Hidden weapons of microbial destruction in plant genomes

Recent bioinformatic analyses of sequenced plant genomes reveal a previously unrecognized abundance of genes encoding antimicrobial cysteine-rich peptides, representing a formidable and dynamic defense arsenal against plant pests and pathogens

Studies on the structure and metabolism of polysaccharides

1. Periodate Oxidation of Glycogens. Proceedings of the Biochemical Society, 17 July 1953. Biochem.J., 1953, , xx. • 2. Multiple - branching in Arnylopectin. With E.L. Hirst. Chem. and Ind., 1954, 224. • 3. The Alkali- stability and Molecular Size of Glycogens. With C.T. Greenwood. Proc. Chem. Soc. , 1957, 26. • 4. Observations on the Absorption Spectra of Polysaccharide - Iodine Complexes. With A.R. Archibald and A. Wright. Proceedings of the Biochemical Society, 25 March 1960. Biochem.J. , 1960, 7,2, in the press. • 5. a -1 :4- Glucosans. Part II. The Molecular Structure of the Liver Glycogen from a Case of von Gierke's Disease. J.Chem.Soc., 1954, 3527. • 6. a- 1:4- Glucosans. Part III. The Molecular Structure of Brewer's Yeast Glycogen. With Khin Maung. J.Chem.Soc., 1955, 867. • 7. a -1 :4- Glucosans. Part IV. A re- examination of the Molecular Structure of Floridean Starch. With I.D. Fleming and E.L. Hirst. J.Chem.Soc., 1936, 2831. • 8. a -1 : 4- Glucosans . Part V. End -group Assay of Glycogens by Periodate Oxidation, and the Oxidation of Maltose by Sodium Metaperiodate. With A.R. Archibald. J.Chem.Soc., 1957, 2205. • 9. a- 1 :4- Glucosans. Part VI. Further Studies on the Molecular Structures of Glycogens. With A. Margaret Liddle. J.Chem.Soc., 1957, 3432. • 10. a -1 :4- Glucosans. Part VII. The Enzymic Degradation and Molecular Structure of Amylase. With J.M.G. Cowie, I.D. Fleming and C.T. Greenwood. J.Chem.Soc., 1957, 4430. • 11. a -1 :4- Glucosans. Part VIII. Multiple- branching in Glycogen and Amylopectin. With A. Margaret Liddle. J.Chem.Soc., 1957, 4708. • 12. a- 1:4- Glucosans. Part IX. The Molecular Structure of a Starch -type Polysaccharide from Dunaliella bioculata. With B.P. Eddy and I.D. Fleming. J.Chem.Soc., 1958, 2827. • 13. a -1 : 4 -Gluco sans. Part 10. Glycogen Structure and Rigor Mortis in Mammalian Muscles. With R.A. Lawrie and A. Wright. Biochem.J., 1959, u, 485. • 14. Physicochemical Studies on Starches. Part XII. The Molecular Weight of Glycogens in Aqueous Solution. With W.A.J. Bryce, C.T. Greenwood and I.G. Jones. J.Chem.Soc., 1958, 711. • 15. Biochemical Investigation of a Case of Glycogen-Storage Disease (von Gierke's Disease). With A. Calderbank, P.W. Kent, J. Lorber and A. Wright. Biochem.J., 1960, 1.4, 223. • 16. Studies on the Metabolism of the Protozoa. Part 6. The Glycogens of the Parasitic Flagellates Trichomonas foetus and Trichomonas gallinae. With J.F. Ryley. Biochem.J., 1955, .53, 369. • 17. Structure of a Reserve Polysaccharide (Leucosin) from Ochromonas malhamensis. With A.R. Archibald and J.F. Ryley. Chem. and Ind., 1958, 1516. • 18. Studies on the Metabolism of The Molecular Structure of a from Chilomonas paramecium. E.L. Hirst and J.F. Ryley. the Protozoa. Part VIII. Starch -type Polysaccharide With A.R. Archibald, J.Chem.Soc., 1960, 556. • 19. A Comparison of IsoLichenin and Lichenin from Iceland Moss (Cetraria islandica). With N.B. Chanda and E.L. Hirst. J.Chem.Soc., 1957, 1951. • 20. Periodate Oxidation of Laminarin. With F.B. Anderson and E.L. Hirst. Chem. and Ind., 1957, 1178. • 21. The Constitution of Laminarin. Part III. The Fine Structure of Insoluble Laminarin. With F.B. Anderson, E.L. Hirst and A.G. Ross. J.Chem.Soc., 1958, 3233. • 22. The Molecular