eChapters

Acid soils are found in India in about 93 million hectares ( Table 1) and they occur in the Himalayan region, the great Indo-Gangetic and Brahmaputra plains, peninsular plateau and uplands and the coastal plains including island eco-systems under varying environmental conditions of landscape, geology, climate and vegetation. Conditions which are conducive for the formation of acid soils, such as high rainfall coupled with high temperature encouraging intense weathering and loss of alkali and alkaline earth metals with a simultaneous accumulation of iron and aluminium hydroxy compounds or the formation of free acidic substances in the humid forest foot hill regions, exist in some region or other in almost all the states in India.  A soil with pH less than 7.0 is deemed as an acid soil (Soil Survey Staff,1951). However, for characterization and classification, acid soils may be defined as those having pH less than 5.5 in 1:1 water extract (Soil Survey Staff, 1999).

Many farmer participatory field  experiments were designed and conducted in different states of India having large area under acid soils, with locally available soil ameliorants to study their effect on soil health and crop performance. This work was done during 2000 & 2005 under an ICAR network project on “Soil characterization and resource management of acid soil regions for increasing productivity”. The details of the field locations are presented in table 1.

The north eastern hill region covers a large share of acid soils of India occupying 14.95 m ha which is a major constraint for sustainable crop production. Acid soil limits the availability of calcium and phosphorus in soil, lowers base saturation and reduces microbial activities in soil adversely affecting the crop growth and yield. About 95 % of the soils of this region, except Nagaland (about 70 %) are acidic in reaction. About 84, 77, 76, 60, 57 and 47 per cent soils of Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Sikkim and Tripura, respectively have soil pH below 5.0 and are considered strongly acidic (Panda, 1998). The soils are highly degraded because of heavy rainfall and removal of top soils. Land slides are also contributing towards land degradation. About 16 % of the area is affected by water erosion (www.india stat.com). About 53.8, 28.2, 42.6, 53.9, 89.2, 60, 33 and 59.9 per cent  area are degraded in Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura, respectively. Including Assam, north-east constitutes 80 % of the total area under acid soils of the country. The land use pattern of north-east region is presented in table 1 and area, production, yield of foodgrains and fertilizer consumption are presented in Table 2.

Jharkhand state lies between 21º58’2" to 25º8’32" North latitude and 83º19’05"to 87º55’03" East longitude covering an area of about 7.97 m.ha. and accounts for  2.4 per cent of  the total geographical area (TGA) of the country. It is bound on the east by West Bengal, on the west by Chhattisgarh, on the north by Bihar and on the south by Odisha. Reliable information on the location, extent and quality of soil and land resources is the first requirement in planning for the sustainable management of land resources. The components of land i.e., soils, climate, water, nutrient and biota are organised into an eco-system, which provides a variety of services that are essential for the maintenance of the life support system and the productive capacity of the environment.

The state of Odisha located in the Coromondal coast of India has a tropical monsoon climate characterized by high humidity, high rainfall (1497 mm) and short and medium winter. It is the 10^th largest and 11th most populous state accounting about 5% of the geographical area and 4% of the population of the country. The geographical area of the state is 15.57 m ha, out of which 0.62 m ha is arable land. Agriculture contributes 28% to  state domestic production and employs 64% of the work force.

Acid soils occupy one fourth of the land in India. The formation and distribution of acid soils depend upon several factors like temperature, vegetation, parent material and hydrological conditions etc. For this reason, these soils have low pH, poor base saturation, high sexquioxide content, which affects the transformation and availability of plant nutrients.  Secondary and micronutrient deficiency as well as toxicity are major problems in cultivation of crops in acidic soils. These soils are generally deficient in Ca, Mg and S and adequate in Fe, Mn and Cu. Apart from the secondary nutrients, Zn, B and Mo deficiencies affect crop production. In lowlands, rice crop suffers from toxicity of Fe. Aluminum toxicity, common in highly acidic soils, also pose major problems in crop production. Management of secondary and micronutrients in acid soils for agriculture is a national priority to achieve food sufficiency and sustainability.

