eBook Chapters

Microorganisms live as single cells in nature in association with other cells in assemblage that we call “Population”. Such populations are composed of group of related cells generally derived by successive cell divisions from a single parent cell. The location in an environment where a population generally lives in association with other populations of cells called “Microbial communities”. Environmental microbiology deals with the study of these microbial communities in different habitats, naturally occurring on earth.

Natural habitats of microorganisms are exceedingly diverse. Any habitat that is suitable for the growth of microorganisms can also support the growth of other microorganisms. But in addition, there are many habitats where, extreme environment, due to chemical and physical factors, higher organisms cannot grow but microorganisms can grow and flourish. In this chapter, different habitats of microorganisms are discussed briefly.

Because microorganisms are so small, their habitats are also small. The term microenvironment is often used in ecology to describe where a microorganism actually lives and metabolites within its habitat.

Earth provides enough to satisfy every man’s need but not every man’s greed.
—Mahatma Gandhi
The term ‘environment’ is derived from French word ‘environner’, which literary means ‘to surround’ or ‘to encircle’ i.e. everything either living (plants, animals, microbes) or nonliving (soil, water, air, temperature, humidity etc.) surrounding us makes our environment. The universe is full of uncountable number of stars, planet and satellites, which has specific type of environment but earth is the only known planet in the universe that contains life supporting environment. The earth environment is a collective term for the nature or ecosystems, that we use and benefit from on a local, national and global scale. The earth ecosystems provide number of benefits called ecosystem services, free of cost.

1-1. Identify the current state of environmental policies in Indian agriculture and the challenges faced in their effective implementation.

1-2. Evaluate the importance of implementing environmental policies and management systems in Indian agriculture to ensure sustainable development.

1-3. Analyze key international standards, such as ISO 14001 and EMAS, and how they can be applied in the context of Indian agriculture.

1-4. Compare and contrast best practices and case studies of companies and organizations that have successfully implemented environmental policies and management systems in Indian agriculture to draw insights and lessons learnt from them.

Many types of geological hazards namely, tsunami, earthquakes, tsunami, floods and drought affect coastal areas like any other place on the Earth. As coastal regions are thickly populated and have abundant urban, industrial and recreational establishments, impacts of geohazards are always severe along coastal regions. Compliance to coastal zone regulations, with protection of sanddunesandmangroveswillbe the best mechanism to minimizethe damages from such hazards. In future, climate change may result in more hazards such as erratic rainfall and increase the frequency of droughts, floods and storm surges, etc. In this context, proposed coastal management zone for the coastal protection, disaster mitigation and management tools in coastal areas are examined in this chapter. It is suggested that extensive use of GIS and development of Geodatabase for the risk prone areas will serve as efficient tool for planners and policy makers to deal with geological hazards. In addition, it is felt that more efforts are needed in legal and institutional framework for integrated disaster management planning on local as well as national level.

INTRODUCTION

Geologic hazards are natural geological processes that inflict severe damage in areas of their operation if the area is utilized by anthropogenic activity in terms of habitation, industrial, recreational or commercial establishments. Many a times, natural geological processes that operated uninhibited for millions of years turn into geological hazards due to human intervention. These losses – lives and economic are not evenly distributed and are more prevalent in the developing countries due to higher population concentration and low level of economic growth. United Nations had realized the need of reducing these losses due to natural disasters and declared the last decade (1991-2000) as the International Decade for Natural Disaster Reduction. Objective of this proclamation was to reduce, through concerted efforts, the loss of life, property damage and socio-economic disruption caused by the natural disasters particularly in the developing countries (Tewar, 2000).

A problem in the 1970s was the emergence of pathogen strains that were resistant to chemical . Concerns from the public about the effects of agricultural pesticides generally on human health and the environment have grown in the 1980s . A number of pesticides have been deregistered, subject to limitations, or taken off the market as a consequence of this issue.

Because of perceptions rather than actual facts, the use of agricultural pesticides frequently raises serious public concerns. Concerns include the potential for human and domestic animal poisoning, contamination of livestock products, harmful effects on beneficial microorganisms like pest predators and pollinating bees, dangerous residue levels in foods made from sprayed crops, ecological disruption at the level of microorganisms, and the potential for water contamination with subsequent fish loss and residue buildup in groundwater.

