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Institution

North Eastern Hill University

EducationShillong, Meghalaya, India
About: North Eastern Hill University is a(n) education organization based out in Shillong, Meghalaya, India. It is known for research contribution in the topic(s): Population & Ruthenium. The organization has 2318 authors who have published 4476 publication(s) receiving 48894 citation(s).


Papers
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Journal ArticleDOI
TL;DR: A review of hydroxylapatite, a biological material of extensive contemporary inter-disciplinary research, can be found in this article, where the authors provide information on preparation techniques, characterization, isomorphous substitutions and solubility equilibria.
Abstract: A few significant physico-chemical aspects of hydroxylapatite, a biological material of extensive contemporary inter-disciplinary research, have been reviewed. Updated information on preparation techniques, characterization, isomorphous substitutions, and solubility equilibria is provided. Recent research trends and aspects which require further clarification have been emphasized.

424 citations

Journal ArticleDOI
TL;DR: The properties and subcellular location of nitrogenase in non-heterocystous cyanobacteria is described, as is the response of N2 fixation to environmental factors such as fixed nitrogen, O2 and the pattern of illumination.
Abstract: Many, though not all, non-heterocystous cyanobacteria can fix N2. However, very few strains can fix N2 aerobically. Nevertheless, these organisms may make a substantial contribution to the global nitrogen cycle. In this general review, N2 fixation by laboratory cultures and natural populations of non-heterocystous cyanobacteria is considered. The properties and subcellular location of nitrogenase in these organisms is described, as is the response of N2 fixation to environmental factors such as fixed nitrogen, O2 and the pattern of illumination. The integration of N2 fixation with other aspects of cell metabolism (in particular photosynthesis) is also discussed. Similarities and differences between different individual strains of non-heterocystous cyanobacteria are highlighted.

400 citations

Journal ArticleDOI
TL;DR: Cyanobacteria are an ancient, morphologically diverse group of prokaryotes with an oxygenic photosynthesis as discussed by the authors, and some of them even possess the ability to fix N2.
Abstract: Summary 449 I. INTRODUCTION 450 II. THE PARTNERS 451 1. Cyanobionts and their role 451 2. Hosts and their role 453 3. Location of cyanobionts in their hosts 455 III. INITIATION AND DEVELOPMENT OF SYMBIOSES 458 1. Initiation of symbioses 458 2. Geosiphon pyriforme 458 3. Cyanolichens 459 4. Liverworts and hornworts 460 5. Azolla 460 6. Cycads 461 7. Gunnera 461 IV. THE SYMBIOSES 462 1. Geographical distribution and ecological significance 462 2. Benefits to the partners 462 (a) Benefits to the cyanobionts 462 (b) Benefits to the hosts 463 3. Duration and stability 463 4. Mode of transmission and perpetuation 463 5. Recognition between the partners 464 6. Specificity and diversity 464 7. Symbiosis-related genes 465 8. Modifications of the cyanobiont 466 (a) Growth and morphology 466 (b) Photosynthesis and carbon metabolism 467 (c) Glutamine synthetase 467 (d) Heterocysts 469 (e) N2fixation 470 9. Nutrient exchange 471 (a) Carbon 471 (b) Nitrogen 472 V. EVOLUTIONARY ASPECTS 472 VI. ARTIFICIAL SYMBIOSES 474 VII. FUTURE OUTLOOK AND PERSPECTIVES 475 1. Cryptic symbioses 476 2. Developmental profile of symbiotic tissues 476 3. Sensing and signalling 476 4. Genetic aspects 476 5. Physiological and biochemical aspects of nutrient exchange 477 6. Microaerobiosis 477 7. Potential applications 477 Acknowledgements 477 References 477 Cyanobacteria are an ancient, morphologically diverse group of prokaryotes with an oxygenic photosynthesis. Many cyanobacteria also possess the ability to fix N2. Although well suited to an independent existence in nature, some cyanobacteria occur in symbiosis with a wide range of hosts (protists, animals and plants). Among plants, such symbioses have independently evolved in phylogenetically diverse genera belonging to the algae, fungi, bryophytes, pteridophytes, gymnosperms and angiosperms. These are N2-fixing symbioses involving heterocystous cyanobacteria, particularly Nostoc, as cyanobionts (cyanobacterial partners). A given host species associates with only a particular cyanobiont genus but such specificity does not extend to the strain level. The cyanobiont is located under a microaerobic environment in a variety of host organs and tissues (bladder, thalli and cephalodia in fungi; cavities in gametophytes of hornworts and liverworts or fronds of the Azolla sporophyte; coralloid roots in cycads; stem glands in Gunnera). Except for fungi, the hosts form these structures ahead of the cyanobiont infection. The symbiosis lasts for one generation except in Azolla and diatoms, in which it is perpetuated from generation to generation. Within each generation, multiple fresh infections occur as new symbiotic tissues and organs develop. The symbioses are stable over a wide range of environmental conditions, and sensing–signalling between partners ensures their synchronized growth and development. The cyanobiont population is kept constant in relation to the host biomass through controlled initiation and infection, nutrient supply and cell division. In most cases, the partners have remained facultative, with the cyanobiont residing extracellularly in the host. However, in the water-fern Azolla and the freshwater diatom Rhopalodia the association is obligate. The cyanobionts occur intracellularly in diatoms, the fungus Geosiphon and the angiosperm Gunner a. Close cell–cell contact and the development of special structures ensure efficient nutrient exchange between the partners. The mobile nutrients are normal products of the donor cells, although their production is increased in symbiosis. Establishment of cyanobacterial–plant symbioses differs from chloroplast evolution. In these symbioses, the cyanobiont undergoes structural–functional changes suited to its role as provider of fixed N rather than fixed C, and the level of intimacy is far less than that of an organelle. This review provides an updated account of cyanobacterial–plant symbioses, particularly concerning developments during the past 10 yr. Various aspects of these symbioses such as initiation and development, symbiont diversity, recognition and signalling, structural–functional modifications, integration, and nutrient exchange are reviewed and discussed, as are evolutionary aspects and the potential uses of cyanobacterial–plant symbioses. Finally we outline areas that require special attention for future research. Not only will these provide information of academic interest but they will also help to improve the use of Azolla as green manure, to enable us to establish artificial N2-fixing associations with cereals such as rice, and to allow the manipulation of free-living cyanobacteria for photobiological ammonia or hydrogen production or for use as biofertilizers.

