Early changes in cytokine expression in peste des petits ruminants disease

Peste des petits ruminants is a viral disease of sheep and goats that has spread through most of Africa as well as the Middle East and the Indian subcontinent. Although, the spread of the disease and its economic impact has made it a focus of international concern, relatively little is known about the nature of the disease itself. We have studied the early stages of pathogenesis in goats infected with six different isolates of Peste des petits ruminants virus representing all four known lineages of the virus. No lineage-specific difference in the pathogenicity of the virus isolates was observed, although there was evidence that even small numbers of cell culture passages could affect the degree of pathogenicity of an isolate. A consistent reduction in CD4⁺ T cells was observed at 4 days post infection (dpi). Measurement of the expression of various cytokines showed elements of a classic inflammatory response but also a relatively early induction of interleukin 10, which may be contributing to the observed disease.     

Magnetic bistability of molecules in homogeneous solution at room temperature

Magnetic bistability, as manifested in the magnetization of ferromagnetic materials or spin crossover in transition metal complexes, has essentially been restricted to either bulk materials or to very low temperatures. We now present a molecular spin switch that is bistable at room temperature in homogeneous solution. Irradiation of a carefully designed nickel complex with blue-green light (500 nanometers) induces coordination of a tethered pyridine ligand and concomitant electronic rearrangement from a diamagnetic to a paramagnetic state in up to 75% of the ensemble. The process is fully reversible on irradiation with violet-blue light (435 nanometers). No fatigue or degradation is observed after several thousand cycles at room temperature under air. Preliminary data show promise for applications in magnetic resonance imaging.     

Alternative methods of carrot (Daucus carota) protection against the northern root knot nematode (Meloidogyne hapla)

Abstract

The presence of northern root knot nematode (Meloidogyne hapla) has considerably increased in the Czech Republic during the last 10 years. The management of this pest is difficult; thus, the aim of this study was to test two alternative pest management techniques on carrots under field conditions. When Indian mustard (Brassica juncea) was ploughed and the treated area was then covered with polyethylene sheets to prolong effect of the treatment, the root gall numbers decreased; whereas a nitrolime application combined with plastic covering had a positive effect on the experimental plants’ fresh weight.     

Effect of a supplemental plate on the stiffness of a type I external fixator

OBJECTIVE: To assess the effect of a supplemental plate on the stiffness of a six-pin unilateral external skeletal fixator. STUDY DESIGN: Mechanical testing performed on models. METHODS: Wooden (birch) dowels were used to create five models of a fracture. A commercially available external fixation system was applied to the model with a uniform unilateral six-pin fixator design. The models were mechanically tested with and without a supplemental plate attached to the 2 clamps adjacent to the fracture gap. Testing was conducted in axial loading, medial to lateral bending, and cranial to caudal bending. RESULTS: Results showed a 4.42-fold increase in stiffness in axial load, a 4.23-fold increase in stiffness in medial to lateral bending, and a 1.94-fold increase in stiffness in cranial to caudal bending with the addition of the plate. CONCLUSIONS: The addition of a supplemental plate increases the mechanical stiffness of unilateral fixators. This was especially true in axial load and medial to lateral bending. CLINICAL RELEVANCE: A supplemental plate can be used with unilateral fixators to increase stiffness of the fixator. Conversely, the plate can be removed to decrease stiffness without the removal of fixation pins.     

Methylglyoxal-induced modifications of significant honeybee proteinous components in manuka honey: Possible therapeutic implications

Methylglyoxal (MGO) is a major antibacterial component of manuka honey. Another antibacterial component found in Revamil honey, peptide defensin1, was not identified in manuka honey. The primary aim of the study was to evaluate the content of defensin1 in honeys of different botanical origins and to investigate a presumed effect of reactive MGO on defensin1 and a dominant protein of honey MRJP1 in manuka honey. Immunoblotting of honey samples showed that defensin1 was a regular but quantitatively variable component of honeys. One of the reasons of varying contents of defensin1 in different honeys seems to be constitutive but varying defensin1 expression in individual honeybees in bee populations that we documented on samples of nurse and forager bees by RT-PCR. Comparative analyses of honeys revealed a size modification of defensin1, MRJP1 and probably also α-glucosidase in manuka honey. We further showed that (i) the treatment of purified defensin1 in solution containing high amount of MGO caused a time-dependent loss of its antibacterial activity and (ii) increasing MGO concentrations in a non-manuka honey were connected with a gradual increase in the molecular weight of MRJP1. Obtained results demonstrate that MGO abrogates the antibacterial activity of defensin1 and modifies MRJP1 in manuka honey. We assume that MGO could also have negative effects on the structure and function of other proteins/peptides in manuka honey, including glucose oxidase, generating hydrogen peroxide.     