7.1 What is Pollution?
 
Pollution is a contamination of the environment by man-made substances or energy that has adverse effects on living or non-living matter. In simple terms, pollution can be seen as the wrong substance in the wrong place in the wrong quantities at the wrong time. This implies that harm is caused to the environment if the same substance is present at levels too low.

Types of pollution
Pollution can be categorized according to the medium in which it occurs such as

3.1 Air Pollution

Air pollution is a phenomenon by which particles either a solid or liquid and gases contaminate the environment. Such contamination can result in health effects on the population, which might be either chronic arising especially from long-term exposure or acute due to accidents. Other effects of pollution may be damage to materials, agricultural damage namely reduced crop yields and tree growth, impairment of visibility namely tiny particles scatter light very efficiently, and even climate change global warming.

3.1.1 Classification of Air Pollutants

Air Pollutants are classified as Natural as well as Anthropogenic. Natural pollutants are those that are found in nature or are emitted from natural sources. For example, volcanic activity produces sulfur dioxide, and particulate pollution may derive from forest fires or windblown dust. Anthropogenic pollutants are those that are produced by humans or controlled processes. For example, sulfur dioxide is produced by fossil fuel combustion and particulate matter comes from diesel engines.

Air pollutants are further classified as primary or secondary. Primary pollutants are those that are emitted directly into the atmosphere from an identifiable source. Examples include carbon monoxide and sulfur dioxide. Secondary pollutants are those that are produced in the atmosphere by chemical and physical processes from primary pollutants and natural constituents. For example, ozone is produced by hydrocarbons and oxides of nitrogen (both of which may be produced by car emissions) and sunlight.

Pollution: Environmental pollution in general, may be described as the contamination of the environment with harmful wastes arising mainly from human activities. These activities release certain materials which produce pollution in the atmosphere water and soil. In simple words, environmental pollution may be defined as direct or indirect changes as a result of human activities, which adversely influence the biological and non-biological equilibrium of the environment.

Metals are toxic and non biodegradable pollutants released into the environment through effluents from agriculture waste, mining, metal processing industries, pharmaceutical industries as well as domestic and natural activities. Metallic pollutants tend to persist indefinitely and eventually get accumulated in the ecosystem. Metals especially arsenic, copper, cadmium, chromium, lead, mercury, nickel, selenium and silver etc. possess a risk to living systems. Conventional processes applied to remediation of metallic pollutants are often restricted due to technical and economical constraints. Particularly when the metal contamination is at very low concentration the conventional methods become inefficient. In this situation application of bioremediation techniques is a technology of choice for environmental protection and clean up.

Introduction

The issue of environmental protection has become increasingly important in recent years, and one of the most effective ways to address this problem is through the use of recycled products. Recycling helps to conserve natural resources, reduce waste, prevent pollution, and combat climate change making it a critical part of any sustainable development strategy. In this chapter, we can explore how recycled products can help protect the environment and the many benefits that come with their use.

Humic substances are the most widely-present, natural, complexing ligands occurring in nature. They are found not only in soils, but in natural waters, sewage, compost heaps, marine and lake sediments, peat bogs, carbonaceous shales, coals and other miscellaneous deposits.

The fate of natural organic matter, especially humic substances, has over recent decades attracted increasing attention of scientists representing various disciplines. Humic substances constitute about 25% of the total organic carbon on the earth. These are a group of naturally occurring complex molecular structures into which biomolecules derived from plant and animal residues are transformed progressively through biotic and abiotic pathways, by aggregation and accumulation processes

    Q.1.    What are the most common isolated environmental Streptococci from mastitis cases?
    Ans.    Streptococcus uberis and Streptococcus dysgalactiae.

    Q.2.    What are the common sources of environmental Streptococcus uberis in a herd?
    Ans.    The common sources are bedding materials, lips, nostrils and abdominal skin of cows.

