Physiology and Biochemistry of the Aerobic Methanotrophs

Author(s):  
Valentina N. Khmelenina ◽  
J. Colin Murrell ◽  
Thomas J. Smith ◽  
Yuri A. Trotsenko
Author(s):  
Valentina N. Khmelenina ◽  
J. Colin Murrell ◽  
Thomas J. Smith ◽  
Yuri A. Trotsenko

Author(s):  
William W. Thomson ◽  
Elizabeth S. Swanson

The oxidant air pollutants, ozone and peroxyacetyl nitrate, are produced in the atmosphere through the interaction of light with nitrogen oxides and gaseous hydrocarbons. These oxidants are phytotoxicants and are known to deleteriously affect plant growth, physiology, and biochemistry. In many instances they induce changes which lead to the death of cells, tissues, organs, and frequently the entire plant. The most obvious damage and biochemical changes are generally observed with leaves.Electron microscopic examination of leaves from bean (Phaseolus vulgaris L.) tobacco (Nicotiana tabacum L.) and cotton (Gossipyum hirsutum L.) fumigated for .5 to 2 hours with 0.3 -1 ppm of the individual oxidants revealed that changes in the ultrastructure of the cells occurred in a sequential fashion with time following the fumigation period. Although occasional cells showed severe damage immediately after fumigation, the most obvious change was an enhanced clarity of the cell membranes.


2013 ◽  
Vol 13 (4) ◽  
pp. 369-384

Many Public Aquaria have been designed and constructed all over the world during the last three decades. The serial arrangement of relatively small, rectangular, concrete tanks has been replaced by fewer large, irregularly shaped tanks, replicating habitats. The “taxonomic concept” of displaying specimens in the old aquaria has now been succeeded by the more ecological, “community concept” type of display. At the same time most of the “old aquaria” have been renovated. Aquarium missions have also been broadened nowadays including research, conservation and education. Aquaria are ideal places for research on husbandry, life cycles, reproduction, behavior, autoecology and fish pathology. Collaboration with Universities and Research Centers increases the research potential in scientific disciplines such as ecology, genetics, physiology and biochemistry. Collaboration also provides mutual benefits in both infrastructure and personnel: The research background in aquaria also forms a sound platform to materialize conservation projects, focusing either on the ex-situ conservation of animals in the aquaria or on environmental protection of surrounding areas and reintroduction of endangered species. In addition to formal educational opportunities, non formal education to visitors, schools and undergraduates seems to become a major mission of aquaria. Aquarium tank displays, preserved biological material, film projections, seminars / lectures and book magazine publications enhance environmental awareness, encouraging people to adopt Environmentally Responsible Behavior. All these missions are feasible because most public aquaria are making a good profit mainly due to their high popularity. There are also benefits for the community in the area; aquaria have enlivened declining water front areas and increased the income of tourist resorts mainly by “stretching out” the tourist season. In the present work the objectives of a public aquarium are reviewed and the main infrastructure subsystems and operational procedures are described; Know how on aquarium systems can also be applied in research laboratories of academic institutions if live organisms have to be kept for experimentation. Aquarium missions on research, conservation and education are discussed.


2008 ◽  
Vol 58 (1) ◽  
pp. 83-87 ◽  
Author(s):  
O. Modin ◽  
K. Fukushi ◽  
F. Nakajima ◽  
K. Yamamoto

Methane would potentially be an inexpensive, widely available electron donor for denitrification of wastewaters poor in organics. Currently, no methanotrophic microbe is known to denitrify. However, aerobic methane oxidation coupled to denitrification (AME-D) has been observed in several laboratory studies. In the AME-D process, aerobic methanotrophs oxidise methane and release organic metabolites and lysis products, which are used by coexisting denitrifiers as electron donors for denitrification. Due to the presence of oxygen, the denitrification efficiency in terms of methane-to-nitrate consumption is usually low. To improve this efficiency the use of a membrane biofilm reactor was investigated. The denitrification efficiency of an AME-D culture in (1) a suspended growth reactor, and (2) a membrane biofilm reactor was studied. The methane-to-nitrate consumption ratio for the suspended culture was 8.7. For the membrane-attached culture the ratio was 2.2. The results clearly indicated that the membrane-attached biofilm was superior to the suspended culture in terms of denitrification efficiency. This study showed that for practical application of the AME-D process, focus should be placed on development of a biofilm reactor.


Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Obulisamy Parthiba Karthikeyan ◽  
Thomas J. Smith ◽  
Shamsudeen Umar Dandare ◽  
Kamaludeen Sara Parwin ◽  
Heetasmin Singh ◽  
...  

AbstractManufacturing and resource industries are the key drivers for economic growth with a huge environmental cost (e.g. discharge of industrial effluents and post-mining substrates). Pollutants from waste streams, either organic or inorganic (e.g. heavy metals), are prone to interact with their physical environment that not only affects the ecosystem health but also the livelihood of local communities. Unlike organic pollutants, heavy metals or trace metals (e.g. chromium, mercury) are non-biodegradable, bioaccumulate through food-web interactions and are likely to have a long-term impact on ecosystem health. Microorganisms provide varied ecosystem services including climate regulation, purification of groundwater, rehabilitation of contaminated sites by detoxifying pollutants. Recent studies have highlighted the potential of methanotrophs, a group of bacteria that can use methane as a sole carbon and energy source, to transform toxic metal (loids) such as chromium, mercury and selenium. In this review, we synthesise recent advances in the role of essential metals (e.g. copper) for methanotroph activity, uptake mechanisms alongside their potential to transform toxic heavy metal (loids). Case studies are presented on chromium, selenium and mercury pollution from the tanneries, coal burning and artisanal gold mining, respectively, which are particular problems in the developing economy that we propose may be suitable for remediation by methanotrophs.


Author(s):  
Muhammad Asaad Bashir ◽  
Xiukang Wang ◽  
Muhammad Naveed ◽  
Adnan Mustafa ◽  
Sobia Ashraf ◽  
...  

Soil pollution with heavy metal is a serious problem across the globe and is on the rise due to the current intensification of chemical industry. The leather industry is one of them, discharging chromium (Cr) in huge quantities during the process of leather tanning and polluting the nearby land and water resources, resulting in deterioration of plant growth. In this study, the effects of biochar application at the rate of 3% were studied on four maize cultivars, namely NK-8441, P-1543, NK-8711, and FH-985, grown in two different tannery polluted Kasur (K) and Sialkot (S) soils. Maize plants were harvested at vegetative growth and results showed that Cr toxicity adversely not only affected their growth, physiology, and biochemistry, but also accumulated in their tissues. However, the level of Cr toxicity, accumulation, and its influence on maize cultivars varied greatly in both soils. In this pot experiment, biochar application played a crucial role in lessening the Cr toxicity level, resulting in significant increase in plant height, biomass (fresh and dry), leaf area, chlorophyll pigments, photosynthesis, and relative water content (RWC) over treatment set as a control. However, applied biochar significantly decreased the electrolyte leakage (EL), antioxidant enzymes, lipid peroxidation, proline content, soluble sugars, and available fraction of Cr in soil as well as Cr (VI and III) concentration in root and shoot tissues of maize plant. In addition to this, maize cultivar differences were also found in relation to their tolerance to Cr toxicity and cultivar P-1543 performed better over other cultivars in both soils. In conclusion, biochar application in tannery polluted soils could be an efficient ecofriendly approach to reduce the Cr toxicity and to promote plant health and growth.


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