Soils become acidic due to natural  and artificial (anthropogenic) reasons. The natural reasons include their origin from acidic parent materials namely granite, rhyolite, pegmatite and dacite etc. and areas under high rainfall  (rainfall  exceeding evapotranspiration) removing  basic cations through leaching and erosion particularly in coarse textured soils with undulated, hilly and sloping topography. Under natural condition, accumulation of organic matter and its decomposition also releases organic acids into the soil system, turning soils  acidic. The anthropogenic factors    responsible for turning soils  acidic,  are (i) removal of basic cations through crop cultivation, (ii) continuous use of acid forming fertilizers and (iii) acid rain in industrial areas.

The adjustment and maintenance of soil pH at a value suitable for optimal crop production is the first step in soil management, because soil pH affects soil properties, nutrient availability and plant nutrition. In India, about 30M ha cultivated  land  suffer from high soil acidity (pH < 5.5). These soils are critically degraded and are of poor health producing crop yields, which are often less than 50% of that in normal soils. Due to this, farmers use much less fertilizers for crops (50 to 80 kg NPK ha^-1), since this is not profitable.

INTRODUCTION

Indigenous knowledge is the knowledge of the indigenous people inhabiting different geographical regions of the world with their own language, culture, tradition, belief, folklore, rites and rituals. In course of their close interactions with nature and natural resources, they are to make a certain decisions as to solve their problems they encounter in their day to day life while managing the land and environmental resources for survival.

Several researchers explained traditional knowledge as holistic, encompassing many fields of scientific knowledge, such as climate, hydrology, soils, plants and animals (Howes and Chambers, 1980, Jungerius, 1985, Wilken, 1987, Agrawal, 1995). Therefore, indigenous knowledge so developed is based on necessities, instinct, curiosity and observations of ethnic groups to mitigate the immediate problems. Several logical observation was used by them in the decision making process as to how, when and where to act depending on the situations.

INTRODUCTION

Knowledge is a familiarity with someone or something, which can include facts, information, descriptions, or skills acquired through experience or education. It can refer to the theoretical or practical understanding of a subject. It can be implicit (as with practical skill or expertise) or explicit (as with the theoretical understanding of a subject); it can be more or less formal or systematic.While many would agree that one of the most universal and significant tools for the transfer of knowledge is writing (of many kinds), argument over the usefulness of the written word exists nonetheless, with some scholars skeptical of its impact on societies. People are often internalizing new information which they perceive to be knowledge but in reality fill their minds with false knowledge.

Introduction

Sustainable exploitation of fish stocks and conservation of fish habitat are matters of concern for fishery scientists and administrators all over the world. Worldwide there is a declining trend in natural fish catch (FAO, 2002) and India is no exception. Increasing harvest pressure, destructive fishing operations, introduction of exotics, are examples of factors from within the sector responsible for increasing pressure on fish stocks. The decline in open water catch has been a serious issue in fisheries as millions of rural households depend on fishing to maintain their livelihood incomes, and because fish is a major protein source in the globe. However, the government in several countries is addressing the issue in a number of ways, such as: (i) moving towards biological management from revenue-oriented management; (ii) involving resource users in capture fisheries management to maintain natural productivity; and (iii) starting programs such as rehabilitating of degraded habitats (FAO, 1999).

Introduction

North East India, a mega-biodiversity centre and a hotspot (Myer et al., 2000) occupy 7.7% of India’s total geographical area supporting 50% of the flora (ca. 8000 species) (Rao, 1994), of which 31.58% (ca. 2526 species) are endemic (Nayar, 1996). It is a transitional zone between the Indo-China and Indo-Burma–Malaysian regions. This region is also a part of the vavilovian centre of biodiversity and origin of many important cultivated plant species and some domesticated animals (Agarwal, 1996). North Eastern Hilly (NEH) region of India supports a rich biodiversity spanning from tropical rainforests to alpine scrubs.  Takhtajan (1969) described the region as the “Cradle of Flowering Plants” because of its diversified angiosperms.  This rich biodiversity has a significant role to balance the ecosystem and has been used ethnologically by locals for various socio-economic and developmental purposes (Yumnam, 2008).