Structure of Glycogens. Adv. Carbohydrate Chem. , 1957, 12, 261. • 23. Structural Analysis of Polysaccharides. Royal Institute of Chemistry; Lectures, Monographs and Reports, 1959, No.2. • 24. The Composition and Structure of Polysaccharides; Structural Analysis of Polysaccharides by Methylation; Structural Analysis of Polysaccharides by Periodate Oxidation. Contributions to the Chemical Section of the 'Biochemists Handbook' to be published in 1960 by E. and F. Spon Ltd. (Abstract). • 25. Observations on the Carbohydrase Activity of certain Seaweed Extracts. With W.A.M. Duncan and A.G. Ross. Proceedings of the Biochemical Society, 9 April 1954. Biochem.J., 1954, 2, xviii. • 26. Enzyme Systems in Marine Algae. Part 1. The Carbohydrase Activities of Unfractionated Extracts of Cladophora rupestris, Laminaria digitata, Rhodrmenia palmata and Ulva lactuca. With W.A.M. Duncan and A.G. Ross. Biochem.J., 1956, 6 , 44. • 27. Enzyme Systems in Marine Algae. Part 2. Trans -a- Glucosylation by Extracts of Cladophora rupestris. With W.A.M. Duncan. Biochem.J., 1958, §.2, 343. • 28. Enzyme Systems in Marine Algae. Part 3. Trans -ß- Glucosylation by Extracts of Cladophora rupestres and Ulva lactuca. With W.A.M. Duncan and J.L. Thompson. Biochem.J., 1959, ,7 , 295. • 29. The Action of 3- Amylase, Muscle Phosphorylase and Potato Phosphorylase on some Glycogens. With A. Margaret Liddle. Proceedings of the Biochemical Society, 16 September 1955. Biochem.J., 1955, 61, xii. • 30. Observations on Barley (3- Glucosidases. Proceedings of the Biochemical Society, 16 September 1955. Biochem.J., 1955, 61, xiii. • 31 Observations on the Specificity of Yeast Isoamylase. With Khin Maung. Chem. and Ind., 1955, 950. 32. Yeast Branching Enzyme. With Khin Maung. Proceedings of the Biochemical Society, 13 April 1956. Biochem.J., 1956, L, 16P. • 33. Mechanism of the Degradation of Potato Amylose by ß- Amylase. With J.M.G. Cowie, I.D. Fleming and C.T. Greenwood. Chem. and Ind., 1957, 634. • 34. Observations on the Specificity of R- Enzyme. With I.D. Fleming. Chem. and Ind., 1958, 831. • 35. Enzymic Conversion of Amylopectin into a Glycogen -Type Polysaccharide. With Zeenat H. Gunja. Chem. and Ind., 1959, 1017. • 36. Physicochemical Studies on Starches. Part IX. The Mechanism of the ß- Amylolysis of Amylose and the Nature of the p -Limit Dextrin. With J.M.G. Cowie, I.D. Fleming and C.T. Greenwood. J.Chem.Soc., 1958, 697. • 37. Studies on Carbohydrate -Metabolizing Enzymes. Part 1. Trans -ß- Glucosylation by Barley Enzymes. With F.B. Anderson. Biochem.J., 1959, 71, 407. • 38. Studies on Carbohydrate -Metabolizing Enzymes. Part 2. Trans -a- Glucosylation by Extracts of Tetrahymena pyriformis. With A.R. Archibald. Biochem.J., 1959, 7, 292. • 39. Studies on Carbohydrate -Metabolizing Enzymes. Part 3. Yeast Branching Enzyme. With Z.H. Gunja and Khin Maung. Biochem.J., 1960, 75, 441. (page proof) . • 40. Studies on Carbohydrate -Metabolizing Enzymes. Part 4. The Action of Z- Enzyme on Starch -type Polysaccharides. With W.L. Cunningham, A. Wright and I.D. Fleming. J.Chem.Soc., 1960, in the press. (Accepted February 1960). • 41. The Enzymic Degradation of Starch and Glycogen. Ann.Re orts, Chem.Soc., 1954, Q, 288. • 42. The Enzymic Degradation of Polysaccharides. Quart. Revs. , 1955, 2, 73 • 43. The Properties of P- Enzyme, Glycogen Phosphorylase, Q- Enzyme and Branching Enzyme. Contributions to the Enzymological Section of the 'Biochemists Handbook' to be published in 1960 by E. and F. Spon Ltd. • 44 Trans a- and ß- Glucosylation Reactions. Bull.Soc.Chim. Biol., 1960, in the press. (Submitted February 1960)

