Journal articles on the topic 'Nitrogen fixation proce'
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1
Atkins, C. A. "The Legume/Rhizobium Symbiosis: Limitations to Maximizing Nitrogen Fixation." Outlook on Agriculture 15, no. 3 (September 1986): 128–34. http://dx.doi.org/10.1177/003072708601500305.
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Although the recent fall in the price of oil will ultimately be reflected in some reduction in the price of nitrogenous fertilizers the cost of the latter will still be sufficient to maintain interest in techniques of biological nitrogen fixation. This is attractive, in the sense that it involves direct utilization of atmospheric nitrogen as a free good but there are some costs, not yet possible to evaluate, to be set on the debit side. There is, therefore, need for much more research.
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Angus, J. F., and M. B. Peoples. "Nitrogen from Australian dryland pastures." Crop and Pasture Science 63, no. 9 (2012): 746. http://dx.doi.org/10.1071/cp12161.
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Legume-based pastures, particularly those containing a large proportion of lucerne (alfalfa, Medicago sativa), have a prodigious capacity to fix atmospheric N2. Budgets of N show that permanent pastures in south-eastern Australia, when growing with no management limitations, can supply more N than is removed in animal products and can eventually lead to excess soil N. For a mixed crop–livestock farm, legume-dominant ley pastures occupying ~40% of the land area can maintain a stable N balance. The actual performance of pastures on farms normally falls below the potential. Pastures are being replaced by crops in the wheat-sheep zone and, to a lesser extent, in the high-rainfall zone. Pasture productivity, as indicated by the area topdressed, the mean stocking rate, input of superphosphate and sale of pasture legume seed has decreased in the period 1990–2010. It is therefore likely that N2 fixation by pastures is falling sharply in the wheat–sheep zone and is static or falling slightly in the high-rainfall zone. Reversing the decrease in N2 fixation by pastures will become important if the real price of N fertilisers increases, as seems likely because the efficiency of fertiliser synthesis is approaching a maximum and the reserves of natural gas feedstock will eventually be depleted. Increased N2 fixation by pastures will depend on more profitable grazing industries, improved management methods and genotypes, and re-adoption of ley pastures by farmers. There is evidence that profitability of grazing enterprises is approaching that of crops so investment in pasture science is likely to lead to increased N2 fixation.
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Hatano, Soshi, Yoichi Fujita, Yoshifumi Nagumo, Norikuni Ohtake, Kuni Sueyoshi, Yoshihiko Takahashi, Takashi Sato, et al. "Effect of the Nitrification Inhibitor 3,4-Dimethylpyrazole Phosphate on the Deep Placement of Nitrogen Fertilizers for Soybean Cultivation." International Journal of Agronomy 2019 (February 3, 2019): 1–11. http://dx.doi.org/10.1155/2019/9724214.
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The deep placement of urea fertilizer (DMU) containing 1% (W/W) of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on soybean growth and seed yield was as effective as those of the coated urea (CU) and lime nitrogen (LN) in a field research. The average seed yields were high in LN (464 g·m−2) and DMU (461 g·m−2) and relatively low in CU (405 g·m−2), U (396 g·m−2), and Cont (373 g·m−2) treatments. The accumulations of dry matter and nitrogen in soybean shoots were higher in the plants with deep placement of CU, LN, and DMU than U and Cont. The daily nitrogen fixation activity and daily nitrogen absorption rate were calculated based on the relative ureide method. Both nitrogen fixation activity and nitrogen absorption rate were higher in DMU, CU, and LN compared with control treatment, suggesting that the deep placement of DMU did not repress nitrogen fixation. Soil incubation test was performed using the same field soil with DMU, U, LN, and urea with DMPP 1%, 2%, and 4%. DMU inhibits nitrification similar to the pattern of LN until 8 weeks. The increasing DMPP concentration did not markedly increase the nitrification inhibition. From these results, it was concluded that urea fertilizer with 1% DMPP is efficient for deep placement of N fertilizer for soybean cultivation due to its lower price compared with CU and LN.
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Walker, T. W. "The value of N-fixation to pastoral agriculture in New Zealand." NZGA: Research and Practice Series 6 (January 1, 1996): 115–18. http://dx.doi.org/10.33584/rps.6.1995.3349.
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White clover in New Zealand fixes nitrogen equivalent to 4.5 million tonnes of urea annually. Experiments on the tactical use of about 50 kg N ha-1 yr-1 to stimulate grass growth when clovers are less active indicate that it is generally profitable, but much heavier dressings have rarely been shown to pay at current cost/price structures. The significance of biological nitrogen fixation (BNF) cannot be measured solely by dry matter yields as the quality of herbage is influenced by the contribution of clover and affects yields of animal products and health. Our dependence on BNF gives us a relatively low energycost system of pastoral farming because of the high energy cost of producing fertiliser-N and is therefore more sustainable. The heavy use of fertiliser-N suppresses clover growth and N-fixation, increases losses of ammonia and nitrous oxide to the air and nitrate in drainage water. The extra stock carried leads to greater emission of methane. Reliance on clovers may give lower production but lessens damage to the environment. Keywords: biological nitrogen fixation, energy costs, environment, fertiliser nitrogen, pastoral agriculture, sustainability
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Pawlowski, Alice, Kai-Uwe Riedel, Werner Klipp, Petra Dreiskemper, Silke Groß, Holger Bierhoff, Thomas Drepper, and Bernd Masepohl. "Yeast Two-Hybrid Studies on Interaction of Proteins Involved in Regulation of Nitrogen Fixation in the Phototrophic Bacterium Rhodobacter capsulatus." Journal of Bacteriology 185, no. 17 (September 1, 2003): 5240–47. http://dx.doi.org/10.1128/jb.185.17.5240-5247.2003.
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ABSTRACT Rhodobacter capsulatus contains two PII-like proteins, GlnB and GlnK, which play central roles in controlling the synthesis and activity of nitrogenase in response to ammonium availability. Here we used the yeast two-hybrid system to probe interactions between these PII-like proteins and proteins known to be involved in regulating nitrogen fixation. Analysis of defined protein pairs demonstrated the following interactions: GlnB-NtrB, GlnB-NifA1, GlnB-NifA2, GlnB-DraT, GlnK-NifA1, GlnK-NifA2, and GlnK-DraT. These results corroborate earlier genetic data and in addition show that PII-dependent ammonium regulation of nitrogen fixation in R. capsulatus does not require additional proteins, like NifL in Klebsiella pneumoniae. In addition, we found interactions for the protein pairs GlnB-GlnB, GlnB-GlnK, NifA1-NifA1, NifA2-NifA2, and NifA1-NifA2, suggesting that fine tuning of the nitrogen fixation process in R. capsulatus may involve the formation of GlnB-GlnK heterotrimers as well as NifA1-NifA2 heterodimers. In order to identify new proteins that interact with GlnB and GlnK, we constructed an R. capsulatus genomic library for use in yeast two-hybrid studies. Screening of this library identified the ATP-dependent helicase PcrA as a new putative protein that interacts with GlnB and the Ras-like protein Era as a new protein that interacts with GlnK.
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Berge, Odile, Thierry Heulin, Wafa Achouak, Claude Richard, Rene Bally, and Jacques Balandreau. "Rahnella aquatilis, a nitrogen-fixing enteric bacterium associated with the rhizosphere of wheat and maize." Canadian Journal of Microbiology 37, no. 3 (March 1, 1991): 195–203. http://dx.doi.org/10.1139/m91-030.
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In a study of dominant diazotrophic bacteria present in the rhizosphere of wheat and maize, 28 strains of Enterobacteriaceae were isolated. They were all Voges-Proskauer positive, motile at 28 °C but not at 37 °C, and they produced a Tween-80 esterase and did not exhibit decarboxylase activity. This fits well with the description of Rahnella aquatilis. The ability of these strains to reduce acetylene in pure culture and in association with their host plant and the DNA hybridization with a nifHDK probe are described. This is the first time that R. aquatilis is reported as a rhizosphere-associated bacterium and also a nitrogen fixer. Key words: Rahnella aquatilis, rhizosphere, wheat, maize, nitrogen fixation.
