pathways to the species’ overall population dynamics is critical for understanding the ecology of migratory species, and also has practical applications for management and conservation. Metrics for assessing habitat contributions have been well‐developed for metapopulations, but an equivalent metric is not currently available for migratory populations. Here, we develop a framework for estimating the demographic contributions of the discrete habitats and pathways used by migratory species throughout the annual cycle by estimating the per capita contribution of cohorts using these locations. Our framework accounts for seasonal movements between multiple breeding and non‐breeding habitats and for both resident and migratory cohorts. We illustrate our framework using a hypothetical migratory network of four habitats, which allows us to better understand how variations in habitat quality affect per capita contributions. Results indicate that per capita contributions for any habitat or pathway are dependent on habitat‐specific survival probabilities in all other areas used as part of the migratory circuit, and that contribution metrics are spatially linked (e.g. reduced survival in one habitat also decreases the contribution metric for other habitats). Our framework expands existing theory on the dynamics of spatiotemporally structured populations by developing a generalized approach to estimate the habitat‐ and pathway‐specific contributions of species migrating between multiple breeding and multiple non‐breeding habitats for a range of life histories or migratory strategies. Most importantly, it provides a means of prioritizing conservation efforts towards those migratory pathways and habitats that are most critical for the population viability of migratory species.     

Optically stimulated luminescence (OSL) dosimetry in irradiated alumina substrates from mobile phone resistors

In this study the dosimetric properties of alumina (Al₂O₃) substrates found in resistors retrieved from mobile phones were investigated. Measurements of the decline of optically stimulated luminescence (OSL) generated following exposure of these substrates to ionising radiation showed that 16% of the signal could still be detected after 2 years (735 days). Further, the magnitude of the regenerative dose (calibration dose; D _i) had no impact on the accuracy of dose estimates. Therefore, it is recommended that the D _i be set as low as is practicable, so as to accelerate data retrieval. The critical dose, D _CL, and dose limit of detection, D _DL, taking into account the uncertainty in the dose–response relation as well as the uncertainty in the background signal, was estimated to be 7 and 13 mGy, respectively, 1 h after exposure. It is concluded that given the significant long-term component of fading, an absorbed dose of 0.5 Gy might still be detectable up to 6 years after the exposure. Thus, OSL from alumina substrates can be used for dosimetry for time periods far in excess of those previously thought.     

Comparison of serum and lung extracts for surveys of wild animals for antibodies to Francisella tularensis biovar palaearctica

A comparative study of the antibody titer against Francisella tularensis biovar palaearctica in serum and lung extract was made using different immunoassays. Samples were taken from experimentally-infected goshawks (Accipiter gentilis) and European beavers (Castor fiber), and in a field survey of wild beavers. Good accordance between the antibody titer in serum and in lung extract was found in the experimental studies. However, the antibody titer was generally one- to three-fold lower in lung extract than was the titer of serum. Results in the field survey were less reliable. Estimating antibody titer in lung extract is a practical method for surveys for antibody levels, and an alternative to serological surveys, despite lower sensitivity as compared to serum.