Verticillium Wilt in Oilseed Rape-the Microbiome is Crucial for Disease Outbreaks as Well as for Efficient Suppression

Microbiome management is a promising way to suppress verticillium wilt, a severe disease in Brassica caused by Verticillium longisporum. In order to improve current biocontrol strategies, we compared bacterial Verticillium antagonists in different assays using a hierarchical selection and evaluation scheme, and we integrated outcomes of our previous studies. The result was strongly dependent on the assessment method chosen (in vitro, in vivo, in situ), on the growth conditions of the plants and their genotype. The most promising biocontrol candidate identified was a Brassica endophyte Serratia plymuthica F20. Positive results were confirmed in field trials and by microscopically visualizing the three-way interaction. Applying antagonists in seed treatment contributes to an exceptionally low ecological footprint, supporting efficient economic and ecological solutions to controlling verticillium wilt. Indigenous microbiome, especially soil and seed microbiome, has been identified as key to understanding disease outbreaks and suppression. We suggest that verticillium wilt is a microbiome-driven disease caused by a reduction in microbial diversity within seeds and in the soil surrounding them. We strongly recommend integrating microbiome data in the development of new biocontrol and breeding strategies and combining both strategies with the aim of designing healthy microbiomes, thus making plants more resilient toward soil-borne pathogens.

Enriching Beneficial Microbial Diversity of Indoor Plants and Their Surrounding Built Environment With Biostimulants

Microbial diversity is suggested as the key for plant and human health. However, how microbial diversity can be enriched is largely unknown but of great interest for health issues. Biostimulants offer the way to directly augment our main living areas by the healthy microbiome of indoor plants. Here, we investigated shifts of the microbiome on leaves of spider plants (Chlorophytum comosum) and its surrounding abiotic surfaces in the built environment after irrigation with a vermicompost-based biostimulant for 12 weeks. The biostimulant could not only promote plant growth, but changed the composition of the microbiome and abundance of intact microbial cells on plant leaves and even stronger on abiotic surfaces in close vicinity under constant conditions of the microclimate. Biostimulant treatments stabilized microbial diversity and resulted in an increase of Bacteroidetes and a surprising transient emerge of new phyla, e.g., Verrucomicrobia, Acidobacteria, and Thaumarchaeota. The proportion of potentially beneficial microorganisms like Brevibacillus, Actinoallomurus, Paenibacillus, Sphaerisporangium increased relatively; microbial diversity was stabilized, and the built environment became more plant-like. Detected metabolites like indole-3-acetic acid in the biostimulant were potentially contributed by species of Pseudomonas. Overall, effects of the biostimulant on the composition of the microbiome could be predicted with an accuracy of 87%. This study shows the potential of biostimulants not only for the plant itself, but also for other living holobionts like humans in the surrounding environment.

Intercalation behaviour of magnesium into natural graphite using organic electrolyte systems

Use of natural graphite based electrodes as insertion anodes in rechargeable magnesium-ion batteries.

Aerial Warfare: A Volatile Dialogue between the Plant Pathogen Verticillium longisporum and Its Antagonist Paenibacillus polymyxa

Verticillium wilt caused by Verticillium spp. results in severe yield losses in a broad range of crops. Verticillium outbreaks are challenging to control, and exacerbated by increases in soil temperatures and drought associated with global warming. Employing natural antagonists as biocontrol agents offers a promising approach to addressing this challenge. Paenibacillus polymyxa Sb3-1 was proven to reduce the growth of Verticillium longisporum during in vitro experiments and was shown to promote the growth of oilseed rape seedlings infested with V. longisporum. Our novel approach combined in vitro and in planta methods with the study of the mode of interaction between Sb3-1 and V. longisporum EVL43 via their volatile organic compounds (VOCs). Volatile and soluble substances, produced by both microorganisms as a reaction to one another's VOCs, were detected by using both gas and liquid chromatography-mass spectrometry. P. polymyxa Sb3-1 continually produced antimicrobial and plant growth promoting VOCs, such as 2-nonanone and 3-hydroxy-2-butanone. Several other antimicrobial volatile substances, such as isoamyl acetate and durenol, were downregulated. The general metabolic activity of Sb3-1, including protein and DNA biotransformations, was upregulated upon contact with EVL43 VOCs. V. longisporum increased its production of antimicrobial substances, such as 1-butanol, and downregulated its metabolic activities upon exposure to Sb3-1 VOCs. Additionally, several stress response substances such as arabitol and protein breakdown products (e.g., L-Isoleucyl-L-glutamic acid), were increased in the co-incubated samples. The results obtained depict an ongoing dialog between these microorganisms resulting in growth inhibition, the slowing down of metabolism, and the cell death of V. longisporum due to contact with the P. polymyxa Sb3-1 VOCs. Moreover, the results indicate that VOCs make a substantial contribution to the interaction between pathogens and their natural antagonists and have the potential to control pathogens in a novel, environmentally friendly manner.

A phase II study of the HSP90 inhibitor AUY922 in chemotherapy refractory advanced pancreatic cancer

OBJECTIVES

AUY922 is a novel heat shock protein inhibitor with preclinical activity in pancreatic cancer. This phase II study evaluated the efficacy of AUY922 in patients with advanced pancreatic cancer previously treated with chemotherapy.

METHODS

In this single-arm, Simon two-stage phase II trial, patients with metastatic or locally advanced pancreatic ductal adenocarcinoma who had progressed on at least one line of chemotherapy and were of good performances status (ECOG 0 or 1) were treated with AUY922 at a dose of 70 mg/m(2) IV weekly. The primary endpoint was disease control rate (objective response and stable disease ≥16 weeks).

