Desert Farming Benefits from Microbial Potential in Arid Soils and Promotes Diversity and Plant Health

BACKGROUND: To convert deserts into arable, green landscapes is a global vision, and desert farming is a strong growing area of agriculture world-wide. However, its effect on diversity of soil microbial communities, which are responsible for important ecosystem services like plant health, is still not known. METHODOLOGY/PRINCIPAL FINDINGS: We studied the impact of long-term agriculture on desert soil in one of the most prominent examples for organic desert farming in Sekem (Egypt). Using a polyphasic methodological approach to analyse microbial communities in soil as well as associated with cultivated plants, drastic effects caused by 30 years of agriculture were detected. Analysing bacterial fingerprints, we found statistically significant differences between agricultural and native desert soil of about 60%. A pyrosequencing-based analysis of the 16S rRNA gene regions showed higher diversity in agricultural than in desert soil (Shannon diversity indices: 11.21/7.90), and displayed structural differences. The proportion of Firmicutes in field soil was significantly higher (37%) than in the desert (11%). Bacillus and Paenibacillus play the key role: they represented 96% of the antagonists towards phytopathogens, and identical 16S rRNA sequences in the amplicon library and for isolates were detected. The proportion of antagonistic strains was doubled in field in comparison to desert soil (21.6%/12.4%); disease-suppressive bacteria were especially enriched in plant roots. On the opposite, several extremophilic bacterial groups, e.g., Acidimicrobium, Rubellimicrobium and Deinococcus-Thermus, disappeared from soil after agricultural use. The N-fixing Herbaspirillum group only occurred in desert soil. Soil bacterial communities were strongly driven by the a-biotic factors water supply and pH. CONCLUSIONS/SIGNIFICANCE: After long-term farming, a drastic shift in the bacterial communities in desert soil was observed. Bacterial communities in agricultural soil showed a higher diversity and a better ecosystem function for plant health but a loss of extremophilic bacteria. Interestingly, we detected that indigenous desert microorganisms promoted plant health in desert agro-ecosystems

The Saharan isolate Saccharothrix algeriensis NRRL B-24137 induces systemic resistance in Arabidopsis thaliana seedlings against Botrytis cinerea

Background and aim Saccharothrix algeriensis NRRL B-24137, isolated from a Saharan soil, has been described as a potential biocontrol agent against Botrytis cinerea and other phytopathogens. However, the plant protection mechanisms involved still need to be described. The aim of this study was to determine this protection phenomenon as well as parts of the mechanisms involved, using Arabidopsis thaliana seedlings and B. cinerea. Methods The bacterial colonization process was evaluated on A. thaliana seedlings using fluorescence in situ hybridization. Protection of A. thaliana seedlings inoculated with NRRL B-24137 against B. cinerea was then evaluated. Parts of the mechanisms involved in the systemic protection against B. cinerea were evaluated using known mutants of genes involved in jasmonate (JA)/ethylene (ET)/salicylic acid (SA) signaling. Other Arabidopsis mutants, AtrhbohD-3, AtrhbohF-3, and ups1-1 were also screened to determine other parts of the mechanisms involved. Results The results showed that the strain NRRL B-24137 colonized, epi- and endophytically, the roots of Arabidopsis seedlings but the strain was not a systemic colonizer during the time of the experiment. The strain NRRL B-24137 also reduced B. cinerea symptoms and the protection was linked to known mechanisms of induced systemic resistance (ISR; JA/ET signaling), as well as to functionality of AtrbohF oxidase and of UPS1. Crosstalk between ET/JA and SA signaling could also be involved. Conclusions The isolate NRRL B-24137, after colonizing the root systems of A. thaliana, induces an ISR against B. cinerea, which is JA/ET dependent, but could also require SA crosstalk and protection could also require NAPDH oxidases and UPS1 functionalities

Different Weighting Methods in Business Tendency Survey Indicators in Swiss Manufacturing Industry

In business cycle analysis the development of inventories still plays a crucial role. The strong movements over time have a large effect particularly on the growth rate of GDP. Quantitative data on inventories are generally of rather low quality. As a complement to quantitative statistics, business tendency surveys (BTS) offer actual data on stocks of different categories and on order books (often called negative inventories) to estimate actual values. However, the qualitative data do not show up in the empirical analysis. One reason could be that the aggregation process in BTS of these two items is often not adequate. Three alternative weighting methods were applied at firm level: no weighting, weighting with the number of employees, weighting with the number of employees plus the ratio of order books/stock to sales. These were compared with the current weighting method which includes stratification and branch weights by value added. The four indicators for each of the BTS questions had a statistically different variance, mean or distribution in most cases. The comparison of these four versions of weighting with the reference series – growth rate of order books and of stocks of finished products – produced quite different results. For the growth rate of order books, the best fit was with the non-weighted responses of the firms to the question on changes of order books. The match with the growth rate of stocks of finished products was generally lower. The best fit was again with the non-weighted responses on the change question on stocks of finished products