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Pederson, Dennis M., Arlene Daday, and Geoffrey D. Smith. "The use of nickel to probe the role of hydrogen metabolism in cyanobacterial nitrogen fixation." Biochimie 68, no. 1 (January 1986): 113–20. http://dx.doi.org/10.1016/s0300-9084(86)81076-8.
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Winzer, Till, Andrea Bairl, Monica Linder, Dietmar Linder, Dietrich Werner, and Peter Müller. "A Novel 53-kDa Nodulin of the Symbiosome Membrane of Soybean Nodules, Controlled by Bradyrhizobium japonicum." Molecular Plant-Microbe Interactions® 12, no. 3 (March 1999): 218–26. http://dx.doi.org/10.1094/mpmi.1999.12.3.218.
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A nodule-specific 53-kDa protein (GmNOD53b) of the symbiosome membrane from soybean was isolated and its LysC digestion products were microsequenced. cDNA clones of this novel nodulin, obtained from cDNA library screening with an RT-PCR (reverse-transcriptase polymerase chain reaction)-generated hybridization probe exhibited no homology to proteins identified so far. The expression of GmNOD53b coincides with the onset of nitrogen fixation. Therefore, it is a late nodulin. Among other changes, the GmNOD53b is significantly reduced in nodules infected with the Bradyrhizobium japonicum mutant 184 on the protein level as well as on the level of mRNA expression, compared with the wild-type infected nodules. The reduction of GmNOD53b mRNA is related to an inactivation of the sipF gene in B. japonicum 184, coding for a functionally active signal peptidase.
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Wirsen, C. O., S. M. Sievert, C. M. Cavanaugh, S. J. Molyneaux, A. Ahmad, L. T. Taylor, E. F. DeLong, and C. D. Taylor. "Characterization of an Autotrophic Sulfide-Oxidizing Marine Arcobacter sp. That Produces Filamentous Sulfur." Applied and Environmental Microbiology 68, no. 1 (January 2002): 316–25. http://dx.doi.org/10.1128/aem.68.1.316-325.2002.
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ABSTRACT A coastal marine sulfide-oxidizing autotrophic bacterium produces hydrophilic filamentous sulfur as a novel metabolic end product. Phylogenetic analysis placed the organism in the genus Arcobacter in the epsilon subdivision of the Proteobacteria. This motile vibrioid organism can be considered difficult to grow, preferring to grow under microaerophilic conditions in flowing systems in which a sulfide-oxygen gradient has been established. Purified cell cultures were maintained by using this approach. Essentially all 4′,6-diamidino-2-phenylindole dihydrochloride-stained cells in a flowing reactor system hybridized with Arcobacter-specific probes as well as with a probe specific for the sequence obtained from reactor-grown cells. The proposed provisional name for the coastal isolate is “Candidatus Arcobacter sulfidicus.” For cells cultured in a flowing reactor system, the sulfide optimum was higher than and the CO2 fixation activity was as high as or higher than those reported for other sulfur oxidizers, such as Thiomicrospira spp. Cells associated with filamentous sulfur material demonstrated nitrogen fixation capability. No ribulose 1,5-bisphosphate carboxylase/oxygenase could be detected on the basis of radioisotopic activity or by Western blotting techniques, suggesting an alternative pathway of CO2 fixation. The process of microbial filamentous sulfur formation has been documented in a number of marine environments where both sulfide and oxygen are available. Filamentous sulfur formation by “Candidatus Arcobacter sulfidicus” or similar strains may be an ecologically important process, contributing significantly to primary production in such environments.
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Prell, Jürgen, Bert Boesten, Philip Poole, and Ursula B. Priefer. "The Rhizobium leguminosarum bv. viciae VF39 γ-aminobutyrate (GABA) aminotransferase gene (gabT) is induced by GABA and highly expressed in bacteroids The GenBank accession number for the sequence determined in this work is AF335502." Microbiology 148, no. 2 (February 1, 2002): 615–23. http://dx.doi.org/10.1099/00221287-148-2-615.
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A Rhizobium leguminosarum bv. viciae VF39 gene (gabT) encoding a γ-aminobutyrate (GABA) aminotransferase was identified, cloned and characterized. This gene is thought to be involved in GABA metabolism via the GABA shunt pathway, a theoretical bypass of the 2-oxoglutarate dehydrogenase complex. Mutants in gabT are still able to grow on GABA as a sole carbon and nitrogen source. 2-Oxoglutarate-dependent GABA aminotransferase activity is absent in these mutants, while pyruvate-dependent activity remains unaffected. This indicates that at least two enzymes with different substrate specifities are involved in the GABA metabolism of R. leguminosarum bv. viciae VF39. The gabT promoter was cloned into a newly constructed, stable promoter-probe vector pJP2, suitable for the study of transcriptional GUS fusions in free-living bacteria and during symbiosis. Under free-living conditions the gabT promoter is induced by GABA and repressed by succinate. Transcriptional regulation is mediated by GabR in a repressor-like manner. During symbiosis with the pea host plant gabT is induced and highly expressed in the symbiotic zone. Nodules induced by gabT mutants, however, are still effective in nitrogen fixation.
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Reiher, Markus, Nathan Wiebe, Krysta M. Svore, Dave Wecker, and Matthias Troyer. "Elucidating reaction mechanisms on quantum computers." Proceedings of the National Academy of Sciences 114, no. 29 (July 3, 2017): 7555–60. http://dx.doi.org/10.1073/pnas.1619152114.
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With rapid recent advances in quantum technology, we are close to the threshold of quantum devices whose computational powers can exceed those of classical supercomputers. Here, we show that a quantum computer can be used to elucidate reaction mechanisms in complex chemical systems, using the open problem of biological nitrogen fixation in nitrogenase as an example. We discuss how quantum computers can augment classical computer simulations used to probe these reaction mechanisms, to significantly increase their accuracy and enable hitherto intractable simulations. Our resource estimates show that, even when taking into account the substantial overhead of quantum error correction, and the need to compile into discrete gate sets, the necessary computations can be performed in reasonable time on small quantum computers. Our results demonstrate that quantum computers will be able to tackle important problems in chemistry without requiring exorbitant resources.
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Parton, R. G. "Ultrastructural localization of gangliosides; GM1 is concentrated in caveolae." Journal of Histochemistry & Cytochemistry 42, no. 2 (February 1994): 155–66. http://dx.doi.org/10.1177/42.2.8288861.
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The ultrastructural distribution of the ganglioside GM1 was investigated in A431 cells. After fixation, the cells were frozen in liquid nitrogen, freeze-substituted, and then embedded in Lowicryl resin at -45 degrees C. By use of the cholera toxin-binding subunit adsorbed to gold as a specific probe to label on the sections, GM1 was shown to be present in endocytic organelles, in the trans-Golgi network, and on the plasma membrane, but was not detectable in the endoplasmic reticulum. GM1 was not distributed uniformly over the plasma membrane but was concentrated approximately four-fold in non-coated invaginations. These were identified as caveolae by labeling frozen sections of cholera toxin-gold surface-labeled cells with antibodies to VIP-21/caveolin. The results strengthen the functional analogy between caveolae and sorting domains of the TGN in polarized epithelial cells.
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Baudouin, Emmanuel, Laurent Pieuchot, Gilbert Engler, Nicolas Pauly, and Alain Puppo. "Nitric Oxide Is Formed in Medicago truncatula-Sinorhizobium meliloti Functional Nodules." Molecular Plant-Microbe Interactions® 19, no. 9 (September 2006): 970–75. http://dx.doi.org/10.1094/mpmi-19-0970.
