A peptide export–import control circuit modulating bacterial development regulates protein phosphatases of the phosphorelay

The phosphorelay signal transduction system activates developmental transcription in sporulation of Bacillus subtilis by phosphorylation of aspartyl residues of the Spo0F and Spo0A response regulators. The phosphorylation level of these response regulators is determined by the opposing activities of protein kinases and protein aspartate phosphatases that interpret positive and negative signals for development in a signal integration circuit. The RapA protein aspartate phosphatase of the phosphorelay is regulated by a peptide that directly inhibits its activity. This peptide is proteolytically processed from an inactive pre-inhibitor protein encoded in the phrA gene. The pre-inhibitor is cleaved by the protein export apparatus to a putative pro-inhibitor that is further processed to the active inhibitor peptide and internalized by the oligopeptide permease. This export–import circuit is postulated to be a mechanism for timing phosphatase activity where the processing enzymes regulate the rate of formation of the active inhibitor. The processing events may, in turn, be controlled by a regulatory hierarchy. Chromosome sequencing has revealed several other phosphatase–prepeptide gene pairs in B. subtilis, suggesting that the use of this mechanism may be widespread in signal transduction.

The H+-Sucrose Cotransporter NtSUT1 Is Essential for Sugar Export from Tobacco Leaves1

In many species translocation of sucrose from the mesophyll to the phloem is carrier mediated. A sucrose/H+-symporter cDNA, NtSUT1, was isolated from tobacco (Nicotiana tabacum) and shown to be highly expressed in mature leaves and at low levels in other tissues, including floral organs. To study the in vivo function of NtSUT1, tobacco plants were transformed with a SUT1 antisense construct under control of the cauliflower mosaic virus 35S promoter. Upon maturation, leaves of transformants expressing reduced amounts of SUT1 mRNA curled downward, and strongly affected plants developed chloroses and necroses that led to death. The leaves exhibited impaired ability to export recently fixed 14CO2 and were unable to export transient starch during extended periods of darkness. As a consequence, soluble carbohydrates accumulated and photosynthesis was reduced. Autoradiographs of leaves show a heterogenous pattern of CO2 fixation even after a 24-h chase. The 14C pattern does not change with time, suggesting that movement of photosynthate between mesophyll cells may also be impaired. The affected lines show a reduction in the development of the root system and delayed or impaired flowering. Taken together, the effects observed in a seed plant (tobacco) demonstrate the importance of SUT1 for sucrose loading into the phloem via an apoplastic route and possibly for intermesophyll transport as well.

Dim-Red-Light-Induced Increase in Polar Auxin Transport in Cucumber Seedlings1 : I. Development of Altered Capacity, Velocity, and Response to Inhibitors

We have developed and characterized a system to analyze light effects on auxin transport independent of photosynthetic effects. Polar transport of [3H]indole-3-acetic acid through hypocotyl segments from etiolated cucumber (Cucumis sativus L.) seedlings was increased in seedlings grown in dim-red light (DRL) (0.5 μmol m−2 s−1) relative to seedlings grown in darkness. Both transport velocity and transport intensity (export rate) were increased by at least a factor of 2. Tissue formed in DRL completely acquired the higher transport capacity within 50 h, but tissue already differentiated in darkness acquired only a partial increase in transport capacity within 50 h of DRL, indicating a developmental window for light induction of commitment to changes in auxin transport. This light-induced change probably manifests itself by alteration of function of the auxin efflux carrier, as revealed using specific transport inhibitors. Relative to dark controls, DRL-grown seedlings were differentially less sensitive to two inhibitors of polar auxin transport, N-(naphth-1-yl) phthalamic acid and 2,3,5-triiodobenzoic acid. On the basis of these data, we propose that the auxin efflux carrier is a key target of light regulation during photomorphogenesis.

