Effect of temperature on succinate transport by an arctic and a temperate strain of rhizobia

1993 ◽  
Vol 39 (10) ◽  
pp. 907-911 ◽  
Author(s):  
Pierre C. Bigwaneza ◽  
Danielle Prévost ◽  
Lucien M. Bordeleau ◽  
Hani Antoun
Keyword(s):  
Transport System ◽  
Cold Adaptation ◽  
Proton Motive Force ◽  
The Arctic ◽  
Transport Systems ◽  
Effect Of Temperature ◽  
Rhizobium Strain ◽  
Onobrychis Viciifolia ◽  
Carbonyl Cyanide ◽  
Similar Kinetic

The effect of temperature on the succinate transport system was studied in the arctic Rhizobium strain N31 (isolated from Astragalus alpinus) and in the temperate strain SM2 (isolated from Onobrychis viciifolia). Only one inducible succinate transport system was found in the two strains as indicated by the linear Eadie–Hofstee plot obtained at 10, 15, and 25 °C. The transport of succinate was not affected by arsenate, but was inhibited by carbonyl cyanide m-chlorophenylhydrazone, KCN, and iodoacetate, implying an active process, a proton motive force, and essential sulfhydryl groups in the system. At 25 °C the apparent Km and Vmax values observed were 6.7 and 7.4 μM and 40.8 and 27.9 nmol∙min−1∙mg protein−1 for strains N31 and SM2, respectively. Similar kinetic parameters for succinate transport at 25 °C were obtained with the cells of both strains grown at 10 or 25 °C. However, when transport was measured at 10 °C the Km and Vmax values obtained with strain SM2 were higher for cells cultured at 10 °C than for those cultured at 25 °C, suggesting that this temperate strain might be more affected by low growth temperature than the arctic strain N31. The succinate transport systems in the two strains were affected by temperature in a similar fashion, as indicated by similar Arrhenius plots of Vmax showing a discontinuity at 20 °C and by comparable apparent energy of activation values. These observations suggest that the cold adaptation of strain N31 is not related to a cold adaptation of the succinate carrier.Key words: arctic, Rhizobium, succinate, symbiosis, transport.

Glucose transport by an arctic and a temperate strain of rhizobia

1991 ◽  
Vol 37 (2) ◽  
pp. 105-109 ◽  
Author(s):  
Pierre C. Bigwaneza ◽  
Danielle Prévost ◽  
Lucien M. Bordeleau ◽  
Hani Antoun
Keyword(s):  
Key Words ◽  
Glucose Transport ◽  
Transport System ◽  
High Energy ◽  
The Arctic ◽  
Transport Systems ◽  
High Energy Phosphate ◽  
Rhizobium Species ◽  
Onobrychis Viciifolia ◽  
Active Mechanism

Glucose transport was studied in two strains of Rhizobium species effective on sainfoin (Onobrychis viciifolia), the arctic strain N31 isolated from Astragalus alpinus and the temperate strain SM2 isolated from sainfoin. The two strains had comparable glucose transport systems with a biphasic kinetics, indicating the presence of a high- and low-affinity transport system. Apparent Km and Vmax values for the high- and low-affinity transport systems were, respectively, 4.7 and 53.4 μM and 12.7 and 58.9 nmol∙min−1∙mg protein−1 with N31 and 2.6 and 72.6 μM and 10.1 and 64.6 nmol∙min−1∙mg protein−1 with SM2. Glucose transport systems were inhibited by 2,4-dinitrophenol, KCN, azide, and N-ethylmaleimide. NaF did not affect glucose transport, while arsenate showed partial inhibition of the low-affinity transport system with strain N31. These results suggest an active mechanism of transport that is dependent on an energized membrane but does not directly utilize high-energy phosphate compounds. In the two strains, glucose transport is constitutive and repressed by succinate, and it is glucose specific. Key words: Arctic, glucose, Rhizobium, symbiosis, transport.

