930 resultados para Refrigeration and refrigerating machinery.
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Using tobacco plants that had been transformed with the cDNA for glycerol-3-phosphate acyltransferase, we have demonstrated that chilling tolerance is affected by the levels of unsaturated membrane lipids. In the present study, we examined the effects of the transformation of tobacco plants with cDNA for glycerol-3-phosphate acyltransferase from squash on the unsaturation of fatty acids in thylakoid membrane lipids and the response of photosynthesis to various temperatures. Of the four major lipid classes isolated from the thylakoid membranes, phosphatidylglycerol showed the most conspicuous decrease in the level of unsaturation in the transformed plants. The isolated thylakoid membranes from wild-type and transgenic plants did not significantly differ from each other in terms of the sensitivity of photosystem II to high and low temperatures and also to photoinhibition. However, leaves of the transformed plants were more sensitive to photoinhibition than those of wild-type plants. Moreover, the recovery of photosynthesis from photoinhibition in leaves of wild-type plants was faster than that in leaves of the transgenic tobacco plants. These results suggest that unsaturation of fatty acids of phosphatidylglycerol in thylakoid membranes stabilizes the photosynthetic machinery against low-temperature photoinhibition by accelerating the recovery of the photosystem II protein complex.
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Transcription factor TFIID consists of TATA binding protein (TBP) and at least eight TBP-associated factors (TAFs). As TAFs are required for activated but not basal transcription, we have proposed that TAFs act as coactivators to mediate signals between activators and the basal transcription machinery. Here we report the cloning, expression, and biochemical characterization of the 32-kDa subunit of human (h) TFIID, termed hTAFII32. We find that hTAFII32 is the human homologue of Drosophila TAFII40. In vitro protein-protein interaction assays reveal that as observed with Drosophila TAFII40, hTAFII32 interacts with the C-terminal 39-amino acid activation domain of the acidic transactivator viral protein 16 (VP16) as well as with the general transcription factor TFIIB. Moreover, a partial recombinant TFIID complex containing hTAFII32 was capable of mediating in vitro transcriptional activation by the VP16 activation domain. These findings indicate that specific activator-coactivator interactions have been conserved between human and Drosophila and provide additional support for the function of these interactions in mediating transcriptional activation.
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Transcriptional stimulation by the model activator GAL4-VP16 (a chimeric protein consisting of the DNA-binding domain of the yeast activator GAL4 and the acidic activation domain of the herpes simplex virus protein VP16) involves a series of poorly understood protein-protein interactions between the VP16 activation domain and components of the RNA polymerase II general transcription machinery. One of these interactions is the VP16-mediated binding and recruitment of transcription factor TFIIB. However, TATA box-binding protein (TBP)-associated factors (TAFs), or coactivators, are required for this interaction to culminate in productive transcription complex assembly, and one such TAF, Drosophila TAF40, reportedly forms a ternary complex with VP16 and TFIIB. Due to TFIIB's central role in gene activation, we sought to directly visualize the surfaces of this protein that mediate formation of the ternary complex. We developed an approach called protease footprinting in which the broad-specificity proteases chymotrypsin and alkaline protease were used to probe binding of 32P-end-labeled TFIIB to GAL4-VP16 or TAF40. Analysis of the cleavage products revealed two regions of TFIIB protected by VP16 from protease attack, one of which overlapped with a region protected by TAF40. The close proximity of the VP16 and TAF40 binding sites on the surface of TFIIB suggests that this region could act as a regulatory interface mediating the effects of activators and coactivators on transcription complex assembly.
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Chitosan is a biopolymer with a wide range of applications. The use of chitosan in clinical medicine to control infections by fungal pathogens such as Candida spp. is one of its most promising applications in view of the reduced number of antifungals available. Chitosan increases intracellular oxidative stress, then permeabilizes the plasma membrane of sensitive filamentous fungus Neurospora crassa and yeast. Transcriptomics reveals plasma membrane homeostasis and oxidative metabolism genes as key players in the response of fungi to chitosan. A lipase and a monosaccharide transporter, both inner plasma membrane proteins, and a glutathione transferase are main chitosan targets in N. crassa. Biocontrol fungi such as Pochonia chlamydosporia have a low content of polyunsaturated free fatty acids in their plasma membranes and are resistant to chitosan. Genome sequencing of P. chlamydosporia reveals a wide gene machinery to degrade and assimilate chitosan. Chitosan increases P. chlamydosporia sporulation and enhances parasitism of plant parasitic nematodes by the fungus. Omics studies allow understanding the mode of action of chitosan and help its development as an antifungal and gene modulator.
