Fusariosis of spring barley cultivated in Lublin region

Diseases of spring barley in 1986–1988 seasons have been examined on barley plantations in Lublin region. Observations in eight weeks after sowing each year spring showed the occurrence of root rot and sheath rot in seedlings. As a result of mycological examination of infected seedlings 34 species of fungi were isolated:Fusarium spp. amounted up to 23% of all isolates. Each year,Fusarium culmorum andF.avenaceum were isolated, butF graminearum only in 1987. On all inspected fields there occurred plants with eye — spots or necrotic stripes on lower internodes. As a result of fungi isolation the colonies belonging to 30 species were identified from stems and roots of examined plants. There was about 35% of fusaria between isolates each year.Fusarium culmorum was most frequently isolated. This fungus both from stems with two mentioned kinds of symptoms and from roots was isolated.Fusarium avenaceum each year andFusarium graminearum in 1986 and 1988 were isolated. Mentioned there species were also isolated from kernels.     

Investigations on some hybrids from theArabis hirsuta complex

Natural and artificial hybrids between the tetraploidArabis hirsuta (L.)Scop. s. str. and two diploid speciesA. sagittata (Bertol.) DC. orA. planisiliqua (Pers.)Reichenb. are the main subject of this paper. The investigations concern pollination behaviour, sterility, occurrence and frequency of hybrids, their morphology and cytology. Some questions concerning relations of the taxa within the complex and the significance of hybrids in the variability of natural mixed populations are discussed.     

NMR studies of malaria P nuclear magnetic resonance of blood from mice infected with Plasmodium berghei

High resolution ³¹P-NMR has been used for the non-invasive observation of metabolites and metabolic rates in blood of normal mice and of mice infected with Plasmodium berghei, the causative agent of malaria. ³¹P-NMR was used to quantitate levels of 2,3-diphosphoglycerate in whole cells as a function of the degree of parasitemia and yielded good agreement with the results of enzymatic assays. The time-dependence of ³¹P metabolites was monitored in both normal and infected erythrocytes, greater rates of decay of 2,3-diphosphoglycerate being observed in malarial blood which correlate with the level of parasitemia. Very high metabolic rates of infected cells render measurement of intracellular pH unreliable on freshly drawn whole blood. When appropriate measures are taken to avoid this complication, no difference is observed in the intracellular pH of parasitized and non-parasitized erythrocytes from infected animals. In both normal and parasitized mice the intraerythrocytic pH is more acidic than that of the suspending medium by 0.15 pH unit at 25°C. Unlike free-living protozoa, the parasitic protozoan Plasmodium does not contain detectable levels of phosphonates or polyphosphates, in either whole cells or perchloric acid extracts thereof.     

Hydroxydiether Lipid Structures in Methanosarcina spp. and Methanococcus voltae

Hydroxylated diether lipids are the most abundant lipids in Methanosarcina acetivorans, Methanosarcina thermophila, and Methanosarcina barkeri MS and Fusaro, regardless of the substrate used for growth. Structural analysis of the lipid moiety freed of polar head groups revealed that the hydroxydiether lipids of all the Methanosarcina strains were hydroxylated at position 3 of sn-2 phytanyl chains. The finding that Methanosarcina strains synthesize the same hydroxydiether structure suggests that this is a taxonomic characteristic of the genus. Methanococcus voltae produced minor amounts of the 3-hydroxydiether characteristic of Methanosarcina spp. and also the 3′-hydroxydiether described previously for Methanosaeta concilii.     

Thermoregulatory ability and mechanism do not differ consistently between neotropical and temperate butterflies