    Q.3.    What are the common sources of environmental Streptococcus dysgalactiae?
    Ans.    The common sources are tonsils, mouth, vagina and mammary gland of cows.

    Q.4.    Why incidence of Streptococcus uberis is highest just prior to calving?
    Ans.    The important reasons are the excessive accumulation of milk due to lack of milking, lack of keratin plugs from the streak canal and immunosuppression at periparturient period.

    Q.5.    The cattle fly sometimes involves in persistent bacterial contamination on teat of a cow. Mention the name of the cattle fly.

Abiotic Environment

The physical or abiotic environment includes all those physical and non-living chemical aspects, which exert an influence on living organisms. The abiotic components are soil, water, air and energy from various sources. These provide both habitation and raw material for the synthesis of organic food.

Introduction

Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the physical systems or living organisms they are in.
 
Pollution can take the form of chemical substances, or energy, such as noise, heat, or light energy.
 
Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels. Sometimes the term pollution is extended to include any substance when it occurs at such unnaturally high concentration within a system that it endangers the stability of that system. For example, water is innocuous and essential for life, and yet at very high concentration, it could be considered a pollutant.

Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the physical systems or living organisms they are in.  
Pollution can take the form of chemical substances, or energy, such as noise, heat, or light energy.

Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels. Sometimes the term pollution is extended to include any substance when it occurs at such unnaturally high concentration within a system that it endangers the stability of that system. For example, water is innocuous and essential for life, and yet at very high concentration, it could be considered a pollutant.

(Method of Joseph Mac Gee, 1959)
Principle

A simple and rapid enzymatic method for the quantitative estimation of total cis-methylene- interrupted polyenoic acids has been devised. Linoleic, linolenic and arachidonic acids, the more common acids of this group were used to calibrate the method. The potassium salts of the fatty acids are oxidised by atmospheric oxygen in the presence of the enzyme lipo-oxidase, and the absorption of the conjugated diene hydroperoxide is measured at 234 mµ. As little as 5 µg of linoleic acid can be quantitatively measured with good accuracy and precision. The total content of polyunsaturated fatty acids containing the cismethylene-interrupted diene structure of fats, oils, hydrogenated oils, fatty acids, esters blood plasma, microorganisms and plant seeds has been measured directly by this method.

1. The Aflatoxin Molecule

Aflatoxins are chemically difuro-coumarin derivatives. Presently, 18 different types of aflatoxins have been identified with aflatoxin B₁, B₂, G₁, G₂, M₁ and M₂ being the most common. Of these Aflatoxin B₁ (AFB₁) and G₁ occur most frequently, with AFB₁ being the most potent. Physicochemical and biochemical characteristics of the AFB₁ molecule reveal two important sites for toxicological activity (Heathcote and Hibbert, 1978). The first site is the double bond in position 8,9 of the furofuran ring (Figure 1). The interactions of aflatoxin, DNA and proteins, which occur at this site alter the normal biochemical functions of these macromolecules and leads to deleterious effects at the cellular level.Monteiro et al. (1966) studied the in vitro interaction of groundnut proteins namely arachin and conarachins with AFB₁ molecule. The second reactive group is the lactone ring in the coumarin moiety (Lee et al., 1981). The lactone ring is easily hydrolyzed and is therefore vulnerable to degradation.

Different enzymatic methods have been proposed as potential alternatives to rumen inoculum studies to determine dry matter digestibility and protein degradation. However, the type of enzyme used and the procedure adopted differ (Marten and Barnes, 1979). The enzyme methods offer distinct advantage under circumstances of the difficulties in maintaining rumen fistulated animals as a source of rumen inoculum. Since, the enzymes used in these techniques are commercially available enzyme preparations, and are not of rumen microbial origin, the digestibility obtained from these techniques are related to in vivo digestibility by means of mathematical equations. Therefore, equations developed to predict energy content using enzyme techniques differ with the type of feedstuff and type of enzymes used in the technique (Table 5.1.) (Martens and Barnes, 1979). The enzyme methods are popular among the feed compounding industries to evaluate raw materials and compound feeds.

The method used by DeBoever et al. (1986) to determine digestibility of mixed feeds is given below.

