eChapters

I. WALL COMPONENTS – CHEMISTRY

The main ingredient in cell walls are polysaccharides (or complex carbohydrates or complex sugars) which are built from monosaccharides (or simple sugars). Eleven sugars are common in these polysaccharides including like glucose and galactose. Carbohydrates are good building blocks because they can produce a nearly infinite variety of structures. There are a variety of other components in the wall including protein, and lignin. Let’s look at these wall components in more detail:

A. Cellulose: β1,4-glucan (structure provided in class). Made of as many as 25,000 individual glucose molecules. Every other molecule (called residues) is “upside down”. Cellobiose (glucose-glucose disaccharide) is the basic building block. Cellulose readily forms hydrogen bonds with itself (intra-molecular H-bonds) and with other cellulose chains (inter-molecular H-bonds). A cellulose chain will form hydrogen bonds with about 36 other chains to yield a microfibril. This is somewhat analogous to the formation of a thick rope from thin fibers. Microfibrils are 5-12 nm wide and give the wall strength - they have a tensile strength equivalent to steel. Some regions of the microfibrils are highly crystalline while others are more “amorphous”.

Cell mediated immune response (CMI) is the major defense mechanism against intracellular microbes and tumor cells. It is mediated mainly by T lymphocytes. T cells originate in bone marrow but the maturation of T cells occurs in thymus.

Cell mediated immune response performs different functions in protecting the immune system. When antigens are destroyed by cells, without producing antibodies, the immunity is called cell-mediated immunity (CMI) or cellular immunity. In this immunity T cells play a major role. The principal role of cell mediated immunity is to detect and eliminate the cells that have intracellular pathogens. When the antigen remains inside the cell the antibody cannot handle them. The intracellular pathogens are controlled by cell- mediated immunity. CMI is invited by the recognition of antigens by T cells. T cell lymphocytes recognize protein antigens of intracellular microbes that are displayed on the cell surface of infected cells. It is also important for elimination of cells which express foreign MHC molecules. Antigen specific and nonspecific cells can contribute to the cell-mediated immune response. The activities of both specific and non-specific components usually depend on effective local concentration of cytokines.

This chapter describes the cells, tissues and organs responsible for immune defence. It examines lymphocytes, macrophages, dendritic cells, neutrophils, mast cells, natural killer cells and plasma cells, emphasizing their respective functions. Primary and secondary lymphoid organs—including bone marrow, thymus, bursa of Fabricius, spleen, lymph nodes and mucosa-associated lymphoid tissue—are discussed. The chapter also covers lymphocyte maturation, antigen presentation, phagocytosis, immune-cell surface markers and the organization of lymph-node regions. Positive and negative selection of T lymphocytes and the formation of memory cells are included. Together, these topics explain how immune components develop, communicate and coordinate effective responses against infectious agents.

Cells are the Working Units of Life

With the possible exception of viruses, every form of life on Earth either is a cell or composed of cells. All cells come into existence through the activity of other cells.

All Cells are either Prokaryotic or Eukaryotic

All cells can be classified as prokaryotic or eukaryotic. All plants, animals, fungi, and protists are either single eukaryotic cells or are composed of eukaryotic cells. Prokaryotic cells are either bacteria or archaea. Eukaryotic cells have most of their DNA contained in a membrane-lined nucleus, whereas prokaryotic cells do not have a nucleus. Eukaryotic cells also have more specialized structures, called organelles, than do prokaryotic cells. All prokaryotes are single-celled, whereas many eukaryotes are multi-celled.

The Eukaryotic Cell

There are five principal components to the eukaryotic animal cell: the nucleus, other organelles, the cytosol, the cytoskeleton, and the plasma membrane. Organelles are “tiny organs” within the cell that carry out specialized functions, such as energy transfer and material recycling. The cytosol is the fluid in which these organelles are immersed (The cytoplasm is the region of the cell inside the plasma membrane but outside the nucleus.) The cytoskeleton is composed of several groups of proteins that give the cell support and facilitate transportation of cellular elements. The plasma membrane is the chemically active outer boundary of the animal cell. Plant cells have a plasma membrane that has, outside of it, a cell wall.

