Genetic approach for the fast discovery of phenazine producing bacteria

A fast and efficient approach was established to identify bacteria possessing the potential to biosynthesize phenazines, which are of special interest regarding their antimicrobial activities. Sequences of phzE genes, which are part of the phenazine biosynthetic pathway, were used to design one universal primer system and to analyze the ability of bacteria to produce phenazine. Diverse bacteria from different marine habitats and belonging to six major phylogenetic lines were investigated. Bacteria exhibiting phzE gene fragments affiliated to Firmicutes, Alpha- and Gammaproteobacteria, and Actinobacteria. Thus, these are the first primers for amplifying gene fragments from Firmicutes and Alphaproteobacteria. The genetic potential for phenazine production was shown for four type strains belonging to the genera Streptomyces and Pseudomonas as well as for 13 environmental isolates from marine habitats. For the first time, the genetic ability of phenazine biosynthesis was verified by analyzing the metabolite pattern of all PCR-positive strains via HPLC-UV/MS. Phenazine production was demonstrated for the type strains known to produce endophenazines, 2-hydroxy-phenazine, phenazine-1-carboxylic acid, phenazine-1,6-dicarboxylic acid, and chlororaphin as well as for members of marine Actinobacteria. Interestingly, a number of unidentified phenazines possibly represent new phenazine structures.     

Pathomorphological changes in the skeletal muscles (musculus longissimus dorsi) in swine following varied transport stresses and resting periods prior to slaughter

The M. longissimus dorsi of 171 pigs were histologically examined for pathological signs. Acute hyaline-plaque degenerations and necrosis (hsD/N) in various degrees of manifestation were recorded from 42.7 and hyaline transverse ligaments (hQb) from 22.8 per cent of all cases. The occurrence of hsD/N following container transport was lower with significance (33.3 per cent) than that following lorry transport (50.5 per cent). The form of transport failed to have any substantive effect on the occurrence of hQb, the figures being 20.5 per cent for container and 24.7 per cent for lorry. Short resting periods, between 0.5 and 1.2 hours, were followed with significantly higher occurrence of hsD/N, as compared to longer resting periods, between five and eight or 23 hours. These pathological findings were not further reduced by extending the resting period from something between five and eight to 20 hours. The pathological hsD/N and hQb findings were recordable from both PSE pork (hsD/N = 51.4 per cent, hQb = 25.7 per cent) and from pork without any quality shortcomings (hsD/N = 39.7 per cent, hQb = 22.1 per cent), but the number of hsD/N cases in the context of PSE pork tended to be higher than that in high-quality pork. No sex dependence was established. The results are discussed under the aspect of aetiopathogenesis of stress-borne myopathy.     

Epizootiology of bovine cysticercosis in the Jindrichuv Hradec District

The results of the study of the epidemiology and epizootology of Taenia saginata in the Jindrich?v Hradec district indicate that this tapeworm species has adapted successfully to anthropogenic conditions. Mass occurrence of bovine cysticercosis, coming from a limited source, was observed in the Jindrich?v Hradec district. Our of the 907 employees of one farm, T. saginata was found in two workers engaged in animal production and in one person working in crop production. Their recovery resulted in the eradication of cysticercosis in the cattle kept on that farm; before eradication the disease was responsible for losses of several hundreds of thousands of crowns.     

Physiological reactions of three breeds of goats to cold,heat and high altitude

A total of 36 goats of the breeds Gemsfarbige Gebirgsziege (G), Saanen (S) and Toggenburger (T) were exposed for periods of 4 hours to the following climatic conditions: normal (20°C, 50% RH); cold (?5°C); heat (40°C, 30% RH) and high altitude (4000 m, 20°C, 50% RH).In the cold the animals were just able to maintain normal core temperature. Skin temperatures on the flank decreased by 3–5°C, those on the ear and the shank by 20–21°C. Respiratory rate and blood-pH decreased. The elevation in heart rate (18 beats/min) and cold shivering were indicative of a rise in heat production.In the heat, rectal temperature increased but attained a plateau at 40.7°C. Respiratory rate rose from 26 to 261 breaths/min, producing a slight respiratory alcolosis with a rise in blood-pH of 0.036 units. Heart rate augmented by 15 beats/min.At high altitude rectal temperature declined by 0.2°C, which was attributed to the quiet behaviour of the goats. There were increases in haemoglobin (+0.83 g/100 ml), haematocrit (+2.5 vol.%), erythrocyte number (+0.78 mill./mm³) and specific gravity of the blood (+0.002). The increases were considered to reflect discharge of blood from reservoirs, since they occurred within 4 hours. A rise in pH, unaccompanied by a rise in respiratory rate, pointed to an increase in tidal volume.There were suggestions of breed differences. The T-breed appeared to be relatively cold tolerant owing to the high thermal insulation of their hair coat, and also relatively heat tolerant, possibly due to their low heat production, as evidenced indirectly by their low normal heart rate (87 compared with 95 beats/min in the other two breeds).     