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Nitric oxide (NO) has recently gained interest as a major signaling molecule during plant development and response to environmental cues. Its role is particularly crucial for plant-pathogen interactions, during which it participates in the control of plant defense response and resistance. Indication for the presence of NO during symbiotic interactions has also been reported. Here, we defined when and where NO is produced during Medicago truncatula-Sinorhizobium meliloti symbiosis. Using the NO-specific fluorescent probe 4,5-diaminofluorescein diacetate, NO production was detected by confocal microscopy in functional nodules. NO production was localized in the bacteroid-containing cells of the nodule fixation zone. The infection of Medicago roots with bacterial strains impaired in nitrogenase or nitrite reductase activities lead to the formation of nodules with an unaffected NO level, indicating that neither nitrogen fixation nor denitrification pathways are required for NO production. On the other hand, the NO synthase inhibitor N-methyl-L-arginine impaired NO detection, suggesting that a NO synthase may participate to NO production in nodules. These data indicate that a NO production occurs in functional nodules. The location of such a production in fully metabolically active cells raises the hypothesis of a new function for NO during this interaction unrelated to defense and cell-death activation.
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Yoo, Won Young, Si Bum Sung, and Chung Sun An. "Nucleotide sequences of the 2-oxoacid ferredoxin oxidoreductase and ferredoxin genes fromFrankiastrain EuIK1, a symbiont ofElaeagnus umbellataroot nodules." Canadian Journal of Botany 77, no. 9 (December 18, 1999): 1279–86. http://dx.doi.org/10.1139/b99-079.
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A genomic clone, pEuNIFII, was isolated by screening a genomic library of Frankia strain EuIK1, a symbiont of Elaeagnus umbellata Thunb. root nodules. A 1.5-kb fragment of pEuNIF4.0, which contained ORF2 and N-terminal part of nifS, was used as a probe. A 7.2-kb BamHI fragment of pEuNIFII, which was proven to be adjacent to the probe, was subjected to sequence determination. The sequence analysis suggested one partial ORF followed by three open reading frames (ORFs). Two ORFs next to nifS encodes an a subunit (672 amino acids) and b subunit (347 amino acids) of a 2-oxoacid ferredoxin oxidoreducatase (OR), respectively. The third ORF encodes 114 amino acids of a 7Fe-type ferredoxin (Fdx). All ORFs are transcribed in the same direction as other nif genes. Alignment of the deduced amino acid sequences from frankiae OR revealed the motifs of gamma and alpha domains seen in other ORs in the a subunit, and the beta domain in the b subunit. Frankia or shows about 44% nucleotide sequence similarity with nifJ from Klebsiella pneumoniae, while frankiae fdx shows about 56% similarity with fdxI from Azotobacter vinelandii. These genes are reported for the first time in Frankia, and putative roles of their products in symbiosis is discussed in relation to nitrogen fixation and carbohydrate metabolism.Key words: 2-oxoacid ferredoxin oxidoreductase, ferredoxin, nucleotide sequence, Frankia EuIK1.
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Kuykendall, L. D., B. Saxena, T. E. Devine, and S. E. Udell. "Genetic diversity in Bradyrhizobium japonicum Jordan 1982 and a proposal for Bradyrhizobium elkanii sp.nov." Canadian Journal of Microbiology 38, no. 6 (June 1, 1992): 501–5. http://dx.doi.org/10.1139/m92-082.
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Fourteen randomly selected clones from cosmid libraries of Bradyrhizobium were used as hybridization probes in Southern blot analysis. Seven of the probes used were from strain USDA 83, a group II strain, and the other seven were from strain I-110, a group Ia strain. The 30 strains examined included 9 strains of Rj4-incompatible soybean bradyrhizobia. Considerable polynucleotide sequence dissimilarity between DNA homology groups was evidenced by striking differences in the number of hybridizing bands, except where the probe carried repetitive DNA. Predictable, simple restriction fragment length polymorphism differences were observed only within DNA homology groups. The previous description that 8 of 9 Rj4-incompatible strains belonged to DNA homology group II was verified. The new data, together with many previously documented differences, make it clear that the DNA homology group II organisms should be classified as a new species, for which the name Bradyrhizobium elkanii is proposed, and strain USDA 76 is designated the type strain. The ATCC number for the type strain is 49852. Key words: DNA:DNA hybridization, soybean, nodulation, bacteria, symbiosis, nitrogen fixation, host compatibility.
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Galindo, Fernando S., Marcelo C. M. Teixeira Filho, Edson C. da Silva, Salatiér Buzetti, Guilherme C. Fernandes, and Willian L. Rodrigues. "Technical and economic viability of cowpea co-inoculated with Azospirillum brasilense and Bradyrhizobium spp. and nitrogen doses." Revista Brasileira de Engenharia Agrícola e Ambiental 24, no. 5 (May 2020): 304–11. http://dx.doi.org/10.1590/1807-1929/agriambi.v24n5p304-311.
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ABSTRACT Biological nitrogen fixation efficiency can be increased by co-inoculation with Bradyrhizobium spp. and Azospirillum brasilense, allowing even greater uptake of water and nutrients, leading to higher yields and enabling the insertion of unusual crops, such as cowpea (Vigna unguiculata L. Walp.), in the agricultural production system in the Cerrado region of Brazil. Thus, this study aimed to evaluate the technical and economic viability of cowpea in the Cerrado region, as a function of N doses and co-inoculation of seeds with Azospirillum brasilense and Bradyrhizobium. The study was carried out in a no-tillage system in Selvíria, MS, Brazil. The experimental design was a randomized block design, with four repetitions, arranged in a 3 x 5 factorial scheme, corresponding to three types of inoculation (without inoculation - control, with two strains of Bradyrhizobium spp. SEMIA 6462 and SEMIA 6463 - the conventional inoculation of cowpea, and these two strains of Bradyrhizobium spp. plus A. brasilense strains Ab-V5 and Ab-V6); and five N doses (0, 20, 40, 80 and 160 kg ha-1), as urea, applied as topdressing. The following evaluations were performed: grain yield, total operating cost, effective operating cost, gross revenue, operating profit, profitability index, equilibrium price and equilibrium yield. Co-inoculation with A. brasilense increases cowpea grain yield, which makes cowpea production in the Cerrado region of Brazil technically and economically viable, without the need to apply N fertilizers in topdressing.
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Wilkins, R. J. "Eco-efficient approaches to land management: a case for increased integration of crop and animal production systems." Philosophical Transactions of the Royal Society B: Biological Sciences 363, no. 1491 (July 25, 2007): 517–25. http://dx.doi.org/10.1098/rstb.2007.2167.
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Eco-efficiency is concerned with the efficient and sustainable use of resources in farm production and land management. It can be increased either by altering the management of individual crop and livestock enterprises or by altering the land-use system. This paper concentrates on the effects of crop sequence and rotation on soil fertility and nutrient use efficiency. The potential importance of mixed farming involving both crops and livestock is stressed, particularly when the systems incorporate biological nitrogen fixation and manure recycling. There is, however, little evidence that the trend in developed countries to farm-level specialization is being reduced. In some circumstances legislation to restrict diffuse pollution may provide incentives for more diverse eco-efficient farming and in other circumstances price premia for produce from eco-efficient systems, such as organic farming, and subsidies for the provision of environmental services may provide economic incentives for the adoption of such systems. However, change is likely to be most rapid where the present systems lead to obvious reductions in the productive potential of the land, such as in areas experiencing salinization. In other situations, there is promise that eco-efficiency could be increased on an area-wide basis by the establishment of linkages between farms of contrasting type, particularly between specialist crop and livestock farms, with contracts for the transfer of manures and, to a lesser extent, feeds.
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Premakumar, R., Marty R. Jacobson, Telisa M. Loveless, and Paul E. Bishop. "Characterization of transcripts expressed from nitrogenase-3 structural genes of Azotobacter vinelandii." Canadian Journal of Microbiology 38, no. 9 (September 1, 1992): 929–36. http://dx.doi.org/10.1139/m92-150.
