Characterization and sequence of a novel nitrate reductase from barley

Summary Barley (Hordeum vulgare L.) has both NADH-specific and NAD(P)H-bispecific nitrate reductases. Genomic and cDNA clones of the NADH nitrate reductase have been sequenced. In this study, a genomic clone (pMJ4.1) of a second type of nitrate reductase was isolated from barley by homology to a partial-length NADH nitrate reductase cDNA and the sequence determined. The open reading frame encodes a polypeptide of 891 amino acids and its interrupted by two small introns. The deduced amino acid sequence has 70% identity to the barley NADH-specific nitrate reductase. The non-coding regions of the pMJ4.1 gene have low homology (ca. 40%) to the corresponding regions of the NADH nitrate reductase gene. Expression of the pMJ4.1 nitrate reductase gene is induced by nitrate in root tissues which corresponds to the induction of NAD(P)H nitrate reductase activity. The pMJ4.1 nitrate reductase gene is sufficiently different from all previously reported higher plant nitrate reductase genes to suggest that it encodes the barley NAD(P)H-bispecific nitrate reductase.Scientific Paper No. 9101-14. College of Agriculture and Home Economics Research Center, Washington State University, Research Project Nos. 0233 and 0745     

Serpentine ecotypic differentiation in a polyploid plant complex: shared tolerance to Mg and Ni stress among di- and tetraploid serpentine populations of <Emphasis Type="Italic">Knautia arvensis</Emphasis> (Dipsacaceae)

Background and aims

Serpentine soils impose limits on plant growth and survival and thus provide an ideal model for studying plant adaptation under environmental stress. Despite the increasing amount of data on serpentine ecotypic differentiation, no study has assessed the potential role of polyploidy. We tested for links between polyploidy and the response to serpentine stress in Knautia arvensis, a diploid-tetraploid, edaphically differentiated complex.

Methods

Variation in growth, biomass yield and tissue Mg and Ni accumulation in response to high Mg and Ni concentrations were experimentally tested using hydroponic cultivation of seedlings from eight populations of different ploidy and edaphic origin.

Results

Regardless of ploidy level, serpentine populations exhibited higher tolerance to both Mg and Ni stress than their non-serpentine counterparts, suggesting an adaptive character of these traits in K. arvensis. The effect of ploidy was rather weak and confined to a slightly better response of serpentine tetraploids to Mg stress and to higher biomass yields in tetraploids from both soil types.

Conclusions

The similar response of diploid and tetraploid serpentine populations to edaphic stress corresponded with their previously described genetic proximity. This suggests that serpentine tolerance might have been transmitted during the local autopolyploid origin of serpentine tetraploids.

     

Clearance rates of the bdelloid rotifer, <Emphasis Type="Italic">Habrotrocha thienemanni</Emphasis>, a tree-hole inhabitant

Bdelloid rotifers are basal consumers in aquatic and limnoterrestrial communities that feed primarily on small bacteria. Unfortunately, we know only a little of the role they play in the trophic dynamics in some unusual habitats they inhabit. Habrotrocha thienemanni is a typical example; it is a typical tree-hole inhabitant, commonly achieving dense populations. Filtering rates of H. thienemanni were estimated using fluorescent microspheres of a size close to natural bacterial community (0.5 μm in diameter) at two temperatures (15 and 20°C). This microspheres artificial food had been coated with BSA protein. Mean clearance rates of this rotifer varied between 1.65 and 3.79 μl ind⁻¹ h⁻¹ under different temperatures. Uptake of particles coated with protein was significantly higher than that on uncoated particles (t = 2.85; P = 0.005). Particle uptake also was correlated to the body size of the animal (r = 0.44; P = 0.004,). The clearance rate of the natural H. thienemanni population (56,800 ind l⁻¹) ranged from 981 to 5170 ml l⁻¹ d⁻¹.     