Impact of oxidative stress and supplementation with vitamins E and C on testes morphology in rats

The aim of the study was to verify whether an increased supply of vitamins E and C prevents the detrimental effects of ozone on the testes. The experiment was performed on 5-month-old rats exposed to ozone (0.5 ppm) for 50 days (5 h daily). Simultaneously, the animals were injected with the vitamins in 5-day intervals and at different doses (0.5, 1.5, 4.5, 5 and 15 mg of vitamin E; 0.5, 3, 9, and 50 mg of vitamin C; or both vitamins together, respectively). Gonad sections were PAS stained. In the ozonized males, depletion of germ cells occurred. In the vitamin E groups, the testes were comparable to the controls, excluding the 0.5-mg-dose vitamin E group in which perivascular fibrosis and intertubular hyalinization were observed. In the vitamin C groups, intertubular hyalinization, partial arrested spermatogenesis, and desquamation of the seminiferous epithelium appeared proportional to the vitamin dose. Additionally, premature spermiation was found at a vitamin C dose of 50-mg. In the rats injected with both vitamins, hyalinization and fibrosis appeared in addition to partial arrest of spermatogenesis and vacuolar degeneration. In conclusion, vitamin E protects against the detrimental effects of ozone in rat testes irrespective of the dose applied. This was not observed for vitamin C. Moreover, administration of higher doses of vitamin C intensified the damage to the testes caused by ozone.     

Osmotic stress and silicon act additively in enhancing pathogen resistance in barley against barley powdery mildew

Osmotic stress as well as silicon (Si) improve the resistance of barley (Hordeum vulgare cv. Ingrid) against barley powdery mildew (Blumeria graminis f. sp. hordei Speer). Nothing is known about interactions, particularly whether Si is necessary for pathogen resistance induced by osmotic stress. In this paper, we show that Si nutrition was not necessary for osmotic‐stress‐induced pathogen resistance. Si‐mediated resistance could, however, be enhanced by osmotic stress and vice versa. Even at maximum Si‐mediated resistance, further enhancement of pathogen resistance by osmotic stress was possible. The fungus was controlled by the formation of effective papillae in both treatments. The combined effect of Si and osmotic stress was as strong as the calculated addition of the Si and the osmotic‐stress effect. Our data clearly show that the effect of osmotic stress and Si is not competitive but additive. A synergistic action of both treatments cannot be supported by our data. It is assumed that the basal pathogen resistance of barley is enhanced by Si due to strengthening of papillae in addition to the increased formation of effective papillae induced by osmotic stress. Therefore, the addition of Si increases pathogen resistance equally at all investigated NaCl concentrations. A function of Si in pathogen defense exceeding the strengthening of papillae is not supported by our data.     

Effects of combined sewer overflows and storm water drains on metal bioavailability in small urban streams (Prague metropolitan area,Czech Republic)

Purpose

The aims of the study were to evaluate the effect of combined sewer overflows (CSO) and storm water drains (SWD) on metal bioavailability in small urban streams in Prague and to evaluate levels of metals in water, sediment, and macroinvertebrates. The following working hypotheses were adopted: (a) sites dominantly affected by SWD are less polluted by metals, and (b) sites dominantly affected by SWD have higher bioavailability of metals.

Materials and methods

Physical and chemical parameters (pH, conductivity, NO₃-N, NH₄-N, COD, alkalinity, and water hardness) and concentrations of the metals Cu, Zn, Pb, Ni, and Cr were determined in samples of water and sediment at five to six sites on four target streams—Záti?ský Creek, Ko?íkovský Creek, Boti? Creek, and Rokytka Creek—three to five times per year during the period 2002–2004. The sites from all studied creeks were categorized into five groups according to the prevailing type of urban drainage impact. Macroinvertebrates were sampled and analyzed for metals at each site for a period of 1 month. The concentration patterns of metals were interpreted by partition coefficient (Kd), hazard quotient (HQ), cumulative criterion unit (CCU), and biota sediment accumulation factor (BSAF).