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L’histoire de la United Shoe Machinery Company (USMC) montre que la réalité ne s’adapte pas toujours aux simplifications de la théorie. Comme le signale l’économie de la fonctionnalité, la stratégie de l’entreprise de vendre l’usage plutôt que la machine fournit plusieurs avantages importants, mais elle a également contribué au fait que les usines de chaussures subissent une véritable dépendance technologique de cette compagnie et au fait que l’USMC soit parvenue à une domination monopolistique du marché. D’autre part, en remettant en cause les rudiments généraux de la théorie économique néoclassique, cette position de monopole n’a pas empêché que l’entreprise ait un fonctionnement efficace et ait facilité la modernisation technologique de l’industrie de la chaussure, aux États-Unis et dans d’autres pays.
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This communication develops the process of interventions of the Renaissance fortress of a new plant built in 1554–57 in Santa Pola. It is one of the earliest examples built with reference to military architecture theoretical treaties (XV–XVI) and best preserved. The study runs its own story from its initial military use, through the use of civil equipment until the final cultural and Museum Center. First, the project of Italian origin is examined and its use as barracks for troops for a duration of three centuries (1557–1850), pointing out the architectural constants of war machinery in a defense position and its origin as a rainwater collector and cistern: a perfect square with two bastions in which a plan of the uprising is preserved (1778). Secondly, we study the changes in the mentioned architecture throughout a century and a half (1850–1990) after its change of ownership (from the state to the municipality), and as a result of the new use as a city hall and public endowment: a market and health and leisure centre, which meant the demolition of defensive elements and the opening up to the outside of the inner parade ground. And thirdly, the new transfer of the municipal offices brings in the beginning of a project of transformations (1990–2015) that retrieves the demolished elements at the same time as it assigns the entire fort for a cultural centre: exhibition, research and history museum, promoting the identity between the citizens and the building which stands in the foundations of their city. The conclusions take us through an interesting route that goes from the approach of defensive tactics, its use as administrative headquarters to the current cultural policy of preservation. In addition, all the known plans of the fort are recovered (of military, civil and cultural use), some unpublished, as well as the project of the North wing that has guided the last operation and which has been set as a pattern of reference.
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In the long term, productivity and especially productivity growth are necessary conditions for the survival of a farm. This paper focuses on the technology choice of a dairy farm, i.e. the choice between a conventional and an automatic milking system. Its aim is to reveal the extent to which economic rationality explains investing in new technology. The adoption of robotics is further linked to farm productivity to show how capital-intensive technology has affected the overall productivity of milk production. The empirical analysis applies a probit model and an extended Cobb-Douglas-type production function to a Finnish farm-level dataset for the years 2000–10. The results show that very few economic factors on a dairy farm or in its economic environment can be identified to affect the switch to automatic milking. Existing machinery capital and investment allowances are among the significant factors. The results also indicate that the probability of investing in robotics responds elastically to a change in investment aids: an increase of 1% in aid would generate an increase of 2% in the probability of investing. Despite the presence of non-economic incentives, the switch to robotic milking is proven to promote productivity development on dairy farms. No productivity growth is observed on farms that keep conventional milking systems, whereas farms with robotic milking have a growth rate of 8.1% per year. The mean rate for farms that switch to robotic milking is 7.0% per year. The results show great progress in productivity growth, with the average of the sector at around 2% per year during the past two decades. In conclusion, investments in new technology as well as investment aids to boost investments are needed in low-productivity areas where investments in new technology still have great potential to increase productivity, and thus profitability and competitiveness, in the long run.
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This study evaluates the degree of segmentation of the market for agricultural machinery and equipment in the EU. We focus on agricultural tractors, the most common and biggest investment in machinery and equipment in the agricultural sector. By using country price data for individual tractor models, we test the law of one price, i.e. the existence of a common price for tractors across EU member states. We find that significant price differences exist, yet unlike most other studies we find that large price deviations are penalised within a short time. The study also shows that transport costs are an important source of price differences, as domestic production leads to lower prices on the domestic market and as price convergence is negatively correlated with distance. Finally, price differences should not solely be understood from a geographical perspective, as evidence supports the idea that farmers’ buying power is significant in explaining price differences within countries.
