eChapters

Anti-transpirants are usually foliar sprays, although they may sometimes be used more conveniently as dips for immersing the above ground plant parts. Foliar sprays may reduce transpiration in three different ways

1. Introduction

The discovery and development of antibiotics have led to dramatic improvement in the ability to treat infectious diseases with emergence of drug – resistant organisms due to irrational and overuse of antibiotics, failure to complete a course of treatment, genetic versatility of microbes and horizontal transfer of resistant genes among bacterial species had led to antibiotic resistance (Amit and Shailendra, 2006; Aibinu, 2007).The need for alternative antimicrobial agents has renewed the interest on plants as a sources of antimicrobial agents due to their use historically and the fact that a good portion of the world’s population, particularly in developing countries, rely on plants for the treatment of infectious and non-infectious diseases.
 
Syzygium aromaticum

Clove (Syzygium aromaticum) is the aromatic dried flower buds of a tree in the family Myrtaceae. The traditional use indicates that Clove has several therapeutic properties, such as an aphrodisiac, stomach, carminative, nervous stimulant and tonic. Reports has been documented  on their aphrodisiac, antibacterial, antifungal, nematocidal, anti-toothache, anti-oxidant, analgesic, anesthetic and hypotensive properties. Although in Iranian traditional medication several formulation containing clove have been used as a nervous stimulant and cognitive enhancer. (Mohammad, et al., 2009).

Introduction
The discovery and widespread use of antibiotics in the mid-20th century marked a transformative era in modern medicine, enabling life-saving interventions in surgery, transplantation, and critical care. Diseases once considered fatal became manageable, and the global burden of infectious diseases significantly declined. However, the remarkable success of antibiotics has been increasingly overshadowed by the rapid rise of antimicrobial resistance (AMR), now recognized by the World Health Organization (WHO) as one of the most serious threats to global health, food security, and sustainable development. Resistant infections already contribute to longer hospital stays, increased healthcare costs, and elevated mortality rates. Alarmingly, if current trends continue, AMR-related deaths are projected to exceed those caused by cancer by 2050.A pivotal yet often underestimated factor in the persistence and spread of AMR is the formation of microbial biofilms. Biofilms are highly organized, surface-attached communities of microorganisms embedded in a self-produced extracellular polymeric substance (EPS) composed of proteins, polysaccharides, lipids, and nucleic acids. This matrix not only anchors microbial population but also confers protection against environmental stressors, immune responses, and antimicrobial agents. Bacteria within biofilms can withstand antibiotic concentrations up to 1000 times higher than their planktonic counterparts due to altered metabolic states, enhanced horizontal gene transfer, and activation of resistance mechanisms such as efflux pumps. Biofilms are implicated in over 80% chronic and device-associated infections, including those caused by ESKAPE pathogensAcinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus. These infections are notoriously difficult to treat and often recur, posing significant clinical challenges. Beyond healthcare settings, biofilm formation in livestock and agricultural environmentsexacerbated using antibiotics as growth promoterscontributes to the emergence of resistant strains that can spread to humans via direct contact, environmental contamination, or the food chain.Understanding the multifaceted resistance mechanisms within biofilms is essential for developing effective containment strategies. These include physical exclusion of antibiotics by the EPS matrix, metabolic dormancy, persister cell formation, quorum sensing-mediated coordination, and stress response activation. Moreover, biofilms often consist of multispecies communities, where interspecies interactions further enhance resilience.In response, antibiofilm agents have emerged as a promising frontier in AMR containment. These include natural compounds (e.g., antimicrobial peptides, essential oils), engineered materials (e.g., nanoparticles, surface coatings), quorum sensing inhibitors, efflux pump blockers, and enzymatic disruptors such as dispersin B and DNases. Ecological approaches like probiotics and positive biofilms offer preventive strategies in agriculture and food systems. Importantly, these agents aim to complement antibiotics by enhancing their efficacy rather than replacing them.Despite challenges in scalability, safety, and regulatory approval, antibiofilm strategies represent a paradigm shift in infection control. Their integration into clinical, veterinary, and environmental practicesaligned with the One Health frameworkis essential for preserving antibiotic effectiveness and mitigating the global AMR crisis.

Poultry has grown significantly over the last few decades; nevertheless, as production has increased, the usage of specific medications and feed additives has become essential for illness prevention, treatment, and growth promotion. Around the world, broiler chickens are regarded as one of the main sources of meat. Poultry consumption has increased by more than 100% in the last few decades, from 13% of total meat consumption in 1965 to 28% in 2015. All around the world, but especially in emerging and Asian nations, there is a growing need for chicken meat. The amount of poultry meat consumed worldwide increased from 11 kg per person in 2000 to 14.4 kg in 2011, with predictions that it will reach 17.2 kg per person by 2030.

