Genetic engineering

Genetically modified plants are created by the process of genetic engineering, which allows scientists to move genetic material between organisms with the aim of changing their characteristics. All organisms are composed of cells that contain the DNA molecule. Molecules of DNA form units of genetic information, known as genes. Each organism has a genetic blueprint made up of DNA that determines the regulatory functions of its cells and thus the characteristics that make it unique.
Genes

Prior to genetic engineering, the exchange of DNA material was possible only between individual organisms of the same species. With the advent of genetic engineering in 1972, scientists have been able to identify specific genes associated with desirable traits in one organism and transfer those genes across species boundaries into another organism. For example, a gene from bacteria, virus, or animal may be transferred into plants to produce genetically modified plants having changed characteristics. Thus, this method allows mixing of the genetic material among species that cannot otherwise breed naturally. The success of a genetically improved plant depends on the ability to grow single modified cells into whole plants. Some plants like potato and tomato grow easily from single cell or plant tissue. Others such as corn, soy bean, and wheat are more difficult to grow.

After years of research, plant specialists have been able to apply their knowledge of genetics to improve various crops such as corn, potato, and cotton. They have to be careful to ensure that the basic characteristics of these new plants are the same as the traditional ones, except for the addition of the improved traits.

The world of biotechnology has always moved fast, and now it is moving even faster. More traits are emerging; more land than ever before is being planted with genetically modified varieties of an ever-expanding number of crops. Research efforts are being made to genetically modify most plants with a high economic value such as cereals, fruits, vegetables, and floriculture and horticulture species.

The Green Revolution

The world's worst recorded food disaster occurred in 1943 in British-ruled India. Known as the Bengal Famine, an estimated 4 million people died of hunger that year in eastern India (which included today's Bangladesh). Initially, this catastrophe was attributed to an acute shortfall in food production in the area. However, Indian economist Amartya Sen (recipient of the Nobel Prize for Economics, 1998) has established that while food shortage was a contributor to the problem, a more potent factor was the result of hysteria related to World War II, which made food supply a low priority for the British rulers.

When the British left India in 1947, India continued to be haunted by memories of the Bengal Famine. It was therefore natural that food security was one of the main items on free India's agenda. This awareness led, on one hand, to the Green Revolution in India and, on the other, legislative measures to ensure that businessmen would never again be able to hoard food for reasons of profit.

The Green Revolution, spreading over the period from1967/68 to 1977/78, changed India’s status from a food-deficient country to one of the world's leading agricultural nations. Until 1967 the government largely concentrated on expanding the farming areas. But the population was growing at a much faster rate than food production. This called for an immediate and drastic action to increase yield. The action came in the form of the Green Revolution. The term ‘Green Revolution’ is a general one that is applied to successful agricultural experiments in many developing countries. India is one of the countries where it was most successful.

There were three basic elements in the method of the Green Revolution

	Continuing expansion of farming areas
	Double-cropping in the existing farmland
	Using seeds with improved genetics.

The area of land under cultivation was being increased from 1947 itself. But this was not enough to meet the rising demand. Though other methods were required, the expansion of cultivable land also had to continue. So, the Green Revolution continued with this quantitative expansion of farmlands.

Double cropping was a primary feature of the Green Revolution. Instead of one crop season per year, the decision was made to have two crop seasons per year. The one-season-per-year practice was based on the fact that there is only one rainy season annually. Water for the second phase now came from huge irrigation projects. Dams were built and other simple irrigation techniques were also adopted.

Using seeds with superior genetics was the scientific aspect of the Green Revolution. The Indian Council for Agricultural Research (which was established by the British in 1929) was reorganized in 1965 and then again in 1973. It developed new strains of high yield variety seeds, mainly wheat and rice and also millet and corn.

The Green Revolution was a technology package comprising material components of improved high yielding varieties of two staple cereals (rice and wheat), irrigation or controlled water supply and improved moisture utilization, fertilizers, and pesticides, and associated management skills.