Summary

Substance that acts as a catalyst in living organisms, regulating the rate at which life’s chemical reactions proceed without being altered in the process. Enzymes reduce the activation energy needed to start these reactions, without them, most such reactions would not take place at a useful rate. Because enzymes are not consumed, only tiny amounts of them are needed. Enzymes catalyze all aspects of cell metabolism, including the digestion of food, in which large nutrient molecules (including proteins, carbohydrates, and fats) are broken down into smaller molecules; the conservation and transformation of chemical energy and the construction of cellular materials and components. Almost all enzymes are proteins; many depend on a nonprotein cofactor, either a loosely associated organic compound (e.g., a vitamin) or a tightly bound metal ion (e.g., iron, zinc) or organic (often metal-containing) group.

The main groups of some diagnostically important enzymes are as below:

1. Oxido Reductases
Glucose 6-phosphate dehydrogenase, Isocitrate Dehydrogenase, Lactate dehydrogenase, Malate dehydrogenase, Sorbitol dehydrogenase.

2. Transferases
Alanine transaminase (GPT)    
Aspartate transaminase (GOT)
Creatin binase
Hexose-1 phosphate uridyltransferase

3. Hydrolases
Acetylcholinesterase
phosphatases
Amylases
Pepsin
Trypsin
Lipase

Objective: To extract and perform enzyme assay of Superoxide dismutase from plant.

Background information:

Superoxide dismutase (SOD, EC 1.15.1.1) is the enzyme that alternately catalyzes the dismutation (or partitioning) of the superoxide (O₂^-) radical into either ordinary molecular oxygen (O₂) or hydrogen peroxide (H₂O₂). Superoxide is produced as a by-product of oxygen metabolism and, if not regulated, may cause cell damage (Hayyan, et al. 2016). Hydrogen peroxide is also responsible for cell damage and may be degraded by other enzymes like catalase. Thus, SOD is an important antioxidant defense in nearly all living cells exposed to oxygen. One exception is Lactobacillus plantarum and related lactobacilli, which use a different mechanism to prevent damage from reactive O₂^-.

Objective: To extract and perform enzyme assay of catalase from plant.

Background information

Catalase is a commonly distributed enzyme and present in approximately all organisms exposed to oxygen (such as bacteria, plants and animals). Catalysis of H₂O₂ into H₂O and O₂ is done by catalase enzyme (Goodsell, 2004).

Objective: To extract and perform enzyme assay of guaiacol peroxidase from plant.

Background information:

Peroxidases are a large family of enzymes that typically catalyze a reaction of the form:

Objective: To extract and perform enzyme assay of polyphenol oxidase from plant.

Background information:

Polyphenol oxidase (PPO or monophenol monooxygenase or polyphenol oxidase I, chloroplastic) is a tetramer that contains four atoms of copper per molecule, and binding sites for two aromatic compounds and oxygen (www.worthington-biochem.com). The enzyme catalyses the o-hydroxylation of monophenol molecules in which the benzene ring contains a single hydroxyl substituent to o-diphenols (phenol molecules containing two hydroxyl substituents). It can also further catalyse the oxidation of o-diphenols to produce o-quinones.

PPO causes the rapid polymerization of o-quinones to produce black, brown or red pigments (polyphenols) that cause fruit browning. The amino acid tyrosine contains a single phenolic ring that may be oxidised by the action of PPOs to form o-quinone. Hence, PPOs are some time referred as tyrosinases (Mayer, 2006).

Jolley et al. (1974) referred to PPO as 4 electron-transferring phenol oxidase and oxygen. It is responsible for browning reactions throughout the phylogenetic scale.

Early and accurate diagnosis of disease is of prime importance for both the successful treatment of the patient and in limiting the spread of disease in the community. It is in this context that immunodiagnostic methods are now being used extensively since they can be extremely sensitive and highly specific. Among the most successful methods are those utilizing labelled antibodies or antigens. Examples of these are immunofluorescence in which antibodies labelled with fluorescent dyes are utilized and radioimmunoassay in which antigens or antibodies are labeled with isotopes. Both of these procedures have proved to be of great value for particular purposes.