309 citations

Journal ArticleDOI
TL;DR: This review is an effort to enlist the valuable information about the qualities of cyanobacteria and their potential role in solving the agricultural and environmental problems for the future welfare of the planet.
Abstract: Keeping in view the challenges concerning agro-ecosystem and environment, the recent developments in biotechnology offers a more reliable approach to address the food security for future generations and also resolve the complex environmental problems. Several unique features of cyanobacteria such as oxygenic photosynthesis, high biomass yield, growth on non-arable lands and a wide variety of water sources (contaminated and polluted waters), generation of useful by-products and bio-fuels, enhancing the soil fertility and reducing green house gas emissions, have collectively offered these bio-agents as the precious bio-resource for sustainable development. Cyanobacterial biomass is the effective bio-fertilizer source to improve soil physico-chemical characteristics such as water-holding capacity and mineral nutrient status of the degraded lands. The unique characteristics of cyanobacteria include their ubiquity presence, short generation time and capability to fix the atmospheric N2. Similar to other prokaryotic bacteria, the cyanobacteria are increasingly applied as bio-inoculants for improving soil fertility and environmental quality. Genetically engineered cyanobacteria have been devised with the novel genes for the production of a number of bio-fuels such as bio-diesel, bio-hydrogen, bio-methane, syngas and therefore, open new avenues for the generation of bio-fuels in the economically sustainable manner. This review is an effort to enlist the valuable information about the qualities of cyanobacteria and their potential role in solving the agricultural and environmental problems for the future welfare of the planet.

276 citations

Journal ArticleDOI
TL;DR: An assessment of the current status of technology development and its future prospects with emphasis on a combinatorial approach is concluded.
Abstract: The phytoremediation is an environment friendly, green technology that is cost effective and energetically inexpensive. Metal hyperaccumulator plants are used to remove metal from terrestrial as well as aquatic ecosystems. The technique makes use of the intrinsic capacity of plants to accumulate metal and transport them to shoots, ability to form phytochelatins in roots and sequester the metal ions. Harbouring the genes that are considered as signatures for the tolerance and hyperaccumulation from identified hyperaccumulator plant species into the transgenic plants provide a platform to develop the technology with the help of genetic engineering. This would result in transgenics that may have large biomass and fast growth a quality essential for removal of metal from soil quickly and in large quantities. Despite so much of a potential, the progress in the field of developing transgenic phytoremediator plant species is rather slow. This can be attributed to the lack of our understanding of complex interactions in the soil and indigenous mechanisms in the plants that allow metal translocation, accumulation and removal from a site. The review focuses on the work carried out in the field of metal phytoremediation from contaminated soil. The paper concludes with an assessment of the current status of technology development and its future prospects with emphasis on a combinatorial approach.

192 citations


Authors

Showing all 2318 results

NameH-indexPapersCitations
Vivek Sharma1503030136228
Patrick J. Carroll5850513046
Majeti Narasimha Vara Prasad5622715193
Arun Sharma5537111364
Michael Schmittel5338710461
Birgitta Bergman5218710975
Harikesh Bahadur Singh463077372
Lal Chand Rai401344513
B. Dey403548089
Hiriyakkanavar Ila364075633
Jürgen-Hinrich Fuhrhop352085130
Sreebrata Goswami341423228
Gagan B.N. Chainy331074151
J.P. Gaur31643957
Hiriyakkanavar Junjappa303494102
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20223
2021350
2020308
2019293
2018306
2017291