Can organic agriculture contribute to sustainable development in the tropics?

Agricultural intensification over last decades has resulted in a great increase of crop yields, but it also had a detrimental impact on biodiversity. The dramatic decline of arable weed diversity is a matter of great concern because weeds have an important ecological function as a key component of the food web of agroecosystems. Weeds are suitable indicators of management effects on wildlife diversity in arable crops because they have high sensitivity to cultivation measures and have a strong relation to other organism groups. Nevertheless, the effect of farming management on weed abundance and diversity will be more reliable on weed seed bank rather than on aboveground weed community because it is the result of processes that have occurred in the past and consequently, it could better reflect the effect of the agricultural practices over the years

Selected mitochondrial DNA landscapes activate the SIRT3 axis of the UPR(mt) to promote metastasis

By causing mitochondrial DNA (mtDNA) mutations and oxidation of mitochondrial proteins, reactive oxygen species (ROS) leads to perturbations in mitochondrial proteostasis. Several studies have linked mtDNA mutations to metastasis of cancer cells but the nature of the mtDNA species involved remains unclear. Our data suggests that no common mtDNA mutation identifies metastatic cells; rather the metastatic potential of several ROS-generating mutations is largely determined by their mtDNA genomic landscapes, which can act either as an enhancer or repressor of metastasis. However, mtDNA landscapes of all metastatic cells are characterized by activation of the SIRT/FOXO/SOD2 axis of the mitochondrial unfolded protein response (UPR(mt)). The UPR(mt) promotes a complex transcription program ultimately increasing mitochondrial integrity and fitness in response to oxidative proteotoxic stress. Using SOD2 as a surrogate marker of the UPR(mt), we found that in primary breast cancers, SOD2 is significantly increased in metastatic lesions. We propose that the ability of selected mtDNA species to activate the UPR(mt) is a process that is exploited by cancer cells to maintain mitochondrial fitness and facilitate metastasis.Oncogene advance online publication, 3 April 2017; doi:10.1038/onc.2017.52

Stability of Metabolic Correlations under Changing Environmental Conditions in Escherichia coli – A Systems Approach

Background: Biological systems adapt to changing environments by reorganizing their cellular and physiological program with metabolites representing one important response level. Different stresses lead to both conserved and specific responses on the metabolite level which should be reflected in the underlying metabolic network. Methodology/Principal Findings: Starting from experimental data obtained by a GC-MS based high-throughput metabolic profiling technology we here develop an approach that: (1) extracts network representations from metabolic condition-dependent data by using pairwise correlations, (2) determines the sets of stable and condition-dependent correlations based on a combination of statistical significance and homogeneity tests, and (3) can identify metabolites related to the stress response, which goes beyond simple observations about the changes of metabolic concentrations. The approach was tested with Escherichia coli as a model organism observed under four different environmental stress conditions (cold stress, heat stress, oxidative stress, lactose diauxie) and control unperturbed conditions. By constructing the stable network component, which displays a scale free topology and small-world characteristics, we demonstrated that: (1) metabolite hubs in this reconstructed correlation networks are significantly enriched for those contained in biochemical networks such as EcoCyc, (2) particular components of the stable network are enriched for functionally related biochemical pathways, and (3) independently of the response scale, based on their importance in the reorganization of the correlation network a set of metabolites can be identified which represent hypothetical candidates for adjusting to a stress-specific response. Conclusions/Significance: Network-based tools allowed the identification of stress-dependent and general metabolic correlation networks. This correlation-network-based approach does not rely on major changes in concentration to identify metabolites important for stress adaptation, but rather on the changes in network properties with respect to metabolites. This should represent a useful complementary technique in addition to more classical approaches

Weed Population Dynamics under Organic, Bio-dynamic, Conventional Bt and Non-Bt Cotton (Gossypium hirsutum)

Aim: In order to compare the weed seed bank and population dynamics under organic, biodynamic, Bt-conventional, and non-Bt conventional management systems of cotton (Gossypium hirsutum), a field experiment was carried out. Study Design: Randomized Block Design (RBD) Place and Duration of Study: bioRe-FiBL research trails, bioRe Association, Kasrawad, Khurgone, Madhya Pradesh during the kharif season of 2020-21. Methodology: Five distinct crop management techniques were used in the field experiment, each duplicated four times, and the experiment was set up using a randomized block design. The treatments were distributed at random to different plots. The five management treatments were Absolute Control (no fertilizers), Conventional management of non-Bt cotton, Conventional management of Bt cotton, Bio-dynamic and Organic management of cotton. For the duration of the experiment, four 1 m × 1 m (1 m2) quadrats were randomly placed on each experimental plot's four sides, and different biometric observations were recorded from each quadrant according to its treatment. For the purpose of collecting the necessary observations, two of these quadrants were regularly weeded every 20 days, while the other two were left unweeded for the duration of the experiment. Results: The dominant weed species includes Panicum dichotomiflorum, Cyperus rotundus, Paspalum dilatatum, Euphorbia hirta, Acalypha indica and Digeria arvensis. Poaceae was the dominant family in terms of composition. There was very less variation in the weed flora between the treatments. Significantly higher weed seed bank, weed species, weed density and weed dry weight were observed in Organic and Biodynamic cotton than in the Conventional cotton. Weed control efficiency was found to be maximum in the Conventional cotton compared to the Organic and Biodynamic cotton. Conclusion: From the experiment, it can be concluded that the Conventional cotton especially Conventional management Bt Cotton was found to be most efficient among all the treatments. However, the Organic cotton was observed with high number of overall plant species and best in conserving the plant species biodiversity