Characterization of inorganic phosphate transport in osteoclast-like cells

2005 ◽  
Vol 288 (4) ◽  
pp. C921-C931 ◽  
Author(s):  
Mikiko Ito ◽  
Naoko Matsuka ◽  
Michiyo Izuka ◽  
Sakiko Haito ◽  
Yuko Sakai ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Transport System ◽  
Inorganic Phosphate ◽  
Phosphate Transport ◽  
Transport Systems ◽  
Raw264.7 Cells ◽  
Transport Activity ◽  
Phosphonoformic Acid ◽  
Carbonyl Cyanide ◽  
Bone Particles

Osteoclasts possess inorganic phosphate (Pi) transport systems to take up external Pi during bone resorption. In the present study, we characterized Pi transport in mouse osteoclast-like cells that were obtained by differentiation of macrophage RAW264.7 cells with receptor activator of NF-κB ligand (RANKL). In undifferentiated RAW264.7 cells, Pi transport into the cells was Na+ dependent, but after treatment with RANKL, Na+-independent Pi transport was significantly increased. In addition, compared with neutral pH, the activity of the Na+-independent Pi transport system in the osteoclast-like cells was markedly enhanced at pH 5.5. The Na+-independent system consisted of two components with Km of 0.35 mM and 7.5 mM. The inhibitors of Pi transport, phosphonoformic acid, and arsenate substantially decreased Pi transport. The proton ionophores nigericin and carbonyl cyanide p-trifluoromethoxyphenylhydrazone as well as a K+ ionophore, valinomycin, significantly suppressed Pi transport activity. Analysis of BCECF fluorescence indicated that Pi transport in osteoclast-like cells is coupled to a proton transport system. In addition, elevation of extracellular K+ ion stimulated Pi transport, suggesting that membrane voltage is involved in the regulation of Pi transport activity. Finally, bone particles significantly increased Na+-independent Pi transport activity in osteoclast-like cells. Thus, osteoclast-like cells have a Pi transport system with characteristics that are different from those of other Na+-dependent Pi transporters. We conclude that stimulation of Pi transport at acidic pH is necessary for bone resorption or for production of the large amounts of energy necessary for acidification of the extracellular environment.

Effet des souches arctiques de Rhizobium sur la structure des nodules du sainfoin (Onobrychis viciifolia) et de légumineuses arctiques (Astragalus et Oxytropis spp.)

1989 ◽  
Vol 67 (11) ◽  
pp. 3164-3168 ◽  
Author(s):  
Danielle Prévost ◽  
L. M. Bordeleau ◽  
H. Antoun
Keyword(s):  
Internal Structure ◽  
Lipid Droplets ◽  
The Arctic ◽  
Rhizobium Strain ◽  
Indeterminate Growth ◽  
Onobrychis Viciifolia ◽  
Nodule Shape ◽  
Membrane Envelope

Rhizobium strain N31, isolated from the arctic legume Astragalus alpinus, nodulates sainfoin (Onobrychis viciifolia) as efficiently as strain SM-2, isolated from sainfoin. Nodule shape and tissue arrangement of 70-day-old plants infected by these two strains were examined. Sainfoin nodules formed by either strain N31 or SM-2 were cylindrical, with indeterminate growth, and similar to those found on arctic legumes. However, in the active symbiotic zone of sainfoin nodules, bacteroids of strain N31 were pleiomorphic or spherical and found individually or in groups of three, surrounded by the membrane envelope, whereas the bacteroids of strain SM-2 were elongated and enclosed in clusters of 3 to 12 by each membrane envelope. Thus, arctic strain N31 affects the internal structure of sainfoin nodules. Nodules of arctic legumes A. alpinus, Oxytropis maydelliana, and Oxytropis arctobia, infected with either strain N31 or SM-2, contained lipid droplets, while sainfoin nodules did not show such characteristics. This phenomenon seems specific to arctic legumes and it is not influenced by the origin of the nodulating strain.