INTRODUCTION

The North Eastern Hill (NEH) Region of India comprising the states of Arunachal Pradesh, Assam, Meghalaya, Mizoram, Manipur, Nagaland, Tripura and Sikkim lies between 20º5’ to 29º30' latitude and 89º49' E to 97º3' E longitude. The region possesses a great diversity in soil and climate as influenced by varied altitudes ranging from 18m MSL to more than 3000m MSL. In the entire region due to high rainfall (1800 mm to 3000 mm/year) humidity is very high (50-100%). The average minimum and maximum temperature is also comparatively low and ranges from below 0°C to a maximum of 35ºC. This region is very rich in natural resources with diverse flora and fauna.

INTRODUCTION

North East India is a rich storehouse of indigenous agricultural practices and local varieties of crops. The region comprising of the states of Arunachal Pradesh, Assam, Meghalaya, Manipur, Tripura, Mizoram, Nagaland and Sikkim can be physiographically categorized into the Eastern Himalayas, Northeast hills (Patkai-Naga Hills and Lushai Hills) and the Brahmaputra and Barak Valley plains. At the confluence of the Indo-Malayan, Indo-Chinese and Indian biogeographically realms, the NE region is unique in providing a profusion of habitats, which features diverse biota with a high level of endemism (Chatterjee et al., 2006). The northeastern region is rich in biological diversity and contains more than one-third of the country’s total biodiversity. This biodiversity and variability of the ecosystem are used and conserved by traditional communities through various informal institutions and using traditional ecological knowledge systems. Ethnic communities of the region practice their traditional cultivation practices of diverse crop suitable in different ecosystems solely on organic conditions without any external inputs to the system; and value the land and the environment for the sustainability of the system for future generations. There is no systematic record to describe what they are, what they do and how they do, how they can be changed, their operations, their boundaries and their applications.

INTRODUCTION

Ethno-Veterinary Medicine (EVM) or Veterinary Anthropology refers to holistic and interdisciplinary study of traditional knowledge, skills, methods, practices and folk beliefs of the people about the health care of animal husbandry and production of livestock (McCorkle, 1986). It encompasses information on diseases and their control; remedies and clinical practices for treatment and prevention; management, feeding and breeding strategies; spiritual elements; and the use of human resources that hold the information and experience (Mathias, 2004).

INTRODUCTION

The fermented products probably came into existence at least before the British Era in Northeastern states of India [before 1824, The Yandabu Agreement between British Govt. and Burma (now Myanmar)] when the British first introduced salt in the region. Interestingly, in all the fermented fish products of this region no salt is used as ingredient which is a major difference with the other fish based fermented fish products of Southeast Asian countries such as Nuac-mum of Vietnam, Budu of Malaysia, Patis of the Philippines etc. Even after the British Era, people used to treat salt as a highly valued and scarce commodity and they used to take an alternative commodity, for example khar in Assam, made from banana plant or papaya. Hence, they could not afford spending salt in fish preservation and they were bound to preserve fish in their own cheaper and easier way.

INTRODUCTION

Jewellery has been a favorite form of adornment since time immemorial in all parts of the worlds and Indian is not an exception. The significance of jewellery in the country is evident from the fact that on many auspicious occasions, jewellery forms a part of gifts. Jewellery has not only been considered for the purpose of adoration, but it can also be sold to overcome the economic crisis. This way, jewellery also serves the purpose of insurance, which can be depended upon. To accentuate their feminine beauty, women use jewellery made of gold, silver and diamonds. Traditionally, jewellery has always been linked with wealth, power and status.