Measuring the RFI environment of the South African SKA site

The Square Kilometre Array (SKA) Project is an international effort to build the world’s largest radio telescope. It will be 100 times more sensitive than any other radio telescope currently in existence and will consist of thousands of dishes placed at baselines up to 3000 km. In addition to its increased sensitivity it will operate over a very wide frequency range (current specification is 100 MHz - 22 GHz) and will use frequency bands not primarily allocated to radio astronomy. Because of this the telescope needs to be located at a site with low levels of radio frequency interference (RFI). This implies a site that is remote and away from human activity. In bidding to host the SKA, South Africa was required to conduct an RFI survey at its proposed site for a period of 12 months. Apart from this core site, where more than half the SKA dishes may potentially be deployed, the measurement of remote sites in Southern Africa was also required. To conduct measurements at these sites, three mobile measurement systems were designed and built by the South African SKA Project. The design considerations, implementation and RFI measurements recorded during this campaign will be the focus for this dissertation

Results from a set of three-dimensional numerical experiments of a hot Jupiter atmosphere

We present highlights from a large set of simulations of a hot Jupiter atmosphere, nominally based on HD 209458b, aimed at exploring both the evolution of the deep atmosphere, and the acceleration of the zonal flow or jet. We find the occurrence of a super-rotating equatorial jet is robust to changes in various parameters, and over long timescales, even in the absence of strong inner or bottom boundary drag. This jet is diminished in one simulation only, where we strongly force the deep atmosphere equator-to-pole temperature gradient over long timescales. Finally, although the eddy momentum fluxes in our atmosphere show similarities with the proposed mechanism for accelerating jets on tidally-locked planets, the picture appears more complex. We present tentative evidence for a jet driven by a combination of eddy momentum transport and mean flow.Comment: 26 pages, 22 Figures. Accepted for publication in Astronomy and Astrophysic

Oded Haklai, Palestinian Ethnonationalism in Israel (Philadelphia: University of Pennsylvania Press)

Plants respond to pathogens either by investing more resources into immunity which is costly to development, or by accelerating reproductive processes such as flowering time to ensure reproduction occurs before the plant succumbs to disease. In this study we explored the link between flowering time and pathogen defense using the interaction between Arabidopsis thaliana and the root infecting fungal pathogen Fusarium oxysporum. We report that F. oxysporum infection accelerates flowering time and regulates transcription of a number of floral integrator genes, including FLOWERING LOCUS C (FLC), FLOWERING LOCUS T (FT) and GIGANTEA (GI). Furthermore, we observed a positive correlation between late flowering and resistance to F. oxysporum in A. thaliana natural ecotypes. Late-flowering gi and autonomous pathway mutants also exhibited enhanced resistance to F. oxysporum, supporting the association between flowering time and defense. However, epistasis analysis showed that accelerating flowering time by deletion of FLC in fve-3 or fpa-7 mutants did not alter disease resistance, suggesting that the effect of autonomous pathway on disease resistance occurs independently from flowering time. Indeed, RNA-seq analyses suggest that fve-3 mediated resistance to F. oxysporum is most likely a result of altered defense-associated gene transcription. Together, our results indicate that the association between flowering time and pathogen defense is complex and can involve both pleiotropic and direct effects

A high-throughput method for the detection of homoeologous gene deletions in hexaploid wheat

<p>Abstract</p> <p>Background</p> <p>Mutational inactivation of plant genes is an essential tool in gene function studies. Plants with inactivated or deleted genes may also be exploited for crop improvement if such mutations/deletions produce a desirable agronomical and/or quality phenotype. However, the use of mutational gene inactivation/deletion has been impeded in polyploid plant species by genetic redundancy, as polyploids contain multiple copies of the same genes (homoeologous genes) encoded by each of the ancestral genomes. Similar to many other crop plants, bread wheat (<it>Triticum aestivum </it>L.) is polyploid; specifically allohexaploid possessing three progenitor genomes designated as 'A', 'B', and 'D'. Recently modified TILLING protocols have been developed specifically for mutation detection in wheat. Whilst extremely powerful in detecting single nucleotide changes and small deletions, these methods are not suitable for detecting whole gene deletions. Therefore, high-throughput methods for screening of candidate homoeologous gene deletions are needed for application to wheat populations generated by the use of certain mutagenic agents (e.g. heavy ion irradiation) that frequently generate whole-gene deletions.</p> <p>Results</p> <p>To facilitate the screening for specific homoeologous gene deletions in hexaploid wheat, we have developed a TaqMan qPCR-based method that allows high-throughput detection of deletions in homoeologous copies of any gene of interest, provided that sufficient polymorphism (as little as a single nucleotide difference) amongst homoeologues exists for specific probe design. We used this method to identify deletions of individual <it>TaPFT1 </it>homoeologues, a wheat orthologue of the disease susceptibility and flowering regulatory gene <it>PFT1 </it>in Arabidopsis. This method was applied to wheat nullisomic-tetrasomic lines as well as other chromosomal deletion lines to locate the <it>TaPFT1 </it>gene to the long arm of chromosome 5. By screening of individual DNA samples from 4500 M2 mutant wheat lines generated by heavy ion irradiation, we detected multiple mutants with deletions of each <it>TaPFT1 </it>homoeologue, and confirmed these deletions using a CAPS method. We have subsequently designed, optimized, and applied this method for the screening of homoeologous deletions of three additional wheat genes putatively involved in plant disease resistance.</p> <p>Conclusions</p> <p>We have developed a method for automated, high-throughput screening to identify deletions of individual homoeologues of a wheat gene. This method is also potentially applicable to other polyploidy plants.</p

