Production of vomitoxin on corn by Fusarium graminearum NRRL 5883 and Fusarium roseum NRRL 6101.

Two vomitoxin-producing isolates of Fusarium spp. were grown on cracked corn for 1 to 8 weeks at 15, 20, 25, 28, and 32 degrees C. Maximum production of vomitoxin by Fusarium graminearum Schw. NRRL 5883 occurred at 30 degrees C and 40 days, and that by Fusarium roseum Schw. NRRL 6101 occurred at 26 degrees C and 41 days. These optimum production points were determined from response surface contour graphs in relation to temperature and time. Only small amounts of vomitoxin were produced at 15 and 20 degrees C by each strain. A 133-microgram quantity of vomitoxin, with an indicated purity of 95%, was isolated per gram of corn fermented with F. graminearum NRRL 5883.     

An estimate of the global error frequency in translation

Summary Electrophoretic heterogeneity in a set of selected proteins is used to estimate the average error frequency during translation. Estimates based upon streptomycin-induced heterogeneity as well as mistranslation of an ochre codon yield an average error frequency of 4x10^-4 for normally growing cells.     

Novel biomarkers for pre-eclampsia detected using metabolomics and machine learning

Pre-eclampsia is a multi-system disorder of pregnancy with major maternal and perinatal implications. Emerging therapeutic strategies are most likely to be maximally effective if commenced weeks or even months prior to the clinical presentation of the disease. Although widespread plasma alterations precede the clinical onset of pre-eclampsia, no single plasma constituent has emerged as a sensitive or specific predictor of risk. Consequently, currently available methods of identifying the condition prior to clinical presentation are of limited clinical use. We have exploited genetic programming, a powerful data mining method, to identify patterns of metabolites that distinguish plasma from patients with pre-eclampsia from that taken from healthy, matched controls. High-resolution gas chromatography time-of-flight mass spectrometry (GC-tof-MS) was performed on 87 plasma samples from women with pre-eclampsia and 87 matched controls. Normalised peak intensity data were fed into the Genetic Programming (GP) system which was set up to produce a model that gave an output of 1 for patients and 0 for controls. The model was trained on 50% of the data generated and tested on a separate hold-out set of 50%. The model generated by GP from the GC-tof-MS data identified a metabolomic pattern that could be used to produce two simple rules that together discriminate pre-eclampsia from normal pregnant controls using just 3 of the metabolite peak variables, with a sensitivity of 100% and a specificity of 98%. Thus, pre-eclampsia can be diagnosed at the level of small-molecule metabolism in blood plasma. These findings justify a prospective assessment of metabolomic technology as a screening tool for pre-eclampsia, while identification of the metabolites involved may lead to an improved understanding of the aetiological basis of pre-eclampsia and thus the development of targeted therapies.     

Isolation of gibberellin metabolic pathway genes from barley and comparative mapping in barley, wheat and rice

Gene sequences encoding gibberellin (GA) biosynthetic and catabolic enzymes were isolated from Himalaya barley. These genes account for most of the enzymes required for the core pathway of GA biosynthesis as well as for the first major catabolic enzyme. By means of DNA gel blot analysis, we mapped coding sequences to chromosome arms in barley and wheat using barley-wheat chromosome addition lines, nulli-tetrasomic substitution and ditelosomic lines of wheat. These same sequences were used to identify closely related sequences from rice, which were mapped in silico, thereby allowing their syntenic relationship with map locations in barley and wheat to be investigated. Determination of the chromosome arm locations for GA metabolic genes provides a framework for future studies investigating possible identity between GA metabolic genes and dwarfing genes in barley and wheat.Wolfgang Spielmeyer and Marc Ellis have contributed equally to this work.     

Identification of markers tightly linked to<Emphasis Type="Italic"> sbm</Emphasis> recessive genes for resistance to<Emphasis Type="Italic"> Pea seed-borne mosaic virus</Emphasis>

Two virus resistance loci on linkage groups II and VI have provided the only sources of natural resistance against Pea seed-borne mosaic virus (PSbMV, Potyviridae) in the important crop plant Pisum sativum L. A combination of parallel approaches was used to collate linked markers, particularly for sbm-1 resistance on linkage group VI. We have identified sequences derived from the genes for the eukaryotic translation initiation factors eIF4E and eIF(iso)4E as being very tightly linked to the resistance gene clusters on linkage groups VI and II, respectively. In particular, no recombinants between sbm-1 and eIF4E were found amongst 500 individuals of an F₂ cross between the BC₄ resistant line (JI1405) and its recurrent susceptible parent Scout. In a different mapping population, the gene eIF(iso)4E was also shown to be linked to sbm-2 on linkage group II. A parallel cDNA-AFLP comparison of pairs of resistant and susceptible lines also identified an expressed tag marker just 0.7 cM from sbm-1. eIF4E and eIF(iso)4E have been associated with resistance to related viruses in other hosts. This correlation strengthens the use of our markers as valuable tools to assist in breeding multiple virus resistances into peas, and identifies potential targets for resistance gene identification in pea.Communicated by C. Möllers     

Cathepsin B mRNA and protein expression following contusion spinal cord injury in rats