Application of size-exclusion chromatography-inductively coupled plasma mass spectrometry for fractionation of element species in seeds of legumes

Fractionation of soluble species of P, Mn, Fe, Co, Ni, Cu, Zn, Se and Mo in pea and lentil seeds was made by on-line hyphenation of size-exclusion chromatography (SEC) and inductively coupled plasma mass spectrometry. Seed samples were extracted with 0.02 mol l(-1) Tris-HCl buffer solution, pH 7.5. SEC was performed on Superdex 75 and Superdex Peptide columns (300 x 10 mm) with the same buffer solution as the mobile phase. Monitoring of oxide ion 47(PO)+ was used for detection of phosphorus compounds. Other elements were detected as ions of 55Mn, 57Fe, 59Co, 62Ni, 65Cu, 66Zn, 82Se and 95Mo nuclides. Elements in individual elution zones were quantified using external calibration. Complete chromatographic recoveries of elements were found in cases of phosphorus, nickel and copper. Substantial parts of manganese and zinc, as well as traces of cobalt, selenium and molybdenum are retained on the column. Injection of EDTA solution removes these elements from the column. Chromatographic profiles of pea and lentil samples are very similar for all elements except Mo. Main element species in the high-molecular-mass region (approx. 190,000 rel. mol. mass unit) were detected in case of Fe. Low-molecular-mass species (<2000 rel. mol. mass unit) as major element forms are typical for Cu and Zn.     

Remote controlled equipment for multiple blood withdrawal in gravitational physiology experiments

Electro-mechanical equipment for multiple blood withdrawal from small experimental animals applied to a centrifuge with maximal 6g gravitational overloading has been developed and tested. The equipment consists of a transmitter and receiver equipped by microcomputers. Active rotor stepping motors are driving four pairs of syringes. It is also possible to measure the instantaneous gravitational force using an accelerometric transducer. This telemetrically regulated blood sampling allows studying selective effects of hypergravity during centrifugation. It can be also used for study of microgravity effects in the animal organism during space flights for the understanding of the mechanism of the changes of the activity of neuroendocrine system and metabolic processes.     

Can prefrontal theta cordance differentiate between depression recovery and dissimulation?

We present a case report of a 37-year old woman diagnosed with depressive disorder, first episode, who was admitted into a psychiatric hospital after a failed suicidal attempt. She responded to antidepressant therapy, as evidenced by a >50% reduction in MADRS total score. She was discharged after 4 weeks of treatment, denying any suicidal ideations. The following day the patient committed suicide; she burned herself to death. It is very likely that the patient dissimulated her symptoms and ideations. Subsequently, her quantitative EEG records were retrospectively analyzed. An increase of prefrontal theta cordance value after the first week of mirtazapine therapy was found. Recently three small studies have revealed that decrease of prefrontal theta cordance after 1 week of antidepressant administration can predict clinical response in patients with unipolar depression. In our previous study the absence of a decreased theta prefrontal cordance was associated with lack of treatment response with NPV 1.0 (Bares et al., 2007). Thus, we hypothesize that prefrontal theta cordance could become an objective marker of change of depressive symptoms, independent of patients' compliance and symptom dissimulation, more precise than objective and self-rated depression rating scales.     

Response of Archaeal and Bacterial Soil Communities to Changes Associated with Outdoor Cattle Overwintering

