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Proteolytic enzymes or fungi have long been identified as causing softening of pickled cucumbers. As the softening of cucumbers occurs mainly in the pasteurized state, this study considers the hypothesis that vinegar and the added spices could be responsible for this softening by studying polygalacturonase (endo-/exo-PG), pectinesterase (PE), and pectin lyase, as well as Alternaria spp. found in the spices. Because of the high endo-PG activity found in dill, this spice emerged as a possible factor causing spoilage. Compared to dill, the enzyme activity in mustard seeds is eight times lower, and only low levels of enzymes or Alternaria spp. are present in onions or vinegar. Different harvest times and the associated degree of freshness of dill also played a crucial role regarding the endo-PG activity of up to 25.11 U/g (30°C, mature and very woody dill in late July) but of less than 9.00 U/g in fresh and soft green dill harvested in late June. A temperature of 80°C, held for 3 min, reduced the enzyme activity to less than 1.0 U/g. A final examination of cucumbers with a fixed quantity of mustard seeds, vinegar, and onions but with different variants of dill showed that the quantity of dill and the other ingredients added to the jars is not a potential factor leading to cucumber softening, which conflicts with the hypothesis of cucumber spoilage by vinegar and spices. PRACTICAL APPLICATION: This work provides insights into the activity of various pectolytic enzymes and the load of Alternaria spp. in different ingredients used for pickle production. Based on these data and additional pasteurization experiments, this paper evaluates the influence of dill, onions, mustard seeds, and vinegar on cucumber softening., (© 2022 The Authors. Journal of Food Science published by Wiley Periodicals LLC on behalf of Institute of Food Technologists.)

The spread by arthropods (zoochory) is an essential dispersal mechanism for many microorganisms, like plant pathogens. Carabid beetles are very abundant and mobile ground-dwelling insects. However, their role in the dispersal of economically relevant phytopathogens, like Fusarium and Alternaria fungi is basically unknown. We quantified the total fungal, Fusarium , and Alternaria load of carabid species collected in the transition zones between small water bodies and wheat fields by screening (i) their body surface for fungal propagules with a culture-dependent method and (ii) their entire bodies for fungal DNA with a qPCR approach. The analysis of entire bodies detects fungal DNA in all carabid beetles but Alternaria DNA in 98% of them. We found that 74% of the carabids carried fungal propagules on the body surface, of which only half (49%) carried Fusarium propagules. We identified eight Fusarium and four Alternaria species on the body surface; F.   culmorum was dominant. The fungal, Fusarium and Alternaria , load differed significantly between the carabid species and was positively affected by the body size and weight of the carabids. Carabid beetles reveal a remarkable potential to disseminate different fungi. Dispersal by ground-dwelling arthropods could affect the spatial-temporal patterns of plant disease and microorganisms in general.

Mycotoxigenic fungal pathogens Fusarium and Alternaria are a leading cause of loss in cereal production. On wheat-ears, they are confronted by bacterial antagonists such as pseudomonads. Studies on these groups' interactions often neglect the infection process's temporal aspects and the associated priority effects. In the present study, the focus was on how the first colonizer affects the subsequent ones. In a climate chamber experiment, wheat-ears were successively inoculated with two different strains ( Alternaria tenuissima At 625, Fusarium graminearum Fg 23, or Pseudomonas simiae Ps 9). Over three weeks, microbial abundances and mycotoxin concentrations were analyzed and visualized via Self Organizing Maps with Sammon Mapping (SOM-SM). All three strains revealed different characteristics and strategies to deal with co-inoculation: Fg 23, as the first colonizer, suppressed the establishment of At 625 and Ps 9. Nevertheless, primary inoculation of At 625 reduced all of the Fusarium toxins and stopped Ps 9 from establishing. Ps 9 showed priority effects in delaying and blocking the production of the fungal mycotoxins. The SOM-SM analysis visualized the competitive strengths: Fg 23 ranked first, At 625 second, Ps 9 third. Our findings of species-specific priority effects in a natural environment and the role of the mycotoxins involved are relevant for developing biocontrol strategies.