Heave Induced Internal Flow Fluctuations in Vertical Transport Systems for Deep Ocean Mining

2014 ◽  
Author(s):  
Stephan D. A. Hannot ◽  
Jort M. van Wijk
Keyword(s):  
Transport System ◽  
Internal Flow ◽  
Deep Ocean ◽  
Vertical Transport ◽  
Transport Systems ◽  
Ship Motions ◽  
Centrifugal Pumps ◽  
Mining System ◽  
Pump System ◽  
Ocean Mining

Deep ocean mining systems will have to operate often in harsh weather conditions with heavy sea states. A typical mining system consists of a Mining Support Vessel (MSV) with a Vertical Transport System (VTS) attached to it. The transport system is a pump pipeline system using centrifugal pumps. The heave motions of the ship are transferred to the pump system due to the riser-ship coupling. Ship motions thus will have a significant influence on the internal flow in the VTS. In this paper, the influence of heave motions on the internal flow in the VTS for a typical mining system for Seafloor Massive Sulfide (SMS) deposits in Papua New Guinea is analyzed. Data on the wave climate in the PNG region is used to compute the ship motions of a coupled MSV-VTS. The ship motions then are translated into forces acting on the internal flow in order to compute fluctuations in the internal flow. In this way, the workability of the mining system with respect to the system’s production can be assessed. Based on a detailed analysis of the internal flow in relation to ship motions, the relevance of a coupled analysis for the design of VTS is made clear. This paper provides a method for performing such analyses.

scholarly journals Trk2 Potassium Transport System in Streptococcus mutans and Its Role in Potassium Homeostasis, Biofilm Formation, and Stress Tolerance

2016 ◽  
Vol 198 (7) ◽  
pp. 1087-1100 ◽  
Author(s):  
Gursonika Binepal ◽  
Kamal Gill ◽  
Paula Crowley ◽  
Martha Cordova ◽  
L. Jeannine Brady ◽  
...  
Keyword(s):  
Stress Tolerance ◽  
Streptococcus Mutans ◽  
Transport System ◽  
Biofilm Formation ◽  
Cellular Response ◽  
Pathogenic Bacteria ◽  
Transport Systems ◽  
Content Type ◽  
Growth And Survival ◽  
Dental Biofilm

ABSTRACTPotassium (K+) is the most abundant cation in the fluids of dental biofilm. The biochemical and biophysical functions of K+and a variety of K+transport systems have been studied for most pathogenic bacteria but not for oral pathogens. In this study, we establish the modes of K+acquisition inStreptococcus mutansand the importance of K+homeostasis for its virulence attributes. TheS. mutansgenome harbors four putative K+transport systems that included two Trk-like transporters (designated Trk1 and Trk2), one glutamate/K+cotransporter (GlnQHMP), and a channel-like K+transport system (Kch). Mutants lacking Trk2 had significantly impaired growth, acidogenicity, aciduricity, and biofilm formation. [K+] less than 5 mM eliminated biofilm formation inS. mutans. The functionality of the Trk2 system was confirmed by complementing anEscherichia coliTK2420 mutant strain, which resulted in significant K+accumulation, improved growth, and survival under stress. Taken together, these results suggest that Trk2 is the main facet of the K+-dependent cellular response ofS. mutansto environment stresses.IMPORTANCEBiofilm formation and stress tolerance are important virulence properties of caries-causingStreptococcus mutans. To limit these properties of this bacterium, it is imperative to understand its survival mechanisms. Potassium is the most abundant cation in dental plaque, the natural environment ofS. mutans. K+is known to function in stress tolerance, and bacteria have specialized mechanisms for its uptake. However, there are no reports to identify or characterize specific K+transporters inS. mutans. We identified the most important system for K+homeostasis and its role in the biofilm formation, stress tolerance, and growth. We also show the requirement of environmental K+for the activity of biofilm-forming enzymes, which explains why such high levels of K+would favor biofilm formation.