RESULTS

Twelve patients were accrued, all of whom received treatment. At least possibly related ≥grade 3 adverse events included fatigue (8 %) and AST elevation (8 %). Ten patients were evaluable for response with 1 (10 %) having stable disease and 9 (90 %) progressive disease. The median progression-free survival was 1.6 months, and the median overall survival was 2.9 months.

CONCLUSIONS

AUY922 was not associated with significant efficacy in previously treated patients with advanced pancreatic cancer.

New stochastic mode reduction strategy for dissipative systems

We present a new methodology for studying non-Hamiltonian nonlinear systems based on an information theoretical extension of a renormalization group technique using a modified maximum entropy principle. We obtain a rigorous dimensionally reduced description for such systems. The neglected degrees of freedom by this reduction are replaced by a systematically defined stochastic process under a constraint on the second moment. This then forms the basis of a computationally efficient method. Numerical computations for the generalized Kuramoto-Sivashinsky equation support our method and reveal that the long-time underlying stochastic process of the fast (unresolved) modes obeys a universal distribution that does not depend on the initial conditions and which we rigorously derive by the maximum entropy principle.

The tertiary structure of endo-beta-1,4-glucanase B (CenB), a multidomain cellulase from the bacterium Cellulomonas fimi

Endo-beta-1,4-glucanase B (CenB) is a large (110 kDa) extracellular enzyme from the cellulolytic bacterium Cellulomonas fimi. CenB contains five domains, including a typical C.fimi cellulose-binding domain, separated by distinctive linker polypeptides (Meinke et al., 1991b). X-ray scattering analyses show that CenB has a highly elongated shape resembling beads on a string. The sizes of the polypeptides produced by treatment of CenB with proteases, together with their N-terminal amino acid sequences, show that at least two of the four linkers connecting the five domains of CenB are more sensitive to proteolysis than the domains themselves. It is concluded that the beads represent the domains of CenB, the string represents the linkers.

Deletion of the linker connecting the catalytic and cellulose-binding domains of endoglucanase A (CenA) of Cellulomonas fimi alters its conformation and catalytic activity

The Pro-Thr box is a linker of 23 amino acids ((PT)4T(PT)7) connecting the catalytic domain and the cellulose-binding domain (CBD) of endoglucanase A (CenA) from the bacterium Cellulomonas fimi. Deletion of the Pro-Thr box alters the conformation of CenA by changing the relative orientation of the catalytic domain and the CBD. The tertiary structures of the catalytic domain and the CBD appear to be unchanged. The change in conformation reduces the catalytic efficiency of the enzyme and masks one of two protease-sensitive sites between the domains. The deletion does not affect the adsorption of the enzyme to microcrystalline cellulose, but it does affect its desorption from cellulose. The results suggest that the Pro-Thr box in CenA has an extended, kinked, and rigid conformation.

Quaternary structure of the giant extracellular hemoglobin of the leech Macrobdella decora

The molecular dimensions of the extracellular hemoglobin of the leech Macrobdella decora, determined by scanning transmission electron microscopy were 29.8 nm x 19.5 nm (diameter x height) for negatively stained specimens. Measurements of molecular mass (Mm) of unstained specimens with the microscope gave Mm = 3560 +/- 160 kDa. Small-angle X-ray scattering measurements gave a diameter of 28.0(+/- 0.5) nm, radius of gyration 10.5(+/- 0.2) nm and volume 7500(+/- 300) nm3. The hemoglobin had no carbohydrate and its iron content was found to be 0.23(+/- 0.02)% (w/w), corresponding to a minimum Mm of 24,000(+/- 1300) kDa. SDS/polyacrylamide gel electrophoresis of the unreduced hemoglobin showed that it consisted of three subunits, which have apparent Mm values of 12 (1), 25 (2) and 29 kDa (3). The reduced hemoglobin consisted of four subunits, I (12 kDa), II (14 kDa), III (26 kDa) and IV (30 kDa). Subunit 1 corresponded to subunit I, subunit 2 to subunits III and IV and subunit 3 to subunit II. Partial N-terminal sequences were obtained for subunit 1, the two chains of subunit 2 and one of the two chains of subunit 3, suggesting that the hemoglobin consists of at least five different polypeptide chains. The percentage fraction of the three unreduced subunits was determined by densitometry of SDS/polyacrylamide gel patterns and quantitative determination of Coomassie R-250 dye bound to the individual bands in reduced and unreduced patterns to be, monomer (subunit I) : non-reducible subunit (subunit 2) : reducible dimer (subunit 3) = 0.35 : 0.29 : 0.35 (S.D. = +/- 0.05). This corresponded to a stoichiometry of 74 +/- 11 : 37 +/- 5 : 38 +/- 6, assuming the molecular masses to be 17 kDa, 30 kDa and 34 kDa, taking into account the anomalously high mobility of annelid globins in SDS-containing gels. The stoichiometry calculated from the amino acid compositions of the hemoglobin and the three subunits was 82 +/- 12 : 29 +/- 4 : 40 +/- 8. Gel filtration of the hemoglobin at pH 9.8, at neutral pH subsequent to dissociation at pH 4 and at neutral pH in the presence of urea and Gu.HCl provided no evidence for the existence of a putative 1/12 of the whole molecule (Mm approx. 300 kDa). Furthermore, the largest subunits obtained had Mm of 60 to 100 kDa and had a much decreased content of subunit 2, suggesting that the hemoglobin was not a simple multimeric protein. Three-dimensional reconstruction from microscope images provided a model of Macrobdella hemoglobin that is very similar to the reconstruction of Lumbricus hemoglobin: the radial mass distribution curves are virtually superimposable.(ABSTRACT TRUNCATED AT 400 WORDS)