The NAICU and the Phillips Curve – An Approach Based on Micro Data

In this paper we propose a straightforward method to derive a non-accelerating inflation capacity utilisation rate (NAICU) based on micro data. We condition the current capacity utilisation of firms on their current and planned price adjustments. The non-accelerating inflation capacity utilisation rate is then defined as the rate where a firm feels no price adjustment pressure. One of the main advantages is that this methodology uses structural aspects and does not make it necessary to operate with –often rather arbitrary– statistical filters. We show that our aggregate NAICU performs remarkably well as an indicator of inflationary pressure in a Phillips curve estimation

The NIRCU and the Phillips Curve- An Approach Based on Micro Data *

Abstract In this paper we propose a straightforward method to derive a non-inflationary rate of capacity utilisation (NIRCU) based on micro data. We condition the current capacity utilisation of firms on their current and planned price adjustments. The non-inflationary capacity utilisation rate is then defined as the rate where a firm feels no price adjustment pressure. One of the main advantages is that this methodology uses structural aspects and does not make it necessary to operate with -often rather arbitrary-statistical filters. We show that our aggregate NIRCU performs remarkably well as an indicator of inflationary pressure in a Phillips curve estimation. JEL classification: E31; E32; E5

The Speed of Adjustment to Demand Shocks: A Markov-chain Measurement Using Micro Panel Data

In this paper we measure the speed at which firms adjust to demand shocks using individual firm data. Identification of shocks is achieved by a combination of quantitative and qualitative judgments on capacity utilisation in micro survey data. A novel feature of our approach is the distinction between positive and negative shocks that allows us to also discriminate between the speed of adjustment following either kind of shock. Furthermore, there is no need for using previous data filtering to extract business cycles or equilibrium definitions but only to observe the states of the firms that define their economic situation. One main result is that the firms’ adjustment to these two shocks is varying in speed. It should therefore be paid regard to the separation of positive and negative shocks in empirical and theoretical models. The findings of this paper bear implications for monetary policy making and model building alike

The NAICU and the Phillips curve – An Approach Based on Micro Data

In this paper we propose a straightforward method to derive a non-accelerating inflation capacity utilisation rate (NAICU) based on micro data. We condition the current capacity utilisation of firms on their current and planned price adjustments. The non-accelerating inflation capacity utilisation rate is then defined as the rate where a firm feels no price adjustment pressure. One of the main advantages is that this methodology uses structural aspects and does not make it necessary to operate with –often rather arbitrary– statistical filters. We show that our aggregate NAICU performs remarkably well as an indicator of inflationary pressure in a Phillips curve estimation.prices, capacity utilisation, NAICU, Phillips curve

Capacity Utilisation, Constraints and Price Adjustments under the Microscope

This paper analyses the interplay of capacity utilisation, capacity constraints, demand constraints and price adjustments, employing a unique firm-level data set for Swiss manufacturing firms. Theoretically, capacity constraints limit the ability of forms to expand production in the short run and lead to increases in prices. Our results show that, on the one hand, price increases are more likely during periods when firms are faced with capacity constraints. Constraints due to the shortage of labour, in particular, lead to price increases. On the other hand, we also find evidence that firms are not reluctant to reduce prices in response to demand constraints. At the macro level, the implied capacity-utilisation Phillips curve has a convex shape during periods of excess demand and a concave shape during periods of excess supply. Our results are robust to the inclusion of proxies for changes in costs and the competitive position of firms.price setting, capacity utilisation, capacity constraints, demand constraints, non-linear Phillips curve, Switzerland

Enthalpy is a proper criterion for comparability of monolayer and bilayer studies: isobaric temperature scanning measurements on glycolipid monolayers