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Five major anfH-hybridizing mRNA species accumulated in Azotobacter vinelandii cells derepressed for nitrogenase-3 (an alternative nitrogenase, which appears to lack Mo and V). Using anfH-, anfD-, anfG-, anfK-, and orf1orf2-specific probes and mutant strains of A. vinelandii these mRNA species have been identified as encoding anfHDGKorf1orf2 (6.0 kb), anfHDGK (4.3 kb), anfHD (2.6 kb), vnfHorfFd (1.3 kb), and vnfH and (or) anfH(1.0 kb). A 0.6-kb mRNA species, which hybridized only to the orf1orf2-specific probe, and a 3.5-kb mRNA species, which hybridized to anfD or anfK, also accumulated under these conditions. Northern blot analysis and S1 nuclease mapping indicate that transcription of the anf structural gene cluster initiates at a unique nif consensus promoter situated 127 base pairs upstream from the anfH coding region. Observation of anfH-hybridizing mRNA species that accumulate in strains derepressed for nitrogen fixation demonstrates that transcription of the anfHDGKorf1orf2 cluster is normally repressed by Mo, V, and NH4+, whereas transcription of the vnfHorfFd cluster does not require the presence of V and is repressed only by Mo, but not NH4+. Analysis of the accumulation of mRNAs in a tungsten-tolerant strain revealed that Mo and V repression of anf transcription must occur by different mechanisms. Key words: Azotobacter vinelandii, nitrogenase-3, transcripts, regulation, molybdenum, vanadium.
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Aare, Ane Kirstine, Stine Rosenlund Hansen, Niels Heine Kristensen, and Henrik Hauggaard-Nielsen. "Valuing in the Agrifood System: The Case of Fresh Grain Legumes in Denmark." Sustainability 15, no. 4 (February 6, 2023): 2946. http://dx.doi.org/10.3390/su15042946.
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Transitioning towards more sustainable food products, such as plant proteins, requires a change in practice by several actors in the agrifood system. Change of this kind involves everyday choices about what food to produce, sell, prepare, and eat. Inspired by science and technology studies (STS) thinking, we investigate how such choices are influenced by socio-material practices of valuing. We use the case of fresh grain legumes for human consumption to explore how valuing is simultaneously affected by and shapes the agrifood system. Through interviews with 24 actors in the Danish agrifood system, we identify valuing parameters ranging from taste, nitrogen fixation, durability, and nutrition to price. The study reveals differences regarding what and how actors value depending on the actors’ position in the agrifood system and how the fresh grain legumes travel from field to plate. Where values conflict, we observe how some valuing practices have the power to exclude others and thereby prevent specific enactments of the fresh grain legumes. We argue that looking for valuing practices can help us understand how agrifood systems come into being, and that valuing differently can represent active involvement, both academically and practically, in encouraging change in the agrifood system. By using STS-thinking, the study brings novel insights about barriers towards more plant-based diets and contributes to the diversification of theoretical perspectives on sustainable transitions.
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Le Moal, M., H. Collin, and I. C. Biegala. "Intriguing diversity among diazotrophic picoplankton along a Mediterranean transect: from the origin of plastids to the dominance of rhizobia." Biogeosciences Discussions 7, no. 6 (December 2, 2010): 8779–816. http://dx.doi.org/10.5194/bgd-7-8779-2010.
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Abstract. The Mediterranean Sea is one of the most oligotrophic marine areas on earth where nitrogen fixation has been formally believed to play an important role in carbon and nitrogen fluxes. Although this view is under debate, the diazotrophs responsible for this activity have still not been investigated in the open sea. In this study we characterised the surface distribution and species richness of unicellular and filamentous diazotrophs across the Mediterranean Sea by combining microscopic counts with size fractionated in situ hybridization (TSA-FISH), and 16S rDNA and nifH phylogenies. These genetic analyses were possible owning to the development of a new PCR protocol adapted for scarce microorganisms (0.2 cell ml−1). Low concentrations of diazotrophic cyanobacteria were detected and this community was dominated at 99.9% by picoplankton hybridized with Nitro821 probe, specific for unicellular diazotrophic cyanobacteria (UCYN). Among filamentous cyanobacteria only 0.02 filament ml−1 of Richelia were detected in the eastern basin, while small (0.7–1.5 μm) and large (2.5–3.2 μm) Nitro821-targeted cells were recovered at all stations and averaged 3.5 cell ml−1. The affiliation of the small Nitro821-targeted cells to UCYN-A was confirmed by 16S and nifH phylogenies in the western Mediterranean Sea. Surprisingly, the larger hybridized cells were not belonging to UCYN-B and C but to plastids of picoeukaryote. NifH gene was not recovered among picoeukaryotes, when rhizobia sequences, including the ones of Bradyrhizobia, were dominating nifH clone libraries from picoplanktonic size fractions. Few sequences of γ-proteobacteria were also detected in central Mediterranean Sea. While low phosphate and iron concentrations could explain the absence of Trichodesmium sp., the factors that prevent the development of UCYN-B and C remain unknown. We also propose that the dominating picoplankters probably developed specific strategies, such as associations with protists or particles and photosynthetic activity to acquire carbon for sustaining diazotrophy. Among UCYN further work will be necessary to understand their suggested role in plastid evolution.
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Le Moal, M., H. Collin, and I. C. Biegala. "Intriguing diversity among diazotrophic picoplankton along a Mediterranean transect: a dominance of rhizobia." Biogeosciences 8, no. 3 (March 29, 2011): 827–40. http://dx.doi.org/10.5194/bg-8-827-2011.
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Abstract. The Mediterranean Sea is one of the most oligotrophic marine areas on earth where nitrogen fixation has formally believed to play an important role in carbon and nitrogen fluxes. Although this view is under debate, the diazotrophs responsible for this activity have still not been investigated in the open sea. In this study, we characterised the surface distribution and species richness of unicellular and filamentous diazotrophs across the Mediterranean Sea by combining microscopic counts with size fractionated in situ hybridization (TSA-FISH), and 16S rDNA and nifH genes phylogenies. These genetic analyses were possible owing to the development of a new PCR protocol adapted to scarce microorganisms that can detect as few as 1 cell ml−1 in cultures. Low concentrations of diazotrophic cyanobacteria were detected and this community was dominated at 99.9% by picoplankton hybridized to the Nitro821 probe, specific for unicellular diazotrophic cyanobacteria (UCYN). Among filamentous cyanobacteria only 0.02 filament ml−1 of Richelia were detected in the eastern basin, while small (0.7–1.5 μm) and large (2.5–3.2 μm) Nitro821-targeted cells were recovered at all stations with a mean concentration of 3.5 cell ml−1. The affiliation of the small Nitro821-targeted cells to UCYN-A was confirmed by 16S and nifH phylogenies in the western Mediterranean Sea. In the central and the eastern Mediterranean Sea no 16S rDNA and nifH sequence from UCYN was obtained as cells concentration were close to, or below PCR detection limit. Bradyrhizobium sequences dominated nifH clone libraries from picoplanktonic size fractions. A few sequences of γ-proteobacteria were also detected in the central Mediterranean Sea. While low phosphate and iron concentrations could explain the absence of Trichodesmium sp., the factors that prevent the development of UCYN-B and C remain unknown. We also propose that the dominating picoplankters probably developed specific strategies, such as associations with protists or particles, and/or photosynthetic activity, to acquire carbon for sustaining diazotrophy.
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Longhini, Vanessa Z., Abmael S. Cardoso, Andressa S. Berça, Robert M. Boddey, Ricardo A. Reis, José C. B. Dubeux, and Ana C. Ruggieri. "Could forage peanut in low proportion replace N fertilizer in livestock systems?" PLOS ONE 16, no. 3 (March 3, 2021): e0247931. http://dx.doi.org/10.1371/journal.pone.0247931.
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Palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster cv. Marandu] is widely used in Brazil and is typically managed with little or no N fertilizer, which often leads to pasture decline in the long-term. The current relationship between beef price and fertilizer cost in Brazil does not favor fertilizer use in pastures. Legume inclusion is an alternative to adding fertilizer N, but often legumes do not reach a significant proportion (> 30%) in pasture botanical composition. This study evaluated herbage responses to N inputs and pasture species composition, under intermittent stocking. Treatments included palisadegrass-forage peanut (Arachis pintoi Krapov. & W.C. Greg. cv. Amarillo) mixture (mixed), unfertilized palisadegrass (control), and palisadegrass fertilized with 150 kg N ha-1 yr-1 (fertilized). Treatments were applied over two rainy seasons with five growth cycle (GC) evaluations each season. Response variables included herbage biomass, herbage accumulation, morphological components, total aboveground N of forage peanut (TAGNFP), and contribution of biological N2 fixation (BNF). Herbage biomass was greater for fertilized palisadegrass [5850 kg dry matter (DM) ha-1] than for the palisadegrass-forage peanut mixture (3940 kg DM ha-1), while the unfertilized palisadegrass (4400 kg DM ha-1) did not differ from the mixed pasture. Nitrogen fertilizer increased leaf mass of palisadegrass (2490 kg DM ha-1) compared with the control and mixed treatments (1700 and 1310 kg DM ha-1, respectively). The contribution of BNF to the forage peanut ranged from 79 to 85% and 0.5 to 5.5 kg N ha-1 cycle-1. Overall, benefits from forage peanut were minimal because legume percentage was less than 10%, while N input in the system by N-fertilizer increased palisadegrass herbage biomass.