Introduction

The entire living organism from the smaller creatures viruses to the advanced human beings are composed of a set up of biochemical reactions which form the metabolism. These set of metabolic reactions are responsible for the life of organism. The rate of these reactions is a major concern for effective working of organism which is governed by biocatalyst. These biocatalysts are known as enzymes, which accelerates rate of biochemical reaction. These are not utilized in reaction. In 1877, Wilhelm Friedrich Kuhne (Kuhne, 1877) proposed the term enzyme which means ‘in yeast’ and is derived from the Greek word; inzume “leavened” or “in yeast”. At the molecular level of study it is observed that enzymes are proteins which are functional as tertiary and quaratanary structures. Enzymes have active site for the binding to substrate. The active site has two positions; binding and catalytic site (Ogeston, 1948). The former help to bind the substrate with the enzyme followed by the catalysis of reaction by the catalytic site.

Introduction

During last four decade poultry has taken giant step and become corporate sector with double digit growth. Especially in India poultry play pivotal role in fight against malnutrition, unemployment and also contributing in women empowerment. In poultry production the biggest single expense is of feed, which accounting for 70% of total production cost per bird (Kumar et al., 2011). So, obviously more Research and Development focus and new innovative technology need to be implemented in poultry nutrition area. Since last 40 years, feed enzymes have played a major part in helping radically to improve the efficiency of meat and egg production by changing the nutritional profile of feed ingredients. 

Introduction

Billions of chemical reactions are happening inside human body and that too with lightning speed. However, the same reactions if carried out in laboratory, they take a very long time. The reasons behind it are the biocatalysts, also known as enzymes, which are synthesized by living cells. Chemically, they are proteins(except ribonucleic acids: RNA), colloidal in nature, thermo-labile in character and very specific in their action. For example, hydrolysis of proteins by a strong acid at 100°C takes a couple of days; but same proteins can be digested within couple of hours inside human body at 37°C. Similarly, carbonic anhydrase is used as a catalyst by living cells to transfer carbon-di-oxide from cells to blood. This process is 107 times quicker than the same process if occurs without the help of enzymes. Therefore, enzymes can be defined as the biomolecules or biocatalysts which can speed up the rate of the chemical reactions. The substance upon which an enzyme acts is called as substrate and the one which is produced as the result of enzyme-substrate reaction is known as product.

1.    The organic molecules which increase the rate of metabolic reactions are referred as

(a) Coenzymes

(b) Enzymes

(c) Reactants

(d) Apoenzymes

2.    Enzymes are

(a) Organic compounds produced by living organism

(b) Inorganic compounds

(c) Both (a) & (b)

(d) None of these

ENZYMES

Enzymes are the heart of Biochemistry

Protein based catalysts.

Enormously effective catalysts: typically enhance rates by 10⁶ to 10¹² fold.

Operate under mild conditions: 0 - 100 °C (or perhaps even 300+ °C for some bacteria in deep ocean), 20 - 40 °C for most organisms; and low pressures (atmospheric).

Very specific: Generally catalyze reaction for a very restricted group of molecules, sometimes for a single naturally occurring molecule of a single chirality.

1. INTRODUCTION

Enzymes are proteins with highly specialized catalytic functions responsible for many essential biochemical reactions in microorganisms, plants, animals and human beings. Enzymes play an important role in many aspects of life since the dawn of civilization that have used enzymes for thousands of years without understanding what they were or how they work. Food processing through the use of biological agents/enzymes is historically a well-established approach. The earliest applications go back to 6000 BC or earlier, with the brewing of beer, bread baking, cheese and wine making. Whereas the first purposeful microbial oxidation dates back 2000 BC, with vinegar production. In the late 19^thcentury, Christian Hansen reported the use of rennet for cheese making and production of bacterial amylases was started at Takamine (latter became part of Genencor). Pectinases have been used for juice clarification in the 1930s and during World War II, invertase was also employed the production of invert sugar syrup in a process that pioneered the use of immobilized enzymes in the sugar industry. Still, the large-scale application of enzymes could only be really established in the 1960s, when the traditional acid hydrolysis of starch was replaced by an approach based in the use of amylases and amyloglucosidases (glucoamylases) and glucose (xylose) isomerase. From then onward, the trend for the design and implementation of processes and production of products by the use of enzymes has steadily increased.