Introduction

In 1928, Alexander Fleming, a Scottish bacteriologist, made a significant observation while studying bacterial cultures. He noticed that colonies of bacteria on a culture plate had been negatively impacted by the presence of a mold called Penicillium notatum, which had accidentally contaminated the culture. Around a decade later, a team of researchers including British biochemist Ernst Chain and Australian pathologist Howard Florey successfully isolated the active compound responsible for this effect and named it penicillin (Lalchhandama, 2021).

Introduction
The discovery of antibiotics in the early 20th century revolutionized medicine, agriculture, and public health. These compounds, capable of inhibiting or destroying pathogenic bacteria, not only saved millions of human lives but also transformed animal production systems by reducing morbidity and mortality, improving growth rates, and ensuring food security (Phillips et al., 2004). The application of antibiotics in food animals,whether for therapeutic, prophylactic, or growth-promoting purposes,has been instrumental in increasing global meat, milk, egg, and fish production, thus addressing the nutritional needs of a growing population (Darwish et al., 2013; Chen et al., 2019). However, the indiscriminate and excessive use of antibiotics in animal agriculture has created unintended consequences, most notably the presence of antibiotic residues in foods of animal origin and the global acceleration of antimicrobial resistance (AMR) (Bacanli & Basaran, 2019; Shahid et al., 2021). Antibiotic residues in food is the trace amounts of active compounds or its metabolites that remain in edible animal tissues, milk, eggs, and aquaculture products causes significant concerns for both consumer safety and public health. Even when below the maximum residue limits (MRLs) established by regulatory authorities, prolonged exposure may lead to allergic reactions, disruption of the gut microbiome, reproductive and developmental toxicity, mutagenicity, nephropathy, and in certain cases carcinogenicity (Ngangom et al., 2019; WHO, 2020). Furthermore, residues contribute to the selection pressure that drives the emergence and dissemination of resistant bacterial strains in humans, animals, and the environment (FAO, 2019; O’Neill, 2016). The One Health framework highlights these interconnected pathways, recognizing food as a critical link between veterinary antibiotic use and human AMR burden (Robinson et al., 2016). Globally, approximately 73% of antibiotics are consumed in food animal production, with projections estimating a further 11–67% increase by 2030,largely by intensification of livestock and aquaculture in developing economies (Van Boeckel et al., 2015; Tiseo et al., 2020). While industrialized nations have implemented bans on antibiotic growth promoters and introduced robust surveillance programs, most low- and-middle-income countries still facing challenges (Antibiotics, 2021; WHO, 2019). Consequently, foods containing antibiotic residues frequently enter local and international markets, undermining food safety standards and exacerbating AMR risks (Darwish et al., 2013; Antibiotics, 2021). Antimicrobial resistance (AMR) has emerged as a major global public health crisis, directly causing an estimated 1.27 million deaths and contributing to nearly 5 million deaths worldwide in 2019. Recognizing its severity, the World Health Organization (WHO) has identified AMR as one of the top ten threats to global health(Murray et al., 2022). By 2050, global economic losses linked to AMR are projected to reach USD 100–210 trillion, with Asia bearing a disproportionate mortality burden (O’Neill, 2016). Countries like India, with large livestock populations, rapidly growing aquaculture industries, and high human antibiotic consumption, represent critical hotspots where food, health, and environmental risks intersect (Chauhan et al., 2018; ICMR, 2020). Given these alarming trends, understanding the occurrence, detection, and consequences of antibiotic residues in foods of animal origin is paramount. This chapter explores the co-relationship between origin of antibiotic residues and AMR, regulatory measures aimed to safeguard food safety and strategies for prevention and control, framed within the One Health approach.

Antibiotics are substances which are produced by micro-organisms and which act against micro-organisms. It is also defined as secondary metabolites produced by microorganism, which inhibits the growth of another microorganism. Most antibiotics known uptill now are products of actinomycetes and some are from fungi and bacteria. The use of the antibiotics in managing plant diseases, particlulaty the disease caused by bacteria, mycoplasma and ricketsia, is well demonstrated and are thought to be effective means because of their selective action directed towards causal agents not to the infected host. The mode of action of the antibiotics varies depending on site of action which in turn detrmines their specificity towards given target host (Table 12). Some time mixture of antibiotics are in practice in managing the diseases to reduce delay the chances of resistance development against a particular antibiotic by the causal agent. The most useful antibiotic mixture is streptocycline, which contains streptomycin and tetracycline.