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Solovjov, Ja A., and V. A. Pilipenko. "EFFECT OF RAPID THERMAL TREATMENT ТЕMPERATURE ON ELECTROPHYSICAL PROPERTIES OF NICKEL FILMS ON SILICON." Doklady BGUIR, no. 1 (March 6, 2020): 81–88. http://dx.doi.org/10.35596/1729-7648-2020-18-1-81-88.
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Present work is devoted to determination the regularity of change of specific resistance and Schottky barrier height of nickel films on n-type silicon (111) at their rapid thermal treatment in the temperatures range from 200 to 550 °C. Nickel films of about 60 nm thickness were deposited by magnetron sputtering onto the silicon substrates having a resistivity of 0.58 to 0.53 Ohms×cm. The rapid thermal treatment was carried out in the range of 200 to 550 °C under heat balance mode by irradiating the backside of the substrates with non-coherent light flux in nitrogen ambient for 7 seconds. The thickness of the nickel films was determined by scanning electron microscopy. The sheet resistance of the samples was measured by a four-probe method. The Schottky barrier height was determined from I-V plots. It is shown that at a temperatureы of rapid thermal treatment of Ni/n-Si (111) 200–250 °C nickel will be transformed to Ni2Si, increasing in thickness by 1.15–1.33 times, specific resistance increases to 26–30 μOhm×cm, and Schottky barrier height decreases from 0.66 to 0.6 V. At a rapid thermal treatment temperature of 300°C the initial nickel film thickness increases by 1.93 times, the resistivity and Schottky barrier height decrease to 26–30 μOhm×cm and 0.59 V respectively due to the conversion of the Ni2Si into NiSi and the fixation of the barrier height by surface states at the silicidesilicon interface. Rapid thermal treatment of 350–550 °C transforms the original nickel film into NiSi, increases its thickness by 2.26–2.67 times, reduces its resistivity to 15–18 μOhm×cm and increases the Schottky barrier height to 0.62–0.64 V. The minimum defects and better reproducibility of electrophysical properties are characterized by NiSi films formed by rapid thermal treatment of nickel films on n-type silicon at a temperature of 400–450 °C. The results obtained can be used in the technology of integrated electronics products containing rectifying contacts.
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Flora, Cornelia Butler. "Food security in the context of energy and resource depletion: Sustainable agriculture in developing countries." Renewable Agriculture and Food Systems 25, no. 2 (March 25, 2010): 118–28. http://dx.doi.org/10.1017/s1742170510000177.
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AbstractFood insecurity remains high in most of sub-Saharan African. That insecurity is made even more acute by the increasing scarcity and degradation of natural resources. Low soil fertility is a consistent problem faced by agriculturalists and herders. The dominant international thrust to increase food production has been to stimulate trade, enhanced by technology and its transfer. While international bodies acknowledge the importance of small farmers, they operate as if improving the technologies, trade regimes and value chains that are characteristic of industrial agriculture will have the same results in local ecosystems in developing countries. Price volatility makes access to purchased inputs more risky for smallholders and the governments that subsidize those inputs. The diverse local contexts that serve as the base of African agriculture are thus assumed to be overridden by technology. In contrast, a systems approach that focuses on sustainability of the local ecosystem, social and cultural relationships and economic security can be as, or more productive than industrial agriculture and have a much better opportunity to increase food security in developing countries. Such a systems-based shift in practices, such as the application of conservation agriculture and integrated systemic approaches in Millennium Villages, have potential of addressing household livelihood strategies and production issues in a sustainable, farmer-based way. Resource-conserving agriculture has been shown to increase yields in developing countries. Priority should be given to developing technologies that follow the systems principles of sustainable agriculture, integrating biological and ecological processes (such as nutrient cycling, nitrogen fixation, soil regeneration and biodiversity) into the production processes; minimizing use of non-renewable inputs that cause harm to the environment or to the health of farmers and consumers; and making productive use of the knowledge and skills of farmers and their collective capacities to work together to solve common problems. A variety of models are on the ground in Africa, and there is political will in the African Union to increase investment in agriculture. What sort of investments, policy interventions and capacity building are more effective in increasing productivity and the well-being of agricultural producers? Are strategies aimed at reducing the number of people involved in farming and herding viable in the context of a stagnant world economy?
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Giller, Ken. "Current Issues in Symbiotic Nitrogen Fixation. Ed. by G. H. ELKAN and R. G. UPCHURCH. 19x26 cm. Pp. iv+196 with numerous plates and figures. Dordrecht, The Netherlands: Kluwer Academic Publishers, 1997. Price f99.00, ISBN 0 7923 4367 0." New Phytologist 140, no. 1 (September 1998): 167–69. http://dx.doi.org/10.1046/j.1469-8137.1998.00262.x.
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Giller, Ken. "Current Issues in Symbiotic Nitrogen Fixation. Ed. by G. H. ELKAN and R. G. UPCHURCH. 19×26 cm. Pp. iv+196 with numerous plates and figures. Dordrecht, The Netherlands: Kluwer Academic Publishers, 1997. Price £99.00, ISBN 0 7923 4367 0." New Phytologist 140, no. 1 (July 7, 2008): 167–69. http://dx.doi.org/10.1111/j.1469-8137.1998.00262.x.
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Cocking, Edward C. "Biological Nitrogen Fixation Associated with Rice Production. Ed. by M. RAHMAN, A. K. PODDER, C. van HOVE, Z. N. T. BEGUM, T. HEULIN and A. HARTMANN. 24×16 cm. Pp. xvi+247. Dordrecht, The Netherlands: Kluwer Academic Publishers, 1996. Price h/b: £79.00, I." New Phytologist 138, no. 4 (July 7, 2008): 743–50. http://dx.doi.org/10.1111/j.1469-8137.1998.149-3.x.
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Cocking, Edward C. "Biological Nitrogen Fixation Associated with Rice Production. Ed. by M. RAHMAN, A. K. PODDER, C. van HOVE, Z. N. T. BEGUM, T. HEULIN and A. HARTMANN. 24x16 cm. Pp. xvi+247. Dordrecht, The Netherlands: Kluwer Academic Publishers, 1996. Price h/b: f79.00, ISBN 0 7923 4197 X. Progress in Nitrogen Cycling Studies. Ed. by O. van CLEEMPUT, G. HOFMAN and A. VERMOESEN. 26x20 cm. Pp. iii+715. Dordrecht, The Netherlands: Kluwer Academic Publishers, 1996. Price h/b: f286.00, ISBN 0 7923 3962 2." New Phytologist 138, no. 4 (April 1998): 743–50. http://dx.doi.org/10.1046/j.1469-8137.1998.00149-3.x.
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Sprent, J. I. "Opportunities for biological nitrogen fixation in rice and other non-legumes. Ed. by J. K. LADHA, F. J. DE BRUIJN and M. A. MALIK. 26.5×19.5 cm. Pp. vii+216 with numerous test-figures and tables. Dordrecht, The Netherlands: Kluwer Academic Publishers, 1997. Price h/b: £85.00, ISBN 0 7923 414 2; p/b: ISBN 0 7923 4748 X." New Phytologist 141, no. 3 (March 1999): 369–71. http://dx.doi.org/10.1046/j.1469-8137.1999.00336-2.x.