Pure Business, Law Enforcement or Sheer Politics? The EU’s WTO Complaints against Chinese Export Restrictions on Raw Materials. EU Diplomacy Paper 06/2013

In light of the growing international competition among states and globally operating companies for limited natural resources, export restrictions on raw materials have become a popular means for governments to strive for various goals, including industrial development, natural resource conservation and environmental protection. For instance, China as a major supplier of many raw materials has been using its powerful position to both economic and political ends. The European Union (EU), alongside economic heavyweights such as the US, Japan and Mexico, launched two high-profile cases against such export restrictions by China at the WTO in 2009 and 2012. Against this background, this paper analyses the EU’s motivations in the initiation of trade disputes on export restrictions at WTO, particularly focusing on the two cases with China. It argues that the EU's WTO complaints against export restrictions on raw materials are to a large extent motivated by its economic and systemic interests rather than political interests. The EU is more likely to launch a WTO complaint, the stronger the potential and actual impact on its economy, the more ambiguous the WTO rules and the stronger the internal or external lobbying by member states or companies. This argumentation is based on the analysis of pertinent factors such as the economic impact, the ambiguity of WTO law on export restrictions and the pressure by individual member states on the EU as well as the role of joint complaints at the WTO and political considerations influencing the EU’s decision-making process.

The Regulatory Framework of Export Restrictions in WTO Law and Regional Free Trade Agreements. IES WORKING PAPER 8/2013

The use of export restrictions has become more and more common in recent years, evidencing the substantial loopholes existing in the WTO regulation on the matter. As a result of this deficient legal framework, the WTO membership experiences important losses of welfare and increasing political tensions. The multilateral negotiations for an updated discipline on export restrictions, in the context of the Doha Development Round, are blocked. Consequently, members have established a set of preferential bilateral and multilateral agreements to relieve the negative effects of these measures. Likewise, some recent WTO members have committed to stricter regulations as part of their Accession Protocols. Nevertheless, these methods have evidenced some important flaws, and the multilateral scene remains the optimum forum to address export restrictions. This Working Paper proposes a number of measures to improve the legal framework of the quantitative export restrictions and export duties, as well as their notification procedures.

Trade policy and export activity in the Mexican manufacturing sector /

Cover title.

The behavior of U.S. export prices and profit margins, 1981-1986 /

Mode of access: Internet.

Directory of combination export managers.

Section 1. Food, feed, and fertilizer.--section 2. Fuel.--section 3. Raw materials and semi-finished products.--section 4. Machinery and vehicles.--section 5. Miscellaneous and unclassified.

Foreign operations, export financing, and related programs appropriations for 2006 : hearings before a Subcommittee of the Committee on Appropriations, House of Representatives, One Hundred Ninth Congress, first session /

Shipping list no.: 2005-0187-P (pt. 1A), 2005-0195-P (pt. 1B), 2005-0178-P (pts. 2-3), 2005-0204-P (pt. 4), 2006-0101-P (pt. 5).

Foreign operations, export financing, and related programs appropriations for 2007 : hearings before a Subcommittee of the Committee on Appropriations, House of Representatives, One Hundred Ninth Congress, second session /

Shipping list no.: 2006-0243-P (pt. 1A), 2006-0276-P (pt. 1B), 2006-0329-P (pt. 2), 2006-0315-P (pt. 3), 2007-0101-P (pt. 4).

Foreign assistance : accuracy of AID statistics on dollars flowing back to the U.S. economy is doubtful : report to the Chairman, Subcommittee on Foreign Operations, Export Financing, and Related Programs, Committee on Appropriations, House of Representatives /

"B-239036"--P. 1.

U.S. solar and conservation technologies in international markets [microform] : hearings before the Subcommittee on Energy Development and Applications and the Subcommittee on Investigations and Oversight of the Committee on Science and Technology, U.S. House of Representatives, Ninety-seventh Congress, second session, June 3, 17, 21, 1982.

"No. 132."

Directory of combination export managers.

Mode of access: Internet.

Export markets for Illinois coal /

"October 1996."