The thermotropic behaviour of glycolipid monolayers has been studied by isobaric temperature scanning measurements to elucidate conditions under which monolayers exhibit thermodynamic and structural properties comparable to those observed in bilayers. A selection of synthetic, stereochemically pure, glyceroglycolipids with identical, ether-linked alkyl chains of 12, 14, or 16 CH2-groups has been investigated. The head groups of the glycolipids consisted of glucose, galactose, maltose, lactose or maltotriose moieties with β-configuration of the glycosidic bond. These glycolipids were chosen to permit a quantitative characterization of three effects, (i) the role of the length of the aliphatic chains, (ii) the influence of the size of the head group, and (iii) the influence of the stereochemistry of the sugar moieties on the structure and stability of the monolayers. To probe the effects of stereochemical alterations in the glycerol moiety 2,3-O-ditetradecyl-1-O-β-d-glucosyl-sn-glycerol (14-2,3-Glc) was compared with 1,2-O-ditetradecyl-3-O-β-d-glucosyl-sn-glycerol (14-1,2-Glc). It has been shown that in general several features of bilayers can be obtained from monolayer studies with reasonable accuracy, provided the proper parameters are chosen. The monolayer is stabilized by elongation of the aliphatic chains of the lipids and destabilized when the monosaccharide head group is replaced by a di-, or trisaccharide, in a similar manner as in the bilayer. The stabilizing effect that has been observed in bilayer studies, when galactose instead of glucose is introduced as head group, has also been established in the monolayer studies. This stabilizing effect is even retained in the lipids having disaccharide head groups. On the basis of these monolayer studies in connection with WAXS and SAXS measurements on multilamellar systems, we suggest that identity of transition enthalpies of the chain melting Lβ-Lα transition is an appropriate criterion for estimating molecular areas and area changes of bilayers from monolayer measurements and vice versa. However, estimates of transition temperatures are poor using the enthalpy criterion. If identity of transition temperature is introduced as criterion, glycolipid monolayers must be compressed to about 43±3 mN m−1. Under these conditions the agreement between the calculated enthalpies and structural properties of monolayers and multilayers is poor. As a general conclusion it can be emphasized that for monolayer and bilayer systems of glycolipids there exists no such parameter as a universal pressure or a universal temperature that automatically renders monolayer data identical to bilayer data. Depending on which property (transition temperatures, transition enthalpies, lateral areas and transitional area changes) one wants to extrapolate from monolayer to bilayer different lateral pressures have to be applied

Kinetics of glycolipid phase transitions: ms laser T-jump synchrotron studies

The kinetics of the lamellar gel (Lβ) to inverse hexagonal (HII) phase transition as well as the LC→Lα phase change of aqueous suspensions of glycolipids were characterized using ms laser T-jump techniques in combination with synchrotron X-ray diffraction. The glycolipids employed were 1,2-di-O-alkyl-3-O-β-D-glucosyl-snglycerols with identical alkyl chains of 16 and 18 carbon atoms, respectively, and 1,2-di-O-alkyl-3-O-β-D-galactosyl-sn-glycerol with C16 chains. The time course of the LC→Lα phase transition was probed using 1,2-di-O-hexadecyl-3-O-β-D-lactosyl-sn-glycerol, whose head group consists of the disaccharide β-D-galactopyranosyl-(1→4)-β-D-glucopyranoside. Surprisingly the phase change from the lamellar to the inverse hexagonal topology is very fast despite the major structural changes involved in the lipid-water interface. The overall phase change of both glucolipids can be quantitatively described by a sequential mechanism of the type equation image. The intermediate I is thinner than both the Lβ and the HII phases. It has a relatively broad distribution of d-spacings and relaxes into the HII phase with half times of approximately 125 ms (16-1,2-Glc) and 244 ms (18-1,2-Glc), respectively. Both rate constants, k1 and k2, are chain length dependent.The galactolipid transforms into the HII phase following a sequential mechanism of the type equation image. The additional intermediate I' can be assigned to a lamellar phase bearing similarity to a thin Lα phase. The specific features of the galactose head group compared to glucose as head group that have been previously observed in equilibrium studies are also evident in the kinetic mechanism in that comparative structural changes in the intermediates are slower in the galactolipid than in the chain-homologous glucolipid. There is evidence from the X-ray data that the general transition mechanism is identical for gluco- and galacto-lipids. However, the first intermediate I' disappears too fast in the glucolipid phase change to be detectable with the present time resolution of the X-ray measurements.The kinetics of the phase change of the lactolipid is characterized within the resolution of the X-ray sequence (5 ms) by a strict two-state mechanism equation image with transient coexistence of the initial and final phase during the kinetic phase transformation. The relaxation time has been found to be highly temperature dependent, being 57 ms at 79.1 ° and 14 ms at 81.1 °.It is worth noting that there appears to be a principal difference in the phase change mechanism between glycolipids with mono- or disaccharide head groups in that the latter (16-1,2-Lac) shows no sign of any kinetic intermediate state