INTRODUCTION

Ethno-entomophagy is the term used to describe the practice of consumption of insects as food by native human populations. Insects are an important source of protein for humans, either through direct consumption or as food supplements for livestock (DeFoliart, 1989). They are nutritious in terms of protein (40–75 g/100g dry weight) and minerals. Their protein is of high quality and has high digestibility (77–98%) with good concentration of essential amino acids (46–96% of the nutritional profile) (Verkerk et al., 2007). The biochemical composition and chemical analysis have revealed that they are comparable with other foods enriched with high proteins, fats, lipids, vitamins and mineral salts (Prasad, 2007). Insects generally have higher food conversion efficiency than other animals. They show a food conversion efficiency of about twice as efficient as pig and boiler chick and more than five times as efficient as beef cattle (Durst and Shono, 2010). Some of the important edible insects include grasshoppers, caterpillars, beetle grubs, adult winged termites, bees, wasps, winged ants, cicadas and a variety of aquatic insects.

INTRODUCTION

Over the past decades, as concerns about declines in local habitats, species, and livelihoods related to agriculture and allied sectors have increased, the potential contributions of local and traditional knowledge (LTK) to ecosystem research and management have been increasingly recognized (Thornton and Scheer, 2012). North Eastern region is well known as one of the 18 hotspot areas of the world and hence is blessed with rich biodiversity and fish fisheries resources. With more than 90% of population being fish eaters, there is heavy demand of fish but a wide gap exists between supply and demand. The region produces over 0.214 million tonnes of fish annually, with almost 50% coming from aquaculture.

INTRODUCTION

Fishing is one of the oldest professions of humans. As the day went by, the fish farmers carry out their own indigenous technology as a common practice through natural resource management. In this line, different traditional fishing communities of West Bengal gained a vast experience in every sphere of aquaculture. Their innovation is based on their own knowledge derived from their day to day effort of solving problems. Actually this indigenous knowledge is the accumulated information, skill and technology of the local farmers derived from the close interaction with the nature. The intimate interaction of the farmers with aquatic ecosystems through their age old practices has developed huge expertise which is essential to be documented and disseminated. It will be helpful for aqua resource management as they can be shared in a, cost effective, eco-friendly as well as socio economically viable proposition.

INTRODUCTION

The origin of fish culture in India probably dates back to 2000 years. Possibly, fishery activity started when the human settlement moved away from the riverbanks to the hinterland. As the days went by, the Indian fish farmers practice their own indigenous technology as a common practice through natural resource management (National Commission on Agriculture, Gov. of India, 1976). The close and intimate observation of farmers through their age-old practices has developed the expertise of acquiring knowledge in aquatic ecosystem in particular. Admittedly, the multifarious knowledge and skill possessed by local people can substantially contribute to productive efforts and endeavors (Dasgupta, 1993).

INTRODUCTION

The enemies of plants have been harming the organized agriculture ever since man started depending on plants for food. Fossil evidence indicates that plants were affected by disease since 250 million years ago. Conditions of food shortage and famines have been created by these enemies of plants. Naturally, the man had been obvious of their presence and proposed explanations and methods of combating them according to the knowledge available at that time all over the world. It is not true that attention to plant diseases was first given in the western countries. In the ancient Indian literature many plant diseases and their remedies were mentioned.

INTRODUCTION

Assam is a heartland of indigenous groups. Since hundreds of years, many indigenous groups have been living in the state, maintaining their originalities in every sphere of life with difficulties. The tribal-indigenous groups constitute almost 12.4% of the total population of Assam. (Sentinelassam.com). Fishing is one of the major livelihood option of many indigenous fishers as the state is blessed with huge water resources with about 3.91 lakh hectare of water area in the form of rivers, beel, derelict water bodies and ponds and tanks. Besides swamps and low-lying areas, two major rivers and their tributaries have a high growth potential for fishing and could play a pivotal role in the socio-economic development and employment generation in the state. Indigenous fishers have developed a close and unique connection with the water resources and its environment in which they are depended for generation to generation for their livelihood. They have generated unique system of knowledge, innovation and skills relating to the uses and management of fishing activities. Over centuries, people have learnt how to get food and to survive in different environment. Farmers are very keen to observe the problems arising during fishing and seek solutions to adjust to their local environmental conditions. They continuously adapt and manage their fishing systems and in this way, they develop a rich storehouse of practical knowledge on their situation.