1.    ———— is a synthetic antimicrobial drug against M. tuberculosis.
    A.    Penicillin    B.    Tetracycline
    C.    Erythromycin    D.    Isoniazid
Ans.    D.
2.    Which of the antibiotic is not used as a food preservative ?
    A.    Pimaricin    B.    Nisin
    C.    Tylosin    D.    b-lactam antibiotic
Ans.    D.
3.    Which of the following bacteria is susceptible to thiophen-2-carboxylic acid hydrazide?
    A.    M. bovis    B.    M. tuberculosis
    C.    M. chelonei    D.    M. fortuitum
Ans.    A.

Feed accounts for a major portion of farm expenses in livestock and poultry production. Thus, to obtain maximum profitability, it must be ensured that the feed should not only be well balanced nutritionally but economical too. Rising prices of feeds certainly have reduced the profitable nature of broiler farming. For better utilization of feed and to improve feed efficiency, antibiotics were used at sub-therapeutic levels in the animal ration.

Development of antibacterials progressed very quickly and as a result, certain new antibacterial substances were discovered and developed for use as growth promoting agents in livestock and poultry. The antibiotics act by reducing nutrient destruction in the intestine, increasing microbial synthesis of certain vitamins and amino acids, reducing the rate of passage of nutrients in the gastrointestinal tract and reducing the thickness of the intestinal wall. This thinner wall and reduced rate of passage have been suggested as factors favoring efficient absorption of nutrients. It is also reported that the antibiotics also inhibit the bacterial production of ammonia and other harmful nitrogenous compounds such as trimethylamine that reduce the growth of chickens.

Antibodies, also called immunoglobulins, are the proteins produced by the immune system against antigens. These are the protective proteins which interact with antigens and neutralize their effects. Antibodies are produced by B lymphocytes. An immunoglobulin has a Y-shaped structure consisting of four polypeptide chains.

Antibodies are a group of glycoproteins having a globular compact structure. They are known as immunoglobulins. On the basis of their experiments, Tiselius and Kabat, in 1939, demonstrated that most antibodies are found in the g globulin fraction of serum proteins. When serum from rabbit, immunized with ova albumin, was subjected to electrophoresis, it showed a peak for g globulin (Fig. 4.1). Studies have revealed that the major part of IgG is found in the g globulin fraction of the serum proteins. Other fractions, a and b, too, have other immunoglobulins along with small part of IgG.

Introduction

Development and standardisation of diagnostics for aquaculture health management have undergone great improvements over the last three decades. Diagnosis in aquaculture health management involves several stages starting from farm-level observations to conventional laboratory identification and histopathology to sophisticated modern molecular tools. Accordingly, diagnosis can be broadly categorised under three levels depending on the level of scientific development.

1. level-I detection system, farm site observation and record-keeping;

2. level-II system, conventional laboratory identification employing microbiology, parasitology, and histopathology and

3. level-III system, advanced and specialized immunological and biomolecular techniques.

The interaction of an antibody with an antigen forms the basis of all immunochemical techniques. Antibody binds specifically to an antigen at epitope or antigenic determinant level and this property has been used for development of immunodiagnosis. Furthermore, as antibodies react with antigen at ambient conditions and do not require sophisticated equipment ideal field test kits can be developed. Biomolecular tools using nucleic acid probes although very sensitive are costly and time-consuming requiring sophisticated equipment and trained personnel. Against this background, there is always a need for developing simple, low-cost, rapid yet sensitive farm- level diagnostics. Such field-level tests facilitate screening a large number of samples by a large number of poor and medium-sized farmers who constitute a majority in developing countries. Large-scale screening besides empowering farmers is considered to be ideal for effective health management. Antibody probes provide an ideal format for developing simple field-level diagnostics as antigens ideally react with antibodies at ambient conditions without requiring sophisticated equipment. Available technology for raising large quantities of monoclonal antibodies (MAbs) against pathogens has increased the scope for developing field detection kits in human, animal and agricultural health management. Several farmer-friendly detection systems also referred to as point-of-care (POC) detection method based on antibodies have been innovated in the recent past. POCT is defined as ‘medical diagnostic testing at the time and place of patient care.

A. Answer the following.

Q.1.     What is the percentage of different subclasses of IgG in the serum ?
Ans.     IgG1 : 65 ; IgG2 : 24 ; IgG3 : 7 ; IgG4 : 4

Q.2.     How many inter heavy chain bonds are there in different subclasses of IgG ?
Ans.     IgG1 : 2 ; IgG2 : 4 ; IgG3 : 13 : IgG4 : 2.

Q.3.     What is the half life of different subclasses of IgG ?
Ans.     IgG1, IgG2 and IgG4 : 23 days ; IgG3: 8 days.