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Patel, P. H., K. S. Panchal, and H. P. Patel. "Molecular Characterization of Free Living N2 Fixing Bacteria Isolated from Agricultural Soils of North Gujarat, India." Indian Journal Of Agricultural Research, Of (March 30, 2022). http://dx.doi.org/10.18805/ijare.a-5776.
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Background: Molecular identification of a wide range of organisms capable of carrying out biological nitrogen fixation (BNF) are diverse in nature and significantly improves plant growth. Biological N2 fixation reflects the activity of a phylogenetically diverse list of microorganisms. Molecular characterization provides efficient means to identify organisms with the potential of N2 fixation. Applying these techniques in an array of environments has considerably broadened our understanding of the suite of organisms that can carry out BNF. Methods: Thirty-four strains of free living N2 fixing bacterial strains were isolated from diverse plants cultivated in North Gujarat, including wheat, cotton, castor and pearl millet, using a nitrogen-free selective medium. Acetylene reduction assay was used to check the ability of all bacteria to fix nitrogen. Hybridization with nifH probe derived from Azotobacter vinelandii with isolated free-living nitrogen-fixing bacteria showed a positive result. The selected strains were characterized by molecular analysis like; ARDRA and 16S rDNA sequencing. Result: Based on molecular characterization 17 strains to known groups of nitrogen-fixing bacteria, including organisms from the genus Azotobacter, Pseudomonas, Enterobacter, Arthrobacter, Bacillus, Variovorax, Nocardiodies, Rhodococcus, Mycobacterium, Planococcus, Microbacterium have been identified. One of the strains was identified as unknown bacteria. The potential strains were identified by 16srDNA analysis and also corroborated by morphological and biochemical characterization.
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Liberton, Michelle, Anindita Bandyopadhyay, and Himadri B. Pakrasi. "Enhanced Nitrogen Fixation in a glgX-Deficient Strain of Cyanothece sp. Strain ATCC 51142, a Unicellular Nitrogen-Fixing Cyanobacterium." Applied and Environmental Microbiology 85, no. 7 (February 1, 2019). http://dx.doi.org/10.1128/aem.02887-18.
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ABSTRACT Cyanobacteria are oxygenic photosynthetic prokaryotes with important roles in the global carbon and nitrogen cycles. Unicellular nitrogen-fixing cyanobacteria are known to be ubiquitous, contributing to the nitrogen budget in diverse ecosystems. In the unicellular cyanobacterium Cyanothece sp. strain ATCC 51142, carbon assimilation and carbohydrate storage are crucial processes that occur as part of a robust diurnal cycle of photosynthesis and nitrogen fixation. During the light period, cells accumulate fixed carbon in glycogen granules to use as stored energy to power nitrogen fixation in the dark. These processes have not been thoroughly investigated, due to the lack of a genetic modification system in this organism. In bacterial glycogen metabolism, the glgX gene encodes a debranching enzyme that functions in storage polysaccharide catabolism. To probe the consequences of modifying the cycle of glycogen accumulation and subsequent mobilization, we engineered a strain of Cyanothece 51142 in which the glgX gene was genetically disrupted. We found that the ΔglgX strain exhibited a higher growth rate than the wild-type strain and displayed a higher rate of nitrogen fixation. Glycogen accumulated to higher levels at the end of the light period in the ΔglgX strain, compared to the wild-type strain. These data suggest that the larger glycogen pool maintained by the ΔglgX mutant is able to fuel greater growth and nitrogen fixation ability. IMPORTANCE Cyanobacteria are oxygenic photosynthetic bacteria that are found in a wide variety of ecological environments, where they are important contributors to global carbon and nitrogen cycles. Genetic manipulation systems have been developed in a number of cyanobacterial strains, allowing both the interruption of endogenous genes and the introduction of new genes and entire pathways. However, unicellular diazotrophic cyanobacteria have been generally recalcitrant to genetic transformation. These cyanobacteria are becoming important model systems to study diurnally regulated processes. Strains of the Cyanothece genus have been characterized as displaying robust growth and high rates of nitrogen fixation. The significance of our study is in the establishment of a genetic modification system in a unicellular diazotrophic cyanobacterium, the demonstration of the interruption of the glgX gene in Cyanothece sp. strain ATCC 51142, and the characterization of the increased nitrogen-fixing ability of this strain.
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Knutson, Carolann M., Meghan N. Pieper, and Brett M. Barney. "Gene Fitness of Azotobacter vinelandii Under Diazotrophic Growth." Journal of Bacteriology, September 27, 2021. http://dx.doi.org/10.1128/jb.00404-21.
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Azotobacter vinelandii is a nitrogen-fixing free-living soil microbe that has been studied for decades in relation to biological nitrogen fixation (BNF). It is highly amenable to genetic manipulation, helping to unravel the intricate importance of different proteins involved in the process of BNF, including the biosynthesis of cofactors that are essential to assembling the complex metal cofactors that catalyze the difficult reaction of nitrogen fixation. Additionally, A. vinelandii accomplishes this feat while growing as an obligate aerobe, differentiating it from many of the nitrogen-fixing bacteria that are associated with plant roots. The ability to function in the presence of oxygen makes A. vinelandii suitable for application in various potential biotechnological schemes. In this study, we employed transposon sequencing (Tn-seq) to measure the fitness defects associated with disruptions of various genes under nitrogen-fixing dependent growth, versus growth with extraneously provided urea as a nitrogen source. The results allowed us to probe the importance of more than 3800 genes, revealing that many genes previously believed to be important, can be successfully disrupted without impacting cellular fitness. Importance These results provide insights into the functional redundancy in A. vinelandii , while also providing a direct measure of fitness for specific genes associated with the process of BNF. These results will serve as a valuable reference tool in future studies to uncover the mechanisms that govern this process.
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Chaudhary, S., R. Dhanker, R. Kumar, and S. Goyal. "Importance of Legumes and Role of Sulphur Oxidizing Bacteria for Their Production: A Review." LEGUME RESEARCH - AN INTERNATIONAL JOURNAL, OF (September 15, 2020). http://dx.doi.org/10.18805/lr-4415.
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Background: Legumes are relatively cheap, non-animal good source of valuable proteins, micro-nutrients and vitamins in human and animal nutrition for many years. Recognizing the potential of legumes in achieving the sustainable solution to the global food security, protein access, eradicate hunger and malnutrition, FAO of the United Nations (The Food and Agriculture Organization), facilitated 2016 as the International Year of Pulses (grain legumes) under the banner ‘nutritious seeds for a sustainable future’. The nutrient, nitrogen and biological nitrogen fixation is very crucial for legume’s growth, besides sulphur deficiency is very sensitive to the nodulation and nitrogen fixation. Despite the amazing beneficial properties, legumes are neglected by most of us due to having tough competition with low price and high yielding cereal varieties. Methods: Therefore keeping in mind the above points, this review discusses the importance and application of legumes in different perspectives, legume cultivation patterns, importance of sulphur nutrition to legumes, role of sulphur oxidizing bacteria in sulphur nutrition, improving soil and environment, challenges and future of legumes. Conclusion: Legumes have variety of applications including food, health, environment and many other sectors but we are not able to produce enough amount according to their genetic potential due to inefficient breeding programs. Sulphur is an important nutrient along with N effecting its growth and yield. Sulphur oxidizing bacteria (SOB) have been proved as an important tool for improving yield and symbiotic nitrogen fixation in legumes. Therefor application of biofertilizers along with SOB and improved genetic breeding programmes may prove leading steps to enhance their production.
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Liu, Huan, Jianliang Huang, Wanying Gao, and Hao Cheng. "A pioneer of research on aureomycin synthesis and bacterial nitrogen fixation in China: Shen San-Chiun." Protein & Cell, January 12, 2023. http://dx.doi.org/10.1093/procel/pwad001.
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Hindersah, Reginawanti, H. Yulina, and Ane Nurbaity. "Penggunaan Pupuk Organik Cair Sebagai Media Produksi Inokulan Azotobacter Chroococcum." Agrologia 2, no. 2 (February 27, 2018). http://dx.doi.org/10.30598/a.v2i2.264.