Fluorescent pseudomonads colonizing wheat ears have a high antagonistic potential against phytopathogenic fungi. To check this hypothesis, the bacterial antagonist Pseudomonas simiae 9 rif+/kan+ was spray-inoculated onto the ears of winter wheat in a locally demarcated experimental field plot. Fusarium and Alternaria fungi naturally occurring on the ears and the formation of their mycotoxins in the ripe grains were investigated. Inoculated bacteria were recovered from the plants in the inoculation cell, but not in the untreated neighboring plots or in the air above the plants. Growth of fusaria and alternaria on the ears was not influenced by the bacterial antagonist. Wheat kernels were co-inoculated in vitro with the antagonist and one mycotoxin-producing strain of Fusarium and Alternaria, respectively. Mycotoxin production was almost completely suppressed in these approaches. Concentrations of zearalenone, deoxynivalenol, alternariol, and tenuazonic acid were also significantly reduced in ripe grains in the field, but to a lesser extent than in vitro. The results of this and previous studies suggest that widespread biological control of the growth of fusaria and alternaria and their mycotoxin formation by naturally occurring pseudomonads with antagonistic activity is rather unlikely.

Natural control of phytopathogenic microorganisms is assumed as a priority function of the commensal plant microbiota. In this study, the suitability of fluorescent pseudomonads in the phyllosphere of crop plants as natural control agents was evaluated. Under field conditions, ears of winter wheat were found to be colonized with high consistency and at a high density by pseudomonads at the late milk dough stage. Isolates of these bacteria were evaluated for their potential to protect the plants from phytopathogenic Alternaria and Fusarium fungi. More Pseudomonas isolates were antagonistically active against alternaria than against fusaria in the dual culture test. The alternaria responded species-specifically and more sensitively to bacterial antagonism than the strain-specific reacting fusaria. A total of 110 randomly selected Pseudomonas isolates were screened for genes involved in the biosynthesis of the antibiotics 2,4-diacetylphloroglucinol, phenazine-1-carboxylic acid, pyoluteorin, and pyrrolnitrin. The key gene for production of the phloroglucinol was found in none of these isolates. At least one of the genes, encoding the biosynthesis of the other antibiotics was detected in 81% of the isolates tested. However, the antagonistic effect found in the dual culture assay was not necessarily associated with the presence of these antibiotic genes. Wheat grains as natural substrate were inoculated with selected antagonistic Pseudomonas isolates and Alternaria and Fusarium strains, respectively. The fungal growth was only slightly delayed, but the mycotoxin production was significantly reduced in most of these approaches. In conclusion, the distribution of phytopathogenic fungi of the genera Alternaria and Fusarium in the field is unlikely to be inhibited by naturally occurring pseudomonads, also because the bacterial antagonists were not evenly distributed in the field. However, pseudomonads can reduce the production of Alternaria and Fusarium mycotoxins in wheat grains and thus have the potential to improve the crop quality.

Biochar has been frequently suggested as an amendment to improve soil quality and mitigate climate change. To investigate the optimal management of nitrogen (N) fertilization, we examined the combined effect of biochar and N fertilizer on plant N uptake and N 2 O emissions in a cereal rotation system in a randomized two-factorial field experiment on a sandy loam soil in Brandenburg, Germany. The biochar treatment received 10Mgha -1 wood-derived biochar in September 2012. Four levels of N fertilizer, corresponding to 0, 50%, 100%, 130% of the recommended fertilizer level, were applied in winter wheat (Triticum aestivum L.)) and winter rye (Secale cereal L.) in 2013 and 2014 followed by the catch crop oil radish (Raphanus sativus L. var. oleiformis). Biomass and N uptake of winter wheat and winter rye were significantly affected by the level of N fertilizer but not by biochar. For N uptake of oil radish an interaction effect was observed for biochar and N fertilizer. Without applied fertilizer, 39% higher N uptake was found in the presence of biochar, accompanied by higher soil NH 4 + content and elevated cumulative CO 2 emissions. At 130% of the recommended fertilizer level, 16% lower N uptake and lower cumulative N 2 O emissions were found in the biochar-mediated treatment. No significant change in abundance of microbial groups and nosZ gene were observed. Our results highlight that biochar can have a greenhouse gas mitigation effect at high levels of N supply and may stimulate nutrient uptake when no N is supplied., (Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.)