Climate change is a major threat to species worldwide, yet it remains uncertain whether tropical or temperate species are more vulnerable to changing temperatures. To further our understanding of this, we used a standardised field protocol to (1) study the buffering ability (ability to regulate body temperature relative to surrounding air temperature) of neotropical (Panama) and temperate (the United Kingdom, Czech Republic and Austria) butterflies at the assemblage and family level, (2) determine if any differences in buffering ability were driven by morphological characteristics and (3) used ecologically relevant temperature measurements to investigate how butterflies use microclimates and behaviour to thermoregulate. We hypothesised that temperate butterflies would be better at buffering than neotropical butterflies as temperate species naturally experience a wider range of temperatures than their tropical counterparts. Contrary to our hypothesis, at the assemblage level, neotropical species (especially Nymphalidae) were better at buffering than temperate species, driven primarily by neotropical individuals cooling themselves more at higher air temperatures. Morphology was the main driver of differences in buffering ability between neotropical and temperate species as opposed to the thermal environment butterflies experienced. Temperate butterflies used postural thermoregulation to raise their body temperature more than neotropical butterflies, probably as an adaptation to temperate climates, but the selection of microclimates did not differ between regions. Our findings demonstrate that butterfly species have unique thermoregulatory strategies driven by behaviour and morphology, and that neotropical species are not likely to be more inherently vulnerable to warming than temperate species.     

1,2-Dioxetanes: Novel chemiluminescent enzyme substrates. Applications to immunoassays

We have synthesized and studied two 1,2-dioxetane-based chemiluminescent enzyme substrates: 3-(2′-spiroadamantane)-4-methoxy-4-(3″-phosphoryloxy)phenyl-1,2-dioxetane (AMPPD), and, 3-(2′-spiroadamantane)-4-methoxy-4- (3″-β-D ′-galactopyrano-yloxy)phenyl-1,2-dioxetane (AMPGD), which can be activated to chemiluminescence at 470 nm by alkaline phosphatase and βD -galactosidase, respectively. In addition, we observed that certain macromolecules enhance the luminescence of AMPPD. For example, the addition of 0.1% bovine serum albumin amplifies the luminescent signal and improves the detection limit for alkaline phosphatase by approximately one order of magnitude under certain conditions. This effect is due to the presence of a hydrophobic microenvironment provided by the enhancer which ‘stabilizes’ the dephosphorylated AMPPD emitter. Alkaline phosphatase catalysed chemiluminescence from AMPPD is constant for a prolonged period of time. Using AMPPD we were able to detect 0.01 attomole quantities of alkaline phosphatase immobilized on membrane supports and imaged on photographic film and, in solution, measured in a luminometer. AMPPD and AMPGD offer alternatives to colorimetric and fluorescent subsrates for alkaline phosphatase and β-D -galactosidase labels used in enzyme immunoassays. The simplicity and sensitivity of this chemiluminescent readout allowed the development of rapid clinical assays (e.g. β-hCG, LH, TSH and others).     

Identification of the heparin-binding domain of TNF-alpha and its use for efficient TNF-alpha purification by heparin-Sepharose affinity chromatography

The N-terminus of the trimeric TNF-alpha molecule comprises two basic arginines within the short amino-acid sequence VRSSSR, which is here shown to be essential for binding of TNF-alpha to heparin-Sepharose. Mixed trimers containing full-length and DeltaN6-truncated subunits revealed a single VRSSSR sequence to be sufficient to achieve binding. On the basis of this newly identified heparin-binding domain, a new method for efficient purification of TNF-alpha is described. Affinity chromatography on heparin-Sepharose was introduced as a key step for highly purified TNF-alpha at a high yield. With minor modifications, this procedure can be used for TNF-alpha analogues that have full-length N-termini, as shown for the less toxic analogue LK-805.     

Solution structure of Phl p 3, a major allergen from timothy grass pollen

The major 97-aa timothy grass (Phleum pratense) allergen Phl p 3 was recently isolated from an extract of timothy grass pollen. Sequence comparison classifies this protein as a group 3 allergen. The solution structure of Phl p 3 as determined by nuclear magnetic resonance spectroscopy reveals that the protein consists of a core of hydrophobic amino-acid side chains from two beta-sheets of five and four anti-parallel beta-strands, respectively. This conformation is very similar to the crystal structure published for Phl p 2 and strongly resembles the known conformation of the carboxy-terminal domain of Phl p 1, the major difference being the loop orientations. Phl p 2 and Phl p 3 show virtually identical immunoreactivity, and comparison of the charged surface amino acids of the two proteins gives initial clues as to the IgE recognition epitopes of these proteins.