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Azotobacter chroococcum based biofertilizers have been widely used in the production of environmentally agriculture. For commercial scale, cheap growth media for Azotobcter inoculant will affect the quality and price of liquid biofertilizer. Growth medium should support cell proliferation as well as its nitrogen fixation and phytohormone production. The objective of this study was to determine whether liquid organic fertilizer (LOF) containing low N can be used as a medium for scaling up A. chroococcum inoculant without lowering the survival of bacteria and its activity in N2 fixation and phytohormones production. LOF generally contains a complete nutrient although in a small quantities. Experiment was set up in completely randomized design which tested two types of commercial LOF. The results showed that both of LOF were only able to support cell growth up to 72 hours and at 96 hours cell viability began to decline compared to the control medium, free-N Ashby. At 72 hour total N and cytokinin concentration in LOF was lower than those in Ashby media. This study revealed that LOF could be used as A. chroococcum growth media, but without optimization of its composition, cell density and cytokinin content would be lower than those of inoculant in Ashby Media.
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Ganesan, Subbulakshmi, Gopalakrisnan Padmapriya, Sanduni Anupama De Zoys, and Izegaegbe Daniel Omoikhoje. "Biofuel as an alternative energy source for environmental sustainability." Physical Sciences Reviews, September 23, 2022. http://dx.doi.org/10.1515/psr-2022-0209.
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Abstract Organic carbon fixation is the primary source of biofuels energy. Plant biomass and municipal and industrial waste are used to make gasoline that is renewable and biodegradable. Biofuel could be beneficial due to the reduced dependency on fuel, to lower the reliance on overseas oil, to lower the emissions of greenhouse gases and it provides job opportunities for the rural people. Moreover, due to the very high demand for fuel, because most of the machines, vehicles use fuel to conduct day today activities. Due to this high demand, the price is also very high. Not only that, the burning of fossil fuel normally release carbon dioxide, carbon monoxide and nitrogen dioxide which are the greenhouse gases. But although biogas too releases those gases, they are released in very lower amounts. Therefore, fuel can act as a good solution for the problems that occur due to global warming and many other environmental problems.
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Veličković, Dušan, Yen-Chen Liao, Stephanie Thibert, Marija Veličković, Christopher Anderton, Josef Voglmeir, Gary Stacey, and Mowei Zhou. "Spatial Mapping of Plant N-Glycosylation Cellular Heterogeneity Inside Soybean Root Nodules Provided Insights Into Legume-Rhizobia Symbiosis." Frontiers in Plant Science 13 (May 16, 2022). http://dx.doi.org/10.3389/fpls.2022.869281.
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Although ubiquitously present, information on the function of complex N-glycan posttranslational modification in plants is very limited and is often neglected. In this work, we adopted an enzyme-assisted matrix-assisted laser desorption/ionization mass spectrometry imaging strategy to visualize the distribution and identity of N-glycans in soybean root nodules at a cellular resolution. We additionally performed proteomics analysis to probe the potential correlation to proteome changes during symbiotic rhizobia-legume interactions. Our ion images reveal that intense N-glycosylation occurs in the sclerenchyma layer, and inside the infected cells within the infection zone, while morphological structures such as the cortex, uninfected cells, and cells that form the attachment with the root are fewer N-glycosylated. Notably, we observed different N-glycan profiles between soybean root nodules infected with wild-type rhizobia and those infected with mutant rhizobia incapable of efficiently fixing atmospheric nitrogen. The majority of complex N-glycan structures, particularly those with characteristic Lewis-a epitopes, are more abundant in the mutant nodules. Our proteomic results revealed that these glycans likely originated from proteins that maintain the redox balance crucial for proper nitrogen fixation, but also from enzymes involved in N-glycan and phenylpropanoid biosynthesis. These findings indicate the possible involvement of Lewis-a glycans in these critical pathways during legume-rhizobia symbiosis.
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Gole, James L., Serdar Ozdemir, Sharka M. Prokes, and David M. Dixon. "Active Nanostructures at Interfaces for Photocatalytic Reactors and Low-power Consumption Sensors." MRS Proceedings 1257 (2010). http://dx.doi.org/10.1557/proc-1257-o09-04.
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AbstractActive nanostructures which provide unique transformations are being introduced to phase matched porous silicon (PS) nano/micropores to form a platform for low power consumption highly selective sensors and microreactors. TiO2-xNx photocatalysts have been formed in seconds at room temperature at the nanoscale via the direct nitration of anatase TiO2 nanocolloids. Tunability throughout the visible depends upon the degree of agglomeration and the ability to seed these nanoparticles with metal ions. Co metal ion seeding leads to the efficient room temperature phase transformation, of anatase to rutile TiO2, where normally much higher temperatures are required. Seeding of a properly nitridated TiO2 nanocolloid with transition metal ions (Co, Ni) allows for the enhancement of the infrared spectra of the TiO2-xNx nitridated titania surface in excess of 10-fold, providing a means to analyze for minor contaminants and intermediates. Evidence for nitrogen fixation is found in Fe treated systems. The TiO2-xNx systems act as visible light absorbing photocatalyts. These photocatalysts and additional nanostructured metal oxides can be placed on the surface of PS-based sensor and microreactor configurations to greatly improve the interface response.
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Jangid, MK, Latika Sharma, and GL Meena. "Economic Performance and Optimum Cropping Patternbased on Alternative Price Scenarios in Arid-Western Plain Zone of Rajasthan State." Agricultural Science Digest - A Research Journal 39, no. 03 (August 7, 2019). http://dx.doi.org/10.18805/ag.d-4923.
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The present investigation was undertaken to work out the economic performance and optimum cropping pattern based on alternative price scenarios in Arid-Western Plain Zone of Rajasthan state. In the present study, the unit-level cost of cultivation data of various crops for the triennium ending year 2013-14 which were collected from “Comprehensive Scheme to Study the Cost of Cultivation of Principal Crops in Rajasthan state. The performance of different crops was assessed by calculating net returns under three alternative price scenarios i.e. (i) Market prices (MP) (ii) Economic prices (EP) and (iii) Net income based on natural resource valuation technique (NRV). This study has considered subsidy as a cost to society. Similarly green house gas emissions from the crops have been taken as cost to the society and nitrogen fixation by leguminous crops have been taken as gain to the society. Results from the study shows that groundnut-barley combination of crop sequence was found the most remunerative in economic return generated over the year of `59418 per hectare followed by groundnut-vegetables (`53930/ha) and groundnut-gram (`52879/ha) combinations. Net gain to the farmers based on the alternative price scenarios viz. market, economic and natural resource valuation prices were estimated as `114.38 lakh, `114.45 lakh and `138.82 lakh, respectively. The overall gain to society has increased at economic prices by `49.39 lakh whereas it was decreased by `93.24 lakh at natural resource valuation due to the lack of cultivation of legume crops. The optimal plan is suggested that more area under cultivation of legume crops like groundnut, clusterbean and gram because of they are less water intensive and more environment friendly and thus have a positive impact on natural resource valuation with the existing water availability.
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Nürnberg, Dennis J., Vicente Mariscal, Jan Bornikoel, Mercedes Nieves-Morión, Norbert Krauß, Antonia Herrero, Iris Maldener, Enrique Flores, and Conrad W. Mullineaux. "Intercellular Diffusion of a Fluorescent Sucrose Analog via the Septal Junctions in a Filamentous Cyanobacterium." mBio 6, no. 2 (March 17, 2015). http://dx.doi.org/10.1128/mbio.02109-14.
