eChapters

Nanomaterials are a field which takes a materials science-based approach to nanotechnology. It studies materials with morphological features on the nanoscale, and especially those which have special properties stemming from their nanoscale dimensions. Nanoscale is usually defined as smaller than a one tenth of a micrometer in at least one dimension, though this term is sometimes also used for materials smaller than one micrometer.

An aspect of nanotechnology is the vastly increased ratio of surface area to volume present in many nanoscale materials which makes possible new quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions. However, it becomes pronounced when the nanometer size range is reached. A certain number of physical properties also alter with the change from macroscopic systems. Novel mechanical properties of nanomaterials are a subject of nanomechanics research. Catalytic activities also reveal new behaviour in the interaction with biomaterials.

What is Nanotechnology? Answers differ depending on who you ask, and their background. Broadly speaking however, nanotechnology is the act of purposefully manipulating matter at the atomic scale, otherwise known as the “nanoscale.” Coined as “nano-technology” in a 1974 paper by Norio Taniguchi at the University of Tokyo, and encompassing a multitude of rapidly emerging technologies, based upon the scaling down of existing technologies to the next level of precision and miniaturization. Taniguchi approached nanotechnology from the ‘top-down’ standpoint, from the viewpoint of a precision engineer.

Foresight Nanotech Institute Founder K. Eric Drexler introduced the term “nanotechnology” to the world in 1986, using it to describe a ‘bottom-up’ approach. Drexler approaches nanotechnology from the point-of-view of a physicist, and defines the term as “large-scale mechano synthesis based on positional control of chemically reactive molecules.” In the future,“ nanotechnology” will likely include building machines and mechanisms with nanoscale dimensions, referred to these days as Molecular Nanotechnology (MNT).

Acetic acid            
    

Molecular weight    60.05        
    Melting point (^ºC)    17        
    Boiling point (^ºC)    118        
    Flash point (^ºC)    40        
    Auto-ignition point (^ºC)    426        
    Specific gravity at 20^ºC    1.05        
    Molarity of the concentrated acid (M)    17.4    
    1 M solution    57.5 ml concentrated acid per litre

11.1 Total DNA Extraction by cTAB Method
    
11.2 Extraction, Purification Estimation of DNA
    
11.3 Potassium Acetate Procedure
    
11.4 DNA  Estimation
    
11.5 Restriction Enzymes

10.1 Plasmids
    
10.2 Retrovirus

9.1 Methylases
    
9.2 Polymerases
    
9.3 Nucleases
    
9.4 Ligases
    
9.5 Phosphatase
    
9.6 Topoisomerase
    
9.7 Restriction enzymes

8.1 Sub Cloning
    
8.2 Cloning into a Yeast Artificial Chromosome (YAC)
    
8.3 DNA Libraries

7.1 Gel Electrophoresis
    
7.2 Polymerase Chain Reaction (PCR)
    
7.3 Restriction Fragment Length Polymorphisms (RFLPs)
    
7.4 Random Amplification of Polymorphic DNA (RAPD)
    
7.5 Amplified Restriction Fragment Length Polymorphism (AFLP)

6.1 Prokaryotic Gene Expression
    
6.2 The lac  Operon
    
6.3 The trp  Operon

5.1 Replication
    DNA Replication in Bacteria
    DNA Replication in Eukaryotes
    
5.2 Transcription

5.3 Translation

4.1 DNA: The word means
    
4.2 Double Helical Structure: The Watson and Crick Model
    
4.3 Family of DNA 
    
4.4 The Chromosomes

DNA (deoxyribonucleic acid), the giant molecule that carries genetic information in living things, is made up of just a few chemical building blocks that bond together in very particular ways. A typical molecule of DNA consists of two strands that are linked together. A segment can be visualized as a ladder-like structure:

The DNA as made of two strands, a left and a right, which are linked in the middle. In reality, since the ladder is twisted, there really is no “right” or “left,” but we use that terminology here since it applies to the model graphs. The square shapes and diamonds you see in the middles of the “rungs” are the links, which are meant to represent the different chemical bonds between the two strands of DNA.

2.1     Regulation of the Cell Cycle 
    
2.2     Mitosis
    
2.3     Meiosis

1.1     Prokaryotic 
    
1.2     Eukaryotic
    
1.3     Cell orgenellie

18.1. INTRODUCTION

Plant genetic resources (PGRs) are the foundation for the development of a food and nutritionally secured society. Food is the foremost important to sustain life and livelihood followed by shelter and cloth. Thus, the slogan of 3Fs may be modified as, “Food, Frame (shelter) and Fibre (cloth)”. All these 3Fs we can get from PGRs. There must be balance between demands and resources. Gradually the demand for basic needs increasing. So, we have to improve the PGRs to cope with the increasing demands. PGRs are the foundation for the development of these 3Fs. India is a country rich in crop biodiversity and genetic resources. The status of Germplasm accessions in the National Gene Bank is being presented in Table 18.1.