INTRODUCTION

Northeast India comprises the contiguous seven sister states.viz., Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland and Tripura and the Himalayan state of Sikkim. The Northeastern states of India are blessed with diversified fish fauna which assumes special interest due to the fact that the region is grained by two important drainages viz., Brahamaputra-Barak and Chindwin Irrawaddy. (Gurumayum and Choudhury, 2009). Riverine fisheries resources of Northeastern States comprise of 19,150 km of streams and rivers. Except the Brahmaputra and Barak Valleys in Assam and Imphal Valley in Manipur, the Northeast mainly comprises of Hills and Mountains which form 65% of its territory (Suguman, 1998).

INTRODUCTION

Fish is a dependable source of animal protein in developing countries like India. In recent years, with the rapid development of the aquaculture enterprises, the infectious diseases caused by fungus, bacteria, virus and parasites became more severe, resulting in huge economic losses. Due to certain unavoidable problems for diagnosing and treating diseases, losses are being born by the poor fish farmers of the country.

The issue is more relevant to rural area like north-east India, where soil and water are highly acidic due to the high content of ferrous ions and high rainfall and their management needs high inputs. The situation gets shoddier when the farmers do not get the access to water and soil laboratory to test their pond samples. It is very hard for the rural farmers to monitor their culture pond condition without any scientific tools and technical knowledge. Moreover, stresses due to over-crowding, wide temperature fluctuations, cold stress, global warming, microorganism, pesticides, insecticides, chemicals, contaminants etc.

INTRODUCTION

The medicinal values of plants are known since prehistoric times. Interestingly, 13000 BC old drawing on Lascaux caves in France suggests that humans were using plants for medicinal purposes. Ancient Egyptians chewed willow bark to relieve fever and headaches; and thousands of years later, scientists discovered that the bark contains salicylic acid- the active ingredient in aspirin. History reveals that in most of the countries natural products including plants, animals and minerals have been the basis of treatment of diseases both in human and veterinary medicines.
 
Plants as a source of medicine has been an ancient practice and is an important component of the health care system in India. The health management of people and domestic animals is based partially on the exploitation of natural resources, which needs proper documentation and research.

INTRODUCTION

The North Eastern Region of India comprises of eight states, viz., Assam, Arunachal Pradesh, Manipur, Meghalaya, Tripura, Nagaland, Mizoram and Sikkim. These north eastern states are home to myriad tribals and several ethnic groups. Most of the people of the north-eastern region of India belong to the Mongolian race and the food habit of the region is fairly similar with that of South-East Asian countries. Fermented foods form an intrinsic part of the diet of these people. Fermentation has been an age long traditional practice of preserving various food products in the region. These fermented products are used as condiments in the preparation of various traditional sauces, strews and dishes (Saisithi, 1994).

INTRODUCTION

In the emerging global knowledge economy, a country’s ability to build and mobilize knowledge capital is equally important for sustainable development like the physical and financial capital (World Bank, 1997). The basic component of any country’s knowledge capital is its indigenous technical knowledge (ITK). ITK is the social capital of the local people, their main asset to invest in the struggle for survival, to produce food, to provide for shelter or to achieve control of their own lives. It is the unique, traditional, local knowledge existing within and developed around specific condition of men and women indigenous to a particular geographical area (Ghosh and Sahoo, 2011). It helps to increase the sustainability of development efforts because of its integration process with mutual learning and adaptation, which in turn contributes to the empowerment of local communities.

INTRODUCTION

Fish are one of the main exploitable resources of the aquatic ecosystems that provide a cheap source of protein which help solving the problem nutritional security particularly NE region of the country. The rapid development of fishing technology in India during the recent years has paved the way for increased production availability of new synthetic materials, evolution of new designs of fishing crafts and gears and avoidance of ignorant harmful fishing techniques etc. It is to be taken into account that any developmental activity adopted should also be base rooted in the objective of uplifting the economy of the fishing communities. This implies that the improvisation of the existing tools and techniques and introduction of new ones to enhance fishing efficiency need a careful study of the traditional infra-technologies. Further selection of fishing methods and gear are influenced by various factors such as physiographic of the water body, nature of fish stock, characteristics of the material from which gear are fabricated and standard of living. Therefore, variation in application of fishing devices can be observed in different type of water bodies, which have characteristic of their own due to unique nature of the water resources of the region.