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ABSTRACTMany filamentous cyanobacteria produce specialized nitrogen-fixing cells called heterocysts, which are located at semiregular intervals along the filament with about 10 to 20 photosynthetic vegetative cells in between. Nitrogen fixation in these complex multicellular bacteria depends on metabolite exchange between the two cell types, with the heterocysts supplying combined-nitrogen compounds but dependent on the vegetative cells for photosynthetically produced carbon compounds. Here, we used a fluorescent tracer to probe intercellular metabolite exchange in the filamentous heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120. We show that esculin, a fluorescent sucrose analog, is incorporated by a sucrose import system into the cytoplasm of Anabaena cells. The cytoplasmic esculin is rapidly and reversibly exchanged across vegetative-vegetative and vegetative-heterocyst cell junctions. Our measurements reveal the kinetics of esculin exchange and also show that intercellular metabolic communication is lost in a significant fraction of older heterocysts. SepJ, FraC, and FraD are proteins located at the intercellular septa and are suggested to form structures analogous to gap junctions. We show that a ΔsepJΔfraCΔfraDtriple mutant shows an altered septum structure with thinner septa but a denser peptidoglycan layer. Intercellular diffusion of esculin and fluorescein derivatives is impaired in this mutant, which also shows a greatly reduced frequency of nanopores in the intercellular septal cross walls. These findings suggest that FraC, FraD, and SepJ are important for the formation of junctional structures that constitute the major pathway for feeding heterocysts with sucrose.IMPORTANCEAnabaena and its relatives are filamentous cyanobacteria that exhibit a sophisticated form of prokaryotic multicellularity, with the formation of differentiated cell types, including normal photosynthetic cells and specialized nitrogen-fixing cells called heterocysts. The question of how heterocysts communicate and exchange metabolites with other cells in the filament is key to understanding this form of bacterial multicellularity. Here we provide the first information on the intercellular exchange of a physiologically important molecule, sucrose. We show that a fluorescent sucrose analog can be imported into the Anabaena cytoplasm by a sucrose import system. Once in the cytoplasm, it is rapidly and reversibly exchanged among all of the cells in the filament by diffusion across the septal junctions. Photosynthetically produced sucrose likely follows the same route from cytoplasm to cytoplasm. We identify some of the septal proteins involved in sucrose exchange, and our results indicate that these proteins form structures functionally analogous to metazoan gap junctions.
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Khasana, Nanda Putri Insan. "The effect of adding casein hydrolysate as a protein source in the culture of the bacteria paenibacillus polymyxa at wilker office of food and horticultural plants protection (PTPH) Bojonegoro." International Journal of Health Science and Technology 3, no. 1 (October 6, 2021). http://dx.doi.org/10.31101/ijhst.v3i1.2244.
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agencia(Biological Control AgentsBiological Control Agents) are currently widely used for the purpose of controlling pests and diseases or plant-disturbing organisms. One of the biological agents that has many benefits for controlling several types of diseases in both food crops and horticulture is Paenibacillus polymyxa. These bacteria are beneficial in nitrogen fixation, promotion of plant growth, solubilization of soil phosphorus, and production of exopolysaccharides, hydrolytic enzymes, antibiotics, and cytokinins. Paenibacillus polymyxa also produces polymyxin antibiotics and it is known that these bacteria contain the hormone gibberellins. Casein hydrolyzate is one of the growth media that can be used for the growth of microorganisms. The media is a complex mixture of 18 amino acids, vitamins, calcium, phosphate, and several microelements which results in their high price. Casein hydrolyzate is known to be more effective for plant tissue culture. Therefore, the purpose of this study was to determine whether the amino acid content in casein hydrolyzate could affect the growth ofbacteria Paenibacillus polymyxa. The simple medium used in this study was soybean boiled water. Soybean as an alternative medium for protein sources to substitute beef extract, beef extract and bacto peptone for the growth ofbacteria Paenibacillus polymyxa. Based on TPC calculation with graded dilution in Paenibacillus polymyxa, it was found that there was no difference in the number of bacteria to the addition of casein. This shows that bacteria can grow optimally even though casein hydrolyzate is not given during the growth process.
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Ireland, Philip, Oliver Old, Steve Hornby, Catherine Kendall, Hugh Barr, Angela Shore, and Nick Stone. "OGC P28 Raman Needle Probe Lymph Node Assessment for Oesophageal Cancer: The DOLOMITE Study." British Journal of Surgery 109, Supplement_9 (December 7, 2022). http://dx.doi.org/10.1093/bjs/znac404.191.
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Abstract Background Oesophageal cancer (OC) accounts for 3% of all new cancer diagnosis in the UK. Presentation is often late, reflected in a poor 5-year survival rate of 12%. The importance of identifying lymph node (LN) metastases has been demonstrated as the single biggest prognostic factor. The current ‘gold standard’ diagnosis of LN metastases is from histopathological assessment of the tissue after surgical resection of the primary tumour and surrounding tissue. The use of imaging techniques to try and gain this information preoperatively is standard practice but far from perfect. Raman spectroscopy (RS) has been investigated as a diagnostic tool to detect cancer and pre-cancerous change in the oesophagus, and preliminary work demonstrating the application of vibrational spectroscopy (Raman and FTIR) to LN analysis has been undertaken. The development of Raman needle probes (RNP) with potential for use in-vivo furthers the clinical impact. The DOLOMITE study started recruitment in the summer of 2022 to investigate the ability of RNP to identify the presence of malignant deposits in resected lymph nodes. Methods Patients identified by the clinical team as needing oesophagectomy to treat their OC were invited to participate in the study. After the specimen has been resected, prior to formalin fixation, three lymph nodes are dissected representing gastric, para-oesophageal and sub-carinal nodes. These are bisected longitudinally with half remaining with the specimen. The half for research is snap frozen in liquid nitrogen until needed for analysis. Adjacent sections are cut from the nodes to create slides for Raman mapping and conventional H&E staining. The bulk node left is used for Raman probe analysis. Spectral data is then analysed using MATlab. Results At this early stage, our initial measurements have provided information used for calibration in advance of completing recruitment. The Raman mapping has been assessed for correlation with the pathology identified in the H&E slides taken from the lymph node block. This data in turn has provided the background for developing interpretation of the Raman probe data, with further samples we will use this to create a classification model. Conclusions With ongoing recruitment the study will be able to fully report by September 2023. References 1. Stone N, Kendall C, Shepherd N, Crow P, Barr H Near-infrared Raman spectroscopy for the classification of epithelial pre-cancers and cancers 2002 33(7):564–573 2. Kong K, Kendall C, Stone N, Notingher I. Raman spectroscopy for medical diagnostics--From in-vitro biofluid assays to in-vivo cancer detection. Adv Drug Deliv Rev. 2015;89:121–34.
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Ofaim, Shany, Snorre Sulheim, Eivind Almaas, Daniel Sher, and Daniel Segrè. "Dynamic Allocation of Carbon Storage and Nutrient-Dependent Exudation in a Revised Genome-Scale Model of Prochlorococcus." Frontiers in Genetics 12 (February 9, 2021). http://dx.doi.org/10.3389/fgene.2021.586293.
Full textAbstract:
Microbial life in the oceans impacts the entire marine ecosystem, global biogeochemistry and climate. The marine cyanobacterium Prochlorococcus, an abundant component of this ecosystem, releases a significant fraction of the carbon fixed through photosynthesis, but the amount, timing and molecular composition of released carbon are still poorly understood. These depend on several factors, including nutrient availability, light intensity and glycogen storage. Here we combine multiple computational approaches to provide insight into carbon storage and exudation in Prochlorococcus. First, with the aid of a new algorithm for recursive filling of metabolic gaps (ReFill), and through substantial manual curation, we extended an existing genome-scale metabolic model of Prochlorococcus MED4. In this revised model (iSO595), we decoupled glycogen biosynthesis/degradation from growth, thus enabling dynamic allocation of carbon storage. In contrast to standard implementations of flux balance modeling, we made use of forced influx of carbon and light into the cell, to recapitulate overflow metabolism due to the decoupling of photosynthesis and carbon fixation from growth during nutrient limitation. By using random sampling in the ensuing flux space, we found that storage of glycogen or exudation of organic acids are favored when the growth is nitrogen limited, while exudation of amino acids becomes more likely when phosphate is the limiting resource. We next used COMETS to simulate day-night cycles and found that the model displays dynamic glycogen allocation and exudation of organic acids. The switch from photosynthesis and glycogen storage to glycogen depletion is associated with a redistribution of fluxes from the Entner–Doudoroff to the Pentose Phosphate pathway. Finally, we show that specific gene knockouts in iSO595 exhibit dynamic anomalies compatible with experimental observations, further demonstrating the value of this model as a tool to probe the metabolic dynamic of Prochlorococcus.