Biological control of cereal seed-borne diseases by seed bacterization with greenhouse-selected bacteria

About 400 bacterial strains, isolated from roots of wild and cultivated plants, were screened for effects against diseases caused by Drechslera teres and/or Microdochium nivale in greenhouse tests and against common bunt caused by Tilletia caries in field tests. Four of the strains showed good biocontrol activity <70% disease reduction) against D. teres and T. caries both in screenings and field tests. One Pseudomonas isolate, MA 342, strongly and reliably suppressed both D. teres and T. caries in the field, while effects against M. nivale were weaker. The effects could not be enhanced by varying pre-application or seed application procedures. This isolate could be stored as a suspension in a refrigerator, frozen or applied to seeds for at least one month without loosing its disease controlling ability.     

Comparative evaluation of the emulsifying properties of phosphatidylcholine after enzymatic acyl modification

The ability of enzymatically synthesized structured phosphatidylcholine (PC) containing caprylic acid to form and stabilize oil-in-water emulsions prepared with different triglycerides [medium chain triglycerides (MCT), soybean oil, and enzymatically synthesized structured lipids] was examined and compared with natural soybean PC and deoiled lecithin. Emulsions were prepared with varying oil and emulsifier concentrations. The particle size distribution, creaming stability, and viscosity were measured for the evaluation of the emulsifying properties. With an increase in the oil concentration, there was an increase in particle size, viscosity, and creaming layer. With an increase in the phospholipid (PL) concentration, there was usually a decrease in particle size and an increase in viscosity, where the emulsion stability was increased. General emulsions prepared with structured lipids resulted in smaller particle sizes as compared to MCT and soybean oil. Deoiled lecithin was able to increase the viscosity more significantly and give smaller particle sizes as compared to the other emulsifiers, thus producing more stable emulsions. However, in certain cases, structured PC was superior to deoiled lecithin and soybean PC. This observation was made for emulsions prepared with soybean oil or structured lipid at an oil/water ratio of 10:90. At an oil/water ratio of 30:70, the deoiled lecithin performed better as compared to the other PLs with all oil types. However, structured PC produced more stable emulsions as compared to natural soybean PC in MCT and soybean oil.     

CD46 in meningococcal disease

The human-specific bacterial pathogen Neisseria meningitidis is a major cause of sepsis and/or meningitis. The pili of N. meningitidis interact with CD46, a human cell-surface protein involved in regulation of complement activation. Transgenic mice expressing human CD46 were susceptible to meningococcal disease, because bacteria crossed the blood-brain barrier in these mice. Development of disease was more efficient with piliated bacteria after intranasal, but not intraperitoneal, challenge of CD46 transgenic mice, suggesting that human CD46 facilitates pilus-dependent interactions at the epithelial mucosa. Hence, the human CD46 transgenic mice model is a potentially useful tool for studying pathogenesis and for vaccine development against meningococcal disease.     

Pulsed-field gel electrophoresis and distribution of the genes zag and fnz in isolates of Streptococcus equi

Streptococcus equi subsp. equi and subsp. zooepidemicus are important pathogens of the equine respiratory tract. Isolates of both subspecies were examined by pulsed-field gel electrophoresis (PFGE). With the exception of eight isolates, a unique band pattern was displayed for each of the 48 subsp. zooepidemicus isolates tested. A method to distinguish isolates of the genetically very homogeneous subsp. equi has hitherto not been available, although several methods have been tested. By the use of PFGE, 50 isolates of subsp. equi could be divided into eleven groups, each with a unique pulsotype. In addition, the recently characterised genes encoding the cell-wall proteins ZAG and FNZ of S. equi subsp. zooepidemicus strain ZV were shown by Southern blots to be present in all 98 tested isolates, including the type strains of the two subspecies. Binding assays showed that the expression of the two genes clearly differentiate between the two subspecies.     

Evaluation of tickGARD(PLUS), a novel vaccine against Boophilus microplus, in lactating Holstein-Friesian cows

The effects of vaccination with the Bm 86 vaccine TickGARD(PLUS) against infestation with cattle tick (Boophilus microplus) and of holding cattle on a feedpad until 09:00 hours after the morning milking was tested on 40 mid lactation Holstein cattle using a factorial design. Vaccination resulted in a 56% reduction in tick numbers in the field over one generation, and a 72% reduction in laboratory measures of the reproductive efficiency of ticks. The liveweight gain of vaccinated cattle over 27 weeks was 18.6 kg higher than that of controls, and vaccinated cattle tended to have lower somatic cell count in milk (SCC). There were no other significant differences in measures of production. Cattle kept on the feedpad after the morning milking carried 26% more ticks than those returned immediately to their paddocks.     