Results and discussion

Concentrations of metals in water as well as in sediment at sites receiving water from SWD were lower than at sites where creeks receive water from CSO, except for Pb. Concentrations of Cu, Zn, and Pb in sediment were higher at sites affected by CSO. Concentrations of metals in aquatic macroinvertebrates, expressed as BSAF, indicated higher values at sites affected by SWD. Frequencies of high BSAF (>1) were lower in CSO compared to SWD. This finding was explained by (a) a decrease of pH on SWD sites compared to the increase of pH on CSO sites during rain events, (b) a greater resuspension of sediment at SWD sites during rain events, and (c) an abundance of organic matter in CSO available for sorption of metals and a corresponding reduction of their bioavailability.

Conclusions

In the study area, the type of urban drainage affects the bioavailability of metals—while SWD increase metal bioavailability, CSO cause its decrease. The sediments in SWD sites do not indicate risk to the benthic community according to the applied environmental quality standards. Water and sediment in creeks affected by SWD are less polluted by metals. Both working hypotheses were therefore supported.

     

Variation in response to infection with Erysiphe graminis hordei and Puccinia hordei in some wild barley populations in a centre of diversity

Summary The Near East Fertile Crescent extending from Iran to Israel is the centre of origin of cultivated barley and a region of great genetic diversity in wild barley, Hordeum spontaneum C. Koch (syn. H. vulgare ssp. spontaneum (C. Koch Thell)). Wild barley accessions collected from different parts of this region were evaluated for their reactions to infection with three isolates of Erysiphe graminis hordei and two of Puccinia hordei. One culture of each pathogen was isolated in Israel and the others, either in Japan or the United States. Out of a total of 330 wild barley accessions collected from 14 sites in Iran, Turkey and Syria, only 18.8% were resistant to the Israeli culture, and 14.8% were resistant to a composite of the Japanese and American cultures of E. graminis hordei. Out of 105 accessions collected from six sites in Iran and Turkey, none was found to be resistant to the Israeli culture and 34.3% were resistant to the American culture of P. hordei. Considerable variation was observed both within and among sites for reactions to infection with different cultures of each of the two pathogens. The results of this study were compared with those of an earlier study involving wild barley accessions from Israel to illustrate the relative importance of different subregions in the Near East Fertile Crescent as sources of new genes for resistance to E. graminis hordei and P. hordei. Implications of these studies for in situ conservation of genetic diversity in wild barley are discussed.     

Precursors and formation of pyrithione and other pyridyl-containing sulfur compounds in drumstick onion, Allium stipitatum

Two novel, structurally unusual cysteine derivatives were isolated from the bulbs of Allium stipitatum (Allium subg. Melanocrommyum) and shown to be S-(2-pyridyl)cysteine N-oxide and S-(2-pyridyl)glutathione N-oxide. The former compound is the first example of a naturally occurring alliinase substrate that contains an N-oxide functionality instead of the S-oxide group. In addition, S-methylcysteine S-oxide (methiin) and S-(methylthiomethyl)cysteine 4-oxide (marasmin) were found in the bulbs. Presented data suggest that the previously reported identification of S-(2-pyridyl)cysteine S-oxide was most likely erroneous. The alliinase-mediated formation of pyridyl-containing compounds following disruption of A. stipitatum bulbs was studied by a combination of HPLC-MS, HPLC-PDA, DART-MS, and NMR techniques. It was found that no pyridyl-containing thiosulfinates are present in homogenized bulbs in detectable quantities. Instead, various pyridine N-oxide derivatives are formed, including N-hydroxypyridine-2(1H)-thione (pyrithione), 2-(methyldithio)pyridine N-oxide, 2-[(methylthio)methyldithio]pyridine N-oxide, di(2-pyridyl) disulfide N-oxide, and di(2-pyridyl) disulfide N,N'-dioxide. This represents the first report of pyrithione formation as a natural product.