Energy-dispersive X-ray (EDX) analysis coupled with an environmental scanning electron microscope (ESEM) was tested as an alternative to the inductively coupled argon plasma (ICP) spectrometer method for nutrient analyses of ectomycorrhizae. The results of EDX-ESEM and ICP were compared for 12 ectomycorrhizal morphotypes collected in beech and Scots pine forests in northern Brandenburg. The amounts of Al, Ca, Mg and S analysed in the outer hyphal layers of the sheath with the EDX-ESEM technique correlated well with the amounts of these elements in the whole mycorrhiza as assessed by ICP. For the elements P and K, no such correlation existed, indicating an uneven distribution of these elements in the ectomycorrhiza. It is concluded that the EDX-ESEM technique could be a useful and reliable tool for the analysis of nutrient elements in ectomycorrhizae, especially for studies focussing on small-scale soil heterogeneity or on infrequent morphotypes.

The components of leghaemoglobin (Lb) from twelve different Pisum sativum L. cvs and three near-isogenic foliar mutants were investigated by anion-exchange high-performance liquid chromatography (HPLC). Five different Lb component profiles could he found. The number of components varied from four to six dependent on cultivar used. An Lb pattern composed of four Lb components could be detected in thirteen P. sativum cultivars and lines. Ten of them showed an identical profile. In nodules of each cultivar, the two known major components, LbI and LbV, but also LbIV, could be detected. Additionally, cultivar-specific Lb components could be identified, each representing up to 10%, of total Lb. One of these components, LbIII, has been described previously, but three new Lb components (LbII, LbVI, and LbVII) were found. The presence of all Lb components detected by HPLC was confirmed by analytical isoelectric focusing. Further, it was shown that age-dependent changes in the relative concentrations of LbI and LbV are common in P. sativum and that these variations are independent of breeding lines and cultivars.

A 4.6 kb DNA region of the Rhizobium meliloti strain AK631 was found to contain seven open reading frames (ORFs), all oriented in the same direction. The putative gene products of four of these ORFs were highly homologous to UreA, UreB and UreC of Klebsiella aerogenes, Proteus mirabilis, Proteus vulgaris and Canavalia ensiformis. The overall organisation of the DNA region analysed was ORF1, ureA (ORF2), ORF3, ureB (ORF4), ORF5, ORF6 and ureC (ORF7), indicating that the organisation of the urease structural genes in R. meliloti differs from that of other urease genes so far characterized. ORF1 was incomplete; only the 3' end of the coding region was present. The six complete ORFs coded for polypeptides of 11.1 (UreA), 8.9 (ORF3), 10.8 (UreB), 15.0 (ORF5), 13.8 (ORF6) and 60.7 kDa (UreC). No sequence homology to known polypeptides could be detected for the gene products of ORF1, ORF3, ORF5 and ORF6. Using a lacZ fusion and insertional mutagenesis it was shown that the seven ORFs identified were all located in the same transcription unit. For mutational analysis a resistance gene cassette was introduced into each of the complete ORFs resulting in apolar mutations. Mutations in ureA, ureB and ureC, but not in ORF3, ORF5 and ORF6, abolished urease activity in R. meliloti. The determination of hydrogen uptake in these R. meliloti mutants revealed that only ORF6 and ureB are necessary for hydrogen uptake.

EPR investigations on the vesiculation process of heated human erythrocytes were performed, using different fatty acid spin labels. Spectrin denaturation and vesiculation do not influence the fluidity of the lipid phase of the remaining membrane of human erythrocytes: Vesicles released differ in chemical composition as well as in the lipid fluidity of their membrane from the intact human erythrocyte membrane. A reduced cholesterol-to-phospholipid ratio and a depletion of spectrin was found. By changing the ionic concentration of the suspension medium an effect on membrane spectra and on vesicle release was established. The adamantane derivative amantadine causes fluidization of the human erythrocyte membrane and inhibits vesicle release. Based on these results, a model for the mechanism by which adamantane-like molecules could interact with membranes is proposed.

Surface potential difference, conductance, and elasticity changes of bilayer lipid membranes induced by the antivirus drugs amantadine and remantadine were measured. An influence on the human erythrocyte shape was shown. Both drugs are stomatocytogenic. The adsorption at the cytoplasmatic membrane was electrophoretically proved. The heat-induced vesiculation is partly inhibited. No microvesicles were observed. Instead, large tails which did not detach from the cell body were seen. The general conclusion is that these amphiphilic adamantane derivatives are membrane agents which modify membrane interaction processes, possibly by influencing the bending properties.