Benefits

Thanks to the new seeds, tens of millions of extra tonnes of grain a year are being harvested.

The Green Revolution resulted in a record grain output of 131 million tonnes in 1978/79. This established India as one of the world's biggest agricultural producers. Yield per unit of farmland improved by more than 30% between1947 (when India gained political independence) and 1979. The crop area under high yielding varieties of wheat and rice grew considerably during the Green Revolution.

The Green Revolution also created plenty of jobs not only for agricultural workers but also industrial workers by the creation of related facilities such as factories and hydroelectric power stations.

Shortcomings

In spite of this, India's agricultural output sometimes falls short of demand even today. India has failed to extend the concept of high yield value seeds to all crops or all regions. In terms of crops, it remains largely confined to foodgrains only, not to all kinds of agricultural produce.

In regional terms, only the states of Punjab and Haryana showed the best results of the Green Revolution. The eastern plains of the River Ganges in West Bengal also showed reasonably good results. But results were less impressive in other parts of India.

The Green Revolution has created some problems mainly to adverse impacts on the environment. The increasing use of agrochemical-based pest and weed control in some crops has affected the surrounding environment as well as human health. Increase in the area under irrigation has led to rise in the salinity of the land. Although high yielding varieties had their plus points, it has led to significant genetic erosion.

Applying nanotechnology to water treatment

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While everybody talks about oil prices, water scarcity and water pollution are two increasingly pressing problems that could easily and quickly surpass the oil issue. Renewable energy sources can substitute for fossil fuels – but freshwater can't be replaced. This makes the ability to remove toxic contaminants from aquatic environments rapidly, efficiently, and within reasonable costs an important technological challenge. Nanotechnology could play an important role in this regard. An active emerging area of research is the development of novel nanomaterials with increased affinity, capacity, and selectivity for heavy metals and other contaminants. The benefits from use of nanomaterials may derive from their enhanced reactivity, surface area and sequestration characteristics. We have addressed this issue extensively in two previous Spotlights: "Nanotechnology and water treatment" and "Water, nanotechnology's promises, and economic reality". Numerous nanomaterials are in various stages of research and development, each possessing unique functionalities that are potentially applicable to the remediation of industrial wastewater, groundwater, surface water and drinking water. The main goal for most of this research is to develop low-cost and environmentally friendly materials for removal of heavy metals from water. A recent example is a novel low-cost magnetic sorbent material for the removal of heavy metal ions from water, developed by scientists in China, who coated iron oxide magnetic nanoparticles (Fe3O4 – magnetite) with humic acid (HA). The coating greatly enhanced material stability and heavy metal removal efficiency of the nanoparticles. "Recently, magnetic nanoparticles were used for this purpose as these materials with the adsorbed heavy metals can be easily recovered by utilizing magnetic separation" Dr. Gui-Bin Jiang explains to Nanowerk. "However, bare magnetite nanoparticles in aqueous systems are very much susceptible to air oxidation and are easily aggregated, which resulted in reduced saturation magnetization and adsorption capacity for metals. In our recent paper, we describe the development of a novel material, humic acid coated Fe3O4 magnetic nanoparticles, to resolve theses problems."



