[Not Available]. / Belastung von Winterweizen mitAlternaria-mykotoxinen im Land Brandenburg.

Knowledge about the contamination of cereals with mycotoxins produced by the fungusAlternaria is rare in Germany. With regard to the fact thatAlternaria spp. were detected in the leaves and in the ears of winter wheat in high frequency and high numbers a monitoring program was started in order to get more information about the actual contamination of winter wheat with the three importantAlternaria-mycotoxins: Alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TeA). In 2000 and 2001 the occurrence ofAlternaria spp and their toxins in kernels and straw of winter wheat harvested in the state of Brandenburg (Germany) was investigated. First, for the sensitive determination of theAlternaria mycotoxins a HPLC method has been developed. Sample preparation included the extraction with acetonitrile/KCI and the purification by a liquid/liquid partition step. The toxins were analysed by HPLC with fluorescence (AOH, AME) or UV/VIS (TeA) detection after separation through a C18 column using methanol + water + zinc sulphate as eluent. AME and TeA were only detected in few kernel probes in concentrations of 45-83 ppb (AME) and 44-105 ppb (TeA), respectively. 50% of the straw probes were highly contaminated with TeA (300 ppb-75 ppm).

Population dynamics and antagonistic potential of enterococci colonizing the phyllosphere of grasses.

AIMS: To investigate the spatial and temporal dynamics of enterococci colonizing forage grass and their ability to produce bacteriocins. METHODS AND RESULTS: Enterococci could be detected on above-ground plant parts throughout the growing season, with high continuity but low cell numbers (2.60 x 101-6.16 x 104 cfu g-1 fresh matter). A total of 750 strains were isolated and identified by their whole-cell protein patterns as Enterococcus faecalis (7.9%), Ent. mundtii (7.9%), Ent. casseliflavus (5.5%), Ent. faecium (5.2%) and Ent. sulfureus (0.1%). The vast majority of the strains (69.7%) formed a homogeneous 16S rDNA genotype that differed from those of known enterococci. A screening for antagonistic activity using an agar spot test revealed that 18.4% of all isolates were potential antagonists. Partially-purified proteins extracted from cell-free culture supernatant fluids of various species were characterized as pH- and heat-stable bacteriocins active against a wide range of lactic acid bacteria, clostridia and Listeria. The producing strains were antagonistically active even on 'phylloplane agar' at temperatures between 4 and 37 degrees C. CONCLUSION: Enterococci are a common part of the epiphytic microflora of grasses, displaying probably some antagonistic activity. SIGNIFICANCE AND IMPACT OF THE STUDY: The results provide new information on the distribution, species diversity and antagonistic potential of enterococci in the phyllosphere.

A taxonomic study of bacteria isolated from grasses: a proposed new species Pseudomonas graminis sp. nov.

The taxonomic position of a yellow-pigmented group of bacteria, isolated from the phyllosphere of grasses was investigated. Results obtained from restriction analysis of amplified 16S rDNA with seven endonucleases (CfoI, HaeIII, AluI, HinfI, MspI, Sau3A and ScrFI) showed identical restriction patterns for each enzyme of all isolates studied, which suggests that all strains belong to the same species. The grass isolates displayed the characteristics of the genus Pseudomonas. They were Gram-negative, aerobic and rod-shaped with polar flagella. Isolates were catalase-positive and oxidase-negative, and unable to oxidize or ferment glucose with the production of acid. The isolates did not reduce nitrate to nitrite but were able to utilize a wide range of compounds individually as a sole carbon source, with preference being given to the utilization of monosaccharides. The disaccharides tested were not utilized as substrates. The DNA base compositions of the tested strains ranged from 60 to 61 mol% G+C. The major isoprenoid quinone of each was ubiquinone Q-9 and hydroxy fatty acids were represented by 3-hydroxydodecanoic acid and 2-hydroxydodecanoic acid. Comparison of 16S rDNA sequences showed that the bacteria were members of the genus Pseudomonas, with similarity values between 91.5 and 97.7%. DNA-DNA hybridization studies with closely related neighbours revealed a low level of homology (< 27%), indicating that the isolates represent an individual species. On the basis of phenotypic and phylogenetic analyses a new species, Pseudomonas graminis sp. nov. (type strain DSM 11363T), is proposed.

The value of angiography in cerebrovascular disease.

The expanding availability of digital subtraction angiography has essentially contributed in lowering the risks in the use of angiography of the cerebral arteries. The best results in imaging the cerebral artery are achieved by conventional subtraction angiography after selective catheterisation. This is, however, only important for diagnosis in intracerebral pathological changes distal of the Circulus Willisi or in connection with preoperative interventional radiological treatment. Pre-clinical diagnosis of patients with cerebrovascular occlusive disease as well as clinical diagnosis with Doppler and B-scan US sonography can be optimally complemented by DSA using 4-5 French catheters entered in the thoracic ascending aorta. Using this technique, the sensitivity and specificity with an image-matrix of 512 is diagnostically adequate and includes an only limited examination risk. Complication with lasting neurological defects will be least observed after intravenous pre-atrial application of contrast media and most after selective angiography of the carotid artery. Here the extent of the multiple arteriosclerotic obliteration is of essential importance. The quality of interpretation of the diagnostic findings essentially depends on indications not only about the grade of obliteration but also on the morphological details. At present DSA with application of contrast media into the thoracic ascending aorta in combination with the duplex-scan method represent the optimum for the diagnosis of cerebrovascular disease. In spite of lower specificity intravenous application of contrast media has to be preferred for post-operative controls and controls of progressing disease with "screening".

[The spectrum of S. mutans OMZ 176 products from different mono- and disaccharides]. / Das Produktspektrum von S. mutans OMZ 176 aus verschiedenen Mono- und Disacchariden.

S. mutans OMZ 176 produced from mono-, disaccharides and hexitols in microbiological culture up to the log. growth phase different amounts of acid. Lactate was the gas chromatographically analyzed prevailing end product. Microbial suspensions of the same living mass prepared from the cultures produced homofermentatively lactate from glucose and sucrose whereas all other substrates (galactose, lactose, sorbitol, mannitol) were turned over partial heterofermentatively.

[Gas chromatographic analysis of the S. mutans product spectrum from glucose turnover]. / Gaschromatographische Analyse des Produktspektrums von S. mutans aus Glucose.

In addition to other acids lactate was detected as prevailing end product in glucose containing broth of 8 S. mutans strains. The total acid amounts differed depending on the microbial origin. Further quantitative and qualitative differences existed between acidic products of the pH-stat controlled reaction with glucose as substrate and defined germ suspensions. S. mutans LM 7 showed the most strongly heterofermentative pathway.