Archaea and bacteria are important drivers for nutrient transformations in soils and catalyse the production and consumption of important greenhouse gases. In this study, we investigate changes in archaeal and bacterial communities of four Czech grassland soils affected by outdoor cattle husbandry. Two show short-term (3 years; STI) and long-term impact (17 years; LTI), one is regenerating from cattle impact (REG) and a control is unaffected by cattle (CON). Cattle manure (CMN), the source of allochthonous microbes, was collected from the same area. We used pyrosequencing of 16S rRNA genes to assess the composition of archaeal and bacterial communities in each soil type and CMN. Both short- and long- term cattle impact negatively altered archaeal and bacterial diversity, leading to increase of homogenization of microbial communities in overwintering soils over time. Moreover, strong shifts in the prokaryotic communities were observed in response to cattle overwintering, with the greatest impact on archaea. Oligotrophic and acidophilic microorganisms (e.g. Thaumarchaeota, Acidobacteria, and α-Proteobacteria) dominated in CON and expressed strong negative response to increased pH, total C and N. Whereas copiotrophic and alkalophilic microbes (e.g. methanogenic Euryarchaeota, Firmicutes, Chloroflexi, Actinobacteria, and Bacteroidetes) were common in LTI showing opposite trends. Crenarchaeota were also found in LTI, though their trophic interactions remain cryptic. Firmicutes, Bacteroidetes, Methanobacteriaceae, and Methanomicrobiaceae indicated the introduction and establishment of faecal microbes into the impacted soils, while Chloroflexi and Methanosarcinaceae suggested increased abundance of soil-borne microbes under altered environmental conditions. The observed changes in prokaryotic community composition may have driven corresponding changes in soil functioning.     

Plant transpiration and net entropy exchange on the Earth’s surface in a Czech watershed

The influence of plant transpiration on the entropy exchange was quantified as associated with the degradation of solar energy on the Earth’s surface covered by plants. Two surfaces were studied: (1) productive surface — plant transpiration taken as equal to the potential one, (2) non-productive surface — plant transpiration taken as equal to zero. The entropy exchanges associated with the absorption of solar radiation and with the conversion of absorbed solar radiation into the sensible heat and latent heat were taken into account. These processes were examined in the experimental watershed Liz (828–1074 m a.s.l.) located in the Bohemian Forest (Czech Republic). We found that in the growing season 1992 the net entropy exchange in humid hydrologic period (the Earth’s surface is productive) was considerably higher than in the arid one (the Earth’s surface was productive in 39% of days, and non-productive in 61% of days). Considering that the biotic effect on the Earth’s functioning can be measured with the help of the net entropy exchange, we can assume that the theory that biotic activities — represented by plant transpiration here — are the cause of the self-organizing processes in Earth’s environment is proved in the watershed scale. Presented at the International Conference on Bioclimatology and Natural Hazards, Poľana nad Detvou, Slovakia, 17–20 September 2007.     

The impact of lower induction values of 50 Hz external electromagnetic fields on in vitro T lymphocyte adherence capabilities

Our research thus far has concerned the impact of external electromagnetic fields (50 Hz) and low (0.01-10 mT) induction on adherence capabilities of T lymphocytes obtained from the blood of patients with head and neck tumors. We know that the in vitro adherence capability of T lymphocytes towards surfaces in cancer patients is less than that of control. Previously, we have found that exposure to electromagnetic fields (50 Hz/0.01-10 mT) increases the capability of T lymphocytes, in larynx/pharynx cancer patients, to adhere in vitro to surfaces, achieving almost physiological values, in not only pre-treatment patients but also those receiving treatment in the course of follow-up. The capability of T lymphocytes in controls (voluntary blood donors) to adhere to surfaces was also increased (50 Hz/0.01-0.5 mT). The present study concentrates on the significance of the level of electromagnetic field induction in order to determine whether low induction values can restore T lymphocytes adherence capabilities. Testing a subset of 20 patients showed a statistically significant difference (p<0.05) in the in vitro adherence capacity of T lymphocytes between both 0.01 and 0.05, and 0.1 mT induction levels. In the control group (patients diagnosed with chronic sensorineural hearing loss) there was even a statistically significant difference between induction values of 0.05 and 0.01 mT. A statistically significant difference (p<0.05) was also achieved with induction levels of 1 and 10 mT compared to 0.5, 0.1, and 0.05 mT, respectively. Therefore, we concluded that lower induction values resulted in a more biologically significant response.