Introduction

Robert Brown discovered the nucleus in some plant cells in 1831. After analyzing tissues from a range of animals and plants, T. Schwann (1839) declared, “All living organisms are composed of cells.”

The fundamental elements of Prokaryotic and Eukaryotic cells

The simplest cells, called prokaryotic cells, have a straightforward structural arrangement. There is only one membrane system in it. They contain rickettsia, spirochete, mycoplasma, virus, blue-green algae, and bacteriablue-green algae, or cyanobacteria are the largest and most intricate prokaryotes, where higher plant photosynthesis occurs and have changed throughout time.

Prokaryotic cells

Prokaryotic cells range in size from 1 to 10 µm. They take place in a range of formats. A bacterial cell is made up of three basic parts:

I. External layer: It is composed of the inner cell or plasma membrane, middle cell wall and outer slimy capsule.

a. Cell membrane: The thin, flexible membrane of the cell, composed of proteins and lipids, regulates the flow of chemicals throughout the cell. It carries respiratory enzymes for reactions that release energy. Respiratory enzymes are found in mesosomes, which are folded regions of the plasma membrane that are compared to the mitochondria in eukaryotic cells. Similarly, the pigments and enzyme molecules found in photosynthetic cells are linked to the in-folds of the plasma membrane known as photosynthetic lamella, which is responsible for absorbing light and converting it into chemical energy.

b. The cell wall: It is the non-living, semi-rigid layer that encloses the cell membrane, with a thickness that varies from 1.5 to 100 µm. It is chemically made up of peptidoglycans. Certain bacteria, such as mycoplasma, don’t have cell walls.

A cellular phone is also known as a mobile phone, cell phone, portable phone and a hand phone. It is a device that can make and receive telephone calls over a radio link while moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile phone operator, allowing access to the public telephone network.

The cell phone was invented by Dr. Martin Cooper who led a team of developers at Motorola and made the first cell phone call in April 3, 1973 at Motorola.

Today, cell phones are becoming capable of doing almost anything a computer is capable to do. Below, are few examples of what a phone can do?

Introduction
Embryogenesis begins with the fertilization of the oocyte by the sperm, leading to the formation of a zygote. This single cell undergoes a series of highly regulated mitotic divisions known as cleavage, forming a multicellular structure called the blastocyst. As the blastocyst implants in the uterine wall, the cells continue to divide and differentiate into the three primary germ layers: the ectoderm, mesoderm, and endoderm. Each of these layers gives rise to specific tissues and organs, controlled by genetic instructions and cellular signalling mechanisms.One of the most critical aspects of embryogenesis is the intricate interplay of cellular signalling pathways and genetic mechanisms, which regulate the precise growth and differentiation of cells into tissues and organs. Understanding these mechanisms not only helps in comprehending normal embryonic development but also in diagnosing and treating developmental disorders in veterinary practice.
Cellular Signalling in Embryonic Development
Cellular signalling is a fundamental process in embryogenesis that ensures cells communicate with each other to perform specific tasks. The coordination of cell proliferation, differentiation, migration, and apoptosis (programmed cell death) is essential for the proper formation of tissues and organs.
Types of cell signalling
1. Short range signalling: It involves communication within a cell as well as between nearby cells. This includes:
a) Paracrine signalling: where a cell releases signals that affect neighbouring cells.
b) Autocrine signalling: where a cell sends signals to itself, affecting its own behaviour.

Introduction

The smallest, most basic, most primitive organisms are known as prokaryotic (Greek: pro= primitive or prior, and karyon = nucleus). Likely, they originated around 3.5 billion years ago. Bacteria, such as Mycoplasma and Cyanobacteria, are known to contain these cells. A prokaryotic cell is a deeply organized single-enveloped system. Its constituent nuclear parts are encased in a plasma membrane, with the cytoplasmic ground substance encircling the center. Prokaryotic cells’ cytoplasm lacks distinct cytoplasmic organelles, the nuclear envelope, and any other cytoplasmic membrane.