Food and beverages and household care industries represent the largest application areas of enzymes, followed by animal feed, biofuels, textile and other technical industries. Recently, several new developments have taken place in the application of enzymes in fruit and vegetable processing. Fruits and vegetables are consumed as fresh or processed into different type of products. Commercial enzyme preparations are used as processing aids in fruit and vegetable processing to improve the process efficiency and product quality, because enzymes show activity on specific substrates under mild processing conditions. Therefore, there has been a striking growth in the enzyme market for applications in the fruit and vegetable industry.

Enzymes are biocatalysts that change the rate of reaction without being changed themselves. All (Most) enzymes are proteins but all proteins are not enzymes. Ribonuclease is the enzyme which is non- protein in nature.

Properties of Enzymes

Enzymes are organic catalysts produced by living organisms. They make possible biochemical reactions. Hence they are called biocatalysts. They are mostly a specialized class of proteins. However, there are some non-protein enzymes like ribozymes, which are RNAses. Enzymes speed up reactions at ambient temperatures. This is in contrast to chemical reactions like saponification of lipids which take place when lipids are boiled for a few hours with concentrated alkali. Enzymes, namely, lipases, hydrolyze lipids at body temperatures in minutes. They are superior to chemical catalysts by a factor of 10⁷ to 10¹⁴ . An enzyme may be a simple protein or a complex protein. They are produced by cells and are mostly globular proteins. Each cell contains an estimated 3000 different enzymes.

The term enzyme was coined in 1878 by Friedrich Wilhelm Kuhne to designate these biological catalysts that had previou-sly been called ferments. As they quicken most of the chemical reactions occurr-ing in the body, the enzymes have been designated as the “manifestations of nature’s impatience”.

Enzymes are organic catalysts produced by living organisms. They make possible biochemical reactions. Hence they are called biocatalysts. They are mostly a specialized class of proteins. However, there are some non-protein enzymes like ribozymes, which are RNAses. Enzymes speed up reactions at ambient temperatures. This is in contrast to chemical reactions like saponification of lipids which take place when lipids are boiled for a few hours with concentrated alkali.  Enzymes, namely, lipases, hydrolyze lipids at body temperatures in minutes. They are superior to chemical catalysts by a factor of 107 to 1014 .  An enzyme may be a simple protein or a complex protein. They are produced by cells and are mostly globular proteins. Each cell contains an estimated 3000 different enzymes.

Feed accounts for a significant cost of production in livestock and poultry. In case of poultry, it represents 65% cost of the production in broilers and 75% in layers. Presently the live stock industry faces a huge challenge due to the high cost of feed ingredients and shortage of the conventional feed ingredients. Over the years, efforts have been made to use unconventional feed ingredients. However, such feed ingredients have many anti nutritional factors that adversely affect the performance of livestock and poultry. Due to the presence of these incriminating factors, the unconventional feed ingredients are poorly digested in livestock and poultry. These poorly digested feed ingredients results in bacterial overgrowth, which becomes a potential substrate for bacterial fermentation leading to intestinal disorders and disease. Application of antibiotics and other anti-microbials help to overcome the ill effects. However, the ban on the use of sub therapeutic level of antibiotics in many countries has increased the relevance of use of exogenous enzymes in the feed of livestock and poultry. These exogenous feed enzymes improve the nutritive value of different feed stuffs, economize livestock and poultry rearing and reduce environmental pollution.

Enzymes are biocatalysts that play a crucial role in accelerating chemical reactions without undergoing any changes themselves. Enzymes enhance the rate of a reaction by reducing its activation energy without affecting the equilibrium position of the reaction. These catalysts specifically target molecules called substrates and convert them into different molecules known as products. Most enzymes have a proteinous nature, and some have a ribonucleic acid nature (like ribozymes and peptidyl-transferase), showing high substrate and stereo-specificity. Enzyme catalysis is indispensable for the majority of metabolic processes in cells, as it ensures that these processes occur at a rate that is sufficient to sustain life. The progression of metabolic pathways heavily relies on the catalytic activity of enzymes to facilitate individual steps.