CONTEMPORARY DIRECTIONS OF URBAN PLANNING IN THE REVIEW OF GRADUATION THESIS OF THE NEW GENERATION

2019 ◽  
Author(s):  
И.Г. Федченко
Keyword(s):  
Urban Planning ◽  
Public Space ◽  
Participatory Design ◽  
The Arctic ◽  
Transport Systems ◽  
University Graduates ◽  
City Development ◽  
Semantic Categories ◽  
Space Projects ◽  
The City

В статье представлен обзор тематики выпускных квалификационных работ по градостроительству, представленных на Международный смотр-конкурс дипломных проектов архитектурных вузов, проводимый Межрегиональной общественной организацией содействия архитектурному образованию (МООСАО) в 2018 и 2019 годах. Проведенный анализ позволил сформулировать современные направления развития градостроительного знания по смысловым категориям проектов: технологические проекты; стратегические проекты различных уровней; проекты развития урбанизированных территорий; проекты уникальных тематик (освоение космоса, Арктики, концепции города будущего, проекты на территориях зарубежных государств). The article provides an overview of the topics of diploma works on urban planning submitted to the International Review Competition of architectural projects of university graduates held by the Interregional Public Organization for the Promotion of Architectural Education in 2018 and 2019. The analysis made it possible to formulate a generalization of topics into semantic categories: technological projects (technologies for urban planning, environmental-friendly planning, participatory design); strategic projects of various levels (the development of agglomerations and resettlement systems, strategies for the development of cities and historical centers, the modernization of transport systems, as well as projects to form the “nuclei” of economic growth); urban development projects (reconstruction of existing buildings, renovation of communal and warehouse areas of the city, development of disturbed territories, public space projects under the federal program “Formation of a comfortable urban environment”); projects of unique topics (space exploration, the Arctic, the concept of the city of the future, projects in foreign countries).

scholarly journals Processes determining the marine alkalinity and calcium carbonate saturation state distributions

2014 ◽  
Vol 11 (24) ◽  
pp. 7349-7362 ◽  
Author(s):  
B. R. Carter ◽  
J. R. Toggweiler ◽  
R. M. Key ◽  
J. L. Sarmiento
Keyword(s):  
Calcium Carbonate ◽  
The Arctic ◽  
Effect Of Temperature ◽  
Minor Role ◽  
Co2 Solubility ◽  
Saturation State ◽  
Marine System ◽  
Calcite Saturation ◽  
River Mouths ◽  
Arctic Surface

Abstract. We introduce a composite tracer for the marine system, Alk*, that has a global distribution primarily determined by CaCO3 precipitation and dissolution. Alk* is also affected by riverine alkalinity from dissolved terrestrial carbonate minerals. We estimate that the Arctic receives approximately twice the riverine alkalinity per unit area as the Atlantic, and 8 times that of the other oceans. Riverine inputs broadly elevate Alk* in the Arctic surface and particularly near river mouths. Strong net carbonate precipitation results in low Alk* in subtropical gyres, especially in the Indian and Atlantic oceans. Upwelling of dissolved CaCO3-rich deep water elevates North Pacific and Southern Ocean Alk*. We use the Alk* distribution to estimate the variability of the calcite saturation state resulting from CaCO3 cycling and other processes. We show that regional differences in surface calcite saturation state are due primarily to the effect of temperature differences on CO2 solubility and, to a lesser extent, differences in freshwater content and air–sea disequilibria. The variations in net calcium carbonate cycling revealed by Alk* play a comparatively minor role in determining the calcium carbonate saturation state.

scholarly journals Regarding some aspects of economic feasibility for the transport integrated use in favor of environmental security

2018 ◽  
Vol 170 ◽  
pp. 05001 ◽  
Author(s):  
Ruben Kazaryan
Keyword(s):  
National Security ◽  
Transport System ◽  
Developed Countries ◽  
Climatic Conditions ◽  
Environmental Security ◽  
Economic Feasibility ◽  
Transport Systems ◽  
Domestic Water ◽  
European Area ◽  
High Dynamics

The transport system in Russia and the transport support issues of national security differ completely from the Occident and other developed countries due to geostrategic and natural climatic conditions of our country. The integrated transport system, where in a sufficiently coherent manner used are the roads and railways, domestic water and air ways, pipeline transport, is more developed in the European area of the country. However there is no assessment of economic feasibility for the integrated transport lines. Firstly, assessment criteria for the transport support efficiency in favor of environmental security; secondly, mathematical economic models of various transport types integrated use in favor of environmental security; thirdly, economic feasibility methods for transport integrated use in favor of environmental security, that unavoidably leads to unreasonable transport operations using the existing rail and water ways at little distances, and increases their base cost by several times versus the transport by road. High dynamics of transport support for economic, demographic and environmental security within a market economy require the development of approach for the transport integrated use in favor of Russia national security. This article describes some practical recommendations for transport systems control bodies.