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This deliverable provides a comparative analysis, among selected EU member states, of the investment demand of a sample of specialised field crop farms for farm buildings, machinery and equipment as determined by different types and levels of Common Agricultural Policy support. It allows for the existence of uncertainty in the price of output farmers receive and for both long- and short-run determinants of investment levels, as well as for the presence of irregularities in the cost adjustment function due to the existence of threshold-type behaviours. The empirical estimation reveals that three investment regimes are consistently identified in Germany and Hungary, across asset and support types, and in France for machinery and equipment. More traditional disinvestment-investment type behaviours characterise investment in farm building in France and the UK, across support types, and Italy for both asset classes under coupled payments. The long-run dynamic adjustment of capital stocks is consistently and significantly estimated to be towards a – mostly non-stationary – lower level of capitalisation of the farm analysed. By contrast, the expected largely positive short-run effects of an increase in output prices are often not significant. The effect of CAP support on both types of investment is positive, although seldom significant, while the proxy for uncertainty employed fails to be significant yet, in most cases, has the expected effect of reducing the investment levels.
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This paper analyses empirically how increasingly close trade relations between China and Russia might affect the European Union (EU). We show that EU countries are complementary to Russia on the Chinese market. However, Chinese exports are increasingly relevant substitutes for EU exports on the Russian market. This means that an increase in China-Russia economic cooperation should have a negative impact on European exports. We simulate a scenario in which trade tariffs between Russia and China are eliminated, which is found to reduce EU exports to Russia. Finally, a more granular approach to the question analyses which sectors in Europe will be more affected by the increasing economic links between China and Russia, and finds that electronic machinery, equipment and machinery, and nuclear reactors will be particularly affected. Such findings obviously show quickly China is moving up the ladder in terms of export structure and how strategically important it is for Europe to continue upgrading its industry to compete at the highest level of that ladder.
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Inducible epigenetic changes in eukaryotes are believed to enable rapid adaptation to environmental fluctuations. We have found distinct regions of the Arabidopsis genome that are susceptible to DNA (de)methylation in response to hyperosmotic stress. The stress-induced epigenetic changes are associated with conditionally heritable adaptive phenotypic stress responses. However, these stress responses are primarily transmitted to the next generation through the female lineage due to widespread DNA glycosylase activity in the male germline, and extensively reset in the absence of stress. Using the CNI1/ATL31 locus as an example, we demonstrate that epigenetically targeted sequences function as distantly-acting control elements of antisense long non-coding RNAs, which in turn regulate targeted gene expression in response to stress. Collectively, our findings reveal that plants use a highly dynamic maternal 'short-term stress memory' with which to respond to adverse external conditions. This transient memory relies on the DNA methylation machinery and associated transcriptional changes to extend the phenotypic plasticity accessible to the immediate offspring.
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This work aimed to evaluate the colour and texture of a Portuguese traditional sweet “egg chestnuts” along a storage period of 12 days under refrigeration. For this, the colour coordinates were measured through a colorimeter and the textural parameters were evaluated by compression and puncture tests using a textutrometer. The results showed that the colour coordinates do not vary along time, corresponding to very low values of total colour difference. Hardness, chewiness and springiness decreased in the first 3 days but after that the values were maintained approximately constant. In contrast, resilience and cohesiveness did not change along time. While crust firmness increased along storage, both the flesh firmness and stickiness did not change. The adhesiveness measured through the penetration test decreased considerably from the first to the last day. Hence, it was concluded that colour is better preserved than texture along a 12 day storage period under refrigeration.
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Plasmodium and Theileria parasites are obligate intracellular protozoa of the phylum Apicomplexa. Theileria infection of bovine leukocytes induces transformation of host cells and infected leukocytes can be kept indefinitely in culture. Theileria-dependent host cell transformation has been the subject of interest for many years and the molecular basis of this unique phenomenon is quite well understood. The equivalent life cycle stage of Plasmodium is the infection of mammalian hepatocytes, where parasites reside for 2-7 days depending on the species. Some of the molecular details of parasite-host interactions in P. berghei-infected hepatocytes have emerged only very recently. Similar to what has been shown for Theileria-infected leukocytes these data suggest that malaria parasites within hepatocytes also protect their host cell from programmed cell death. However, the strategies employed to inhibit host cell apoptotic pathways appear to be different to those used by Theileria. This review discusses similarities and differences at the molecular level of Plasmodium- and Theileria-induced regulation of the host cell survival machinery.
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