The proteinous enzymes are classified into simple and conjugated enzymes.

1. Simple enzymes: Enzymes are made up of only protein components.

2. Conjugated enzymes: Enzymes comprise both protein (apoenzyme) and non-protein components (cofactor).

Etiology

It is a relatively rare skin disease or dermatologic condition. Hypersensitivity reaction is one of the suggestive cause for this condition characterized by nodules or plaques which are seen in the skin, oral mucosa and external ear canal.

INTRODUCTION

In India, medicinal plants have traditionally occupied an important place in the socio-cultural, spiritual and health related aspects of peoples’ life. As much as 34% (ca. 6000) of total plant wealth have some known medicinal value (Ved, 2008). The genus Ephedra is one such important group of medicinal plants, from which the drug Ephedrine and a range of medicinally active compounds such as ephedrine, pseudoephedrine, norephedrine, norpseudoephedrine, methyl ephedrine, methyl pseudoephedrine, alkaloids, phenols, terpenoids are obtained. Owing to its medicinal properties, genus Ephedra is in high demand by pharmaceutical industries. It is currently facing heavy extraction pressure from its restricted habitat in the wild, and utterly lacks effective proper conservation and management efforts. For long-term conservation management of this genus, a better and comprehensive understanding of the species remains a top priority, for which detailed studies on its biology, habitat ecology, and agro-technology are required.

Veterinary epidemiology is the study of disease within a livestock population, dealing with the investigation (including identification, quantification, and examination), of the direct and indirect determinants of disease distribution in animal populations. Any epidemiological investigation starts with whether there is an animal health problem in a population, which requires data collection on animal, management, economic, and environmental factors. These data are then analyzed descriptively to assess the frequency of disease occurrence. The results are then used to decide whether investigations of causal relationships between disease occurrence and potential risk factors are necessary for the development of control or prevention policies. Once the relationships are understood, necessary interventions for the disease are then planned and their impacts assessed. Hence, the goal of epidemiological investigations is the control and prevention of animal disease problems by integrating the available pieces of evidence into the decision-making process for disease control policy development.

True/False

Q.1.    The purpose of most medical research is to identify the causes of disease and search out the ways to prevent or cure them.
Q.2.    Now a day, epidemiology has become a basic science for public health
Q.3.    The studies of diagnostics therapeutic and prognostic procedures have successfully incorporated into growing stream of “Clinical Epidemiology”.

Epidemiology is the study of diseases in a population in its natural setting. In epidemiology, the population is the patient and hence epidemiology is population medicine. All epidemiological studies are field based. In aquatic epidemiology, aquaculture ponds serve as the laboratory. This can be a great advantage over laboratory studies, which cannot be easily extrapolated to field conditions.

Diseases are among the greatest deterrents to the sustained production in aquaculture. Diseases such as Epizootic Ulcerative Syndrome (EUS) in fishes and White Spot Syndrome (WSS) in shrimps have devastated aquaculture with bad impact on productivity and profitability. Various diagnostic and health management tools are being used to devise disease control strategies. It is becoming increasingly difficult to manage pathogens that have become endemic. Epidemiological approaches which have been very successful in human and veterinary medicine are now being increasingly recognised as important weapons that can be used in aquaculture to formulate disease control programmes.

Concept of Cause for a Disease

Cause from an epidemiological perspective is interpreted in quite a wide sense. This is somewhat different to the more traditional view of the role of cause being restricted to etiological agents. An epidemiological definition of a cause of a disease is “an event, condition or characteristic that plays an essential role in producing an occurrence of the disease”. Epidemiologists avoid defining the word cause for any disease outbreak, but prefer to use words such as determinants, exposures and risk factors. Alternatively, they will categorise causes as direct or indirect; necessary or sufficient; and single or multiple rather than defining primary etiology.