Scheme of the removal of heavy metals with the humic acid coated Fe3O4 magnetic nanoparticles. (Reprinted with permission from American Chemical Society) Jiang, a professor at the Research Center for Eco-Environmental Sciences of the State Key Laboratory of Environmental Chemistry and Ecotoxicology, Chinese Academy of Sciences in Beijing, together with his colleagues Jing-Fu Liu and Zong-Shan Zhao, found that coating Fe3O4 magnetic nanoparticles with humic acid can 1) greatly enhance the stability of dispersed nanoparticles by preventing their aggregation; 2) maintain the saturation magnetization by avoiding their oxidation; and 3) enlarge the adsorption capacity for some heavy metals by making use of the abundant carboxylic acid and phenolic hydroxyl functional groups of humic acid to complex with heavy metal ions. The scientists published their findings in the August 14, 2008 online edition of Environmental Science & Technology ("Coating Fe3O4 Magnetic Nanoparticles with Humic Acid for High Efficient Removal of Heavy Metals in Water"). Jiang notes that bare magnetite nanoparticles are very much susceptible to air oxidation and are easily aggregated in aqueous systems. "We were aware of recent research which indicated that humic acid has high affinity to Fe3O4 nanoparticles, and that sorption of HA on the Fe3O4 nanoparticles enhanced the stability of nanodispersions by preventing their aggregation," he says. "It is also well-known that HA, which is abundant in natural aqueous systems, has a skeleton of alkyl and aromatic units that attach with carboxylic acid, phenolic hydroxyl, and quinone functional groups. These functional groups have high complex capacity with heavy metal ions and HA has therefore been applied to remove heavy metal ions from water." In previous research it was also found that the adsorption capacity for metal ions with the complexes of HA and iron oxides was larger than that with the respective iron oxides and HA alone. The Chinese researchers therefore hypothesized that by coating Fe3O4 magnetic nanoparticles with HA they could develop a very effective sorbent material for the removal of heavy metals from water. For removal of metals from freshwater, 50 mg of the coated iron oxide nanoparticles – prepared by a co-precipitation procedure with cheap and environmentally friendly iron salts and HA – was added into 100 mL of water. Then the magnetic Fe3O4/HA with sorbed heavy metals were separated from the mixture with a permanent hand-held magnet. To test the effect of time on the leaching of Fe3O4/HA components and the sorbed heavy metals, Jiang and his colleagues resuspended Fe3O4/HA laden with heavy metals in de-ionized water. The results indicated that the leaching of both the sorbed heavy metals and the material components were negligible. "We also found that the removal of heavy metals by Fe3O4/HA was not affected by the environmentally relevant parameters such as pH, salinity and dissolved organic matter" says Jiang. "Furthermore, the proposed procedure was very efficient as the sorption equilibrium was reached in less than 20 min, and the Fe3O4/HA with adsorbed heavy metals can be simply recovered from water with magnetic separations at very low magnetic field gradients within a few minutes." This research is a good example of the ways nanotechnology can be used to take substances that are abundant in nature (like iron oxide and humic acid) and use them to synthesize novel, highly effective adsorbent materials that are low-cost and have no adverse effect on the environment. The result will not only be more effective and efficient water treatment processes but also lower overall costs.

Artificial Liver

The Extracorporeal Liver Assist Device, or ELAD, is the first artificial liver to use cells from humans rather than from pigs. The device is used to sustain patients awaiting a liver transplant or whose own liver is not functioning and needs to recover.

The ELAD uses a chamber system in which each of the two chambers is filled with cartridges that contain liver cells. Similar to a dialysis machine, when the device is connected via blood vessels, the blood is filtered, remixed, and returned to the body.

Devices that used pig cells caused several concerns. Patients were exposed to animal cells which could harbor potentially dangerous infectious agents. Scientists hope that with the use of human cells, the potential for adverse reactions will be minimized.

The ELAD also has a longer use period. The pig cell device could only be used for six to ten hours; the new device could potentially be used continuously by swapping cartridges. Clinical trials of the ELAD are set to begin at the University of Chicago hospitals. The trials will attempt to determine both the safety and effectiveness of the device in acute situations.

The trials will focus on using the ELAD to assist people with fulminant hepatic failure (FHF), a liver disease. FHF occurs in otherwise healthy people and can possibly be precipitated by exposure to toxins and certain drugs. Its exact cause remains unknown.

The device will be used to protect the patient's other vital organs during liver failure and to provide adequate time for the patient's liver to recover from the effects of the disease.

Scientists are optimistic that by providing this additional time for a patient's liver to recover, the number of people needing transplants may decrease, particularly for those with limited damage to the liver. Should the patient's liver not recover, the device will be used to allow additional time for a liver transplant. It is estimated that some 12.5 thousand people currently need a liver transplant. Less than 5,000 livers are donated in the average year, thus the need for such a device.