Molecular mimicry regulates ABA signaling by SnRK2 kinases and PP2C phosphatases

Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, while the conserved ABA-sensing tryptophan of PP2C inserts into the kinase catalytic cleft, thus mimicking receptor-PP2C interactions. These structural results provide a simple mechanism that directly couples ABA binding to SnRK2 kinase activation and highlight a new paradigm of kinase-phosphatase regulation through mutual packing of their catalytic sites.     

Molecular epidemiology of antimicrobial resistance in veterinary medicine: where do we go?

Molecular epidemiology allows us to trace specific microorganisms and mobile genetic elements and to assess their epidemiological and evolutionary relationships. Examples of molecular epidemiology investigations in veterinary hospitals are discussed. They demonstrate the great similarities with the situation in human medicine and the potential usefulness of molecular epidemiology in our fight against antimicrobial resistance and nosocomial infections in veterinary hospitals. A broad knowledge of the diversity of antimicrobial resistance determinants in some major groups of pathogens and commensals from animals such as Enterobacteriaceae, Pasteurellaceae, enterococci and staphylococci is emerging. However, there are important gaps in this knowledge, which are discussed here. Many more molecular epidemiology studies will be necessary to understand and follow the evolution of the problem in veterinary medicine and agriculture on a global scale. To be able to build useful surveillance programs and reliable epidemiological models, and to identify critical intervention points, we need to improve our understanding of antimicrobial resistance at the animal and farm levels. Studies assessing the dynamics of bacterial populations and of resistance determinants at these levels are desperately needed. Understanding the relationships between antimicrobial resistance, colonization factors, and virulence also represents a major issue for which molecular epidemiology investigations will be needed.     

Evaluation of PCR,IEF and ELISA techniques for the detection and identification of potato cyst nematodes from field soil samples in England and Wales

Effective management of potato cyst nematodes (PCNs) requires simple, rapid and accurate identification and quantification of field populations. Soil samples from a survey of 484 fields in potato rotations in England and Wales were used to compare the identification and quantification of PCNs using IEF, PCR, ELISA and bait plant tests. The cyst counts and bait plant test revealed that 64.3% of field samples contained PCNs. Bait plant tests increased the detection rate of PCNs in field samples by 4–6.4%. This means that some infestations are cryptic and would not normally be detected by standard counts. IEF, PCR and ELISA methods distinguished between Globodera rostochiensis and G pallida and were able to register mixed populations; however they were not in full agreement. All methods suggested that G pallida is the dominant species in the field samples tested. The PCR results indicated that 66% of field samples contained pure G pallida, 8% contained pure G rostochiensis and 26% contained mixtures of the two species. Estimates of the relative process times taken per sample in the PCR, IEF and ELISA techniques are given. © 2001 Society of Chemical Industry     

Potential enhancement of degradation of the nematicides aldicarb,oxamyl and fosthiazate in UK agricultural soils through repeated applications

BACKGROUND: The potential for enhanced degradation of the carbamoyloxime nematicides aldicarb and oxamyl and the organophosphate fosthiazate was investigated in 35 UK agricultural soils. Under laboratory conditions, soil samples received three successive applications of nematicide at 25 day intervals. RESULTS: The second and third applications of aldicarb were degraded at a faster rate than the first application in six of the 15 aldicarb‐treated soils, and a further three soils demonstrated rapid degradation of all three applications. High organic matter content and low pH had an inhibitory effect on the rate of aldicarb degradation. Rapid degradation was observed in nine out of the ten soils treated with oxamyl. In contrast, none of the fosthiazate‐treated soils demonstrated enhanced degradation. CONCLUSION: The potential for enhanced degradation of aldicarb and oxamyl was demonstrated in nine out of 15 and nine out of ten soils respectively that had previously been treated with these active substances. Degradation of fosthiazate occurred at a much slower rate, with no evidence of enhanced degradation. Fosthiazate may provide a useful alternative in cases where the efficacy of aldicarb and oxamyl has been reduced as a result of enhanced degradation. Copyright © 2009 Society of Chemical Industry     

Mapping QTL controlling soybean seed sucrose and oligosaccharides in a single family of soybean nested association mapping (SoyNAM) population

The meal value of Soybean for monogastric animals is determined partly by sucrose, raffinose and stachyose. Of these, sucrose is desirable, while raffinose and stachyose are indigestible, causing flatulence and abdominal discomfort. The objective of this study was to identify quantitative trait loci (QTL) controlling seed sucrose, raffinose, and stachyose in a set of 140 SoyNAM (Nested Association Mapping) recombinant inbred lines (RILs), developed from the cross between lines IA3023 and LD02‐4485. A total of 3,038 SNP markers from the Illumina SoyNAM BeadChip SNP were used to map the QTLs for sucrose and the RFOs, raffinose, and stachyose. Significant genotypic differences (p < .001) among RILs were observed for sucrose, raffinose and stachyose contents across years. A 3038 Illumina SoyNAM BeadChip SNPs identified three QTLs for sucrose, one on chromosome 1, explaining 10% variance and two on chromosome 3 each explaining 22%. Raffinose QTL was detected on chromosome 6, explaining 6% variance. The mapped QTLs were novel and spanned regions harbouring candidate genes with roles in plant growth including seed development.     

Association of TALS developmental disorder with defect in minor splicing component U4atac snRNA

The spliceosome, a ribonucleoprotein complex that includes proteins and small nuclear RNAs (snRNAs), catalyzes RNA splicing through intron excision and exon ligation to produce mature messenger RNAs, which, in turn serve as templates for protein translation. We identified four point mutations in the U4atac snRNA component of the minor spliceosome in patients with brain and bone malformations and unexplained postnatal death [microcephalic osteodysplastic primordial dwarfism type 1 (MOPD 1) or Taybi-Linder syndrome (TALS); Mendelian Inheritance in Man ID no. 210710]. Expression of a subgroup of genes, possibly linked to the disease phenotype, and minor intron splicing were affected in cell lines derived from TALS patients. Our findings demonstrate a crucial role of the minor spliceosome component U4atac snRNA in early human development and postnatal survival.