scholarly journals Determining the Extent of Territorial Transport Services When Using Rail Transport

2019 ◽  
Vol 10 (2) ◽  
pp. 61-69
Author(s):  
Milan Dedík ◽  
Jozef Gašparík ◽  
Nikolina Brnjac
Keyword(s):  
Transport System ◽  
Rail Transport ◽  
Transport Systems ◽  
Transport Service ◽  
Factors Affecting ◽  
Transport Services ◽  
Complex Process ◽  
The Subject ◽  
Efficient Transport ◽  
Transport Potential

Abstract Planning the extent of transport services within a selected territory is a topical issue especially in the context of developing integrated transport systems. The objective of this research study is to design a sustainable system of public passenger transport that would be an alternative to expanding individual transport. The implementation of a quality and efficient transport service is a relatively complex process, since, currently, there are no generally applicable principles for its design. This manuscript presents general results of research aimed at solving the problem of transport service within a selected territory issue with a focus on rail transport as an efficient transport system representing a backbone of a transport system. The subject of the investigation is to compile a set of factors affecting the design of the transport concept. The output of the manuscript consists in a proposal of a generally applicable procedure including a calculation of transport potential and characteristics of the inputs. Subsequently, based on the resulting values, it will be possible to determine the extent of the transport services provided by rail transport in any territory, which will contribute to a more efficient and high quality theoretical graph of train running.

scholarly journals The Glucuronic Acid Utilization Gene Cluster from Bacillus stearothermophilus T-6

1999 ◽  
Vol 181 (12) ◽  
pp. 3695-3704 ◽  
Author(s):  
Smadar Shulami ◽  
Orit Gat ◽  
Abraham L. Sonenshein ◽  
Yuval Shoham
Keyword(s):  
Gene Cluster ◽  
Transport System ◽  
Bacillus Stearothermophilus ◽  
Glucuronic Acid ◽  
Genomic Library ◽  
Regulatory Gene ◽  
Sugar Transport ◽  
Transcriptional Unit ◽  
Transport Systems ◽  
Potential Operator

ABSTRACT A λ-EMBL3 genomic library of Bacillus stearothermophilus T-6 was screened for hemicellulolytic activities, and five independent clones exhibiting β-xylosidase activity were isolated. The clones overlap each other and together represent a 23.5-kb chromosomal segment. The segment contains a cluster of xylan utilization genes, which are organized in at least three transcriptional units. These include the gene for the extracellular xylanase, xylanase T-6; part of an operon coding for an intracellular xylanase and a β-xylosidase; and a putative 15.5-kb-long transcriptional unit, consisting of 12 genes involved in the utilization of α-d-glucuronic acid (GlcUA). The first four genes in the potential GlcUA operon (orf1, -2, -3, and -4) code for a putative sugar transport system with characteristic components of the binding-protein-dependent transport systems. The most likely natural substrate for this transport system is aldotetraouronic acid [2-O-α-(4-O-methyl-α-d-glucuronosyl)-xylotriose] (MeGlcUAXyl3). The following two genes code for an intracellular α-glucuronidase (aguA) and a β-xylosidase (xynB). Five more genes (kdgK,kdgA, uxaC, uxuA, anduxuB) encode proteins that are homologous to enzymes involved in galacturonate and glucuronate catabolism. The gene cluster also includes a potential regulatory gene, uxuR, the product of which resembles repressors of the GntR family. The apparent transcriptional start point of the cluster was determined by primer extension analysis and is located 349 bp from the initial ATG codon. The potential operator site is a perfect 12-bp inverted repeat located downstream from the promoter between nucleotides +170 and +181. Gel retardation assays indicated that UxuR binds specifically to this sequence and that this binding is efficiently prevented in vitro by MeGlcUAXyl3, the most likely molecular inducer.

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