Introduction

North East India constitutes the states of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Tripura and Sikkim which reflects ecological and cultural contrasts between the hills and the plains. It is one of the most biodiversity regions in the world, with more than a hundred and fifty tribes forming a melting pot of variegated cultural mosaic of people and races constitute a vital component in this region (Dutta and Dutta, 2005).
 
More than 70% people of the region are engaged in agriculture while rice is the staple food crop (Bhattacharjee and Ray, 2010). The farmers from different ethnic diversity of the region have developed their own systems of cultivation of various crops (Islam et al. 2004). These indigenous traditional knowledge systems are quite endemic to this region (Deka et al. 2006).

INTRODUCTION

Traditional knowledge is the knowledge, innovations and practices of indigenous and local communities around the world. Developed from experience gained over centuries and adapted to the local culture and environment, it is transmitted orally from generation to generation. It tends to be collectively owned and takes the form of stories, songs, folklore, proverbs, cultural values, beliefs, rituals, community laws, local language. Sometimes it is referred to as an oral tradition for it is practiced, sung, danced, painted, carved, chanted and performed down through millennia. Traditional knowledge is mainly of a practical nature, particularly in such fields as fisheries, health, horticulture, forestry and environmental management in general. Appreciation of the value of traditional knowledge is growing. This knowledge is valuable not only to those who depend on it in their daily lives, but to modern industry and farming as well. Many widely used products, such as plant-based medicines, health products and cosmetics, are derived from traditional knowledge. Other such valuable products include agricultural and non-wood forest products as well as handicraft. Traditional knowledge can make a significant contribution to sustainable development.

Cell culture has become one of the major tools used in the life sciences today. Viruses replicate only within the living cells. With the advent of cell culture technique, it has become easier to grow the viruses under in vitro condition (cell culture). Viruses are usually propagated in cell culture, embryonated hen’s egg, laboratory animals or natural hosts. In 1949, Enders, Weller and Robbins first reported that polio virus could be grown in cultured non-neural cells with the production of recognizable cytopathic changes. Although the cell culture technique has been evolved long back, it is only since the advent of antibiotics that cell culture became a matter of simple routine technique. Aseptic precautions are still essential, but the problems of contamination with bacteria, mycoplasma, fungi and yeasts can be checked by antibiotics and anti-fungal agents. The term in vitro literally means ‘in glass’ although today most cell culture is performed in or on plastic.

The cell is the unit of structure of all plants and animals. With increasing complexity of organization, masses of different cell types tend to become localized and to form recognizable patterns. An aggregation of cells forming a definite pattern is called tissue. A still higher level of organization, tissues aggregate to form organs. The animal cell is a highly organized structure. Plant cell is different from animal cell  by having a cellulose cell wall.  There are a number of well defined structures viz., nucleus, mitochondria, lysosomes, Golgi apparatus etc in the cell. Animal cells also have centrioles whereas plant cells contain plastids such as chloroplasts. The remainder of the cell is the cytoplasm.

The best environment for growing cells is similar to  the conditions what they experience in vivo. A number of various environmental factors affecting the tissues are :
 
    (1)    Temperature : In living matter, complicated chemical reactions are happened at comparatively low temperature.  In most of the mammalian and avian tissues the temperature  is 37^ºC to 38.5^ºC. If the temperature is enhanced to 45^ºC, cells are destroyed within  an hour but survive 12-24 hours at 42^ºC. It is applicable to most of the fibroblasts and epithelial  types of cells arising  from  mammalian tissues. Some of the mammalian cells ( human skin epithelial cells)  and amphibian cells  prefer lower temperature but fish tissue will not survive beyond 20^ºC.

Types of cells : Animal cells are usually defined by the tissue of their origin. On the basis of morphology, they can be divided into 5 types.