Early activation of wheat polyamine biosynthesis during Fusarium head blight implicates putrescine as an inducer of trichothecene mycotoxin production

<p>Abstract</p> <p>Background</p> <p>The fungal pathogen <it>Fusarium graminearum </it>causes Fusarium Head Blight (FHB) disease on wheat which can lead to trichothecene mycotoxin (<it>e.g</it>. deoxynivalenol, DON) contamination of grain, harmful to mammalian health. DON is produced at low levels under standard culture conditions when compared to plant infection but specific polyamines (<it>e.g</it>. putrescine and agmatine) and amino acids (<it>e.g</it>. arginine and ornithine) are potent inducers of DON by <it>F. graminearum </it>in axenic culture. Currently, host factors that promote mycotoxin synthesis during FHB are unknown, but plant derived polyamines could contribute to DON induction in infected heads. However, the temporal and spatial accumulation of polyamines and amino acids in relation to that of DON has not been studied.</p> <p>Results</p> <p>Following inoculation of susceptible wheat heads by <it>F. graminearum</it>, DON accumulation was detected at two days after inoculation. The accumulation of putrescine was detected as early as one day following inoculation while arginine and cadaverine were also produced at three and four days post-inoculation. Transcripts of ornithine decarboxylase (ODC) and arginine decarboxylase (ADC), two key biosynthetic enzymes for putrescine biosynthesis, were also strongly induced in heads at two days after inoculation. These results indicated that elicitation of the polyamine biosynthetic pathway is an early response to FHB. Transcripts for genes encoding enzymes acting upstream in the polyamine biosynthetic pathway as well as those of ODC and ADC, and putrescine levels were also induced in the rachis, a flower organ supporting DON production and an important route for pathogen colonisation during FHB. A survey of 24 wheat genotypes with varying responses to FHB showed putrescine induction is a general response to inoculation and no correlation was observed between the accumulation of putrescine and infection or DON accumulation.</p> <p>Conclusions</p> <p>The activation of the polyamine biosynthetic pathway and putrescine in infected heads prior to detectable DON accumulation is consistent with a model where the pathogen exploits the generic host stress response of polyamine synthesis as a cue for production of trichothecene mycotoxins during FHB disease. However, it is likely that this mechanism is complicated by other factors contributing to resistance and susceptibility in diverse wheat genetic backgrounds.</p

In Situ Visualization of Block Copolymer Self-Assembly in Organic Media by Super-Resolution Fluorescence Microscopy

Analytical methods that enable visualization of nanomaterials derived from solution self‐assembly processes in organic solvents are highly desirable. Herein, we demonstrate the use of stimulated emission depletion microscopy (STED) and single molecule localization microscopy (SMLM) to map living crystallization‐driven block copolymer (BCP) self‐assembly in organic media at the sub‐diffraction scale. Four different dyes were successfully used for single‐colour super‐resolution imaging of the BCP nanostructures allowing micelle length distributions to be determined in situ. Dual‐colour SMLM imaging was used to measure and compare the rate of addition of red fluorescent BCP to the termini of green fluorescent seed micelles to generate block comicelles. Although well‐established for aqueous systems, the results highlight the potential of super‐resolution microscopy techniques for the interrogation of self‐assembly processes in organic media

The non-gibberellic acid-responsive semi-dwarfing gene uzu affects Fusarium crown rot resistance in barley

BACKGROUND: Studies in Arabidopsis show that DELLA genes may differentially affect responses to biotrophic and necrophic pathogens. A recent report based on the study of DELLA-producing reduced height (Rht) genes in wheat and barley also hypothesized that DELLA genes likely increased susceptibility to necrotrophs but increased resistance to biotrophs. RESULTS: Effects of uzu, a non-GA (gibberellic acid)-responsive semi-dwarfing gene, on Fusarium crown rot (FCR) resistance in barley were investigated. Fifteen pairs of near isogenic lines for this gene were generated and assessed under two different temperature regimes. Similar to its impacts on plant height, the semi-dwarfing gene uzu also showed larger effects on FCR severity in the high temperature regime when compared with that in the low temperature regime. CONCLUSIONS: Results from this study add to the growing evidence showing that the effects of plant height on Fusarium resistances are unlikely related to DELLA genes but due to direct or indirect effects of height difference per se. The interaction between these two characteristics highlights the importance of understanding relationships between resistance and other traits of agronomic importance as the value of a resistance gene could be compromised if it dramatically affects plant development and morphology