We provide the first data that cathepsin B (Cath B), a lysosomal cysteine protease, is up-regulated following contusion-spinal cord injury (SCI). Following T12 laminectomy and moderate contusion, Cath B mRNA and protein expression profiles were examined from 2 to 168 h post-injury in rats using real-time PCR and immunoblots, respectively. Contusion injury significantly increased [mRNA]Cath B in the injury site and adjacent segments over sham injury levels. While the largest [mRNA]Cath B induction (20-fold over naive) was seen in the injury site, the caudal segment routinely yielded [mRNA]Cath B levels greater than 10-fold over naive. Interestingly, sham injury animals also experienced mRNA induction at several time points at the injury site and in segments rostral and caudal to the injury site. Contusion injury also significantly elevated levels of Cath B proenzyme protein (37 kDa) over sham injury in the injury site (48, 72 and 168 h post-injury). Furthermore, significant protein increases of single and double chain Cath B (both active forms) occurred at the injury site at 72 and 168 h post-injury. Similar significant increases in Cath B protein levels were seen in areas adjacent to the injury site. The induction of Cath B mRNA and protein expression following contusion injury is previously undescribed and suggests that Cath B may potentially be involved in the secondary injury cascade, perhaps for as long as 1 week post-injury.     

Insertional polymorphism and antiquity of PDR1 retrotransposon insertions in pisum species

Sequences flanking 73 insertions of the retrotransposon PDR1 have been characterized, together with an additional 270 flanking regions from one side alone, from a diverse collection of Pisum germ plasm. Most of the identified flanking sequences are repetitious DNAs but more than expected (7%) lie within nuclear gene protein-coding regions. The approximate age of 52 of the PDR1 insertions has been determined by measuring sequence divergence among LTR pairs. These data show that PDR1 transpositions occurred within the last 5 MY, with a peak at 1-2.5 MYA. The insertional polymorphism of 68 insertions has been assessed across 47 selected Pisum accessions, representing the diversity of the genus. None of the insertions are fixed, showing that PDR1 insertions can persist in a polymorphic state for millions of years in Pisum. The insertional polymorphism data have been compared with the age estimations to ask what rules control the proliferation of PDR1 insertions in Pisum. Relatively recent insertions (< approximately 1.5 MYA) tend to be found in small subsets of the Pisum accessions set, "middle-aged" insertions (between approximately 1.5 and 2.5 MYA) vary greatly in their occurrence, and older insertions (> approximately 2.5 MYA) are mostly found in small subsets of Pisum. Finally, the average age estimate for PDR1 insertions, together with an existing data set for PDR1 retrotransposon SSAP markers, has been used to derive an estimate of the effective population size for Pisum of approximately 7.5 x 10(5).     

Magnetic resonance imaging for in vivo assessment of three-dimensional patellar tracking

We have developed a non-invasive measurement technique which can ultimately be used to quantify three-dimensional patellar kinematics of human subjects for a range of static positions of loaded flexion and assessed its accuracy. Knee models obtained by segmenting and reconstructing one high-resolution scan of the knee were registered to bone outlines obtained by segmenting fast, low-resolution scans of the knee in static loaded flexion. We compared patellar tracking measurements made using the new method to measurements made using Roentgen stereophotogrammetric analysis in three cadaver knee specimens loaded through a range of flexion in a test rig. The error in patellar spin and tilt measurements was less than 1.02 degrees and the error in lateral patellar shift was 0.88 mm. Sagittal plane scans provided more accurate final measurements of patellar spin and tilt, whereas axial plane scans provided more accurate measurements of lateral translation and patellar flexion. Halving the number of slices did not increase measurement error significantly, which suggests that scan times can be reduced without reducing accuracy significantly. The method is particularly useful for multiple measurements on the same subject because the high-resolution bone-models need only be created once; thus, the potential variability in coordinate axes assignment and model segmentation during subsequent measurements is removed.     

Proteasome mutants, pre4-2 and ump1-2, suppress the essential function but not the mitochondrial RNase P function of the Saccharomyces cerevisiae gene RPM2

The Saccharomyces cerevisiae nuclear gene RPM2 encodes a component of the mitochondrial tRNA-processing enzyme RNase P. Cells grown on fermentable carbon sources do not require mitochondrial tRNA processing activity, but still require RPM2, indicating an additional function for the Rpm2 protein. RPM2-null cells arrest after 25 generations on fermentable media. Spontaneous mutations that suppress arrest occur with a frequency of approximately 9 x 10(-6). The resultant mutants do not grow on nonfermentable carbon sources. We identified two loci responsible for this suppression, which encode proteins that influence proteasome function or assembly. PRE4 is an essential gene encoding the beta-7 subunit of the 20S proteasome core. A Val-to-Phe substitution within a highly conserved region of Pre4p that disrupts proteasome function suppresses the growth arrest of RPM2-null cells on fermentable media. The other locus, UMP1, encodes a chaperone involved in 20S proteasome assembly. A nonsense mutation in UMP1 also disrupts proteasome function and suppresses Deltarpm2 growth arrest. In an RPM2 wild-type background, pre4-2 and ump1-2 strains fail to grow at restrictive temperatures on nonfermentable carbon sources. These data link proteasome activity with Rpm2p and mitochondrial function.