Evaluation of the Effective Inactivation of Enteric Bacteria and Viruses From Swine Effluent and Sludge at Tropical Temperatures

The safe recycling of organic wastes such as the nutrients obtained from agriculture activities is a relevant aspect of the “One Health” strategy, a worldwide initiative including all aspects of health care for humans and animals, as well as aspects related to the conservation and development of the environment. It represents an important opportunity to mitigate the potential impact of microbial pathogens likely present in nutrient natural sources, as digestate, when applied to land as fertilizers. The objectives of the current study were to determine the inactivation of enteric microorganisms in swine digestate (effluent and sludge) during storage in anaerobic conditions and at different ambient temperatures of tropical zones (16, 22, and 37 °C). Human adenovirus 2 (HAdV-2), bacteriophage PhiX-174, and Salmonella enterica serovar typhimurium (S. typhimurium) were used as enteric microbial models to determine the minimum storage time required to reduce at least 3log of enteric microorganisms load in both matrices at the mentioned temperatures. The minimum storage time required for S. typhimurium was shorter than those observed for viruses at 37 °C, while reduction of at least 3log for S. typhimurium was observed after just 1 day; 20 and 90 days were needed for similar reductions for HAdV-2 and PhiX-174, respectively. Similar results were also observed at lower temperatures: 30 and 45 days were needed for S. typhimurium at 22 and 16 °C, respectively, but 30 and 90 days were needed at 22 °C for HAdV-2 PhiX-174, respectively, or 90 and 120 days at 16 °C for HAdV-2 PhiX-174, respectively. This is a pioneering study on the evaluation of inactivation of enteric viruses in swine digestate in usual tropical ambient temperatures; it demonstrates that the time for a considerable inactivation is longer than that observed for a enteric microorganisms (S. typhimurium), and shows that the storage of swine digestate at the referred temperatures can be used as a low-cost post-treatment to inactivate enteric microorganisms, allowing a further use as safer fertilizer.     

Yeasts as antagonists against fireblight

Yeasts are potential antagonists of microorganisms in the phyllosphere. Due to their osmotolerance, they should also be able to colonize apple flowers. In field experiments, we applied yeast agents against fireblight at two different sites in the southern part of Germany. They showed efficiencies 0–20% below Plantomycin (streptomycin). Co-culture experiments in liquid basal media with synthetic nectar resulted in suppression of Erwinia amylovora by yeast. This effect could not be confirmed with population studies of yeasts and E. amylovora in flower clusters. Field and laboratory experiments indicated that yeasts have antagonistic properties against fireblight but further research is needed to investigate this potential.     

Induced Disease Resistance in Plants by Chemicals

Plants can be induced locally and systemically to become more resistant to diseases through various biotic or abiotic stresses. The biological inducers include necrotizing pathogens, non- pathogens or root colonizing bacteria. Through at network of signal pathways they induce resistance spectra and marker proteins that are characteristic for the different plant species and activation systems. The best characterized signal pathway for systemically induced resistance is SAR (systemic acquired resistance) that is activated by localized infections with necrotizing pathogens. It is characterized by protection against a broad range of pathogens, by a set of induced proteins and by its dependence on salicylic acid (SA) Various chemicals have been discovered that seem to act at various points in these defense activating networks and mimic all or parts of the biological activation of resistance. Of these, only few have reached commercialization. The best- studied resistance activator is acibenzolar-5-methyl (BION). At low rates it activates resistance in many crops against a broad spectrum of diseases, including fungi, bacteria and viruses. In monocots, activated resistance by BION typically is very long lasting, while the lasting effect is less pronounced in dicots. BION is translocated systemically in plants and can take the place of SA in the natural SAR signal pathway, inducing the same spectrum of resistance and the same set of molecular markers. Probenazole (ORYZEMATE) is used mainly on rice against rice blast and bacterial leaf blight. Its mode of action is not well understood partly because biological systems of systemically induced resistance are not well defined in rice. Treated plants clearly respond faster and in a resistant manner to infections by the two pathogens. Other compounds like beta-aminobutyric acid as wdl as extracts from plants and microorganisms have also been described as resistance inducers. For most of these, neither the mode of action nor reliable pre-challenge markers are known and still other pathways for resistance activation are suspected. Resistance inducing chemicals that are able to induce broad disease resistance offer an additional option for the farmer to complement genetic disease resistance and the use of fungicides. If integrated properly in plant health management programs, they can prolong the useful life of both the resistance genes and the fungicides presently used.     

Self-trapping of dark incoherent light beams

"Dark beams" are nonuniform optical beams that contain either a one-dimensional (1D) dark stripe or a two-dimensional (2D) dark hole resulting from a phase singularity or an amplitude depression in their optical field. Thus far, self-trapped dark beams (dark solitons) have been observed using coherent light only. Here, self-trapped dark incoherent light beams (self-trapped dark incoherent wavepackets) were observed. Both dark stripes and dark holes nested in a broad partially spatially incoherent wavefront were self-trapped to form dark solitons in a host photorefractive medium. These self-trapped 1D and 2D dark beams induced refractive-index changes akin to planar and circular dielectric waveguides. The experiments introduce the possibility of controlling high-power coherent laser beams with low-power incoherent light sources such as light emitting diodes.