eChapters

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.

Enzymes are biological catalysts that regulate biochemical reactions and control metabolic pathways. This chapter explains how metabolomics can contribute to the discovery and functional characterization of enzymes by identifying changes in metabolite concentrations associated with enzymatic activity. Comparative metabolomics, gene knockout experiments, stable-isotope labeling, and multi-omics integration are discussed as approaches for linking metabolites with enzyme functions. Analytical platforms such as GC–MS, LC–MS, and NMR, together with databases including KEGG, BRENDA, HMDB, and METLIN, support metabolite identification and pathway analysis. The chapter also considers experimental validation, bioinformatics, challenges associated with unknown metabolites, and future applications involving artificial intelligence and computational biology.

Among various immunodiagnostic tools enzyme immunoassay becomes increasingly popular for the detection of humoral immune response (seroconversion) or microbial antigens for the purpose of diagnosis. Enzyme Linked Immunosorbent Assay (ELISA) is widely used in studies of infectious diseases.Despite several merits of ELISA, it has some limitations such as requirement of ELISA reader to obtain accurate measurements. To overcome this, the dot immunobinding assay was developed .In Dot Immunoassay nitrocellulose membrane is used as an adsorbent matrix instead of plastic surface.The antigen is dotted onto the nitrocellulose membrane and the membrane then incubated with test antibody, and secondly with enzyme conjugated antibody directed against the first antibody.In case of positve
reaction, (specific antigen –antibody reaction) color dot is developed against the white background at the site of antigen deposition.In case of negative reaction, no color development takes place at the site of antigen deposition .
Principle
• In direct ELISA antibody is directly attached to solid phase and targeted by added antigen (detecting antigen).
• These added antigens are targeted by antispecies antibodies linked to enzyme termed as conjugates.
• The bound enzyme is developed by the addition of substrate /chromogen, then stopped and finally read using a spectrophotometer

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.

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.

Natural Habitat
The bactrerium is widespread in nature and has been recovered from a wide variety of wild and domestic animals including mammals, fish (both fresh and salt water), birds, reptiles and amphibians. It is present in the soil and can survive for 20 days or longer in alkaline soil. The major source of infection for swine and turkeys is carrier animals of the same species. It is reported that 30-50% of pigs carry the bacterium in their tonsils, other lymphoid tissues. It is present in slurry of piglets and can be recovered from the faeces of carrier pigs.
Morpholgy
Erysipelothrix rhusiopathiae (previously named Erysipelothrix insidiosa) from S (Smooth) -form colonies and usually from acute syndromes is a grampositive rod, the R (rough) form colonies usually from chronic disease is a gram-positive filament. The organism is non-motile, non-spore forming, nonacid fast, capsulated occur either in singly, in groups or in chains.

Cultural Characters
It is a facultative anarobe, but growth is enhanced by 10% CO2. It is able to grow in a temperature range of 50C to 420C, within a pH range 6.7 to 9.2 and 8% NaCl2. Growth occurs on nutrient agar but is improved by the addition of serum or blood. It will not grow on Mac Conkey agar. Media contain either sodium azide (0.1%) or crystal violet (0.001%) may be used as selective media. On blood agar, non-haemolytic pinpoint colonies (0.5 mm) appear at 24hrs incubation. Colonial variation becomes obvious at 48hrs incubation when azone of greenish haemolysis often develops under and just around the colonies.
 

Escherichia coli is an important model organism for studying microbial metabolism, metabolic regulation, and metabolic engineering. This chapter introduces the use of metabolomics to investigate the metabolic architecture and physiological responses of E. coli. It examines metabolite profiling, central carbon metabolism, metabolic pathways, environmental responses, and metabolic flux analysis. The chapter explains how metabolomic data can reveal changes in cellular metabolism and support the identification of pathway bottlenecks and regulatory mechanisms. Applications in microbial biotechnology, recombinant production, metabolic engineering, and optimization of fermentation processes are considered. The chapter demonstrates how E. coli serves as a useful experimental system for connecting metabolite changes with cellular function.

Introduction
Escherichia coli (commonly abbreviated as E. coli) is a Gram-negative, facultative anaerobic, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms).
Escherichia coli are common inhabitants of the terminal small intestine and large intestine of mammals. They are often the most abundant facultative anaerobes in this environment. They can occasionally be isolated in association with the intestinal tract of non-mammalian animals and insects. The presence of E.coli in the environment is usually considered to reflect faecal contamination and not the ability to replicate freely outside the intestine.
Morphology
E.coli is Gram-negative, facultative anaerobic and non-sporulating. Cells are typically rod-shaped, and are about 2.0 micrometers (μm) long and 0.25- 1.0 μm in diameter, with a cell volume of 0.6–0.7 μm. It can live on a wide variety of substrates. Strains that possess flagella are motile. The flagella have a peritrichous arrangement. It is motile by peritrichous flagellae, though some strains are non-motile.Spores are not formed. Capsules and fimbriae are found in some strains.
Cultural Characteristics
Escherichia coli or E.coli cells may grow on a solid or in a liquid growth medium under a laboratory condition. Solid and liquid media may have exactly the same composition except that the solid medium contains an extra 1.5% agar. Different E.coli clones may have different properties. Colonies growing on solid media represent different clones. It is an aerobe and a facultative anaerobe. Optimal growth of E. coli occurs at 37°C (98.6°F) but some laboratory strains can multiply at temperatures of up to 49°C (120°F).