Despite being incredibly thin and delicate structures, in Eukaryotes plasma membranes are essential to many of a cell’s most vital processes. Membranes are lipid-protein assemblages where non-covalent linkages hold the constituents in place in a thin sheet. Both integral protein and phospholipid lateral mobility are significantly impacted by the physical condition of the lipid bilayer. The plasma membrane is a selectively permeable barrier that permits solute passage via assisted diffusion, active transport, and simple diffusion via membrane channels or the lipid bilayer. A system of membrane organelles, such as the endoplasmic reticulum, Golgi complex, and lysosomes, is found in the cytoplasm of eukaryotic cells. These organelles are physically and functionally connected to the plasma membrane and one another. The cytoplasm is separated into a luminal region inside the ER membranes and a cytosolic space outside the membranes by the endoplasmic reticulum (ER), a network of tubules, cisternae, and vesicles. Additionally, the ER is where the majority of a cell’s membrane lipids are generated and transported to different locations. Proteins’ asparagine residues are added with sugars (a process known as glycosylation), which starts in the rough ER and continues in the Golgi complex.

Estimation of Cellulose in Feeds and Fodders
Principle

The feed well ground is digested with acetic acid which dissolves all other constituents like protein, disaccharides, fatty acids, etc., and cellulose and mineral contents are unaffected. The residue is made acid and alcohol free by washings. Alcohol removes water, benzene removes pigments and fat and at the end the sample is dried and ashed. The difference between the dried weight before ashing and weight after ashing gives cellulose content of the feed sample.

Centesis is a surgical puncture or perforation into body cavity or structure usually done to aspirate fluid, air or tissue. The medical purpose of puncturing body cavities is not only to obtain fluid sample for diagnostic purpose but also to remove excessive fluid for therapeutic purpose for alleviating the respiratory distress owing to excessive fluid accumulation in peritoneal cavity, pleural cavity or pericardial sac. This procedure is usually done to get fluid from abdominal cavity, thoracic cavity, pericardial sac or joint capsule and is aptly known as abdominocentesis, thoracentesis, pericardiocentesis or arthrocentesis respectively.

Brain

The brain, a command centre of the body, is a complex organ. The substance of the brain is made of the grey matter and the white matter. The grey matter is often identified as cerebral cortex but other parts of the brain also contain the grey matter. Inside the brain, the grey matter is organized into large accumulations of neurons which are called the nuclei of the brain. Each nucleus is associated with a specific function. In addition to neurons, there is other type of cells the glial cells called neuroglia. The neurons are responsible for sending and receiving impulses or signals. The glial cells are nonneuronal and provide support and nutrition to neuronal cells, form myelin and facilitate signal transmission in the nervous system. The white matter is made of millions of nerve fibres that are coming from neurons and are going to establish communications with different parts of the brain and spinal cord. Since these nerve fibres are coated with myelin sheath around them these appear white and the area occupied by these nerve fibres become the white matter of the brain.

The brain has three basic components, the forebrain, midbrain and the hindbrain.

Fore brain: The forebrain (Prosencephalon) is the rostral portion of the brain. It consists of cerebrum (Telencephalon) and the thalamus, hypothalamus and pineal gland together constituting the interbrain (Diencephalon).

Mid brain: The midbrain (Mesencephalon) is the middle portion of the brain. It is in the centre lying between the interbrain and hindbrain. It consists of a cranial part of brain stem.

Hind brain: The hindbrain (Rhombencephalon) is the caudal most portion of the brain. It consists of remaining (caudal) part of the brain stem, the medulla oblongata (Myelencephalon) and the cerebellum and pons (Metencephalon).

Cereal Processing

    1.    The protein content of wheat grain varies widely, but for bread making a value of at least 11% is required.

    2.    Low grain sulphur will result in low concentrations of the sulphur-containing amino acids, cystine and methionine, and may result in poor loaf volume.

    3.    During seed germination endosperm starch is converted into soluble glucose and maltose to support the developing embryo. This is brought about by enzymatic activity, especially the enzyme a-amylase.

    4.    Excessive a-amylase levels result in the formation of a darkened loaf crust as a result of sugar caramelization and a sticky crumb structure which can cause problems during slicing.

    5.    Wheat with a protein level below 10% is preferred to reduce gluten elasticity.

    6.    There is a very good correlation between grain nitrogen and the amount of malt extract achieved, low grain nitrogen giving more fermentable extract

    7.    The term ‘coarse grains milling’ is a very broad one that refers to the comminution of the berries of the wheat, barley and other coarse grain crops.