Epidemiology

Vanderplank has called epidemiology the science of disease in population. Epidemiology puts its emphasis on population phenomena. The important populations are those of the host, on the one hand, and of the pathogen, on the other. But further, epidemiology is concerned with host-pathogen interactions that lead to disease and crop losses. These interactions are often environmentally dependent. So epidemiology deals with effects of the biotic and abiotic environments. Finally , man has had important effects on hosts, pathogens and the environments, effect that today are increasing in magnitude and scale of importance. Epidemiology therefore also deals with the effects of man on disease and sometimes with the effects of plant disease on mankind. All of this can be symbolized by the disease tetrahedron.

1 Study of distribution of diseases and the factors determining its distribution in a population is known as

a) Ethology b) Epidemiology

c) Ecology d) Etiology

Bhuva is a small village in north-west Gujarat – India.  My mother was born there. The loving people of Bhuva called me ‘Bhano’ (Sister’s Son / Nephew) and it was my favourite place to go as a child. I have my fondest memories of Bhuva, but could not visit for several decades, until when I was once at the Junagadh Campus of Gujarat Agricultural University, to inaugurate the International Conference on New Developments in Agriculture. Bhuva was not too far and I decided to go there. Soon as I reached, a familiar face, now aged with time, recognized me from a distance and with tears rolling from his old eyes (and mine) he hugged me, calling out “MaroBhano, MaroBhano” (My sister’s son, my sister’s son)! Now in his eighties, it was overwhelming to meet Nanji Ata, who I always remembered being wise, educated and cheerful. He was a relatively progressive farmer with about 6 to 7 acres of land, a few cows and a buffalo. Though water was scarce and saline, he managed to make a good living and was considered a well to do man.

7.1 Summary

Climate change is a complex global phenomenon that poses significant challenges for agriculture including uncertainty about future weather patterns, soil conditions, and other environmental factors. Farmers are facing the difficult task of interpreting and responding to these changes in order to maintain their livelihoods and ensure food security for growing populations. In this context, mental modelling has emerged as a useful approach for understanding how farmers interpret and respond to climate change. Mental models are cognitive representations of how individuals understand and make decisions about complex systems, and can be used to identify key drivers of behaviour and decision-making.

The present study has explored the social, ecological, and economic factors that influence farmers’ mental models on perception of climate change, level of uncertainty and trend of agricultural change in the selected study area. It argues that farmers’ mental models are shaped by a range of factors, including their own experiences and observations, social networks and interactions, access to information and resources, and broader economic and political contexts. The present study has also highlighted the role of uncertainty in shaping farmers’ mental models and decision-making. Uncertainty about the future impacts of climate change can create significant challenges for farmers, as they must make decisions based on incomplete information and uncertain predictions.

The current research work was carried out in the new alluvial zone which is one of the agro-ecological regions in the state of West Bengal. To conduct the study, three villages located in the Haringhata block of Nadia district were chosen randomly. A total of 90 farmers were selected with 30 respondents each from the villages of Kastadanga, JalkarBhomra and Subuddipur. Initially a list of contact farmers was collected from the Kastadanga SKUS and few contact farmers were selected randomly from the list. Afterwards Snowball sampling method was followed to select respondents.

7.1 Summary

Climate change is a complex global phenomenon that poses significant challenges for agriculture including uncertainty about future weather patterns, soil conditions, and other environmental factors. Farmers are facing the difficult task of interpreting and responding to these changes in order to maintain their livelihoods and ensure food security for growing populations. In this context, mental modelling has emerged as a useful approach for understanding how farmers interpret and respond to climate change. Mental models are cognitive representations of how individuals understand and make decisions about complex systems, and can be used to identify key drivers of behaviour and decision-making.

The present study has explored the social, ecological, and economic factors that influence farmers’ mental models on perception of climate change, level of uncertainty and trend of agricultural change in the selected study area. It argues that farmers’ mental models are shaped by a range of factors, including their own experiences and observations, social networks and interactions, access to information and resources, and broader economic and political contexts. The present study has also highlighted the role of uncertainty in shaping farmers’ mental models and decision-making. Uncertainty about the future impacts of climate change can create significant challenges for farmers, as they must make decisions based on incomplete information and uncertain predictions.