This chapter outlines fundamental molecular biology protocols essential for genomic analysis and molecular characterisation. Modern molecular biology relies heavily on precise analytical techniques for studying genetic material. Hence, this section presents a typical workflow encompassing nucleic acid extraction, amplification, and subsequent analysis. These methodologies are fundamental to various applications in molecular biology, including phylogenetic analysis, gene expression studies, and molecular diagnostics.
The chapter covers four core molecular biology and bioinformatics techniques, each building upon the previous:
1. Genomic DNA Extraction: Protocols for efficient isolation of DNA from biological samples. This encompasses cell lysis, protein denaturation, and nucleic acid purification through standard separation techniques. The quality and purity of extracted DNA significantly influences downstream applications.
2. Primer Design with Primer3: In silico design of oligonucleotide primers for PCR amplification. This section covers primer design parameters including optimal melting temperature (Tm), GC content, primer length, and considerations for avoiding secondary structures and primer-dimer formation.

At times, we hear our young generation questioning the need for obtaining degrees for conducting any research work. To some extend they are right. If we look back, there are many examples where persons without any former degree attained what is impossible by many degree holders. Tulsidas has written ‘Ramacharitmanas’, incorporating so many principles of Vedas and stories from Puranas without obtaining any degree. Srinivasa Ramanujan (21) narrated mathematics theorems without any degree in mathematics. His achievements may be appreciated by the fact that we celebrate his birthday 22nd December as National Mathematical day.

Mycotoxins are toxic secondary metabolites produced by different types of moulds which are present in soil, plant and feed ingredients. Ingestion of toxins will result in reduced growth and production performance due to reduced nutrient utilization, illness or death of animals. Analysing the presence of mycotoxin and its concentration in grain and feeds is necessary to eliminate the adverse health effects of mycotoxins in animals. Estimation of mycotoxin in feed ingredients is a challenging task because the concentration of toxin is at µg/kg or parts-per billion levels. At the same time, analysing inappropriate samples is a waste of resources. Mycotoxins are not evenly distributed in feeds or grains. If the specimen collected for analysis includes contaminated grain, the mycotoxin will be detected. If not, the mycotoxin will not be detected.

Sample collection for mycotoxin analysis

The objective of sample collection is to collect the specimen samples from as many parts of the feed lot as possible. The size of the collected specimen depends on the size of the load received. Sample collecting probes can be used to collect the samples from bags.

AI-enabled livestock technologies can improve productivity, health monitoring, animal welfare and environmental performance, but they also raise significant ethical and governance concerns. This chapter examines data ownership, privacy, algorithmic bias, transparency, accountability, cybersecurity, socioeconomic inequality and animal well-being. Precision livestock systems continuously monitor animals through sensors, computer vision, machine learning and IoT networks, enabling preventive decisions and automated interventions. However, excessive dependence on algorithms may reduce human oversight and treat animals merely as data-producing units. The chapter advocates an interdisciplinary framework for responsible AI that aligns innovation with animal-welfare standards, farmer interests, social values, equitable access, regulatory requirements and long-term environmental sustainability.

Collection of blood Blood sample should be collected in a capped clean and dry vial containing an appropriate amount of anticoagulant. The commonly used anticoagulants are ethylene diamine tetra acetic acid (EDTA) @ 1-2 mg/ml and heparin @ 5 I.U./ ml of blood. Sites for blood collection Before collection of blood clean the site of collection by applying some antiseptic solution. If the area is hairy shaving of the site under aseptic condition should be done. Tip of the ear should be preferred for prompt or early diagnosis of haemoprotozoan infections. The vein can then be punctured with hypodermic needle and the collected blood is transferred to a clean glass vial. For collection of blood various preferred sites in different animals are as under

12.1 Assays for molecular diagnosis of Acute Myeloid Leukaemia (AML)

Acute Myeloid Leukaemia (AML), also known as Acute Myelogenous Leukaemia or Acute Myeloblastic Leukaemia or Acute Granulocytic Leukaemia or Acute non Lymphocytic Leukaemia is an aggressive type of cancer which affects blood and bone marrow. AML is a heterogeneous disorder if one considers its clinical status, therapeutic responses and overall prognosis.¹ This disease called acute because it progresses very fast and myeloid as it originates from myeloid cell line in the bone marrow.

In bone marrow blood cells are made in a controlled way. When AML occurs excess numbers of immature leukaemia cells are produced. Overproduction of leukaemia cells in bone marrow disables bone marrow to make mature white blood cells. These accumulated immature cells are unable to function properly (Inability to fight infection).

Diagnosis: Correct diagnosis is important for a successive treatment for AML. There are several tests available to diagnose AML but not all tests will be used for each person. The following tests may be used to diagnose AML.