    1.    Epithelial cells : Epithelial tissues consist of a layer of cells which cover organs and line cavity. Example skin and the lining of alimentary canal. They grow well as single cell monolayer in culture.

    2.    Fibroblast cells : Connective tissue form the major structural component of animals. The tissue contains fibroblasts and most widely used cell in the laboratory. Fibroblasts are bound to the fibrous protein collagen in the connective tissue. They have excellent growth characteristics.

A finite growth capacity is a characteristic of all cells derived form the normal animal tissue. The cells pass through a series of age related changes before being incapable to divide further. The finite number of generations of growth is a characteristic of the cell type, age and species of origin and referred to as the “Hayflick limit”. The cells derived from embryonic tissue have a greater growth capacity than those derived from adult tissue.

A cell culture laboratory should allow the sterile handling of cultured cells with no or minimum level of contamination. The growth of bacteria and fungi is very high and no level of contamination can be allowed in animal cell culture. However, it is impractical to design a laboratory free from potentially contaminated microorganism. Further, it is possible to establish a laboratory with minimal risk of contamination. Several points should be taken into consideration while designing a new cell culture laboratory.

Once cells are obtained from a culture collection or isolated from animal tissue,, cells are put in the flask with growth medium. The cells are inoculated at a density of 104-105 cells/ml to get a concentration of 106 cells/ml or 105 cells/cm2 in a solid surface in 2-3 days because of nutrient limitation, accumulation of toxic metabolite or lacking of growth surface.

Cell culture medium : To grow cells in in vitro, environment should be as close as possible to in vivo condition. But a number of factors are important to grow cells in vitro namely substrate, temperature and medium. There is a number of ready made medium available commercially and made the cell culture work easier. Any successful medium consists of isotonic buffer solution containing inorganic salts, amino acids, vitamins, a energy source and various supplements. Usually serum or serum replacement is used as supplement.

Primary cells are often preferred to established cell lines as they better represent the cells in vivo in terms of activity and functions. On the other hand, there is significant difference between original culture and present culture and even between cultures of the same cells in different laboratories. The rate of growth increases and there is change in chromosome numbers of lines over the time. The differences in phenotypes can cause problems in comparison and interpretation of results. The advantage of cell lines are ease handling, grow continuously, large yield and readily available. Primary cell cultures compared to established cell line are more fastidious in their growth requirements because many cell lines are derived from tumour tissue and demonstrate reduced growth factor requirements.

Cell growth and cell passage : Different types of cells have different growth requirements but in all cases the surrounding medium must supply all the essential nutrients. The temperature, pH, osmolarity and humidity must be kept within limits. Again, toxic or inhibitory substances must not be allowed to accumulate. Serum, a source of macromolecular growth factors, is essential to the growth of many cell types. Anchorage dependent cells require nontoxic or biologically inert glass or plastic surface for attachment.

In may cases, it becomes necessary to send the cells from one laboratory to another laboratory within or outside the country. The ideal method is to fill the flask containing cells at log/exponential phase with growth medium, tightly close the cap, seal it with parafilm and tape and pack it properly with polythene containing tissue paper and cotton. The tissue paper and cotton is used to soak the medium in case of accidental breakage. The polythene containing tissue culture flask having the adherent cell sheet should again be packed with thick paper. Finally, it is to be kept in a wooden/metal box or container.

Vero (monkey, African green, kidney) 
Morphology: Fibroblast
Species:, African green monkey 
Tissue: Kidney

Properties: Virology, virus titration, virus replication, plaque assays, bacterial cytotoxicity

If the concentration of cells in suspension cell culture has reached to 7X10⁵ cells/ml, it is to be subcultured. Suspension cells are diluted to concentration of approximately 1X10⁵ cells/ml although it varies from cell line to cell line. So, to subculture into a 3 litre glass flask using 500 ml of suspension of cells, there is a need of 5X10⁷ cells. As the concentration of cells is 7X10⁵ cells/ml, there is a need of 71.4 ml of cells. Adherent cells are put in the culture flasks at a concentration of 5X10⁴ cells in a 25 cm² flask. For example, after trypsinization, the cells have been resuspended in 5 ml of medium and cell concentration is 1X10⁵ cells/ml or total number is 5X10⁵ cells. If one wants to put cells into two 25 cm² flasks each containing 5X10⁴ cells in 5 ml volume, there is a need of 1X10⁵ cells, which can be obtained from one ml of cell suspension (1X10⁵ cells/ml).