17.1. INTRODUCTION

Yam bean is one of the adaptable, low-maintenance, and nutritious food crop grown in moderate soil. It has many synonyms, in India it is known as Mishrikand (Hindi), Keshar or Ram-kaseru or Shankalu (Bengali). The root crops produced by legumes have long recognized as important and the FAO (1979) has recommended them as a source of human nutrition. The tuber is rich in starch (15-20%), 3-4% sugar, and have considerable amount of protein (2-3%). The harvested crop keeps well for months under ambient temperature. Kale (2006) observed relatively high iron contents in storage roots (up to 130 mg/kg of storage root dry matter). It can also be used for alcohol production.

The crop is very hardy, resistant to common insect pests and diseases. Most important is that the crop is not grazed neither by goats nor cows. The crop grows well in hot-humid environment and requires long, warm frost-free growing season. A moist, light textural soil is preferred for production of tuberous roots. As a legume crop, it can be grown without nitrogen fertilizer. Under good growing condition its root nodules habour symbiotic colonies of nitrogen-fixing bacteria- Rhizobium spp. (Nielsen et al., 1998b). A season crop of yam beans can release as much as 53 tons of usable nitrogen per acre into the soil. Mycorrhyzae also associated with the crop, thus facilitating phosphorus uptake. Thus, yam bean is highly suited to the needs of small farmers, and from both an ecological and a socioeconomic perspective

16.1. INTRODUCTION

Millets are a large part of the basic diet for farm households in the world's poorest people in the poorest countries. The production of millets on average for the 5 years have been given in Table 16.1. Top consuming countries are India, Nigeria, Niger and China. However, just because a country is a top global consumer does not mean that millet is a significant source of calories for them. India and China are rank as the 1st and 4th consumers of millet, but due to their population size they rank 11th and 38th in per-capita consumption, accordingly.

Millet particularly the finger millet) is an excellent dietary source of calcium, iron, manganese, and methionine-  an amino acid lacking in the diets of hundred of millions of the poor who live on starchy foods such as cassava, plantain, polished rice, and maize meal. Millet use is diverse, including in cereals (including porridge and kasha), soups, breads and stuffings, fermented beverages, and baby food.

15.1. INTRODUCTION

Finger millet Eleusine indica (L.) is an Old World cereal grass commonly known as ‘finger millet’, is one of the staple food crop especially in India and Africa, which is widely grown in the arid regions of Asia and Africa and important minor millet grown in India.  Eleusine, the generic name, is obtained after the “Eleusine” the Greek Goddess of cereals and the common name finger millet is derived from the finger like branching of the panicle. It is also know by Goosegrass, Yardgrass, Wiregrass, Silver Crabgrass, Crowfoot Grass. It is commonly known as Finger millet in English, Kelvaragu in Tamil, Nachani in Marathi etc. Some Indian varieties of finger millet are Kempu ragi, Ragalli shivalli, Pichakaddi etc.  This crop is one among the hardiest crops which can with stand severe drought conditions and can also grow well under scanty rainfall condition. However with good irrigation facilities the yield of finger millet matches with crops like rice. Finger millet seeds remain free of pests and insects for a long duration extending up to 50 years hence serving as a food reserve in case of tough situations like famine.

14.1. INTRODUCTION

Barley (Hordeum vulgare L. emend. Bowden) is one the most important ancient crops and played very important role in the development of agriculture and human civilization. It has also played crucial role in the progress of science of agriculture, physiology, genetics, plant breeding and malting and brewing science. It is the fourth most cereal crop after rice, wheat and maize in acreages and production in the world.  It is grown and used all around the world in many countries and has fed livestock, poultry and people since ancient time.  Barley was domesticated about 10,000 years ago in the Fertile Crescent of the Near East. Fertile Crescent is considered the first of at least seven primary centres of agriculture origin in the world (Smith, 1998; Baik and Ulrich, 2008). Barley is best known around the world as a feed grain and a premier grains for malting and brewing. When most people think of composition of beer, they only think of barley over other cereals. Although utilization of barley for food is relatively low as compared to other cereals today, throughout its history barley has remained an important and major food source poor people living in Western and Eastern Asia and Northern and Eastern Himalayan region nation like Tibet, Nepal and in Northern and Eastern Africa (Newman and Newman, 2006, 2008). Moreover, there has been resurgence of interest and use of barley as food primarily in the developed world due to an increasing emphasis on incorporating the diversity in consumption of whole grain in people’s diets due to its health benefits.

13.1. INTRODUCTION

Pearl millet crop has a wide adaptability to local environments. It is hardy and can be grown in areas which are very hot and dry and on soils too poor for sorghum. Pearl millet is considered more efficient in utilization of soil moisture and has a higher level of heat tolerance than even sorghum and maize. It is adapted to warm and dry climate but most of the area under the crop is in drought- prone areas of the world. In these areas, pearl millet is usually grown with limited inputs, sparse rainfall, low soil fertility, and also face disease and pest problems, with correspondingly poor yields.
 
The low average yields are primarily a result of the hot, dry conditions where pearl millet is mostly grown, rather than pearl millet plant’s capability. Pearl millet hybrids grown under better conditions yield 3000 to 4000 kg/ha compared to 300 to 800 kg/ha when moisture and soil fertility become limiting factors. A majority of the subsistence farmers who typically cultivate this crop are unable to take advantage of high yield potential because they have limited options for improving their management practices. Pearl millet production can be increased through growing varieties/hybrids with improved tolerance to drought, diseases and responding to higher rates of fertilizer applications.