Introduction
This method consists of mixing the microorganisms in a small amount of India ink or nigrosine and spreading the mixture over a clean slide. These two pigments are not really bacterial stain and do not penetrate the microorganisms. These pigments make the background dark thus making organisms transparent against dark background. This method is useful for determining cell morphology and accurate size as no shrinkage of cells due to heat.
Materials
1. Bacterial culture (B. subtilis)
2. Microscopic slides (Clean, Grease Free)
3. Inoculating needle
4. Cedar wood oil
5. Microscope
6. Xylene

Introduction
Antimicrobial resistance (AMR) is rapidly emerging as one of the most critical global health challenges of the 21st century. Antimicrobial resistance can be defined as a condition in which microbes develop resistance against the spectrum of conventional antibiotics, also known as multidrug resistance and these microbes are typically known as drug-resistant pathogens. The infections associated with antibiotic resistant pathogens are usually accompanied by substantial morbidity and mortality along with the massive economic burden on global healthcare, which causing approximately 4.95 million deaths globally each year. The prevalent issue is largely attributed to the repercussions of antimicrobial overuse or irresponsible utilization across diverse contexts, predominantly in clinical treatment, agricultural practices, animal healthcare, war crisis and the food system and a lack of regulation in their supply. Nature has long been a rich reservoir of biologically active compounds with diverse chemical structures and pharmacological properties, offering valuable resources for treating a wide array of diseases. In recent years, the rising threat of antimicrobial resistance has renewed global interest in natural products as promising sources for novel antimicrobial agents. Among these, plant-derived phytochemicals, microbial metabolites, marine bioactive compounds, and animal-based substances have shown significant potential in combating drug-resistant pathogens. These natural compounds exhibit unique mechanisms of action that can overcome existing resistance pathways, making them important candidates in the development of nextgeneration antibiotics. From alkaloids and flavonoids in medicinal plants to secondary metabolites produced by actinomycetes, antimicrobial peptides from animals, and complex molecules derived from marine organisms, nature offers a vast and largely untapped arsenal of antimicrobial agents. Exploring and harnessing these natural resources presents a sustainable and innovative strategy to address the growing global crisis of antimicrobial resistance. The enormous potential of natural products in the fight against antibiotic resistance is examined in this chapter. The different kinds of bioactive chemicals, their modes of action, and the creative approaches being used to maximize their medicinal potential are highlighted.
Challenges in Addressing AMR with Conventional Methods
1. Weak Implementation of National Action Plans: Only a small percentage of the more than 170 nations that have created AMR action plans have operationalized them with specialized financing and monitoring mechanisms. This leads to a gap between policy and practice, especially in low- and middle-income nations.
2. Restrictions in the Management of Antimicrobials: Lack of qualified staff, insufficient microbiological assistance, and shoddy governance frameworks are some of the common obstacles that antimicrobial stewardship initiatives must overcome. Due to the lack of quick diagnosis, broad-spectrum antibiotics are still empirically used in many hospitals.
3. Diagnostic Barriers: Rapid diagnostic methods are still few, and traditional culture-based susceptibility testing is sluggish. Resistance selection is accelerated by this diagnostic latency, which frequently forces physicians to use broad-spectrum empirical treatment.
4. Surveillance Gaps: Despite the growth of programs like the Global Antimicrobial Resistance and Use Surveillance System (GLASS), data quality and surveillance coverage are still uneven. The inability of many nations to track resistance in important diseases compromises prompt policy responses.
5. Limited Innovation in Drug Development: Only a few new types of antibiotics are now in advanced clinical development, making the pipeline still rather thin. Under the present traditional paradigm, pharmaceutical innovation is discouraged by market failure due to low return on investment.

A. Gram’s Staining
Introduction
The most widely used staining procedure in microbiology is the Gram stain, discovered by the Danish scientist and physician Hans Christian Joachim Gram in 1884. Gram staining is a differential staining technique that differentiates bacteria into two groups: gram-positives and gram-negatives. The procedure is based on the ability of microorganisms to retain color of the stains used during the gram stain reaction. Gram-negative bacteria are decolorized by the alcohol, losing the color of the primary stain, purple. Gram positive bacteria are not decolorized by alcohol and will remain as purple. After decolorization step, a counterstain is used to impart a pink color to the decolorized gramnegative organisms.
The Gram stain procedure enables bacteria to retain color of the stains, based on the differences in the chemical and physical properties of the cell wall.
1. Gram positive bacteria: Stain dark purple due to retaining the primary dye called Crystal Violet in the cell wall. Example: Staphylococcus aureus
2. Gram negative bacteria: Stain red or pink due to retaining the counter staining dye called Safranin

As the Veterinary colleges, and Parasitology being an integral part of them, are part of Agricultural universities framed on USA land grant pattern, or separated as Veterinary university imbibing the same philosophy, extension is an integral part of the system. Here, a team of the experts visit the villages to teach the villagers about the basic problems, faced by them in day to day dealing with animals. For explaining a particular problem to the villagers, the experts generally take help of the pamphlets which they have prepared. These pamphlets or extension literature deal the subject with common sense and illustrate the material with line drawings.