ABSTRACT

Three medicinal plants namely, Eryngium foetidum (Apiaceae), Centella asiatic (Apiaceae) and Hemidesmus indicus (Asclepiadaceae) were collected from Similipa Biosphere Reserve forest and used in this investigation. Ethanolic, methanolic chloroform and aqueous extracts of different parts like leaf, root and stem were prepare through standard techniques and screened for their anticandidal potencies agains Candida albicans, C. tropicalis and C. krusei. Anticandidal activity of the extracts wer tested using preliminary and secondary screening methods, like disc diffusion metho (DDM) & agar-cup-plate-method (ACPM) and poisoned food technique (PFT respectively. On an average the inhibitory tendency of the extracts can be arranged as ethanolic extracts > methanolic extacts > chloroform extracts > aqueous extracts Maximum degree of inhibition was observed against C. krusei. Among the plant Hemidesmus indicus showed better anticandidal activities in comparison to other tw plants tested.

Foods are classified into three groups on the basis of ease of spoilage. Spoilage meant a condition produced by the excessive growth of microorganisms leading gradually to decay or decomposition. The stable or non perishable foods like sugar, flour, grains and dry products do not ordinarily spoil unless handled carelessly. The semi-perishable food like potatoes, onions, apples, waxed fruits, fruits and vegetables having thick skin can be protected from spoilage if properly handled and processed. The perishable foods, like livestock products, seafood, and poultry items, dairy products, and most fruit and vegetables spoil readily unless special preservatives methods are used. The spoilage of foods may be caused by molds, yeast, bacteria, enzymes, food constituents and insects. The use of food additives have become necessary to prevent spoilage other wise caused by the growth of bacteria, yeasts and molds.

Food spoilage usually refers to undesirable changes occurring in food due to the action of micro-organisms, insects and enzymes. The original nutritional value, texture, flavour of the food are damaged, the food become harmful to people and unsuitable to eat. Today however, preservation has used such factors as temperature, water activity, pH, gases, organic acids, salts, antibiotics, irradiation, packaging and various combinations of these factors. Foods vary greatly in the length of time for which they can be held in their natural form without spoilage. Preservatives retard product spoilage caused by mold, air, bacteria, fungi or yeast. Bacterial contamination can cause food-borne illness, including life-threatening botulism.

A. Answer the following.

Q.1.     What is the difference between cell wall of Gram positive and Gram negative bacteria ?
Ans.     The cell wall of Gram positive bacteria is largely composed of peptidoglycans. These are chains of alternating N-acetylglucosamine and N-acetylmuramic acid cross linked by short peptide side chains. On the other hand, the cell wall in Gram negative bacteria has thinner peptidoglycan layer, an outer membrane composed of a polysaccharide-lipid-protein structure. The oligosaccharide attached to a lipid (lipidA) and a series of repeating trisaccharides. The polysaccharide antigens are called ‘O’ antigens. The cell wall lipopolysaccharides of Gram negative bacteria are also called endotoxins.

The interactions between antigens and antibodies are specific in nature in which an antibody recognizes an antigen through complementarities of shapes on paratope and epitope. An antigen reacts only with antibodies produced by itself or with closely related antigens. The reaction is similar to a lock and key. As a standard lock can be opened by its own key only similarly, an antibody can react only with its own antigen. Antibodies recognize molecular shapes (epitopes) on antigens.

Antigen-antibody interaction is very specific one in which an antibody recognizes an antigen through complementarities of shapes on paratope and epitope.  It is like lock and key, as occurs in case of enzyme-substrate reaction. It does not involve covalent linkage rather a spatial complementarity occurs between antigen and antibody. For example, when antibodies, raised against m-amino benzene sulphonate, are tested for their ability to bind with ortho-, meta- and para-isomers of the hapten, the antibodies show highest strength with meta than ortho- isomer.  Antibodies show poor reactivity with para isomer. This is because though chemically all these molecules are same but structurally they are different.

When the body is exposed to a microbe or a foreign substance, the body makes some response which is called immune response. Immune responses are initiated by the interaction between a ligand, present on the surface of the microbe or secreted by the microbe or a foreign substance, and a receptor protein on the cell’s surface or a soluble receptor. There are several factors such as shape, charge and presence of other receptors which influence this interaction between the ligand and receptor. This ligand which is recognized by the immune system is called antigen. An antigen can be defined as an organism, a molecule, or part of a molecule which is recognized by the immune system. Often, the term immunogen is also used for antigen. Though, antigen and immunogen are used as synonyms but specifically, they are different from each other.

The main purpose of the immune system is to protect the body from foreign substances, diseases or infections. When the body is exposed to a microbe or a foreign substance (antigen), the body makes some response which is called immune response. The purpose of immune response is to recognize, neutralize and eliminate the antigens from the body. Generally, the term immunogen is also used for antigen. Both, antigen and immunogen are used as synonyms but specifically, they are different from each other.