Influence of arbuscular mycorrhizal fungi on storage metabolites,mineral nutrition,and nitrogen-assimilating enzymes in potato (Solanum tuberosum L.) plant

Mycorrhizae are fungal symbionts forming mutualistic relationship with plant roots. In this study, surface-sterilized potato tubers were sown in earthen pots filled with sterile soil. Half of the pots were inoculated with sterilized arbuscular mycorrhizal fungi (AMF) spores and sterilized inoculated maize root fragments, and another half without any AMF inoculation representing control. Inoculation was done twice 3 days before sowing the tubers and on the onset of seedling emergence. Plants, along with their controls, were sampled at 20-day intervals upto 80 days after tuber initiation. The tubers of potato are shown to present a higher level of metabolites and mineral nutrition in the mycorrhizal inoculated compared to the non-inoculated. The results showed that AMF has a potential in enhancing potato production by increasing the storage metabolites, mineral nutrition in tubers and nitrogen assimilating enzymes in plant.     

Formation of aroma compounds and lipoxygenase (EC 1.13.11.12) activity in unblanched leek (Allium ampeloprasum Var. Bulga) slices during long-term frozen storage

The content of aroma compounds (dynamic headspace) and catalytic activity of lipoxygenase (LOX) (EC. 1.13.11.12) were analyzed in 15 mm unblanched leek slices seven times during 12 months of frozen storage. The aroma profile changed from consisting of almost only sulfur compounds such as dipropyl disulfide [concentration in fresh leek (FL) = 0.197 mg/L, concentration after 12 months of frozen storage (12M) = 0.0409 mg/L] and propyl (E)-propenyl disulfide (FL = 0.0437 mg/L, 12M = 0.00452 mg/L) in the fresh leeks to being dominated by numerous saturated and unsaturated aldehydes, such as hexanal (FL = 1.53 mg/L, 12M = 3.63 mg/L), (E,E)-2,4-nonadienal (FL = 0.000 mg/L, 12M = 0.0647 mg/L), and (E,E)-2,4-decadienal (FL = 0.129 mg/L, 12M = 0.594 mg/L) at the end of the storage period. The catalytic activity of LOX diminished throughout frozen storage, but approximately 25% of the original activity was present after 12 months of storage.     

Evolution, safety, and highly pathogenic influenza viruses

Experience with influenza has shown that predictions of virus phenotype or fitness from nucleotide sequence are imperfect and that predicting the timing and course of evolution is extremely difficult. Such uncertainty means that the risk of experiments with mammalian-transmissible, possibly highly virulent influenza viruses remains high even if some aspects of their laboratory biology are reassuring; it also implies limitations on the ability of laboratory observations to guide interpretation of surveillance of strains in the field. Thus, we propose that future experiments with virulent pathogens whose accidental or deliberate release could lead to extensive spread in human populations should be limited by explicit risk-benefit considerations.     

Mycorrhizal influence on storage metabolites and mineral nutrition in seed propagated potato (Solanum tuberosum L.) plant

Abstract

Potato (Solanum tuberosum) showed a well-established mutualistic association with arbuscular mycorrhizal fungi. In the present study, earthen pots containing autoclaved soil were taken in which surface sterilized potato seeds were sown. The seed sowed earthen pots were inoculated by sterilized spores of arbuscular mycorrhizal fungi along with sterilized inoculated maize-root fragments, while the rest half of the seed filled pots, without any inoculation depicting control but were provided with non-inoculated maize root fragments. The inoculation was performed twice; first inoculation was done 3 days prior to sowing of potato seeds and second at the time of seedling emergence. Sampling of the inoculated as well as of control plants was performed at 20-day intervals till 80?days after tuber initiation. An increment in the level of metabolites as well as mineral nutrient was found in mycorrhizal inoculated potato tubers in contrast to non-inoculated. Our work demonstrates that inoculation has a great potential in enriching storage metabolites and nutrients in potato plant in low yielding soils.     

Introduction to the symposium

A number of multi-stakeholder initiatives (MSIs) and commodity roundtables have been created since the 1990s to respond to the growing criticism of agriculture’s environmental and social impacts. Driven by private and global-scale actors, these initiatives are setting global standards for sustainable agricultural practices. They claim to follow the new standard-making virtues of inclusiveness and consensus and base their legitimacy on their claim of balanced representation of, and participation by, all categories of stakeholders. This principle of representing a wide range of interests with a balance of power is at the heart of a new type of action that forms part of a broader political liberal model for building coalitions of interest groups. The intention of this symposium is to assess the nature of processes and outcomes of this model while paying particular attention to the forms of inclusion and exclusion they generate. In this introduction, we highlight the differences in theoretical approaches to analyzing MSIs and the manifestation of power through them. We distinguish between more traditional political–economy approaches and approaches concerned with ideational and normative power, such as convention theory. We discuss some of the main paradoxes of MSIs related to their willingness to be “inclusive” and at the same time their exclusionary or “closure” effects due in part to interactions with existing political economic contexts and embedded power inequalities, as well as more subtle manifestations of power linked to the favoring of some forms of knowledge and engagement over others.     

Identification of Four New agr Quorum Sensing-Interfering Cyclodepsipeptides from a Marine Photobacterium

During our search for new natural products from the marine environment, we discovered a wide range of cyclic peptides from a marine Photobacterium, closely related to P. halotolerans. The chemical fingerprint of the bacterium showed primarily non-ribosomal peptide synthetase (NRPS)-like compounds, including the known pyrrothine antibiotic holomycin and a wide range of peptides, from diketopiperazines to cyclodepsipeptides of 500–900 Da. Purification of components from the pellet fraction led to the isolation and structure elucidation of four new cyclodepsipeptides, ngercheumicin F, G, H, and I. The ngercheumicins interfered with expression of virulence genes known to be controlled by the agr quorum sensing system of Staphylococcus aureus, although to a lesser extent than the previously described solonamides from the same strain of Photobacterium.     

Milk production and composition in Danish Holstein,Danish Red,and Danish Jersey cows supplemented with saturated or unsaturated fat

The aim of the experiment was to study the response in milk production and composition of substituting barley with either saturated or unsaturated fat in mixed rations (MR) for dairy cows. The experiment included 35 Danish Holstein (DH), 39 Danish Red (DR), and 31 Danish Jersey (DJ) cows from parturition until week 30 of lactation. Cows were ad libitum fed one of the three MR based on maize and grass/clover silage, barley, soybean meal, and dried sugar beet pulp. In the saturated ration (SFA), C16 rich fat substituted barley on dry matter (DM) basis; in the unsaturated ration (UFA), ground rape and linseed (0.74:0.26 ratio) substituted barley on DM basis; and in the control ration (CO), no barley was substituted. Concentrations of crude fat (CF) of total ration DM was 3.03% in CO, and in diets supplemented to intended similar fat levels 5.65% (SFA) and 5.81% (UFA), respectively. Statistical analyses were performed within breed and random regression was used to test for differences between treatment responses throughout lactations.