1. Introduction

The development of food products using composite flour has increased and is attracting much attention from researchers, especially in the production of bakery products and pastries. This article focuses on the use of composite flour to produce food products, namely bread, biscuits, and pasta, with looks at on its impact, following some improvements made, on the sensory quality, rheology characteristics, and nutritional values as well as its overall acceptance. The blending of wheat flour with various sources of tubers, legumes, cereals and fruit flour in different percentages to produce variety of food products are also reported. The positive effects of the use of composite flour can be seen in the final product related to the functional and physicochemical properties and health benefits of raw blended flour along with percentage blending. Overall, composite flour is a good new approach to utilizing uncommon food products as the application of composite flour produced products with different characteristics and quality, depending on the types and percentage of wheat flour used in the formulation.

Bread has been the staple food worldwide and habit of bread is derived in part due to the convenience and wholesomeness. Wheat is a commonly used cereal for making bread as it gives the desired texture due to the presence of gluten forming proteins like gliadins and glutenins (Decock & Cappelle, 2005). In earlier times idea of composite flour in developing countries originated in order to cut down on import of wheat (as it was not grown in many countries) but in recent past refined wheat flour consumption has lead to health issues and thus in order to improve nutritional and functional properties composite flour has been the norm. Composite flour is the one obtained by mixing wheat flour with cereal and legume flours for making bread and biscuits (Dendy, 1992). However, mixing of non-wheat flours, roots and tubers, legumes or other raw materials can also be regarded as composite flour.

Introduction

About sixty percent of the world’s food intake comes from the three major crops, i.e., wheat, rice and maize (Thielecke and Nugent, 2018). Depending upon the country of utilization and consumption, the products made from cereals such as barley, wheat, maize, triticale, spelt, buckwheat, rice etc. can vary in the range of pasta, bread, pastries, soups, chapatti, cooked rice etc. World cereal utilization in 2021/22 is forecasted at 2,811 million tonnes and the worldwide production of cereals is expected to reach 2,818 million tonnes by 2025 (FAO, 2020).

    1.    Rice is a
        a)    Edible fruit    b)    Edible Vegetable
        c)    Edible flower    d)    All
    2.    Major components in cereal seeds are 
        a)    Endosperm    b)    Germ or embryo
        c)    a & b    d)    None
    3.    Bran is composed of 
        a)    Pericarp    b)    Testa
        c)    aleuron layer    d)    All
    4.    Oats contains ______________ percent of hull
        a)    50    b)    40
        c)    30    d)    20

Cerebrospinal fluid examination is an important diagnostic procedure for evaluating diseases affecting the central nervous system. This chapter describes techniques for CSF collection, including appropriate sampling approaches and precautions. Collected fluid may be submitted for physical, chemical, cytological and microbial examination. Important parameters include colour, turbidity, protein concentration, glucose, chloride, enzymes and nucleated cell counts. Cytological evaluation and culture may assist in identifying inflammatory or infectious processes. Proper sample handling and timely processing are emphasized because cellular and biochemical characteristics can change after collection. CSF findings should be interpreted alongside neurological examination and other diagnostic investigations.

Large Animals The collection and evaluation of cerebrospinal fluid (CSF) in farm animals with signs of diseases of nervous system provides very valuable diagnostic and prognostic information. Routinely, CSF is evaluated for total protein level, erythrocyte and leukocyte counts, and a differential cell count. Additional tests are available for specific neurologic conditions. CSF is primarily produced by the choroid plexuses in the lateral, third, and fourth ventricles through plasma ultra filtration and active transport across the blood-brain barrier. Smaller amounts of CSF are generated by the ependymal lining, pia arachnoid, meningeal blood vessels, and spinal cord’s central canal. The turnover rate is about 1% per minute, meaning systemic electrolyte or acid-base changes take several minutes to affect CSF

Animal body contains several fluids other than blood and lymph which have specialized functions for specific organs. Two of these fluids are cerebrospinal fluid and synovial fluid. The cerebrospinal fluids protects and supports brain and spinal cord function. Synovial fluid protects the functioning of the movement of the body by bone-muscular joints.