Small volume cultures are useful for experiments such as studying cell morphology, titration of viruses, plaque assay, pock assay, SNT and to compare the effect of agents on growth and metabolism. However, there are other application where there is a need of large number of cells such as extraction of DNA/RNA from cells, production of viruses for vaccine production and a number of products namely interferons, interleukins, hormones, enzymes, antibodies, glycoproteins etc. The large quantity of cells can be obtained by using a large number of flasks/bottles but it is tedius, labour intensive, expensive and there is a risk of contiamination. Although the unit processes are more cost effective and efficient, it needs some modification to overcome limiting factors such as oxygen depletion, shear damage and metabolic toxicity. There are a number of aberrations available to scale up cell culture described below.

There are a number of different cell lines derived from human and animals. With the dramatic increase in numbers of cell lines, the risk of intraspecies and interspecies cross contamination rises proportionally. It is particularly a major problem in laboratories where many different cell lines of human and animal origin are handled at a time. The purity of the primary cell or continuous cell lines and species of its origin should be checked on a regular basis to authenticate the cell line identity. In the absence of such monitoring, inter and intra species cell line contamination are likely to occur in the laboratory resulting in loss of investigator’s time effort and resources. The advantages of working with a well defined cell line free from contaminating organisms would appear obvious.

Early passage cell lines are relatively unstable and go through a period of adaptation to culture. However, between 5^th and 35^th generation (human diploid fibroblasts), the culture is fairly consistent although it varies from one cell to another cell. Finite cell lines should be preserved after adaptation but before senescence (getting older). Cells should be preserved to protect cell line instability, availability in case of contamination, incubator failure or accidental loss.

Cell culture contamination continues to be a major problem and a subject of great concern. Contamination may enter the cell culture system as physical, chemical or biological component of the environment and biological contamination represent the greatest threat as living organism metabolize and replicate. Replication increases the titre of the contaminant.
 
Physical contamination : Physical components of cell culture systems such as radiation, irradiation (UV light and fluorescent light), temperature extremes can cause reduced cell growth and cell death. To minimize the problems, incubators should be located where ambient temperature is relatively constant and no vibration (near centrifuge). Media and media components should not be stored in glass door refrigerators, next to radioisotopes, bench tops or outside the refrigerator or in the hood for prolonged period.

Enumeration of cells is essential to determine the multiplicity of infection, efficiency of plating and to obtain the specific number of cells for an experiment. The concentration of cells of a suspension can be counted using a haemocytometer. Each chamber is divided into a grid of nine large squares. Each large square is 1mmX1mm (area 1 mm²) and the depth is o.1 mm. The volume of each square is 0.1 mm³ or 10^-4 cm³. Since 1 cm³ is equal to 1 ml, the number of cells per ml of suspension can be obtained by multiply the average count per large square by 10⁴ and reciprocal of dilution factor. Dilution is made in such a way that one large square contain about 20-60 cells. The haemocytometer chambers should be filled by capillary action and cell clump are counted as one cell. A total count does not distinguish between living and dead cells. The number of viable cells can be determined by staining the cells with trypan blue or erythrosine B. In trypan blue staining cells appear as unstained whereas dead cells appear as blue.

Cell culture is the most convenient and widely used system for the isolation and propagation of many viruses. Either primary cell culture or established cell lines can be used to isolate the suspected viruses. One can normally get 10-100 virus particles per cell inoculated. Many details of the infection process are controllable to a high degree (including cell density, age, multiplicity of infection (M.O.I.), medium composition, cell type and length and temperature of incubation). Many cell types from different species can be susceptible to a particular virus and vice versa. For replication to occur, the cell type used must be permissive for a particular virus under study.