Einfluss von Erntezeitpunkt und Lagerverfahren auf die Druckstellenempfindlichkeit von Äpfeln

The influence of harvest date and storage method on bruises sensitivity of apples was investigated. The cultivars ‘Braeburn’, ‘Jonagold’ and ‘Golden Delicious’ were harvested at three times in an interval of 10 days. Fruits have been stored at 2°C in normal atmosphere (cold storage) or in film bags (CA-/ULO-storage; CA?=?Controlled Atmosphere, ULO?=?Ultra Low Oxygen) for three months. Monthly fruits were bruised by a penetrometer applying a range of pressures. One day later the appearance of bruises were evaluated. Increasing pressures resulted in bruises of increasing severity. Early harvest led to less severe bruises. No differences were observed in storage conditions, but duration of storage increased bruise sensitivity of ‘Braeburn’. In comparison of the three cultivars ‘Braeburn’ was less sensitive than ‘Jonagold’ and ‘Golden Delicious’.     

Diagnostic value of rectal temperature of African cattle of variable coat colour infected with trypanosomes and tick-borne infections

Diagnosis of major endemic bovine parasitic diseases in sub-Saharan Africa such as trypanosomosis, theileriosis, anaplasmosis, babesiosis and cowdriosis is increasingly relying on clinical diagnosis due to deterioration of veterinary services and laboratory facilities. Pyrexia is a common clinical feature of aforementioned diseases whose detection relies on measurement of rectal temperature. The research undertaken in this study was aimed at assessing the effects of diurnal changes and variable coat colour of indigenous Nkedi Zebu cattle on the diagnostic value of rectal temperature under tropical conditions. The results revealed that variation in rectal temperature was significantly influenced by time of day it was taken and by the coat colour of the Nkedi Zebu cattle (P < 0.001). Rectal temperature experienced diurnal changes: steadily rising to reach a peak at 17.00 h before declining. The mean rectal temperature of unhealthy cattle was significantly higher (P < 0.05) than that of the healthy ones only between 13.00 and 17.00 h of the day. During which period the proportion of unhealthy cattle having a rectal temperature of 39.4 °C or higher was significantly higher than that of healthy ones (P < 0.001). Regarding the variable coat colour of indigenous breeds, rectal temperature among cattle of different coat colours was significantly different (P < 0.05). In conclusion it is important to consider diurnal changes in rectal temperature and differences due to variable coat colour of indigenous African breeds when measuring rectal temperature for assessing pyrexia, during clinical diagnosis of bovine trypanosomosis and tick-borne diseases that are endemic in many countries in sub-Saharan Africa.     

Fibril angle variability in earlywood of Norway spruce using soft rot cavities and polarization confocal microscopy

The main purpose of this study was to investigate the variability of the fibril angle of tracheids in earlywood of Norway spruce (Picea abies L. Karst.). Polarization confocal microscopy was chosen and compared with the method utilizing the orientation of soft rot cavities. There was a significant correlation between the soft rot and polarization confocal microscopy methods, which showed the same trend of high fibril angles in the first part of the earlywood followed by a decrease toward the end of earlywood. This declining trend was less pronounced in annual rings containing compression wood. Moreover, large variations in fibril angle occurred between neighboring tracheids. The investigation also emphasized the differences between X-ray diffraction and microscopic methods, as the large variation seen by the latter methods is not seen by the X-ray diffraction approach because of its large area of measurement. No correlation was found between fiber morphology (i.e., average length, width, density) and the average fibril angle in the investigated annual rings.     

The fibrillar orientation in the S2-layer of wood fibres as determined by X-ray diffraction analysis

Summary It is the fibrillar orientation in the S2-layer which to a great extent determines the mechanical properties of the wood fibre, with regard both to strength and stiffness and to swelling properties. Measurements of the average fibril angle of fibres are not however easy and the results differ between the methods used. In order to evaluate in more detail how the fibril angle varies in spruce wood, an X-ray method based on diffraction from the 040-plane was developed. By comparison with microscopic examination it is concluded that reliable results relating to the fibrillar orientation in the S2-layer are obtained with the X-ray technique. It is shown that the fibril angle of mature wood is rather constant with regard to both age of the annual ring and its position in the height of the tree. The fibril angle of the earlywood is found to be only slightly higher than that of latewood fibres. It is also shown that compression wood may be easily identified by virtue of the fact that its fibril angle is much higher than that of normal mature wood.The authors thank Ms Ulla Jonsson for the microscopic measurements and Dr Anthony Bristow for the linguistic revision